From patchwork Fri Feb 8 17:34:05 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10803481 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7466F922 for ; Fri, 8 Feb 2019 17:34:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 651D82DCD1 for ; Fri, 8 Feb 2019 17:34:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 591772DCD6; Fri, 8 Feb 2019 17:34:36 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EA7C62DCD1 for ; Fri, 8 Feb 2019 17:34:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726869AbfBHRef (ORCPT ); Fri, 8 Feb 2019 12:34:35 -0500 Received: from mail-it1-f193.google.com ([209.85.166.193]:55021 "EHLO mail-it1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726679AbfBHRef (ORCPT ); Fri, 8 Feb 2019 12:34:35 -0500 Received: by mail-it1-f193.google.com with SMTP id i145so10653763ita.4 for ; Fri, 08 Feb 2019 09:34:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=pB0024BHqxQbFqcC6bm8p7+6qjmI2rEZP9GcpS5QfRU=; b=iYiz1bQR07wqnjnyz3vfSH43HNU9ZABaxfYwqTG5lyJ5MqOjfRr3931RWMEnR6GV/y EyaPrwXODuc78oOLse2w2+8pXeF6wRnbz9P816bGzkDmxUM6r3RM0Ng4AAz6Zo/we3/Q QUjDoL5tPHFeOvr+6lXiH3LgQEHdnwcsiGA6UsLjQxsG6AubepUV4dldqsooeW0GlQa+ kMvQI+6HhgSXfpGR7FwotfhtQ059D/h0IvyQvhK3vuT5DBbQNTAYGuA4AOka5hfJqEiJ LRi9Gynx2aDFsRi7oleQ4xSKua/t81VK1RoKqgR9X0Z2Ma9PFJ5c6EMuvO5Ibq1ckndb WEwg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=pB0024BHqxQbFqcC6bm8p7+6qjmI2rEZP9GcpS5QfRU=; b=U6yL4GQ0EdhAKbUDX3O9waJesv6GGlIzIraSyQm5o6sev2mKaSwMm45nwKQNnTiwb5 IJY5+d+9lx0xPGtR3JmE3FOKQenXMH097ygbSnngO4tYyDnDlNZ/puiHX5FN9CSsKKnm IpUlraUnTYu53QDl6Pop6pors2s+EPJF7EFPldjkBImRg09TU4jK6jcwzWUkf+U/cZgG wykLxjCsnY3Bld+kUUZ5mbuSz4LC74kyJuILexAxDtiUKYTdnu0C5T2OR5/eLrCpfNNQ XhM5GBtE5rH+AcLA12kX2KBr5Ec3yQJjnjKAS0dkSj6fJsEBE8Ncd2fzP7KIgjaP5wsG 5aZA== X-Gm-Message-State: AHQUAuYPC6cVTlRJwBUee+wooIG0bU1RC4igTKli+Uebc/uSmwzizinY RlZ5EVymDT3kipooVtVN2vlnAw== X-Google-Smtp-Source: AHgI3IYlOYebmGR61bbl3Xb6VuLFn2tvs7ZB1VVaBVMa2tuHuqu04lb3Ob55JET1boWz36p9W3BX1g== X-Received: by 2002:a24:6f51:: with SMTP id x78mr6717997itb.121.1549647274209; Fri, 08 Feb 2019 09:34:34 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id f142sm1522627itc.15.2019.02.08.09.34.30 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Feb 2019 09:34:31 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 01/19] fs: add an iopoll method to struct file_operations Date: Fri, 8 Feb 2019 10:34:05 -0700 Message-Id: <20190208173423.27014-2-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Christoph Hellwig This new methods is used to explicitly poll for I/O completion for an iocb. It must be called for any iocb submitted asynchronously (that is with a non-null ki_complete) which has the IOCB_HIPRI flag set. The method is assisted by a new ki_cookie field in struct iocb to store the polling cookie. Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe Reviewed-by: Hannes Reinecke --- Documentation/filesystems/vfs.txt | 3 +++ include/linux/fs.h | 2 ++ 2 files changed, 5 insertions(+) diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 8dc8e9c2913f..761c6fd24a53 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -857,6 +857,7 @@ struct file_operations { ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *); ssize_t (*read_iter) (struct kiocb *, struct iov_iter *); ssize_t (*write_iter) (struct kiocb *, struct iov_iter *); + int (*iopoll)(struct kiocb *kiocb, bool spin); int (*iterate) (struct file *, struct dir_context *); int (*iterate_shared) (struct file *, struct dir_context *); __poll_t (*poll) (struct file *, struct poll_table_struct *); @@ -902,6 +903,8 @@ otherwise noted. write_iter: possibly asynchronous write with iov_iter as source + iopoll: called when aio wants to poll for completions on HIPRI iocbs + iterate: called when the VFS needs to read the directory contents iterate_shared: called when the VFS needs to read the directory contents diff --git a/include/linux/fs.h b/include/linux/fs.h index 29d8e2cfed0e..dedcc2e9265c 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -310,6 +310,7 @@ struct kiocb { int ki_flags; u16 ki_hint; u16 ki_ioprio; /* See linux/ioprio.h */ + unsigned int ki_cookie; /* for ->iopoll */ } __randomize_layout; static inline bool is_sync_kiocb(struct kiocb *kiocb) @@ -1787,6 +1788,7 @@ struct file_operations { ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *); ssize_t (*read_iter) (struct kiocb *, struct iov_iter *); ssize_t (*write_iter) (struct kiocb *, struct iov_iter *); + int (*iopoll)(struct kiocb *kiocb, bool spin); int (*iterate) (struct file *, struct dir_context *); int (*iterate_shared) (struct file *, struct dir_context *); __poll_t (*poll) (struct file *, struct poll_table_struct *); From patchwork Fri Feb 8 17:34:06 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10803483 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 70C0F1390 for ; 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Fri, 08 Feb 2019 09:34:37 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id f142sm1522627itc.15.2019.02.08.09.34.34 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Feb 2019 09:34:36 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 02/19] block: wire up block device iopoll method Date: Fri, 8 Feb 2019 10:34:06 -0700 Message-Id: <20190208173423.27014-3-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Christoph Hellwig Just call blk_poll on the iocb cookie, we can derive the block device from the inode trivially. Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe Reviewed-by: Hannes Reinecke --- fs/block_dev.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/fs/block_dev.c b/fs/block_dev.c index 58a4c1217fa8..f18d076a2596 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -293,6 +293,14 @@ struct blkdev_dio { static struct bio_set blkdev_dio_pool; +static int blkdev_iopoll(struct kiocb *kiocb, bool wait) +{ + struct block_device *bdev = I_BDEV(kiocb->ki_filp->f_mapping->host); + struct request_queue *q = bdev_get_queue(bdev); + + return blk_poll(q, READ_ONCE(kiocb->ki_cookie), wait); +} + static void blkdev_bio_end_io(struct bio *bio) { struct blkdev_dio *dio = bio->bi_private; @@ -410,6 +418,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) bio->bi_opf |= REQ_HIPRI; qc = submit_bio(bio); + WRITE_ONCE(iocb->ki_cookie, qc); break; } @@ -2076,6 +2085,7 @@ const struct file_operations def_blk_fops = { .llseek = block_llseek, .read_iter = blkdev_read_iter, .write_iter = blkdev_write_iter, + .iopoll = blkdev_iopoll, .mmap = generic_file_mmap, .fsync = blkdev_fsync, .unlocked_ioctl = block_ioctl, From patchwork Fri Feb 8 17:34:07 2019 Content-Type: text/plain; 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Fri, 08 Feb 2019 09:34:39 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 03/19] block: add bio_set_polled() helper Date: Fri, 8 Feb 2019 10:34:07 -0700 Message-Id: <20190208173423.27014-4-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP For the upcoming async polled IO, we can't sleep allocating requests. If we do, then we introduce a deadlock where the submitter already has async polled IO in-flight, but can't wait for them to complete since polled requests must be active found and reaped. Utilize the helper in the blockdev DIRECT_IO code. Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe Reviewed-by: Hannes Reinecke --- fs/block_dev.c | 4 ++-- include/linux/bio.h | 14 ++++++++++++++ 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/fs/block_dev.c b/fs/block_dev.c index f18d076a2596..392e2bfb636f 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -247,7 +247,7 @@ __blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter, task_io_account_write(ret); } if (iocb->ki_flags & IOCB_HIPRI) - bio.bi_opf |= REQ_HIPRI; + bio_set_polled(&bio, iocb); qc = submit_bio(&bio); for (;;) { @@ -415,7 +415,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES); if (!nr_pages) { if (iocb->ki_flags & IOCB_HIPRI) - bio->bi_opf |= REQ_HIPRI; + bio_set_polled(bio, iocb); qc = submit_bio(bio); WRITE_ONCE(iocb->ki_cookie, qc); diff --git a/include/linux/bio.h b/include/linux/bio.h index 7380b094dcca..f6f0a2b3cbc8 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -823,5 +823,19 @@ static inline int bio_integrity_add_page(struct bio *bio, struct page *page, #endif /* CONFIG_BLK_DEV_INTEGRITY */ +/* + * Mark a bio as polled. Note that for async polled IO, the caller must + * expect -EWOULDBLOCK if we cannot allocate a request (or other resources). + * We cannot block waiting for requests on polled IO, as those completions + * must be found by the caller. This is different than IRQ driven IO, where + * it's safe to wait for IO to complete. + */ +static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb) +{ + bio->bi_opf |= REQ_HIPRI; + if (!is_sync_kiocb(kiocb)) + bio->bi_opf |= REQ_NOWAIT; +} + #endif /* CONFIG_BLOCK */ #endif /* __LINUX_BIO_H */ From patchwork Fri Feb 8 17:34:08 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10803487 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 48B32922 for ; Fri, 8 Feb 2019 17:34:45 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 39A0C2DCD6 for ; Fri, 8 Feb 2019 17:34:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2DBE32DCDB; Fri, 8 Feb 2019 17:34:45 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A8B5D2DCD6 for ; Fri, 8 Feb 2019 17:34:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727700AbfBHReo (ORCPT ); Fri, 8 Feb 2019 12:34:44 -0500 Received: from mail-it1-f193.google.com ([209.85.166.193]:39637 "EHLO mail-it1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726747AbfBHRen (ORCPT ); Fri, 8 Feb 2019 12:34:43 -0500 Received: by mail-it1-f193.google.com with SMTP id a6so10786751itl.4 for ; Fri, 08 Feb 2019 09:34:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=kBV8dzOOhCbt68ELwObNvYoJE2gQ/QTxNte5p6AS0oA=; b=LdZioPebk2T2OGuNl3krz20ngGEdF9rCinWT+wW1z+CmA5bYpjzf0alPqNY1RRLZRd U2Odwo/xiNy0k+1zd06z7PSDdIIbgm9A+eFyaVsI8Qg4NBKhRkzY9OEvhLvkWVLFUrik 4pZLg/kDMS2eP+aSFROhRqqn/q6xnK7O6df+HXVnAYOTZ0I10iTF5YqZo/x+XE4B5rzc 5q32XurrQW0Lvrj6v4Jo4Lp9ihs/wmzThpNBk0FbC8JQP0cWPdpXbmkSFDpV+P6n/wZk 9sSm/YlSjN9Uh1ZYACAzoInzv+VSkcbdGrxkZFbZg0eWOxnOSuGxqhKouZHYii+8TOER PxHg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=kBV8dzOOhCbt68ELwObNvYoJE2gQ/QTxNte5p6AS0oA=; b=Y3wJAqQK3vomg6rcQ/EKcR2VjJpIC+C/25Tc6kfpJ+sKDZG22OfKj9mqxBvgFVfJyo 6Ga5rkSov125vM1ddj7lEtkqbPlUzp5HD9yiod77Eri/iVHAhCTVUhM3tCG7BU00whRg BQg0axW+xB33ZsSBXUpoAekTejggt96xgST4/xziCmYcfrlNTp4C5/k7eJ2ZNmD6rDuG irywqDhtXHaOjsOCt0aSodOVXmBZClEC2sTtQozHtnqj7BqHwIgT3f8Ujcdub76WPyZC S3VTzrWVzgLwtpyv7qQKU1QAUc78HOreolI+d824+0JE8SakN7PvVI9idOZcyvY3q1r+ QeYQ== X-Gm-Message-State: AHQUAubDzVT24LFflI5vK6mvNzEga76qFrFMPoX+bvNT7W1s4E7dHKYu bBrdhnoxfVaaVdsYli3XZRCASg== X-Google-Smtp-Source: AHgI3IZagnaPIIMMW5g8Lw9oMEQA7P230DkwBjkNQCUm9GAGCRZbj4NN0t5jx+jKBq0H4gRCYm7AAg== X-Received: by 2002:a02:f04:: with SMTP id h4mr3902316jad.50.1549647282846; Fri, 08 Feb 2019 09:34:42 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id f142sm1522627itc.15.2019.02.08.09.34.40 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Feb 2019 09:34:41 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 04/19] iomap: wire up the iopoll method Date: Fri, 8 Feb 2019 10:34:08 -0700 Message-Id: <20190208173423.27014-5-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Christoph Hellwig Store the request queue the last bio was submitted to in the iocb private data in addition to the cookie so that we find the right block device. Also refactor the common direct I/O bio submission code into a nice little helper. Signed-off-by: Christoph Hellwig Modified to use bio_set_polled(). Signed-off-by: Jens Axboe Reviewed-by: Hannes Reinecke --- fs/gfs2/file.c | 2 ++ fs/iomap.c | 43 ++++++++++++++++++++++++++++--------------- fs/xfs/xfs_file.c | 1 + include/linux/iomap.h | 1 + 4 files changed, 32 insertions(+), 15 deletions(-) diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index a2dea5bc0427..58a768e59712 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -1280,6 +1280,7 @@ const struct file_operations gfs2_file_fops = { .llseek = gfs2_llseek, .read_iter = gfs2_file_read_iter, .write_iter = gfs2_file_write_iter, + .iopoll = iomap_dio_iopoll, .unlocked_ioctl = gfs2_ioctl, .mmap = gfs2_mmap, .open = gfs2_open, @@ -1310,6 +1311,7 @@ const struct file_operations gfs2_file_fops_nolock = { .llseek = gfs2_llseek, .read_iter = gfs2_file_read_iter, .write_iter = gfs2_file_write_iter, + .iopoll = iomap_dio_iopoll, .unlocked_ioctl = gfs2_ioctl, .mmap = gfs2_mmap, .open = gfs2_open, diff --git a/fs/iomap.c b/fs/iomap.c index 897c60215dd1..2ac9eb746d44 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -1463,6 +1463,28 @@ struct iomap_dio { }; }; +int iomap_dio_iopoll(struct kiocb *kiocb, bool spin) +{ + struct request_queue *q = READ_ONCE(kiocb->private); + + if (!q) + return 0; + return blk_poll(q, READ_ONCE(kiocb->ki_cookie), spin); +} +EXPORT_SYMBOL_GPL(iomap_dio_iopoll); + +static void iomap_dio_submit_bio(struct iomap_dio *dio, struct iomap *iomap, + struct bio *bio) +{ + atomic_inc(&dio->ref); + + if (dio->iocb->ki_flags & IOCB_HIPRI) + bio_set_polled(bio, dio->iocb); + + dio->submit.last_queue = bdev_get_queue(iomap->bdev); + dio->submit.cookie = submit_bio(bio); +} + static ssize_t iomap_dio_complete(struct iomap_dio *dio) { struct kiocb *iocb = dio->iocb; @@ -1575,7 +1597,7 @@ static void iomap_dio_bio_end_io(struct bio *bio) } } -static blk_qc_t +static void iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos, unsigned len) { @@ -1589,15 +1611,10 @@ iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos, bio->bi_private = dio; bio->bi_end_io = iomap_dio_bio_end_io; - if (dio->iocb->ki_flags & IOCB_HIPRI) - flags |= REQ_HIPRI; - get_page(page); __bio_add_page(bio, page, len, 0); bio_set_op_attrs(bio, REQ_OP_WRITE, flags); - - atomic_inc(&dio->ref); - return submit_bio(bio); + iomap_dio_submit_bio(dio, iomap, bio); } static loff_t @@ -1700,9 +1717,6 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, bio_set_pages_dirty(bio); } - if (dio->iocb->ki_flags & IOCB_HIPRI) - bio->bi_opf |= REQ_HIPRI; - iov_iter_advance(dio->submit.iter, n); dio->size += n; @@ -1710,11 +1724,7 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, copied += n; nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES); - - atomic_inc(&dio->ref); - - dio->submit.last_queue = bdev_get_queue(iomap->bdev); - dio->submit.cookie = submit_bio(bio); + iomap_dio_submit_bio(dio, iomap, bio); } while (nr_pages); /* @@ -1925,6 +1935,9 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, if (dio->flags & IOMAP_DIO_WRITE_FUA) dio->flags &= ~IOMAP_DIO_NEED_SYNC; + WRITE_ONCE(iocb->ki_cookie, dio->submit.cookie); + WRITE_ONCE(iocb->private, dio->submit.last_queue); + /* * We are about to drop our additional submission reference, which * might be the last reference to the dio. There are three three diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index e47425071e65..60c2da41f0fc 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1203,6 +1203,7 @@ const struct file_operations xfs_file_operations = { .write_iter = xfs_file_write_iter, .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, + .iopoll = iomap_dio_iopoll, .unlocked_ioctl = xfs_file_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = xfs_file_compat_ioctl, diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 9a4258154b25..0fefb5455bda 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -162,6 +162,7 @@ typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret, unsigned flags); ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, const struct iomap_ops *ops, iomap_dio_end_io_t end_io); +int iomap_dio_iopoll(struct kiocb *kiocb, bool spin); #ifdef CONFIG_SWAP struct file; From patchwork Fri Feb 8 17:34:09 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10803491 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 91615922 for ; Fri, 8 Feb 2019 17:34:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7B5042DCDD for ; Fri, 8 Feb 2019 17:34:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6EFA92DCDB; Fri, 8 Feb 2019 17:34:51 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 30F762DCDD for ; Fri, 8 Feb 2019 17:34:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727726AbfBHRes (ORCPT ); Fri, 8 Feb 2019 12:34:48 -0500 Received: from mail-it1-f196.google.com ([209.85.166.196]:39986 "EHLO mail-it1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727689AbfBHRer (ORCPT ); Fri, 8 Feb 2019 12:34:47 -0500 Received: by mail-it1-f196.google.com with SMTP id h193so10785397ita.5 for ; Fri, 08 Feb 2019 09:34:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=tp8WOjg6s3OHfK7m8mUjdBcSf/8ZpcseEpQAfOCnKN8=; b=YpxX+G7qwdAz4dM0IonjlwwCD9xceiQ/9leo3dxcrOE9AINha+I0S4w4zS9F76JnyI YKeOR73snCvBfaktTcmH3RUFclk0YZREmcqw+rD9uJyLRFxTQbFFGSVKzTJoZcy1PFrm ZHdxvMDJxrCWMIBE8WUv7mTeQJ/16XQ2G+40wJCZ2MnZ9f2nYd0vl/h/Z7/D72YYLos8 jkvQM0b5SVKu2olWTSp44GlSENCvR7HQitxZ3rWncpva9Ul1Vv53jXxkEYyuf3/kA74j Ck6GkglJpv0SCtGrLDbaOPxjwqyxrpnnDRbwiZjzOHe5yv1GqvKVLy/A6ovs2IVMTr14 BRJg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=tp8WOjg6s3OHfK7m8mUjdBcSf/8ZpcseEpQAfOCnKN8=; b=mt1Zk4lgFYiaEIedL3pwlLpMPFbu9lA4SywdWuuOfxeS13IgR1hhYtwRM0ZYyFSiax JfAm6Yr6GSgLNmZs6xL+8eu6eqTonzCY6cG3LjbpT56Y87m5ikPDm78iGeZKWK8DRIEx UdxEWABM6SSvYO/t0AOkDXJ4NlTY94RjNPZ/jcrcgLUAEeTVMfv9sKn7V3Wxs6ZCVd5e /SHTFQ1UFa6k4vJnDOYOGPZWe1x6tv1Y7sLeahNFR+4+vx5Uw/swqwwvn2gjpf6wLcu6 8RedeTrO9Uct6JnhgMKuvs2lg93lh7lyCRsgpHi4zgOGBTNyvzp28+gsTht4JIPkPWBx ucZw== X-Gm-Message-State: AHQUAuYrtTVm9nqcAKFovkuPP3nsIZqRQafDdvjDa/9qRh3QGEYg+IT1 vVQk49l0Jt21xLmVfCY284JjaA== X-Google-Smtp-Source: AHgI3IbUbZgoJoXwKUwvUhVzPe+Nc/9FBAzIEBq0WCF0vzAklCVvXywUVyr5P4vYJuOuvF7ek+10/A== X-Received: by 2002:a24:78c7:: with SMTP id p190mr8386985itc.21.1549647285172; Fri, 08 Feb 2019 09:34:45 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id f142sm1522627itc.15.2019.02.08.09.34.42 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Feb 2019 09:34:43 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 05/19] Add io_uring IO interface Date: Fri, 8 Feb 2019 10:34:09 -0700 Message-Id: <20190208173423.27014-6-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The submission queue (SQ) and completion queue (CQ) rings are shared between the application and the kernel. This eliminates the need to copy data back and forth to submit and complete IO. IO submissions use the io_uring_sqe data structure, and completions are generated in the form of io_uring_cqe data structures. The SQ ring is an index into the io_uring_sqe array, which makes it possible to submit a batch of IOs without them being contiguous in the ring. The CQ ring is always contiguous, as completion events are inherently unordered, and hence any io_uring_cqe entry can point back to an arbitrary submission. Two new system calls are added for this: io_uring_setup(entries, params) Sets up an io_uring instance for doing async IO. On success, returns a file descriptor that the application can mmap to gain access to the SQ ring, CQ ring, and io_uring_sqes. io_uring_enter(fd, to_submit, min_complete, flags, sigset, sigsetsize) Initiates IO against the rings mapped to this fd, or waits for them to complete, or both. The behavior is controlled by the parameters passed in. If 'to_submit' is non-zero, then we'll try and submit new IO. If IORING_ENTER_GETEVENTS is set, the kernel will wait for 'min_complete' events, if they aren't already available. It's valid to set IORING_ENTER_GETEVENTS and 'min_complete' == 0 at the same time, this allows the kernel to return already completed events without waiting for them. This is useful only for polling, as for IRQ driven IO, the application can just check the CQ ring without entering the kernel. With this setup, it's possible to do async IO with a single system call. Future developments will enable polled IO with this interface, and polled submission as well. The latter will enable an application to do IO without doing ANY system calls at all. For IRQ driven IO, an application only needs to enter the kernel for completions if it wants to wait for them to occur. Each io_uring is backed by a workqueue, to support buffered async IO as well. We will only punt to an async context if the command would need to wait for IO on the device side. Any data that can be accessed directly in the page cache is done inline. This avoids the slowness issue of usual threadpools, since cached data is accessed as quickly as a sync interface. Sample application: http://git.kernel.dk/cgit/fio/plain/t/io_uring.c Signed-off-by: Jens Axboe Reviewed-by: Hannes Reinecke --- arch/x86/entry/syscalls/syscall_32.tbl | 2 + arch/x86/entry/syscalls/syscall_64.tbl | 2 + fs/Makefile | 1 + fs/io_uring.c | 1175 ++++++++++++++++++++++++ include/linux/fs.h | 9 + include/linux/syscalls.h | 6 + include/uapi/asm-generic/unistd.h | 6 +- include/uapi/linux/io_uring.h | 95 ++ init/Kconfig | 9 + kernel/sys_ni.c | 2 + net/unix/garbage.c | 3 + 11 files changed, 1309 insertions(+), 1 deletion(-) create mode 100644 fs/io_uring.c create mode 100644 include/uapi/linux/io_uring.h diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index 3cf7b533b3d1..481c126259e9 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -398,3 +398,5 @@ 384 i386 arch_prctl sys_arch_prctl __ia32_compat_sys_arch_prctl 385 i386 io_pgetevents sys_io_pgetevents __ia32_compat_sys_io_pgetevents 386 i386 rseq sys_rseq __ia32_sys_rseq +425 i386 io_uring_setup sys_io_uring_setup __ia32_sys_io_uring_setup +426 i386 io_uring_enter sys_io_uring_enter __ia32_sys_io_uring_enter diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index f0b1709a5ffb..6a32a430c8e0 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -343,6 +343,8 @@ 332 common statx __x64_sys_statx 333 common io_pgetevents __x64_sys_io_pgetevents 334 common rseq __x64_sys_rseq +425 common io_uring_setup __x64_sys_io_uring_setup +426 common io_uring_enter __x64_sys_io_uring_enter # # x32-specific system call numbers start at 512 to avoid cache impact diff --git a/fs/Makefile b/fs/Makefile index 293733f61594..8e15d6fc4340 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -30,6 +30,7 @@ obj-$(CONFIG_TIMERFD) += timerfd.o obj-$(CONFIG_EVENTFD) += eventfd.o obj-$(CONFIG_USERFAULTFD) += userfaultfd.o obj-$(CONFIG_AIO) += aio.o +obj-$(CONFIG_IO_URING) += io_uring.o obj-$(CONFIG_FS_DAX) += dax.o obj-$(CONFIG_FS_ENCRYPTION) += crypto/ obj-$(CONFIG_FILE_LOCKING) += locks.o diff --git a/fs/io_uring.c b/fs/io_uring.c new file mode 100644 index 000000000000..927d61ebecf3 --- /dev/null +++ b/fs/io_uring.c @@ -0,0 +1,1175 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Shared application/kernel submission and completion ring pairs, for + * supporting fast/efficient IO. + * + * Copyright (C) 2018-2019 Jens Axboe + */ +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "internal.h" + +#define IORING_MAX_ENTRIES 4096 + +struct io_uring { + u32 head ____cacheline_aligned_in_smp; + u32 tail ____cacheline_aligned_in_smp; +}; + +struct io_sq_ring { + struct io_uring r; + u32 ring_mask; + u32 ring_entries; + u32 dropped; + u32 flags; + u32 array[]; +}; + +struct io_cq_ring { + struct io_uring r; + u32 ring_mask; + u32 ring_entries; + u32 overflow; + struct io_uring_cqe cqes[]; +}; + +struct io_ring_ctx { + struct { + struct percpu_ref refs; + } ____cacheline_aligned_in_smp; + + struct { + unsigned int flags; + bool compat; + + /* SQ ring */ + struct io_sq_ring *sq_ring; + unsigned cached_sq_head; + unsigned sq_entries; + unsigned sq_mask; + struct io_uring_sqe *sq_sqes; + } ____cacheline_aligned_in_smp; + + /* IO offload */ + struct workqueue_struct *sqo_wq; + struct mm_struct *sqo_mm; + + struct { + /* CQ ring */ + struct io_cq_ring *cq_ring; + unsigned cached_cq_tail; + unsigned cq_entries; + unsigned cq_mask; + struct wait_queue_head cq_wait; + struct fasync_struct *cq_fasync; + } ____cacheline_aligned_in_smp; + + struct user_struct *user; + + struct completion ctx_done; + + struct { + struct mutex uring_lock; + wait_queue_head_t wait; + } ____cacheline_aligned_in_smp; + + struct { + spinlock_t completion_lock; + } ____cacheline_aligned_in_smp; + +#if defined(CONFIG_UNIX) + struct socket *ring_sock; +#endif +}; + +struct sqe_submit { + const struct io_uring_sqe *sqe; + unsigned short index; + bool has_user; +}; + +struct io_kiocb { + struct kiocb rw; + + struct sqe_submit submit; + + struct io_ring_ctx *ctx; + struct list_head list; + unsigned int flags; +#define REQ_F_FORCE_NONBLOCK 1 /* inline submission attempt */ + u64 user_data; + + struct work_struct work; +}; + +#define IO_PLUG_THRESHOLD 2 + +static struct kmem_cache *req_cachep; + +static const struct file_operations io_uring_fops; + +struct sock *io_uring_get_socket(struct file *file) +{ +#if defined(CONFIG_UNIX) + if (file->f_op == &io_uring_fops) { + struct io_ring_ctx *ctx = file->private_data; + + return ctx->ring_sock->sk; + } +#endif + return NULL; +} +EXPORT_SYMBOL(io_uring_get_socket); + +static void io_ring_ctx_ref_free(struct percpu_ref *ref) +{ + struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs); + + complete(&ctx->ctx_done); +} + +static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) +{ + struct io_ring_ctx *ctx; + + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); + if (!ctx) + return NULL; + + if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free, 0, GFP_KERNEL)) { + kfree(ctx); + return NULL; + } + + ctx->flags = p->flags; + init_waitqueue_head(&ctx->cq_wait); + init_completion(&ctx->ctx_done); + mutex_init(&ctx->uring_lock); + init_waitqueue_head(&ctx->wait); + spin_lock_init(&ctx->completion_lock); + return ctx; +} + +static void io_commit_cqring(struct io_ring_ctx *ctx) +{ + struct io_cq_ring *ring = ctx->cq_ring; + + if (ctx->cached_cq_tail != ring->r.tail) { + /* order cqe stores with ring update */ + smp_wmb(); + WRITE_ONCE(ring->r.tail, ctx->cached_cq_tail); + /* write side barrier of tail update, app has read side */ + smp_wmb(); + + if (wq_has_sleeper(&ctx->cq_wait)) { + wake_up_interruptible(&ctx->cq_wait); + kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN); + } + } +} + +static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx) +{ + struct io_cq_ring *ring = ctx->cq_ring; + unsigned tail; + + tail = ctx->cached_cq_tail; + smp_rmb(); + if (tail + 1 == READ_ONCE(ring->r.head)) + return NULL; + + ctx->cached_cq_tail++; + return &ring->cqes[tail & ctx->cq_mask]; +} + +static void io_cqring_fill_event(struct io_ring_ctx *ctx, u64 ki_user_data, + long res, unsigned ev_flags) +{ + struct io_uring_cqe *cqe; + + /* + * If we can't get a cq entry, userspace overflowed the + * submission (by quite a lot). Increment the overflow count in + * the ring. + */ + cqe = io_get_cqring(ctx); + if (cqe) { + cqe->user_data = ki_user_data; + cqe->res = res; + cqe->flags = ev_flags; + } else + ctx->cq_ring->overflow++; +} + +static void io_cqring_add_event(struct io_ring_ctx *ctx, u64 ki_user_data, + long res, unsigned ev_flags) +{ + unsigned long flags; + + spin_lock_irqsave(&ctx->completion_lock, flags); + io_cqring_fill_event(ctx, ki_user_data, res, ev_flags); + io_commit_cqring(ctx); + spin_unlock_irqrestore(&ctx->completion_lock, flags); + + if (waitqueue_active(&ctx->wait)) + wake_up(&ctx->wait); +} + +static void io_ring_drop_ctx_refs(struct io_ring_ctx *ctx, unsigned refs) +{ + percpu_ref_put_many(&ctx->refs, refs); + + if (waitqueue_active(&ctx->wait)) + wake_up(&ctx->wait); +} + +static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx) +{ + struct io_kiocb *req; + + if (!percpu_ref_tryget(&ctx->refs)) + return NULL; + + req = kmem_cache_alloc(req_cachep, __GFP_NOWARN); + if (req) { + req->ctx = ctx; + req->flags = 0; + return req; + } + + io_ring_drop_ctx_refs(ctx, 1); + return NULL; +} + +static void io_free_req(struct io_kiocb *req) +{ + io_ring_drop_ctx_refs(req->ctx, 1); + kmem_cache_free(req_cachep, req); +} + +static void kiocb_end_write(struct kiocb *kiocb) +{ + if (kiocb->ki_flags & IOCB_WRITE) { + struct inode *inode = file_inode(kiocb->ki_filp); + + /* + * Tell lockdep we inherited freeze protection from submission + * thread. + */ + if (S_ISREG(inode->i_mode)) + __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE); + file_end_write(kiocb->ki_filp); + } +} + +static void io_complete_rw(struct kiocb *kiocb, long res, long res2) +{ + struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw); + + kiocb_end_write(kiocb); + + fput(kiocb->ki_filp); + io_cqring_add_event(req->ctx, req->user_data, res, 0); + io_free_req(req); +} + +/* + * If we tracked the file through the SCM inflight mechanism, we could support + * any file. For now, just ensure that anything potentially problematic is done + * inline. + */ +static bool io_file_supports_async(struct file *file) +{ + umode_t mode = file_inode(file)->i_mode; + + if (S_ISBLK(mode) || S_ISCHR(mode)) + return true; + if (S_ISREG(mode) && file->f_op != &io_uring_fops) + return true; + + return false; +} + +static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, + bool force_nonblock) +{ + struct kiocb *kiocb = &req->rw; + unsigned ioprio; + int fd, ret; + + /* For -EAGAIN retry, everything is already prepped */ + if (kiocb->ki_filp) + return 0; + + fd = READ_ONCE(sqe->fd); + kiocb->ki_filp = fget(fd); + if (unlikely(!kiocb->ki_filp)) + return -EBADF; + if (force_nonblock && !io_file_supports_async(kiocb->ki_filp)) + force_nonblock = false; + kiocb->ki_pos = READ_ONCE(sqe->off); + kiocb->ki_flags = iocb_flags(kiocb->ki_filp); + kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp)); + + ioprio = READ_ONCE(sqe->ioprio); + if (ioprio) { + ret = ioprio_check_cap(ioprio); + if (ret) + goto out_fput; + + kiocb->ki_ioprio = ioprio; + } else + kiocb->ki_ioprio = get_current_ioprio(); + + ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags)); + if (unlikely(ret)) + goto out_fput; + if (force_nonblock) { + kiocb->ki_flags |= IOCB_NOWAIT; + req->flags |= REQ_F_FORCE_NONBLOCK; + } + if (kiocb->ki_flags & IOCB_HIPRI) { + ret = -EINVAL; + goto out_fput; + } + + kiocb->ki_complete = io_complete_rw; + return 0; +out_fput: + fput(kiocb->ki_filp); + return ret; +} + +static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) +{ + switch (ret) { + case -EIOCBQUEUED: + break; + case -ERESTARTSYS: + case -ERESTARTNOINTR: + case -ERESTARTNOHAND: + case -ERESTART_RESTARTBLOCK: + /* + * We can't just restart the syscall, since previously + * submitted sqes may already be in progress. Just fail this + * IO with EINTR. + */ + ret = -EINTR; + /* fall through */ + default: + kiocb->ki_complete(kiocb, ret, 0); + } +} + +static int io_import_iovec(struct io_ring_ctx *ctx, int rw, + const struct sqe_submit *s, struct iovec **iovec, + struct iov_iter *iter) +{ + const struct io_uring_sqe *sqe = s->sqe; + void __user *buf = u64_to_user_ptr(READ_ONCE(sqe->addr)); + size_t sqe_len = READ_ONCE(sqe->len); + + if (!s->has_user) + return EFAULT; + +#ifdef CONFIG_COMPAT + if (ctx->compat) + return compat_import_iovec(rw, buf, sqe_len, UIO_FASTIOV, + iovec, iter); +#endif + + return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter); +} + +static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s, + bool force_nonblock) +{ + struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; + struct kiocb *kiocb = &req->rw; + struct iov_iter iter; + struct file *file; + ssize_t ret; + + ret = io_prep_rw(req, s->sqe, force_nonblock); + if (ret) + return ret; + file = kiocb->ki_filp; + + ret = -EBADF; + if (unlikely(!(file->f_mode & FMODE_READ))) + goto out_fput; + ret = -EINVAL; + if (unlikely(!file->f_op->read_iter)) + goto out_fput; + + ret = io_import_iovec(req->ctx, READ, s, &iovec, &iter); + if (ret) + goto out_fput; + + ret = rw_verify_area(READ, file, &kiocb->ki_pos, iov_iter_count(&iter)); + if (!ret) { + ssize_t ret2; + + /* Catch -EAGAIN return for forced non-blocking submission */ + ret2 = call_read_iter(file, kiocb, &iter); + if (!force_nonblock || ret2 != -EAGAIN) + io_rw_done(kiocb, ret2); + else + ret = -EAGAIN; + } + kfree(iovec); +out_fput: + /* Hold on to the file for -EAGAIN */ + if (unlikely(ret && ret != -EAGAIN)) + fput(file); + return ret; +} + +static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s, + bool force_nonblock) +{ + struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; + struct kiocb *kiocb = &req->rw; + struct iov_iter iter; + struct file *file; + ssize_t ret; + + ret = io_prep_rw(req, s->sqe, force_nonblock); + if (ret) + return ret; + /* Hold on to the file for -EAGAIN */ + if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT)) + return -EAGAIN; + + ret = -EBADF; + file = kiocb->ki_filp; + if (unlikely(!(file->f_mode & FMODE_WRITE))) + goto out_fput; + ret = -EINVAL; + if (unlikely(!file->f_op->write_iter)) + goto out_fput; + + ret = io_import_iovec(req->ctx, WRITE, s, &iovec, &iter); + if (ret) + goto out_fput; + + ret = rw_verify_area(WRITE, file, &kiocb->ki_pos, + iov_iter_count(&iter)); + if (!ret) { + /* + * Open-code file_start_write here to grab freeze protection, + * which will be released by another thread in + * io_complete_rw(). Fool lockdep by telling it the lock got + * released so that it doesn't complain about the held lock when + * we return to userspace. + */ + if (S_ISREG(file_inode(file)->i_mode)) { + __sb_start_write(file_inode(file)->i_sb, + SB_FREEZE_WRITE, true); + __sb_writers_release(file_inode(file)->i_sb, + SB_FREEZE_WRITE); + } + kiocb->ki_flags |= IOCB_WRITE; + io_rw_done(kiocb, call_write_iter(file, kiocb, &iter)); + } + kfree(iovec); +out_fput: + if (unlikely(ret)) + fput(file); + return ret; +} + +/* + * IORING_OP_NOP just posts a completion event, nothing else. + */ +static int io_nop(struct io_kiocb *req, u64 user_data) +{ + struct io_ring_ctx *ctx = req->ctx; + + io_cqring_add_event(ctx, user_data, 0, 0); + io_free_req(req); + return 0; +} + +static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, + const struct sqe_submit *s, bool force_nonblock) +{ + ssize_t ret; + int opcode; + + if (unlikely(s->index >= ctx->sq_entries)) + return -EINVAL; + req->user_data = READ_ONCE(s->sqe->user_data); + + opcode = READ_ONCE(s->sqe->opcode); + switch (opcode) { + case IORING_OP_NOP: + ret = io_nop(req, req->user_data); + break; + case IORING_OP_READV: + ret = io_read(req, s, force_nonblock); + break; + case IORING_OP_WRITEV: + ret = io_write(req, s, force_nonblock); + break; + default: + ret = -EINVAL; + break; + } + + return ret; +} + +static void io_sq_wq_submit_work(struct work_struct *work) +{ + struct io_kiocb *req = container_of(work, struct io_kiocb, work); + struct sqe_submit *s = &req->submit; + u64 user_data = READ_ONCE(s->sqe->user_data); + struct io_ring_ctx *ctx = req->ctx; + mm_segment_t old_fs = get_fs(); + int ret; + + /* Ensure we clear previously set forced non-block flag */ + req->flags &= ~REQ_F_FORCE_NONBLOCK; + req->rw.ki_flags &= ~IOCB_NOWAIT; + + if (!mmget_not_zero(ctx->sqo_mm)) { + ret = -EFAULT; + goto err; + } + + use_mm(ctx->sqo_mm); + set_fs(USER_DS); + s->has_user = true; + + ret = __io_submit_sqe(ctx, req, s, false); + + set_fs(old_fs); + unuse_mm(ctx->sqo_mm); + mmput(ctx->sqo_mm); +err: + if (ret) { + io_cqring_add_event(ctx, user_data, ret, 0); + io_free_req(req); + } +} + +static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s) +{ + struct io_kiocb *req; + ssize_t ret; + + /* enforce forwards compatibility on users */ + if (unlikely(s->sqe->flags)) + return -EINVAL; + + req = io_get_req(ctx); + if (unlikely(!req)) + return -EAGAIN; + + req->rw.ki_filp = NULL; + + ret = __io_submit_sqe(ctx, req, s, true); + if (ret == -EAGAIN) { + memcpy(&req->submit, s, sizeof(*s)); + INIT_WORK(&req->work, io_sq_wq_submit_work); + queue_work(ctx->sqo_wq, &req->work); + ret = 0; + } + if (ret) + io_free_req(req); + + return ret; +} + +static void io_commit_sqring(struct io_ring_ctx *ctx) +{ + struct io_sq_ring *ring = ctx->sq_ring; + + if (ctx->cached_sq_head != ring->r.head) { + WRITE_ONCE(ring->r.head, ctx->cached_sq_head); + /* write side barrier of head update, app has read side */ + smp_wmb(); + } +} + +/* + * Undo last io_get_sqring() + */ +static void io_drop_sqring(struct io_ring_ctx *ctx) +{ + ctx->cached_sq_head--; +} + +/* + * Fetch an sqe, if one is available. Note that s->sqe will point to memory + * that is mapped by userspace. This means that care needs to be taken to + * ensure that reads are stable, as we cannot rely on userspace always + * being a good citizen. If members of the sqe are validated and then later + * used, it's important that those reads are done through READ_ONCE() to + * prevent a re-load down the line. + */ +static bool io_get_sqring(struct io_ring_ctx *ctx, struct sqe_submit *s) +{ + struct io_sq_ring *ring = ctx->sq_ring; + unsigned head; + + /* + * The cached sq head (or cq tail) serves two purposes: + * + * 1) allows us to batch the cost of updating the user visible + * head updates. + * 2) allows the kernel side to track the head on its own, even + * though the application is the one updating it. + */ + head = ctx->cached_sq_head; + smp_rmb(); + if (head == READ_ONCE(ring->r.tail)) + return false; + + head = READ_ONCE(ring->array[head & ctx->sq_mask]); + if (head < ctx->sq_entries) { + s->index = head; + s->sqe = &ctx->sq_sqes[head]; + ctx->cached_sq_head++; + return true; + } + + /* drop invalid entries */ + ctx->cached_sq_head++; + ring->dropped++; + smp_wmb(); + return false; +} + +static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit) +{ + int i, ret = 0, submit = 0; + struct blk_plug plug; + + if (to_submit > IO_PLUG_THRESHOLD) + blk_start_plug(&plug); + + for (i = 0; i < to_submit; i++) { + struct sqe_submit s; + + if (!io_get_sqring(ctx, &s)) + break; + + s.has_user = true; + ret = io_submit_sqe(ctx, &s); + if (ret) { + io_drop_sqring(ctx); + break; + } + + submit++; + } + io_commit_sqring(ctx); + + if (to_submit > IO_PLUG_THRESHOLD) + blk_finish_plug(&plug); + + return submit ? submit : ret; +} + +/* + * Wait until events become available, if we don't already have some. The + * application must reap them itself, as they reside on the shared cq ring. + */ +static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, + const sigset_t __user *sig, size_t sigsz) +{ + struct io_cq_ring *ring = ctx->cq_ring; + sigset_t ksigmask, sigsaved; + DEFINE_WAIT(wait); + int ret = 0; + + smp_rmb(); + if (ring->r.head != ring->r.tail) + return 0; + if (!min_events) + return 0; + + if (sig) { + ret = set_user_sigmask(sig, &ksigmask, &sigsaved, sigsz); + if (ret) + return ret; + } + + do { + prepare_to_wait(&ctx->wait, &wait, TASK_INTERRUPTIBLE); + + ret = 0; + smp_rmb(); + if (ring->r.head != ring->r.tail) + break; + + schedule(); + + ret = -EINTR; + if (signal_pending(current)) + break; + } while (1); + + finish_wait(&ctx->wait, &wait); + + if (sig) + restore_user_sigmask(sig, &sigsaved); + + return ring->r.head == ring->r.tail ? ret : 0; +} + +static int io_sq_offload_start(struct io_ring_ctx *ctx) +{ + int ret; + + mmgrab(current->mm); + ctx->sqo_mm = current->mm; + + /* Do QD, or 2 * CPUS, whatever is smallest */ + ctx->sqo_wq = alloc_workqueue("io_ring-wq", WQ_UNBOUND | WQ_FREEZABLE, + min(ctx->sq_entries - 1, 2 * num_online_cpus())); + if (!ctx->sqo_wq) { + ret = -ENOMEM; + goto err; + } + + return 0; +err: + mmdrop(ctx->sqo_mm); + ctx->sqo_mm = NULL; + return ret; +} + +static void io_unaccount_mem(struct user_struct *user, unsigned long nr_pages) +{ + if (capable(CAP_IPC_LOCK)) + return; + atomic_long_sub(nr_pages, &user->locked_vm); +} + +static int io_account_mem(struct user_struct *user, unsigned long nr_pages) +{ + unsigned long page_limit, cur_pages, new_pages; + + if (capable(CAP_IPC_LOCK)) + return 0; + + /* Don't allow more pages than we can safely lock */ + page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; + + do { + cur_pages = atomic_long_read(&user->locked_vm); + new_pages = cur_pages + nr_pages; + if (new_pages > page_limit) + return -ENOMEM; + } while (atomic_long_cmpxchg(&user->locked_vm, cur_pages, + new_pages) != cur_pages); + + return 0; +} + +static void io_mem_free(void *ptr) +{ + struct page *page = virt_to_head_page(ptr); + + if (put_page_testzero(page)) + free_compound_page(page); +} + +static void *io_mem_alloc(size_t size) +{ + gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP | + __GFP_NORETRY; + + return (void *) __get_free_pages(gfp_flags, get_order(size)); +} + +static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries) +{ + struct io_sq_ring *sq_ring; + struct io_cq_ring *cq_ring; + size_t bytes; + + bytes = struct_size(sq_ring, array, sq_entries); + bytes += array_size(sizeof(struct io_uring_sqe), sq_entries); + bytes += struct_size(cq_ring, cqes, cq_entries); + + return (bytes + PAGE_SIZE - 1) / PAGE_SIZE; +} + +static void io_ring_ctx_free(struct io_ring_ctx *ctx) +{ + if (ctx->sqo_wq) + destroy_workqueue(ctx->sqo_wq); + if (ctx->sqo_mm) + mmdrop(ctx->sqo_mm); +#if defined(CONFIG_UNIX) + if (ctx->ring_sock) + sock_release(ctx->ring_sock); +#endif + + io_mem_free(ctx->sq_ring); + io_mem_free(ctx->sq_sqes); + io_mem_free(ctx->cq_ring); + + percpu_ref_exit(&ctx->refs); + io_unaccount_mem(ctx->user, + ring_pages(ctx->sq_entries, ctx->cq_entries)); + free_uid(ctx->user); + kfree(ctx); +} + +static __poll_t io_uring_poll(struct file *file, poll_table *wait) +{ + struct io_ring_ctx *ctx = file->private_data; + __poll_t mask = 0; + + poll_wait(file, &ctx->cq_wait, wait); + smp_rmb(); + if (ctx->sq_ring->r.tail + 1 != ctx->cached_sq_head) + mask |= EPOLLOUT | EPOLLWRNORM; + if (ctx->cq_ring->r.head != ctx->cached_cq_tail) + mask |= EPOLLIN | EPOLLRDNORM; + + return mask; +} + +static int io_uring_fasync(int fd, struct file *file, int on) +{ + struct io_ring_ctx *ctx = file->private_data; + + return fasync_helper(fd, file, on, &ctx->cq_fasync); +} + +static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) +{ + mutex_lock(&ctx->uring_lock); + percpu_ref_kill(&ctx->refs); + mutex_unlock(&ctx->uring_lock); + + wait_for_completion(&ctx->ctx_done); + io_ring_ctx_free(ctx); +} + +static int io_uring_release(struct inode *inode, struct file *file) +{ + struct io_ring_ctx *ctx = file->private_data; + + file->private_data = NULL; + io_ring_ctx_wait_and_kill(ctx); + return 0; +} + +static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) +{ + loff_t offset = (loff_t) vma->vm_pgoff << PAGE_SHIFT; + unsigned long sz = vma->vm_end - vma->vm_start; + struct io_ring_ctx *ctx = file->private_data; + unsigned long pfn; + struct page *page; + void *ptr; + + switch (offset) { + case IORING_OFF_SQ_RING: + ptr = ctx->sq_ring; + break; + case IORING_OFF_SQES: + ptr = ctx->sq_sqes; + break; + case IORING_OFF_CQ_RING: + ptr = ctx->cq_ring; + break; + default: + return -EINVAL; + } + + page = virt_to_head_page(ptr); + if (sz > (PAGE_SIZE << compound_order(page))) + return -EINVAL; + + pfn = virt_to_phys(ptr) >> PAGE_SHIFT; + return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot); +} + +SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, + u32, min_complete, u32, flags, const sigset_t __user *, sig, + size_t, sigsz) +{ + struct io_ring_ctx *ctx; + long ret = -EBADF; + int submitted = 0; + struct fd f; + + if (flags & ~IORING_ENTER_GETEVENTS) + return -EINVAL; + + f = fdget(fd); + if (!f.file) + return -EBADF; + + ret = -EOPNOTSUPP; + if (f.file->f_op != &io_uring_fops) + goto out_fput; + + ret = -ENXIO; + ctx = f.file->private_data; + if (!percpu_ref_tryget(&ctx->refs)) + goto out_fput; + + if (to_submit) { + to_submit = min(to_submit, ctx->sq_entries); + + mutex_lock(&ctx->uring_lock); + submitted = io_ring_submit(ctx, to_submit); + mutex_unlock(&ctx->uring_lock); + + if (submitted < 0) + goto out_ctx; + } + if (flags & IORING_ENTER_GETEVENTS) { + /* + * The application could have included the 'to_submit' count + * in how many events it wanted to wait for. If we failed to + * submit the desired count, we may need to adjust the number + * of events to poll/wait for. + */ + if (submitted < to_submit) + min_complete = min_t(unsigned, submitted, min_complete); + + ret = io_cqring_wait(ctx, min_complete, sig, sigsz); + } + +out_ctx: + io_ring_drop_ctx_refs(ctx, 1); +out_fput: + fdput(f); + return submitted ? submitted : ret; +} + +static const struct file_operations io_uring_fops = { + .release = io_uring_release, + .mmap = io_uring_mmap, + .poll = io_uring_poll, + .fasync = io_uring_fasync, +}; + +static int io_allocate_scq_urings(struct io_ring_ctx *ctx, + struct io_uring_params *p) +{ + struct io_sq_ring *sq_ring; + struct io_cq_ring *cq_ring; + size_t size; + + sq_ring = io_mem_alloc(struct_size(sq_ring, array, p->sq_entries)); + if (!sq_ring) + return -ENOMEM; + + ctx->sq_ring = sq_ring; + sq_ring->ring_mask = p->sq_entries - 1; + sq_ring->ring_entries = p->sq_entries; + ctx->sq_mask = sq_ring->ring_mask; + ctx->sq_entries = sq_ring->ring_entries; + + size = array_size(sizeof(struct io_uring_sqe), p->sq_entries); + if (size == SIZE_MAX) + return -EOVERFLOW; + + ctx->sq_sqes = io_mem_alloc(size); + if (!ctx->sq_sqes) { + io_mem_free(ctx->sq_ring); + return -ENOMEM; + } + + cq_ring = io_mem_alloc(struct_size(cq_ring, cqes, p->cq_entries)); + if (!cq_ring) { + io_mem_free(ctx->sq_ring); + io_mem_free(ctx->sq_sqes); + return -ENOMEM; + } + + ctx->cq_ring = cq_ring; + cq_ring->ring_mask = p->cq_entries - 1; + cq_ring->ring_entries = p->cq_entries; + ctx->cq_mask = cq_ring->ring_mask; + ctx->cq_entries = cq_ring->ring_entries; + return 0; +} + +static int io_uring_get_fd(struct io_ring_ctx *ctx) +{ + struct file *file; + int ret; + +#if defined(CONFIG_UNIX) + ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP, + &ctx->ring_sock); + if (ret) + return ret; +#endif + + ret = get_unused_fd_flags(O_RDWR | O_CLOEXEC); + if (ret < 0) + goto err; + + file = anon_inode_getfile("[io_uring]", &io_uring_fops, ctx, + O_RDWR | O_CLOEXEC); + if (IS_ERR(file)) { + put_unused_fd(ret); + ret = PTR_ERR(file); + goto err; + } + +#if defined(CONFIG_UNIX) + ctx->ring_sock->file = file; +#endif + fd_install(ret, file); + return ret; +err: +#if defined(CONFIG_UNIX) + sock_release(ctx->ring_sock); + ctx->ring_sock = NULL; +#endif + return ret; +} + +static int io_uring_create(unsigned entries, struct io_uring_params *p) +{ + struct user_struct *user = NULL; + struct io_ring_ctx *ctx; + int ret; + + if (!entries || entries > IORING_MAX_ENTRIES) + return -EINVAL; + + /* + * Use twice as many entries for the CQ ring. It's possible for the + * application to drive a higher depth than the size of the SQ ring, + * since the sqes are only used at submission time. This allows for + * some flexibility in overcommitting a bit. + */ + p->sq_entries = roundup_pow_of_two(entries); + p->cq_entries = 2 * p->sq_entries; + + user = get_uid(current_user()); + ret = io_account_mem(user, ring_pages(p->sq_entries, p->cq_entries)); + if (ret) { + free_uid(user); + return ret; + } + + ctx = io_ring_ctx_alloc(p); + if (!ctx) { + io_unaccount_mem(user, ring_pages(p->sq_entries, + p->cq_entries)); + free_uid(user); + return -ENOMEM; + } + ctx->compat = in_compat_syscall(); + ctx->user = user; + + ret = io_allocate_scq_urings(ctx, p); + if (ret) + goto err; + + ret = io_sq_offload_start(ctx); + if (ret) + goto err; + + ret = io_uring_get_fd(ctx); + if (ret < 0) + goto err; + + memset(&p->sq_off, 0, sizeof(p->sq_off)); + p->sq_off.head = offsetof(struct io_sq_ring, r.head); + p->sq_off.tail = offsetof(struct io_sq_ring, r.tail); + p->sq_off.ring_mask = offsetof(struct io_sq_ring, ring_mask); + p->sq_off.ring_entries = offsetof(struct io_sq_ring, ring_entries); + p->sq_off.flags = offsetof(struct io_sq_ring, flags); + p->sq_off.dropped = offsetof(struct io_sq_ring, dropped); + p->sq_off.array = offsetof(struct io_sq_ring, array); + + memset(&p->cq_off, 0, sizeof(p->cq_off)); + p->cq_off.head = offsetof(struct io_cq_ring, r.head); + p->cq_off.tail = offsetof(struct io_cq_ring, r.tail); + p->cq_off.ring_mask = offsetof(struct io_cq_ring, ring_mask); + p->cq_off.ring_entries = offsetof(struct io_cq_ring, ring_entries); + p->cq_off.overflow = offsetof(struct io_cq_ring, overflow); + p->cq_off.cqes = offsetof(struct io_cq_ring, cqes); + return ret; +err: + io_ring_ctx_wait_and_kill(ctx); + return ret; +} + +/* + * Sets up an aio uring context, and returns the fd. Applications asks for a + * ring size, we return the actual sq/cq ring sizes (among other things) in the + * params structure passed in. + */ +static long io_uring_setup(u32 entries, struct io_uring_params __user *params) +{ + struct io_uring_params p; + long ret; + int i; + + if (copy_from_user(&p, params, sizeof(p))) + return -EFAULT; + for (i = 0; i < ARRAY_SIZE(p.resv); i++) { + if (p.resv[i]) + return -EINVAL; + } + + if (p.flags) + return -EINVAL; + + ret = io_uring_create(entries, &p); + if (ret < 0) + return ret; + + if (copy_to_user(params, &p, sizeof(p))) + return -EFAULT; + + return ret; +} + +SYSCALL_DEFINE2(io_uring_setup, u32, entries, + struct io_uring_params __user *, params) +{ + return io_uring_setup(entries, params); +} + +static int __init io_uring_init(void) +{ + req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC); + return 0; +}; +__initcall(io_uring_init); diff --git a/include/linux/fs.h b/include/linux/fs.h index dedcc2e9265c..61aa210f0c2b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3517,4 +3517,13 @@ extern void inode_nohighmem(struct inode *inode); extern int vfs_fadvise(struct file *file, loff_t offset, loff_t len, int advice); +#if defined(CONFIG_IO_URING) +extern struct sock *io_uring_get_socket(struct file *file); +#else +static inline struct sock *io_uring_get_socket(struct file *file) +{ + return NULL; +} +#endif + #endif /* _LINUX_FS_H */ diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 257cccba3062..3072dbaa7869 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -69,6 +69,7 @@ struct file_handle; struct sigaltstack; struct rseq; union bpf_attr; +struct io_uring_params; #include #include @@ -309,6 +310,11 @@ asmlinkage long sys_io_pgetevents_time32(aio_context_t ctx_id, struct io_event __user *events, struct old_timespec32 __user *timeout, const struct __aio_sigset *sig); +asmlinkage long sys_io_uring_setup(u32 entries, + struct io_uring_params __user *p); +asmlinkage long sys_io_uring_enter(unsigned int fd, u32 to_submit, + u32 min_complete, u32 flags, + const sigset_t __user *sig, size_t sigsz); /* fs/xattr.c */ asmlinkage long sys_setxattr(const char __user *path, const char __user *name, diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index d90127298f12..87871e7b7ea7 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -740,9 +740,13 @@ __SC_COMP(__NR_io_pgetevents, sys_io_pgetevents, compat_sys_io_pgetevents) __SYSCALL(__NR_rseq, sys_rseq) #define __NR_kexec_file_load 294 __SYSCALL(__NR_kexec_file_load, sys_kexec_file_load) +#define __NR_io_uring_setup 425 +__SYSCALL(__NR_io_uring_setup, sys_io_uring_setup) +#define __NR_io_uring_enter 426 +__SYSCALL(__NR_io_uring_enter, sys_io_uring_enter) #undef __NR_syscalls -#define __NR_syscalls 295 +#define __NR_syscalls 427 /* * 32 bit systems traditionally used different diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h new file mode 100644 index 000000000000..ac692823d6f4 --- /dev/null +++ b/include/uapi/linux/io_uring.h @@ -0,0 +1,95 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Header file for the io_uring interface. + * + * Copyright (C) 2019 Jens Axboe + * Copyright (C) 2019 Christoph Hellwig + */ +#ifndef LINUX_IO_URING_H +#define LINUX_IO_URING_H + +#include +#include + +/* + * IO submission data structure (Submission Queue Entry) + */ +struct io_uring_sqe { + __u8 opcode; /* type of operation for this sqe */ + __u8 flags; /* as of now unused */ + __u16 ioprio; /* ioprio for the request */ + __s32 fd; /* file descriptor to do IO on */ + __u64 off; /* offset into file */ + __u64 addr; /* pointer to buffer or iovecs */ + __u32 len; /* buffer size or number of iovecs */ + union { + __kernel_rwf_t rw_flags; + __u32 __resv; + }; + __u64 user_data; /* data to be passed back at completion time */ + __u64 __pad2[3]; +}; + +#define IORING_OP_NOP 0 +#define IORING_OP_READV 1 +#define IORING_OP_WRITEV 2 + +/* + * IO completion data structure (Completion Queue Entry) + */ +struct io_uring_cqe { + __u64 user_data; /* sqe->data submission passed back */ + __s32 res; /* result code for this event */ + __u32 flags; +}; + +/* + * Magic offsets for the application to mmap the data it needs + */ +#define IORING_OFF_SQ_RING 0ULL +#define IORING_OFF_CQ_RING 0x8000000ULL +#define IORING_OFF_SQES 0x10000000ULL + +/* + * Filled with the offset for mmap(2) + */ +struct io_sqring_offsets { + __u32 head; + __u32 tail; + __u32 ring_mask; + __u32 ring_entries; + __u32 flags; + __u32 dropped; + __u32 array; + __u32 resv1; + __u64 resv2; +}; + +struct io_cqring_offsets { + __u32 head; + __u32 tail; + __u32 ring_mask; + __u32 ring_entries; + __u32 overflow; + __u32 cqes; + __u64 resv[2]; +}; + +/* + * io_uring_enter(2) flags + */ +#define IORING_ENTER_GETEVENTS (1U << 0) + +/* + * Passed in for io_uring_setup(2). Copied back with updated info on success + */ +struct io_uring_params { + __u32 sq_entries; + __u32 cq_entries; + __u32 flags; + __u32 resv[7]; + struct io_sqring_offsets sq_off; + struct io_cqring_offsets cq_off; +}; + +#endif diff --git a/init/Kconfig b/init/Kconfig index c9386a365eea..8b5e0da04384 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1414,6 +1414,15 @@ config AIO by some high performance threaded applications. Disabling this option saves about 7k. +config IO_URING + bool "Enable IO uring support" if EXPERT + select ANON_INODES + default y + help + This option enables support for the io_uring interface, enabling + applications to submit and completion IO through submission and + completion rings that are shared between the kernel and application. + config ADVISE_SYSCALLS bool "Enable madvise/fadvise syscalls" if EXPERT default y diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index ab9d0e3c6d50..ee5e523564bb 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -46,6 +46,8 @@ COND_SYSCALL(io_getevents); COND_SYSCALL(io_pgetevents); COND_SYSCALL_COMPAT(io_getevents); COND_SYSCALL_COMPAT(io_pgetevents); +COND_SYSCALL(io_uring_setup); +COND_SYSCALL(io_uring_enter); /* fs/xattr.c */ diff --git a/net/unix/garbage.c b/net/unix/garbage.c index c36757e72844..f81854d74c7d 100644 --- a/net/unix/garbage.c +++ b/net/unix/garbage.c @@ -108,6 +108,9 @@ struct sock *unix_get_socket(struct file *filp) /* PF_UNIX ? */ if (s && sock->ops && sock->ops->family == PF_UNIX) u_sock = s; + } else { + /* Could be an io_uring instance */ + u_sock = io_uring_get_socket(filp); } return u_sock; } From patchwork Fri Feb 8 17:34:10 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10803489 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3CE3E1390 for ; Fri, 8 Feb 2019 17:34:49 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2D0602DCD6 for ; Fri, 8 Feb 2019 17:34:49 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 20FC92DCDB; Fri, 8 Feb 2019 17:34:49 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AD6092DCD6 for ; Fri, 8 Feb 2019 17:34:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727773AbfBHRes (ORCPT ); Fri, 8 Feb 2019 12:34:48 -0500 Received: from mail-it1-f195.google.com ([209.85.166.195]:35736 "EHLO mail-it1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727726AbfBHRer (ORCPT ); Fri, 8 Feb 2019 12:34:47 -0500 Received: by mail-it1-f195.google.com with SMTP id r6so10902217itk.0 for ; Fri, 08 Feb 2019 09:34:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=GApnfsa7c+mg+tc0yKqlcv3g9TPKkz7bCJNbZx5pt0A=; b=xcj+bFqjW0s1JR1Zs/398yokoDoLbdW5Lyx4owiDTrBmaRhw2U1VQyFZ5AUpKTo7UU SWA/3M0CnwWNfY3zsenP+glLgRpeoZ0otgra8ayOhgKxhqs5TQ723vm1wGw/TF8J2lQ7 VdRTz2s2WZhF28H84xyLqJta9loGvY7Ejj5sELXt/1g9IXTNVfPQQ4kzpgLehixnI84Z FH2u49+1BDIR8HikzIELG6Ps6wZvNHbZrPIZSv4VCJeeBmu5DPv8smNDhVLofsWPnfXJ K52QHOsGk99xkNbxjLbAO4cb9I3NqxqmLpFbomROJRzpSn6qV+YGnEyLH5dt/Y09Uczk xkYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=GApnfsa7c+mg+tc0yKqlcv3g9TPKkz7bCJNbZx5pt0A=; b=id0Sqsed/ZH+BtS4DvnlEypq9r3FNz7wDvGCDwPlkz8FICvSnYPIO4iQeNf0aRnBXU 1lns3nJbNHHew1AJOwPNsrwKc8qNwXls6M/kZuk2I/XX7nU0817PmeS/u2Lr0G1Qp1/5 6TWUVB2BMsp3MF5jttutq3hOSlOeE1ll/pLZTj6kiWTpcWkqzk7HMG4mTRfnVo/At82z s4ur8VqxrUUVrBnnnf8MmEQNTvun9RBFHRRUNzyB03zcb4y00E5n6uNI9bC3gTLBdMEG WwrlUBAAtWPwXOe/RT1Yg6qnSQUIhI4g6xfjENj5Z6KY7W8ayeLzaJWmpun+iVFLVfwW FYGQ== X-Gm-Message-State: AHQUAuaKZWzRxIGRvdye64PmVc+VX6mWq6SRwUGtwNdkhhfcZVz6w628 LUBn2Up1ByWAQ/v0sM6O4zH4f+G3VYHn+w== X-Google-Smtp-Source: AHgI3IYctximbItKyUBcCPUdJRnb/1kxjfhS/hN0mQe/lVZduXlZNgKjNJx6aHBRKGzBEHAzMUBNMA== X-Received: by 2002:a6b:8f48:: with SMTP id r69mr11936602iod.128.1549647286762; Fri, 08 Feb 2019 09:34:46 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id f142sm1522627itc.15.2019.02.08.09.34.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Feb 2019 09:34:45 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 06/19] io_uring: add fsync support Date: Fri, 8 Feb 2019 10:34:10 -0700 Message-Id: <20190208173423.27014-7-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Christoph Hellwig Add a new fsync opcode, which either syncs a range if one is passed, or the whole file if the offset and length fields are both cleared to zero. A flag is provided to use fdatasync semantics, that is only force out metadata which is required to retrieve the file data, but not others like metadata. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe Reviewed-by: Hannes Reinecke --- fs/io_uring.c | 40 +++++++++++++++++++++++++++++++++++ include/uapi/linux/io_uring.h | 8 ++++++- 2 files changed, 47 insertions(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 927d61ebecf3..6cdf11373304 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4,6 +4,7 @@ * supporting fast/efficient IO. * * Copyright (C) 2018-2019 Jens Axboe + * Copyright (c) 2018-2019 Christoph Hellwig */ #include #include @@ -518,6 +519,42 @@ static int io_nop(struct io_kiocb *req, u64 user_data) return 0; } +static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe, + bool force_nonblock) +{ + struct io_ring_ctx *ctx = req->ctx; + loff_t sqe_off = READ_ONCE(sqe->off); + loff_t sqe_len = READ_ONCE(sqe->len); + loff_t end = sqe_off + sqe_len; + unsigned fsync_flags; + struct file *file; + int ret, fd; + + /* fsync always requires a blocking context */ + if (force_nonblock) + return -EAGAIN; + + if (unlikely(sqe->addr || sqe->ioprio)) + return -EINVAL; + + fsync_flags = READ_ONCE(sqe->fsync_flags); + if (unlikely(fsync_flags & ~IORING_FSYNC_DATASYNC)) + return -EINVAL; + + fd = READ_ONCE(sqe->fd); + file = fget(fd); + if (unlikely(!file)) + return -EBADF; + + ret = vfs_fsync_range(file, sqe_off, end > 0 ? end : LLONG_MAX, + fsync_flags & IORING_FSYNC_DATASYNC); + + fput(file); + io_cqring_add_event(ctx, sqe->user_data, ret, 0); + io_free_req(req); + return 0; +} + static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, const struct sqe_submit *s, bool force_nonblock) { @@ -539,6 +576,9 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, case IORING_OP_WRITEV: ret = io_write(req, s, force_nonblock); break; + case IORING_OP_FSYNC: + ret = io_fsync(req, s->sqe, force_nonblock); + break; default: ret = -EINVAL; break; diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index ac692823d6f4..4589d56d0b68 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -24,7 +24,7 @@ struct io_uring_sqe { __u32 len; /* buffer size or number of iovecs */ union { __kernel_rwf_t rw_flags; - __u32 __resv; + __u32 fsync_flags; }; __u64 user_data; /* data to be passed back at completion time */ __u64 __pad2[3]; @@ -33,6 +33,12 @@ struct io_uring_sqe { #define IORING_OP_NOP 0 #define IORING_OP_READV 1 #define IORING_OP_WRITEV 2 +#define IORING_OP_FSYNC 3 + +/* + * sqe->fsync_flags + */ +#define IORING_FSYNC_DATASYNC (1U << 0) /* * IO completion data structure (Completion Queue Entry) From patchwork Fri Feb 8 17:34:11 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10803493 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AA84E1823 for ; Fri, 8 Feb 2019 17:34:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9A0F42DCD6 for ; Fri, 8 Feb 2019 17:34:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8C1162DCE1; Fri, 8 Feb 2019 17:34:51 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A6ED32DCD6 for ; Fri, 8 Feb 2019 17:34:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727783AbfBHReu (ORCPT ); Fri, 8 Feb 2019 12:34:50 -0500 Received: from mail-it1-f193.google.com ([209.85.166.193]:50435 "EHLO mail-it1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727689AbfBHRet (ORCPT ); Fri, 8 Feb 2019 12:34:49 -0500 Received: by mail-it1-f193.google.com with SMTP id z7so10745744iti.0 for ; 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Fri, 08 Feb 2019 09:34:48 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id f142sm1522627itc.15.2019.02.08.09.34.46 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Feb 2019 09:34:47 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 07/19] io_uring: support for IO polling Date: Fri, 8 Feb 2019 10:34:11 -0700 Message-Id: <20190208173423.27014-8-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add support for a polled io_uring instance. When a read or write is submitted to a polled io_uring, the application must poll for completions on the CQ ring through io_uring_enter(2). Polled IO may not generate IRQ completions, hence they need to be actively found by the application itself. To use polling, io_uring_setup() must be used with the IORING_SETUP_IOPOLL flag being set. It is illegal to mix and match polled and non-polled IO on an io_uring. Signed-off-by: Jens Axboe Reviewed-by: Hannes Reinecke --- fs/io_uring.c | 274 ++++++++++++++++++++++++++++++++-- include/uapi/linux/io_uring.h | 5 + 2 files changed, 270 insertions(+), 9 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 6cdf11373304..036230ebd33d 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -103,6 +103,14 @@ struct io_ring_ctx { struct { spinlock_t completion_lock; + bool poll_multi_file; + /* + * ->poll_list is protected by the ctx->uring_lock for + * io_uring instances that don't use IORING_SETUP_SQPOLL. + * For SQPOLL, only the single threaded io_sq_thread() will + * manipulate the list, hence no extra locking is needed there. + */ + struct list_head poll_list; } ____cacheline_aligned_in_smp; #if defined(CONFIG_UNIX) @@ -114,6 +122,7 @@ struct sqe_submit { const struct io_uring_sqe *sqe; unsigned short index; bool has_user; + bool needs_lock; }; struct io_kiocb { @@ -125,12 +134,15 @@ struct io_kiocb { struct list_head list; unsigned int flags; #define REQ_F_FORCE_NONBLOCK 1 /* inline submission attempt */ +#define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */ u64 user_data; + u64 error; struct work_struct work; }; #define IO_PLUG_THRESHOLD 2 +#define IO_IOPOLL_BATCH 8 static struct kmem_cache *req_cachep; @@ -175,6 +187,7 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) mutex_init(&ctx->uring_lock); init_waitqueue_head(&ctx->wait); spin_lock_init(&ctx->completion_lock); + INIT_LIST_HEAD(&ctx->poll_list); return ctx; } @@ -269,12 +282,153 @@ static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx) return NULL; } +static void io_free_req_many(struct io_ring_ctx *ctx, void **reqs, int *nr) +{ + if (*nr) { + kmem_cache_free_bulk(req_cachep, *nr, reqs); + io_ring_drop_ctx_refs(ctx, *nr); + *nr = 0; + } +} + static void io_free_req(struct io_kiocb *req) { io_ring_drop_ctx_refs(req->ctx, 1); kmem_cache_free(req_cachep, req); } +/* + * Find and free completed poll iocbs + */ +static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events, + struct list_head *done) +{ + void *reqs[IO_IOPOLL_BATCH]; + struct io_kiocb *req; + int to_free = 0; + + while (!list_empty(done)) { + req = list_first_entry(done, struct io_kiocb, list); + list_del(&req->list); + + io_cqring_fill_event(ctx, req->user_data, req->error, 0); + + reqs[to_free++] = req; + (*nr_events)++; + + fput(req->rw.ki_filp); + if (to_free == ARRAY_SIZE(reqs)) + io_free_req_many(ctx, reqs, &to_free); + } + io_commit_cqring(ctx); + + io_free_req_many(ctx, reqs, &to_free); +} + +static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events, + long min) +{ + struct io_kiocb *req, *tmp; + LIST_HEAD(done); + bool spin; + int ret; + + /* + * Only spin for completions if we don't have multiple devices hanging + * off our complete list, and we're under the requested amount. + */ + spin = !ctx->poll_multi_file && *nr_events < min; + + ret = 0; + list_for_each_entry_safe(req, tmp, &ctx->poll_list, list) { + struct kiocb *kiocb = &req->rw; + + /* + * Move completed entries to our local list. If we find a + * request that requires polling, break out and complete + * the done list first, if we have entries there. + */ + if (req->flags & REQ_F_IOPOLL_COMPLETED) { + list_move_tail(&req->list, &done); + continue; + } + if (!list_empty(&done)) + break; + + ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin); + if (ret < 0) + break; + + if (ret && spin) + spin = false; + ret = 0; + } + + if (!list_empty(&done)) + io_iopoll_complete(ctx, nr_events, &done); + + return ret; +} + +/* + * Poll for a mininum of 'min' events. Note that if min == 0 we consider that a + * non-spinning poll check - we'll still enter the driver poll loop, but only + * as a non-spinning completion check. + */ +static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events, + long min) +{ + while (!list_empty(&ctx->poll_list)) { + int ret; + + ret = io_do_iopoll(ctx, nr_events, min); + if (ret < 0) + return ret; + if (!min || *nr_events >= min) + return 0; + } + + return 1; +} + +/* + * We can't just wait for polled events to come to us, we have to actively + * find and complete them. + */ +static void io_iopoll_reap_events(struct io_ring_ctx *ctx) +{ + if (!(ctx->flags & IORING_SETUP_IOPOLL)) + return; + + mutex_lock(&ctx->uring_lock); + while (!list_empty(&ctx->poll_list)) { + unsigned int nr_events = 0; + + io_iopoll_getevents(ctx, &nr_events, 1); + } + mutex_unlock(&ctx->uring_lock); +} + +static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events, + long min) +{ + int ret = 0; + + do { + int tmin = 0; + + if (*nr_events < min) + tmin = min - *nr_events; + + ret = io_iopoll_getevents(ctx, nr_events, tmin); + if (ret <= 0) + break; + ret = 0; + } while (min && !*nr_events && !need_resched()); + + return ret; +} + static void kiocb_end_write(struct kiocb *kiocb) { if (kiocb->ki_flags & IOCB_WRITE) { @@ -301,6 +455,53 @@ static void io_complete_rw(struct kiocb *kiocb, long res, long res2) io_free_req(req); } +static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2) +{ + struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw); + + kiocb_end_write(kiocb); + + req->error = res; + if (res != -EAGAIN) + req->flags |= REQ_F_IOPOLL_COMPLETED; +} + +/* + * After the iocb has been issued, it's safe to be found on the poll list. + * Adding the kiocb to the list AFTER submission ensures that we don't + * find it from a io_iopoll_getevents() thread before the issuer is done + * accessing the kiocb cookie. + */ +static void io_iopoll_req_issued(struct io_kiocb *req) +{ + struct io_ring_ctx *ctx = req->ctx; + + /* + * Track whether we have multiple files in our lists. This will impact + * how we do polling eventually, not spinning if we're on potentially + * different devices. + */ + if (list_empty(&ctx->poll_list)) { + ctx->poll_multi_file = false; + } else if (!ctx->poll_multi_file) { + struct io_kiocb *list_req; + + list_req = list_first_entry(&ctx->poll_list, struct io_kiocb, + list); + if (list_req->rw.ki_filp != req->rw.ki_filp) + ctx->poll_multi_file = true; + } + + /* + * For fast devices, IO may have already completed. If it has, add + * it to the front so we find it first. + */ + if (req->flags & REQ_F_IOPOLL_COMPLETED) + list_add(&req->list, &ctx->poll_list); + else + list_add_tail(&req->list, &ctx->poll_list); +} + /* * If we tracked the file through the SCM inflight mechanism, we could support * any file. For now, just ensure that anything potentially problematic is done @@ -321,6 +522,7 @@ static bool io_file_supports_async(struct file *file) static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, bool force_nonblock) { + struct io_ring_ctx *ctx = req->ctx; struct kiocb *kiocb = &req->rw; unsigned ioprio; int fd, ret; @@ -356,12 +558,22 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, kiocb->ki_flags |= IOCB_NOWAIT; req->flags |= REQ_F_FORCE_NONBLOCK; } - if (kiocb->ki_flags & IOCB_HIPRI) { - ret = -EINVAL; - goto out_fput; - } + if (ctx->flags & IORING_SETUP_IOPOLL) { + ret = -EOPNOTSUPP; + if (!(kiocb->ki_flags & IOCB_DIRECT) || + !kiocb->ki_filp->f_op->iopoll) + goto out_fput; - kiocb->ki_complete = io_complete_rw; + req->error = 0; + kiocb->ki_flags |= IOCB_HIPRI; + kiocb->ki_complete = io_complete_rw_iopoll; + } else { + if (kiocb->ki_flags & IOCB_HIPRI) { + ret = -EINVAL; + goto out_fput; + } + kiocb->ki_complete = io_complete_rw; + } return 0; out_fput: fput(kiocb->ki_filp); @@ -514,6 +726,9 @@ static int io_nop(struct io_kiocb *req, u64 user_data) { struct io_ring_ctx *ctx = req->ctx; + if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) + return -EINVAL; + io_cqring_add_event(ctx, user_data, 0, 0); io_free_req(req); return 0; @@ -534,6 +749,8 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe, if (force_nonblock) return -EAGAIN; + if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) + return -EINVAL; if (unlikely(sqe->addr || sqe->ioprio)) return -EINVAL; @@ -584,7 +801,22 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, break; } - return ret; + if (ret) + return ret; + + if (ctx->flags & IORING_SETUP_IOPOLL) { + if (req->error == -EAGAIN) + return -EAGAIN; + + /* workqueue context doesn't hold uring_lock, grab it now */ + if (s->needs_lock) + mutex_lock(&ctx->uring_lock); + io_iopoll_req_issued(req); + if (s->needs_lock) + mutex_unlock(&ctx->uring_lock); + } + + return 0; } static void io_sq_wq_submit_work(struct work_struct *work) @@ -608,8 +840,19 @@ static void io_sq_wq_submit_work(struct work_struct *work) use_mm(ctx->sqo_mm); set_fs(USER_DS); s->has_user = true; + s->needs_lock = true; - ret = __io_submit_sqe(ctx, req, s, false); + do { + ret = __io_submit_sqe(ctx, req, s, false); + /* + * We can get EAGAIN for polled IO even though we're forcing + * a sync submission from here, since we can't wait for + * request slots on the block side. + */ + if (ret != -EAGAIN) + break; + cond_resched(); + } while (1); set_fs(old_fs); unuse_mm(ctx->sqo_mm); @@ -724,6 +967,8 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit) break; s.has_user = true; + s.needs_lock = false; + ret = io_submit_sqe(ctx, &s); if (ret) { io_drop_sqring(ctx); @@ -877,6 +1122,8 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx) sock_release(ctx->ring_sock); #endif + io_iopoll_reap_events(ctx); + io_mem_free(ctx->sq_ring); io_mem_free(ctx->sq_sqes); io_mem_free(ctx->cq_ring); @@ -916,6 +1163,7 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) percpu_ref_kill(&ctx->refs); mutex_unlock(&ctx->uring_lock); + io_iopoll_reap_events(ctx); wait_for_completion(&ctx->ctx_done); io_ring_ctx_free(ctx); } @@ -996,6 +1244,8 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, goto out_ctx; } if (flags & IORING_ENTER_GETEVENTS) { + unsigned nr_events = 0; + /* * The application could have included the 'to_submit' count * in how many events it wanted to wait for. If we failed to @@ -1005,7 +1255,13 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, if (submitted < to_submit) min_complete = min_t(unsigned, submitted, min_complete); - ret = io_cqring_wait(ctx, min_complete, sig, sigsz); + if (ctx->flags & IORING_SETUP_IOPOLL) { + mutex_lock(&ctx->uring_lock); + ret = io_iopoll_check(ctx, &nr_events, min_complete); + mutex_unlock(&ctx->uring_lock); + } else { + ret = io_cqring_wait(ctx, min_complete, sig, sigsz); + } } out_ctx: @@ -1188,7 +1444,7 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params) return -EINVAL; } - if (p.flags) + if (p.flags & ~IORING_SETUP_IOPOLL) return -EINVAL; ret = io_uring_create(entries, &p); diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 4589d56d0b68..5c457ea396e6 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -30,6 +30,11 @@ struct io_uring_sqe { __u64 __pad2[3]; }; +/* + * io_uring_setup() flags + */ +#define IORING_SETUP_IOPOLL (1U << 0) /* io_context is polled */ + #define IORING_OP_NOP 0 #define IORING_OP_READV 1 #define IORING_OP_WRITEV 2 From patchwork Fri Feb 8 17:34:12 2019 Content-Type: text/plain; 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Fri, 08 Feb 2019 09:34:49 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 08/19] fs: add fget_many() and fput_many() Date: Fri, 8 Feb 2019 10:34:12 -0700 Message-Id: <20190208173423.27014-9-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Some uses cases repeatedly get and put references to the same file, but the only exposed interface is doing these one at the time. As each of these entail an atomic inc or dec on a shared structure, that cost can add up. Add fget_many(), which works just like fget(), except it takes an argument for how many references to get on the file. Ditto fput_many(), which can drop an arbitrary number of references to a file. Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe Reviewed-by: Hannes Reinecke --- fs/file.c | 15 ++++++++++----- fs/file_table.c | 9 +++++++-- include/linux/file.h | 2 ++ include/linux/fs.h | 4 +++- 4 files changed, 22 insertions(+), 8 deletions(-) diff --git a/fs/file.c b/fs/file.c index 3209ee271c41..97df385d6ab0 100644 --- a/fs/file.c +++ b/fs/file.c @@ -705,7 +705,7 @@ void do_close_on_exec(struct files_struct *files) spin_unlock(&files->file_lock); } -static struct file *__fget(unsigned int fd, fmode_t mask) +static struct file *__fget(unsigned int fd, fmode_t mask, unsigned int refs) { struct files_struct *files = current->files; struct file *file; @@ -720,7 +720,7 @@ static struct file *__fget(unsigned int fd, fmode_t mask) */ if (file->f_mode & mask) file = NULL; - else if (!get_file_rcu(file)) + else if (!get_file_rcu_many(file, refs)) goto loop; } rcu_read_unlock(); @@ -728,15 +728,20 @@ static struct file *__fget(unsigned int fd, fmode_t mask) return file; } +struct file *fget_many(unsigned int fd, unsigned int refs) +{ + return __fget(fd, FMODE_PATH, refs); +} + struct file *fget(unsigned int fd) { - return __fget(fd, FMODE_PATH); + return __fget(fd, FMODE_PATH, 1); } EXPORT_SYMBOL(fget); struct file *fget_raw(unsigned int fd) { - return __fget(fd, 0); + return __fget(fd, 0, 1); } EXPORT_SYMBOL(fget_raw); @@ -767,7 +772,7 @@ static unsigned long __fget_light(unsigned int fd, fmode_t mask) return 0; return (unsigned long)file; } else { - file = __fget(fd, mask); + file = __fget(fd, mask, 1); if (!file) return 0; return FDPUT_FPUT | (unsigned long)file; diff --git a/fs/file_table.c b/fs/file_table.c index 5679e7fcb6b0..155d7514a094 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -326,9 +326,9 @@ void flush_delayed_fput(void) static DECLARE_DELAYED_WORK(delayed_fput_work, delayed_fput); -void fput(struct file *file) +void fput_many(struct file *file, unsigned int refs) { - if (atomic_long_dec_and_test(&file->f_count)) { + if (atomic_long_sub_and_test(refs, &file->f_count)) { struct task_struct *task = current; if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) { @@ -347,6 +347,11 @@ void fput(struct file *file) } } +void fput(struct file *file) +{ + fput_many(file, 1); +} + /* * synchronous analog of fput(); for kernel threads that might be needed * in some umount() (and thus can't use flush_delayed_fput() without diff --git a/include/linux/file.h b/include/linux/file.h index 6b2fb032416c..3fcddff56bc4 100644 --- a/include/linux/file.h +++ b/include/linux/file.h @@ -13,6 +13,7 @@ struct file; extern void fput(struct file *); +extern void fput_many(struct file *, unsigned int); struct file_operations; struct vfsmount; @@ -44,6 +45,7 @@ static inline void fdput(struct fd fd) } extern struct file *fget(unsigned int fd); +extern struct file *fget_many(unsigned int fd, unsigned int refs); extern struct file *fget_raw(unsigned int fd); extern unsigned long __fdget(unsigned int fd); extern unsigned long __fdget_raw(unsigned int fd); diff --git a/include/linux/fs.h b/include/linux/fs.h index 61aa210f0c2b..80e1b199a4b1 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -952,7 +952,9 @@ static inline struct file *get_file(struct file *f) atomic_long_inc(&f->f_count); return f; } -#define get_file_rcu(x) atomic_long_inc_not_zero(&(x)->f_count) +#define get_file_rcu_many(x, cnt) \ + atomic_long_add_unless(&(x)->f_count, (cnt), 0) +#define get_file_rcu(x) get_file_rcu_many((x), 1) #define fput_atomic(x) atomic_long_add_unless(&(x)->f_count, -1, 1) #define file_count(x) atomic_long_read(&(x)->f_count) From patchwork Fri Feb 8 17:34:13 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10803497 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E8D0F922 for ; Fri, 8 Feb 2019 17:34:54 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D7D572DCD6 for ; Fri, 8 Feb 2019 17:34:54 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CC3D22DCE0; 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Fri, 08 Feb 2019 09:34:52 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id f142sm1522627itc.15.2019.02.08.09.34.50 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Feb 2019 09:34:51 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 09/19] io_uring: use fget/fput_many() for file references Date: Fri, 8 Feb 2019 10:34:13 -0700 Message-Id: <20190208173423.27014-10-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add a separate io_submit_state structure, to cache some of the things we need for IO submission. One such example is file reference batching. io_submit_state. We get as many references as the number of sqes we are submitting, and drop unused ones if we end up switching files. The assumption here is that we're usually only dealing with one fd, and if there are multiple, hopefuly they are at least somewhat ordered. Could trivially be extended to cover multiple fds, if needed. On the completion side we do the same thing, except this is trivially done just locally in io_iopoll_reap(). Signed-off-by: Jens Axboe Reviewed-by: Hannes Reinecke --- fs/io_uring.c | 142 ++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 121 insertions(+), 21 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 036230ebd33d..b7b8e9dd0c7a 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -144,6 +144,19 @@ struct io_kiocb { #define IO_PLUG_THRESHOLD 2 #define IO_IOPOLL_BATCH 8 +struct io_submit_state { + struct blk_plug plug; + + /* + * File reference cache + */ + struct file *file; + unsigned int fd; + unsigned int has_refs; + unsigned int used_refs; + unsigned int ios_left; +}; + static struct kmem_cache *req_cachep; static const struct file_operations io_uring_fops; @@ -304,9 +317,11 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events, struct list_head *done) { void *reqs[IO_IOPOLL_BATCH]; + int file_count, to_free; + struct file *file = NULL; struct io_kiocb *req; - int to_free = 0; + file_count = to_free = 0; while (!list_empty(done)) { req = list_first_entry(done, struct io_kiocb, list); list_del(&req->list); @@ -316,12 +331,28 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events, reqs[to_free++] = req; (*nr_events)++; - fput(req->rw.ki_filp); + /* + * Batched puts of the same file, to avoid dirtying the + * file usage count multiple times, if avoidable. + */ + if (!file) { + file = req->rw.ki_filp; + file_count = 1; + } else if (file == req->rw.ki_filp) { + file_count++; + } else { + fput_many(file, file_count); + file = req->rw.ki_filp; + file_count = 1; + } + if (to_free == ARRAY_SIZE(reqs)) io_free_req_many(ctx, reqs, &to_free); } io_commit_cqring(ctx); + if (file) + fput_many(file, file_count); io_free_req_many(ctx, reqs, &to_free); } @@ -502,6 +533,48 @@ static void io_iopoll_req_issued(struct io_kiocb *req) list_add_tail(&req->list, &ctx->poll_list); } +static void io_file_put(struct io_submit_state *state, struct file *file) +{ + if (!state) { + fput(file); + } else if (state->file) { + int diff = state->has_refs - state->used_refs; + + if (diff) + fput_many(state->file, diff); + state->file = NULL; + } +} + +/* + * Get as many references to a file as we have IOs left in this submission, + * assuming most submissions are for one file, or at least that each file + * has more than one submission. + */ +static struct file *io_file_get(struct io_submit_state *state, int fd) +{ + if (!state) + return fget(fd); + + if (state->file) { + if (state->fd == fd) { + state->used_refs++; + state->ios_left--; + return state->file; + } + io_file_put(state, NULL); + } + state->file = fget_many(fd, state->ios_left); + if (!state->file) + return NULL; + + state->fd = fd; + state->has_refs = state->ios_left; + state->used_refs = 1; + state->ios_left--; + return state->file; +} + /* * If we tracked the file through the SCM inflight mechanism, we could support * any file. For now, just ensure that anything potentially problematic is done @@ -520,7 +593,7 @@ static bool io_file_supports_async(struct file *file) } static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, - bool force_nonblock) + bool force_nonblock, struct io_submit_state *state) { struct io_ring_ctx *ctx = req->ctx; struct kiocb *kiocb = &req->rw; @@ -532,7 +605,7 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, return 0; fd = READ_ONCE(sqe->fd); - kiocb->ki_filp = fget(fd); + kiocb->ki_filp = io_file_get(state, fd); if (unlikely(!kiocb->ki_filp)) return -EBADF; if (force_nonblock && !io_file_supports_async(kiocb->ki_filp)) @@ -576,7 +649,10 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, } return 0; out_fput: - fput(kiocb->ki_filp); + /* in case of error, we didn't use this file reference. drop it. */ + if (state) + state->used_refs--; + io_file_put(state, kiocb->ki_filp); return ret; } @@ -622,7 +698,7 @@ static int io_import_iovec(struct io_ring_ctx *ctx, int rw, } static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s, - bool force_nonblock) + bool force_nonblock, struct io_submit_state *state) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct kiocb *kiocb = &req->rw; @@ -630,7 +706,7 @@ static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s, struct file *file; ssize_t ret; - ret = io_prep_rw(req, s->sqe, force_nonblock); + ret = io_prep_rw(req, s->sqe, force_nonblock, state); if (ret) return ret; file = kiocb->ki_filp; @@ -666,7 +742,7 @@ static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s, } static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s, - bool force_nonblock) + bool force_nonblock, struct io_submit_state *state) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct kiocb *kiocb = &req->rw; @@ -674,7 +750,7 @@ static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s, struct file *file; ssize_t ret; - ret = io_prep_rw(req, s->sqe, force_nonblock); + ret = io_prep_rw(req, s->sqe, force_nonblock, state); if (ret) return ret; /* Hold on to the file for -EAGAIN */ @@ -773,7 +849,8 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe, } static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, - const struct sqe_submit *s, bool force_nonblock) + const struct sqe_submit *s, bool force_nonblock, + struct io_submit_state *state) { ssize_t ret; int opcode; @@ -788,10 +865,10 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, ret = io_nop(req, req->user_data); break; case IORING_OP_READV: - ret = io_read(req, s, force_nonblock); + ret = io_read(req, s, force_nonblock, state); break; case IORING_OP_WRITEV: - ret = io_write(req, s, force_nonblock); + ret = io_write(req, s, force_nonblock, state); break; case IORING_OP_FSYNC: ret = io_fsync(req, s->sqe, force_nonblock); @@ -843,7 +920,7 @@ static void io_sq_wq_submit_work(struct work_struct *work) s->needs_lock = true; do { - ret = __io_submit_sqe(ctx, req, s, false); + ret = __io_submit_sqe(ctx, req, s, false, NULL); /* * We can get EAGAIN for polled IO even though we're forcing * a sync submission from here, since we can't wait for @@ -864,7 +941,8 @@ static void io_sq_wq_submit_work(struct work_struct *work) } } -static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s) +static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s, + struct io_submit_state *state) { struct io_kiocb *req; ssize_t ret; @@ -879,7 +957,7 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s) req->rw.ki_filp = NULL; - ret = __io_submit_sqe(ctx, req, s, true); + ret = __io_submit_sqe(ctx, req, s, true, state); if (ret == -EAGAIN) { memcpy(&req->submit, s, sizeof(*s)); INIT_WORK(&req->work, io_sq_wq_submit_work); @@ -892,6 +970,26 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s) return ret; } +/* + * Batched submission is done, ensure local IO is flushed out. + */ +static void io_submit_state_end(struct io_submit_state *state) +{ + blk_finish_plug(&state->plug); + io_file_put(state, NULL); +} + +/* + * Start submission side cache. + */ +static void io_submit_state_start(struct io_submit_state *state, + struct io_ring_ctx *ctx, unsigned max_ios) +{ + blk_start_plug(&state->plug); + state->file = NULL; + state->ios_left = max_ios; +} + static void io_commit_sqring(struct io_ring_ctx *ctx) { struct io_sq_ring *ring = ctx->sq_ring; @@ -954,11 +1052,13 @@ static bool io_get_sqring(struct io_ring_ctx *ctx, struct sqe_submit *s) static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit) { + struct io_submit_state state, *statep = NULL; int i, ret = 0, submit = 0; - struct blk_plug plug; - if (to_submit > IO_PLUG_THRESHOLD) - blk_start_plug(&plug); + if (to_submit > IO_PLUG_THRESHOLD) { + io_submit_state_start(&state, ctx, to_submit); + statep = &state; + } for (i = 0; i < to_submit; i++) { struct sqe_submit s; @@ -969,7 +1069,7 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit) s.has_user = true; s.needs_lock = false; - ret = io_submit_sqe(ctx, &s); + ret = io_submit_sqe(ctx, &s, statep); if (ret) { io_drop_sqring(ctx); break; @@ -979,8 +1079,8 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit) } io_commit_sqring(ctx); - if (to_submit > IO_PLUG_THRESHOLD) - blk_finish_plug(&plug); + if (statep) + io_submit_state_end(statep); return submit ? submit : ret; } From patchwork Fri Feb 8 17:34:14 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10803499 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5716C922 for ; 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Fri, 08 Feb 2019 09:34:53 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id f142sm1522627itc.15.2019.02.08.09.34.52 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Feb 2019 09:34:53 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 10/19] io_uring: batch io_kiocb allocation Date: Fri, 8 Feb 2019 10:34:14 -0700 Message-Id: <20190208173423.27014-11-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Similarly to how we use the state->ios_left to know how many references to get to a file, we can use it to allocate the io_kiocb's we need in bulk. Signed-off-by: Jens Axboe Reviewed-by: Hannes Reinecke --- fs/io_uring.c | 45 ++++++++++++++++++++++++++++++++++++++------- 1 file changed, 38 insertions(+), 7 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index b7b8e9dd0c7a..a1e764515f2b 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -147,6 +147,13 @@ struct io_kiocb { struct io_submit_state { struct blk_plug plug; + /* + * io_kiocb alloc cache + */ + void *reqs[IO_IOPOLL_BATCH]; + unsigned int free_reqs; + unsigned int cur_req; + /* * File reference cache */ @@ -277,20 +284,40 @@ static void io_ring_drop_ctx_refs(struct io_ring_ctx *ctx, unsigned refs) wake_up(&ctx->wait); } -static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx) +static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx, + struct io_submit_state *state) { struct io_kiocb *req; if (!percpu_ref_tryget(&ctx->refs)) return NULL; - req = kmem_cache_alloc(req_cachep, __GFP_NOWARN); - if (req) { - req->ctx = ctx; - req->flags = 0; - return req; + if (!state) { + req = kmem_cache_alloc(req_cachep, __GFP_NOWARN); + if (unlikely(!req)) + goto out; + } else if (!state->free_reqs) { + size_t sz; + int ret; + + sz = min_t(size_t, state->ios_left, ARRAY_SIZE(state->reqs)); + ret = kmem_cache_alloc_bulk(req_cachep, __GFP_NOWARN, sz, + state->reqs); + if (unlikely(ret <= 0)) + goto out; + state->free_reqs = ret - 1; + state->cur_req = 1; + req = state->reqs[0]; + } else { + req = state->reqs[state->cur_req]; + state->free_reqs--; + state->cur_req++; } + req->ctx = ctx; + req->flags = 0; + return req; +out: io_ring_drop_ctx_refs(ctx, 1); return NULL; } @@ -951,7 +978,7 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s, if (unlikely(s->sqe->flags)) return -EINVAL; - req = io_get_req(ctx); + req = io_get_req(ctx, state); if (unlikely(!req)) return -EAGAIN; @@ -977,6 +1004,9 @@ static void io_submit_state_end(struct io_submit_state *state) { blk_finish_plug(&state->plug); io_file_put(state, NULL); + if (state->free_reqs) + kmem_cache_free_bulk(req_cachep, state->free_reqs, + &state->reqs[state->cur_req]); } /* @@ -986,6 +1016,7 @@ static void io_submit_state_start(struct io_submit_state *state, struct io_ring_ctx *ctx, unsigned max_ios) { blk_start_plug(&state->plug); + state->free_reqs = 0; state->file = NULL; state->ios_left = max_ios; } From patchwork Fri Feb 8 17:34:15 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10803501 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 53B9F1390 for ; Fri, 8 Feb 2019 17:34:58 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 446412DCD6 for ; Fri, 8 Feb 2019 17:34:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 386BB2DCE0; Fri, 8 Feb 2019 17:34:58 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A8AC82DCD6 for ; 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Fri, 08 Feb 2019 09:34:54 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 11/19] block: implement bio helper to add iter bvec pages to bio Date: Fri, 8 Feb 2019 10:34:15 -0700 Message-Id: <20190208173423.27014-12-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP For an ITER_BVEC, we can just iterate the iov and add the pages to the bio directly. This requires that the caller doesn't releases the pages on IO completion, we add a BIO_NO_PAGE_REF flag for that. The current two callers of bio_iov_iter_get_pages() are updated to check if they need to release pages on completion. This makes them work with bvecs that contain kernel mapped pages already. Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe Reviewed-by: Hannes Reinecke --- block/bio.c | 59 ++++++++++++++++++++++++++++++++------- fs/block_dev.c | 5 ++-- fs/iomap.c | 5 ++-- include/linux/blk_types.h | 1 + 4 files changed, 56 insertions(+), 14 deletions(-) diff --git a/block/bio.c b/block/bio.c index 4db1008309ed..330df572cfb8 100644 --- a/block/bio.c +++ b/block/bio.c @@ -828,6 +828,23 @@ int bio_add_page(struct bio *bio, struct page *page, } EXPORT_SYMBOL(bio_add_page); +static int __bio_iov_bvec_add_pages(struct bio *bio, struct iov_iter *iter) +{ + const struct bio_vec *bv = iter->bvec; + unsigned int len; + size_t size; + + len = min_t(size_t, bv->bv_len, iter->count); + size = bio_add_page(bio, bv->bv_page, len, + bv->bv_offset + iter->iov_offset); + if (size == len) { + iov_iter_advance(iter, size); + return 0; + } + + return -EINVAL; +} + #define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *)) /** @@ -876,23 +893,43 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) } /** - * bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio + * bio_iov_iter_get_pages - add user or kernel pages to a bio * @bio: bio to add pages to - * @iter: iov iterator describing the region to be mapped + * @iter: iov iterator describing the region to be added + * + * This takes either an iterator pointing to user memory, or one pointing to + * kernel pages (BVEC iterator). If we're adding user pages, we pin them and + * map them into the kernel. On IO completion, the caller should put those + * pages. If we're adding kernel pages, we just have to add the pages to the + * bio directly. We don't grab an extra reference to those pages (the user + * should already have that), and we don't put the page on IO completion. + * The caller needs to check if the bio is flagged BIO_NO_PAGE_REF on IO + * completion. If it isn't, then pages should be released. * - * Pins pages from *iter and appends them to @bio's bvec array. The - * pages will have to be released using put_page() when done. * The function tries, but does not guarantee, to pin as many pages as - * fit into the bio, or are requested in *iter, whatever is smaller. - * If MM encounters an error pinning the requested pages, it stops. - * Error is returned only if 0 pages could be pinned. + * fit into the bio, or are requested in *iter, whatever is smaller. If + * MM encounters an error pinning the requested pages, it stops. Error + * is returned only if 0 pages could be pinned. */ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) { + const bool is_bvec = iov_iter_is_bvec(iter); unsigned short orig_vcnt = bio->bi_vcnt; + /* + * If this is a BVEC iter, then the pages are kernel pages. Don't + * release them on IO completion. + */ + if (is_bvec) + bio_set_flag(bio, BIO_NO_PAGE_REF); + do { - int ret = __bio_iov_iter_get_pages(bio, iter); + int ret; + + if (is_bvec) + ret = __bio_iov_bvec_add_pages(bio, iter); + else + ret = __bio_iov_iter_get_pages(bio, iter); if (unlikely(ret)) return bio->bi_vcnt > orig_vcnt ? 0 : ret; @@ -1634,7 +1671,8 @@ static void bio_dirty_fn(struct work_struct *work) next = bio->bi_private; bio_set_pages_dirty(bio); - bio_release_pages(bio); + if (!bio_flagged(bio, BIO_NO_PAGE_REF)) + bio_release_pages(bio); bio_put(bio); } } @@ -1650,7 +1688,8 @@ void bio_check_pages_dirty(struct bio *bio) goto defer; } - bio_release_pages(bio); + if (!bio_flagged(bio, BIO_NO_PAGE_REF)) + bio_release_pages(bio); bio_put(bio); return; defer: diff --git a/fs/block_dev.c b/fs/block_dev.c index 392e2bfb636f..051ab41d1c61 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -338,8 +338,9 @@ static void blkdev_bio_end_io(struct bio *bio) struct bio_vec *bvec; int i; - bio_for_each_segment_all(bvec, bio, i) - put_page(bvec->bv_page); + if (!bio_flagged(bio, BIO_NO_PAGE_REF)) + bio_for_each_segment_all(bvec, bio, i) + put_page(bvec->bv_page); bio_put(bio); } } diff --git a/fs/iomap.c b/fs/iomap.c index 2ac9eb746d44..9389cf0a1c6f 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -1591,8 +1591,9 @@ static void iomap_dio_bio_end_io(struct bio *bio) struct bio_vec *bvec; int i; - bio_for_each_segment_all(bvec, bio, i) - put_page(bvec->bv_page); + if (!bio_flagged(bio, BIO_NO_PAGE_REF)) + bio_for_each_segment_all(bvec, bio, i) + put_page(bvec->bv_page); bio_put(bio); } } diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index d66bf5f32610..791fee35df88 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -215,6 +215,7 @@ struct bio { /* * bio flags */ +#define BIO_NO_PAGE_REF 0 /* don't put release vec pages */ #define BIO_SEG_VALID 1 /* bi_phys_segments valid */ #define BIO_CLONED 2 /* doesn't own data */ #define BIO_BOUNCED 3 /* bio is a bounce bio */ From patchwork Fri Feb 8 17:34:16 2019 Content-Type: text/plain; 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Fri, 08 Feb 2019 09:34:56 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 12/19] io_uring: add support for pre-mapped user IO buffers Date: Fri, 8 Feb 2019 10:34:16 -0700 Message-Id: <20190208173423.27014-13-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If we have fixed user buffers, we can map them into the kernel when we setup the io_uring. That avoids the need to do get_user_pages() for each and every IO. To utilize this feature, the application must call io_uring_register() after having setup an io_uring instance, passing in IORING_REGISTER_BUFFERS as the opcode. The argument must be a pointer to an iovec array, and the nr_args should contain how many iovecs the application wishes to map. If successful, these buffers are now mapped into the kernel, eligible for IO. To use these fixed buffers, the application must use the IORING_OP_READ_FIXED and IORING_OP_WRITE_FIXED opcodes, and then set sqe->index to the desired buffer index. sqe->addr..sqe->addr+seq->len must point to somewhere inside the indexed buffer. The application may register buffers throughout the lifetime of the io_uring instance. It can call io_uring_register() with IORING_UNREGISTER_BUFFERS as the opcode to unregister the current set of buffers, and then register a new set. The application need not unregister buffers explicitly before shutting down the io_uring instance. It's perfectly valid to setup a larger buffer, and then sometimes only use parts of it for an IO. As long as the range is within the originally mapped region, it will work just fine. For now, buffers must not be file backed. If file backed buffers are passed in, the registration will fail with -1/EOPNOTSUPP. This restriction may be relaxed in the future. RLIMIT_MEMLOCK is used to check how much memory we can pin. A somewhat arbitrary 1G per buffer size is also imposed. Signed-off-by: Jens Axboe Reviewed-by: Hannes Reinecke --- arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + fs/io_uring.c | 356 ++++++++++++++++++++++++- include/linux/sched/user.h | 2 +- include/linux/syscalls.h | 2 + include/uapi/asm-generic/unistd.h | 4 +- include/uapi/linux/io_uring.h | 13 +- kernel/sys_ni.c | 1 + 8 files changed, 363 insertions(+), 17 deletions(-) diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index 481c126259e9..2eefd2a7c1ce 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -400,3 +400,4 @@ 386 i386 rseq sys_rseq __ia32_sys_rseq 425 i386 io_uring_setup sys_io_uring_setup __ia32_sys_io_uring_setup 426 i386 io_uring_enter sys_io_uring_enter __ia32_sys_io_uring_enter +427 i386 io_uring_register sys_io_uring_register __ia32_sys_io_uring_register diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 6a32a430c8e0..65c026185e61 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -345,6 +345,7 @@ 334 common rseq __x64_sys_rseq 425 common io_uring_setup __x64_sys_io_uring_setup 426 common io_uring_enter __x64_sys_io_uring_enter +427 common io_uring_register __x64_sys_io_uring_register # # x32-specific system call numbers start at 512 to avoid cache impact diff --git a/fs/io_uring.c b/fs/io_uring.c index a1e764515f2b..50c48e43d56e 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include #include @@ -32,6 +33,8 @@ #include #include #include +#include +#include #include @@ -61,6 +64,13 @@ struct io_cq_ring { struct io_uring_cqe cqes[]; }; +struct io_mapped_ubuf { + u64 ubuf; + size_t len; + struct bio_vec *bvec; + unsigned int nr_bvecs; +}; + struct io_ring_ctx { struct { struct percpu_ref refs; @@ -92,6 +102,10 @@ struct io_ring_ctx { struct fasync_struct *cq_fasync; } ____cacheline_aligned_in_smp; + /* if used, fixed mapped user buffers */ + unsigned nr_user_bufs; + struct io_mapped_ubuf *user_bufs; + struct user_struct *user; struct completion ctx_done; @@ -704,6 +718,44 @@ static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) } } +static int io_import_fixed(struct io_ring_ctx *ctx, int rw, + const struct io_uring_sqe *sqe, + struct iov_iter *iter) +{ + size_t len = READ_ONCE(sqe->len); + struct io_mapped_ubuf *imu; + unsigned index, buf_index; + size_t offset; + u64 buf_addr; + + /* attempt to use fixed buffers without having provided iovecs */ + if (unlikely(!ctx->user_bufs)) + return -EFAULT; + + buf_index = READ_ONCE(sqe->buf_index); + if (unlikely(buf_index >= ctx->nr_user_bufs)) + return -EFAULT; + + index = array_index_nospec(buf_index, ctx->nr_user_bufs); + imu = &ctx->user_bufs[index]; + buf_addr = READ_ONCE(sqe->addr); + + if (buf_addr + len < buf_addr) + return -EFAULT; + if (buf_addr < imu->ubuf || buf_addr + len > imu->ubuf + imu->len) + return -EFAULT; + + /* + * May not be a start of buffer, set size appropriately + * and advance us to the beginning. + */ + offset = buf_addr - imu->ubuf; + iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len); + if (offset) + iov_iter_advance(iter, offset); + return 0; +} + static int io_import_iovec(struct io_ring_ctx *ctx, int rw, const struct sqe_submit *s, struct iovec **iovec, struct iov_iter *iter) @@ -711,6 +763,15 @@ static int io_import_iovec(struct io_ring_ctx *ctx, int rw, const struct io_uring_sqe *sqe = s->sqe; void __user *buf = u64_to_user_ptr(READ_ONCE(sqe->addr)); size_t sqe_len = READ_ONCE(sqe->len); + u8 opcode; + + opcode = READ_ONCE(sqe->opcode); + if (opcode == IORING_OP_READ_FIXED || + opcode == IORING_OP_WRITE_FIXED) { + ssize_t ret = io_import_fixed(ctx, rw, sqe, iter); + *iovec = NULL; + return ret; + } if (!s->has_user) return EFAULT; @@ -854,7 +915,7 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe, if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; - if (unlikely(sqe->addr || sqe->ioprio)) + if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index)) return -EINVAL; fsync_flags = READ_ONCE(sqe->fsync_flags); @@ -892,9 +953,19 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, ret = io_nop(req, req->user_data); break; case IORING_OP_READV: + if (unlikely(s->sqe->buf_index)) + return -EINVAL; ret = io_read(req, s, force_nonblock, state); break; case IORING_OP_WRITEV: + if (unlikely(s->sqe->buf_index)) + return -EINVAL; + ret = io_write(req, s, force_nonblock, state); + break; + case IORING_OP_READ_FIXED: + ret = io_read(req, s, force_nonblock, state); + break; + case IORING_OP_WRITE_FIXED: ret = io_write(req, s, force_nonblock, state); break; case IORING_OP_FSYNC: @@ -923,28 +994,47 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, return 0; } +static inline bool io_sqe_needs_user(const struct io_uring_sqe *sqe) +{ + u8 opcode = READ_ONCE(sqe->opcode); + + return !(opcode == IORING_OP_READ_FIXED || + opcode == IORING_OP_WRITE_FIXED); +} + static void io_sq_wq_submit_work(struct work_struct *work) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); struct sqe_submit *s = &req->submit; - u64 user_data = READ_ONCE(s->sqe->user_data); struct io_ring_ctx *ctx = req->ctx; - mm_segment_t old_fs = get_fs(); + mm_segment_t old_fs; + bool needs_user; + u64 user_data; int ret; /* Ensure we clear previously set forced non-block flag */ req->flags &= ~REQ_F_FORCE_NONBLOCK; req->rw.ki_flags &= ~IOCB_NOWAIT; - if (!mmget_not_zero(ctx->sqo_mm)) { - ret = -EFAULT; - goto err; - } - - use_mm(ctx->sqo_mm); - set_fs(USER_DS); - s->has_user = true; + user_data = READ_ONCE(s->sqe->user_data); s->needs_lock = true; + s->has_user = false; + + /* + * If we're doing IO to fixed buffers, we don't need to get/set + * user context + */ + needs_user = io_sqe_needs_user(s->sqe); + if (needs_user) { + if (!mmget_not_zero(ctx->sqo_mm)) { + ret = -EFAULT; + goto err; + } + use_mm(ctx->sqo_mm); + old_fs = get_fs(); + set_fs(USER_DS); + s->has_user = true; + } do { ret = __io_submit_sqe(ctx, req, s, false, NULL); @@ -958,9 +1048,11 @@ static void io_sq_wq_submit_work(struct work_struct *work) cond_resched(); } while (1); - set_fs(old_fs); - unuse_mm(ctx->sqo_mm); - mmput(ctx->sqo_mm); + if (needs_user) { + set_fs(old_fs); + unuse_mm(ctx->sqo_mm); + mmput(ctx->sqo_mm); + } err: if (ret) { io_cqring_add_event(ctx, user_data, ret, 0); @@ -1242,6 +1334,187 @@ static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries) return (bytes + PAGE_SIZE - 1) / PAGE_SIZE; } +static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx) +{ + int i, j; + + if (!ctx->user_bufs) + return -ENXIO; + + for (i = 0; i < ctx->sq_entries; i++) { + struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; + + for (j = 0; j < imu->nr_bvecs; j++) + put_page(imu->bvec[j].bv_page); + + io_unaccount_mem(ctx->user, imu->nr_bvecs); + kfree(imu->bvec); + imu->nr_bvecs = 0; + } + + kfree(ctx->user_bufs); + ctx->user_bufs = NULL; + return 0; +} + +static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst, + void __user *arg, unsigned index) +{ + struct iovec __user *src; + +#ifdef CONFIG_COMPAT + if (ctx->compat) { + struct compat_iovec __user *ciovs; + struct compat_iovec ciov; + + ciovs = (struct compat_iovec __user *) arg; + if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov))) + return -EFAULT; + + dst->iov_base = (void __user *) (unsigned long) ciov.iov_base; + dst->iov_len = ciov.iov_len; + return 0; + } +#endif + src = (struct iovec __user *) arg; + if (copy_from_user(dst, &src[index], sizeof(*dst))) + return -EFAULT; + return 0; +} + +static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg, + unsigned nr_args) +{ + struct vm_area_struct **vmas = NULL; + struct page **pages = NULL; + int i, j, got_pages = 0; + int ret = -EINVAL; + + if (ctx->user_bufs) + return -EBUSY; + if (!nr_args || nr_args > UIO_MAXIOV) + return -EINVAL; + + ctx->user_bufs = kcalloc(nr_args, sizeof(struct io_mapped_ubuf), + GFP_KERNEL); + if (!ctx->user_bufs) + return -ENOMEM; + + for (i = 0; i < nr_args; i++) { + struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; + unsigned long off, start, end, ubuf; + int pret, nr_pages; + struct iovec iov; + size_t size; + + ret = io_copy_iov(ctx, &iov, arg, i); + if (ret) + break; + + /* + * Don't impose further limits on the size and buffer + * constraints here, we'll -EINVAL later when IO is + * submitted if they are wrong. + */ + ret = -EFAULT; + if (!iov.iov_base || !iov.iov_len) + goto err; + + /* arbitrary limit, but we need something */ + if (iov.iov_len > SZ_1G) + goto err; + + ubuf = (unsigned long) iov.iov_base; + end = (ubuf + iov.iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT; + start = ubuf >> PAGE_SHIFT; + nr_pages = end - start; + + ret = io_account_mem(ctx->user, nr_pages); + if (ret) + goto err; + + if (!pages || nr_pages > got_pages) { + kfree(vmas); + kfree(pages); + pages = kmalloc_array(nr_pages, sizeof(struct page *), + GFP_KERNEL); + vmas = kmalloc_array(nr_pages, + sizeof(struct vma_area_struct *), + GFP_KERNEL); + if (!pages || !vmas) { + ret = -ENOMEM; + io_unaccount_mem(ctx->user, nr_pages); + goto err; + } + got_pages = nr_pages; + } + + imu->bvec = kmalloc_array(nr_pages, sizeof(struct bio_vec), + GFP_KERNEL); + if (!imu->bvec) { + io_unaccount_mem(ctx->user, nr_pages); + goto err; + } + + down_write(¤t->mm->mmap_sem); + pret = get_user_pages_longterm(ubuf, nr_pages, FOLL_WRITE, + pages, vmas); + if (pret == nr_pages) { + /* don't support file backed memory */ + for (j = 0; j < nr_pages; j++) { + struct vm_area_struct *vma = vmas[j]; + + if (vma->vm_file && + !is_file_hugepages(vma->vm_file)) { + ret = -EOPNOTSUPP; + break; + } + } + } else { + ret = pret < 0 ? pret : -EFAULT; + } + up_write(¤t->mm->mmap_sem); + if (ret) { + /* + * if we did partial map, or found file backed vmas, + * release any pages we did get + */ + if (pret > 0) { + for (j = 0; j < pret; j++) + put_page(pages[j]); + } + io_unaccount_mem(ctx->user, nr_pages); + goto err; + } + + off = ubuf & ~PAGE_MASK; + size = iov.iov_len; + for (j = 0; j < nr_pages; j++) { + size_t vec_len; + + vec_len = min_t(size_t, size, PAGE_SIZE - off); + imu->bvec[j].bv_page = pages[j]; + imu->bvec[j].bv_len = vec_len; + imu->bvec[j].bv_offset = off; + off = 0; + size -= vec_len; + } + /* store original address for later verification */ + imu->ubuf = ubuf; + imu->len = iov.iov_len; + imu->nr_bvecs = nr_pages; + } + kfree(pages); + kfree(vmas); + ctx->nr_user_bufs = nr_args; + return 0; +err: + kfree(pages); + kfree(vmas); + io_sqe_buffer_unregister(ctx); + return ret; +} + static void io_ring_ctx_free(struct io_ring_ctx *ctx) { if (ctx->sqo_wq) @@ -1254,6 +1527,7 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx) #endif io_iopoll_reap_events(ctx); + io_sqe_buffer_unregister(ctx); io_mem_free(ctx->sq_ring); io_mem_free(ctx->sq_sqes); @@ -1594,6 +1868,60 @@ SYSCALL_DEFINE2(io_uring_setup, u32, entries, return io_uring_setup(entries, params); } +static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, + void __user *arg, unsigned nr_args) +{ + int ret; + + percpu_ref_kill(&ctx->refs); + wait_for_completion(&ctx->ctx_done); + + switch (opcode) { + case IORING_REGISTER_BUFFERS: + ret = io_sqe_buffer_register(ctx, arg, nr_args); + break; + case IORING_UNREGISTER_BUFFERS: + ret = -EINVAL; + if (arg || nr_args) + break; + ret = io_sqe_buffer_unregister(ctx); + break; + default: + ret = -EINVAL; + break; + } + + /* bring the ctx back to life */ + reinit_completion(&ctx->ctx_done); + percpu_ref_reinit(&ctx->refs); + return ret; +} + +SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode, + void __user *, arg, unsigned int, nr_args) +{ + struct io_ring_ctx *ctx; + long ret = -EBADF; + struct fd f; + + f = fdget(fd); + if (!f.file) + return -EBADF; + + ret = -EOPNOTSUPP; + if (f.file->f_op != &io_uring_fops) + goto out_fput; + + ctx = f.file->private_data; + + mutex_lock(&ctx->uring_lock); + ret = __io_uring_register(ctx, opcode, arg, nr_args); + mutex_unlock(&ctx->uring_lock); +out_fput: + fdput(f); + return ret; +} + static int __init io_uring_init(void) { req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC); diff --git a/include/linux/sched/user.h b/include/linux/sched/user.h index 39ad98c09c58..c7b5f86b91a1 100644 --- a/include/linux/sched/user.h +++ b/include/linux/sched/user.h @@ -40,7 +40,7 @@ struct user_struct { kuid_t uid; #if defined(CONFIG_PERF_EVENTS) || defined(CONFIG_BPF_SYSCALL) || \ - defined(CONFIG_NET) + defined(CONFIG_NET) || defined(CONFIG_IO_URING) atomic_long_t locked_vm; #endif diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 3072dbaa7869..3681c05ac538 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -315,6 +315,8 @@ asmlinkage long sys_io_uring_setup(u32 entries, asmlinkage long sys_io_uring_enter(unsigned int fd, u32 to_submit, u32 min_complete, u32 flags, const sigset_t __user *sig, size_t sigsz); +asmlinkage long sys_io_uring_register(unsigned int fd, unsigned int op, + void __user *arg, unsigned int nr_args); /* fs/xattr.c */ asmlinkage long sys_setxattr(const char __user *path, const char __user *name, diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index 87871e7b7ea7..d346229a1eb0 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -744,9 +744,11 @@ __SYSCALL(__NR_kexec_file_load, sys_kexec_file_load) __SYSCALL(__NR_io_uring_setup, sys_io_uring_setup) #define __NR_io_uring_enter 426 __SYSCALL(__NR_io_uring_enter, sys_io_uring_enter) +#define __NR_io_uring_register 427 +__SYSCALL(__NR_io_uring_register, sys_io_uring_register) #undef __NR_syscalls -#define __NR_syscalls 427 +#define __NR_syscalls 428 /* * 32 bit systems traditionally used different diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 5c457ea396e6..cf28f7a11f12 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -27,7 +27,10 @@ struct io_uring_sqe { __u32 fsync_flags; }; __u64 user_data; /* data to be passed back at completion time */ - __u64 __pad2[3]; + union { + __u16 buf_index; /* index into fixed buffers, if used */ + __u64 __pad2[3]; + }; }; /* @@ -39,6 +42,8 @@ struct io_uring_sqe { #define IORING_OP_READV 1 #define IORING_OP_WRITEV 2 #define IORING_OP_FSYNC 3 +#define IORING_OP_READ_FIXED 4 +#define IORING_OP_WRITE_FIXED 5 /* * sqe->fsync_flags @@ -103,4 +108,10 @@ struct io_uring_params { struct io_cqring_offsets cq_off; }; +/* + * io_uring_register(2) opcodes and arguments + */ +#define IORING_REGISTER_BUFFERS 0 +#define IORING_UNREGISTER_BUFFERS 1 + #endif diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index ee5e523564bb..1bb6604dc19f 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -48,6 +48,7 @@ COND_SYSCALL_COMPAT(io_getevents); COND_SYSCALL_COMPAT(io_pgetevents); COND_SYSCALL(io_uring_setup); COND_SYSCALL(io_uring_enter); +COND_SYSCALL(io_uring_register); /* fs/xattr.c */ From patchwork Fri Feb 8 17:34:17 2019 Content-Type: text/plain; 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Fri, 08 Feb 2019 09:34:58 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe , netdev@vger.kernel.org, "David S . Miller" Subject: [PATCH 13/19] net: split out functions related to registering inflight socket files Date: Fri, 8 Feb 2019 10:34:17 -0700 Message-Id: <20190208173423.27014-14-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We need this functionality for the io_uring file registration, but we cannot rely on it since CONFIG_UNIX can be modular. Move the helpers to a separate file, that's always builtin to the kernel if CONFIG_UNIX is m/y. No functional changes in this patch, just moving code around. Cc: netdev@vger.kernel.org Cc: David S. Miller Signed-off-by: Jens Axboe Acked-by: David S. Miller Reviewed-by: Hannes Reinecke --- include/net/af_unix.h | 1 + net/unix/Kconfig | 5 ++ net/unix/Makefile | 2 + net/unix/af_unix.c | 63 +----------------- net/unix/garbage.c | 71 +------------------- net/unix/scm.c | 146 ++++++++++++++++++++++++++++++++++++++++++ net/unix/scm.h | 10 +++ 7 files changed, 168 insertions(+), 130 deletions(-) create mode 100644 net/unix/scm.c create mode 100644 net/unix/scm.h diff --git a/include/net/af_unix.h b/include/net/af_unix.h index ddbba838d048..3426d6dacc45 100644 --- a/include/net/af_unix.h +++ b/include/net/af_unix.h @@ -10,6 +10,7 @@ void unix_inflight(struct user_struct *user, struct file *fp); void unix_notinflight(struct user_struct *user, struct file *fp); +void unix_destruct_scm(struct sk_buff *skb); void unix_gc(void); void wait_for_unix_gc(void); struct sock *unix_get_socket(struct file *filp); diff --git a/net/unix/Kconfig b/net/unix/Kconfig index 8b31ab85d050..3b9e450656a4 100644 --- a/net/unix/Kconfig +++ b/net/unix/Kconfig @@ -19,6 +19,11 @@ config UNIX Say Y unless you know what you are doing. +config UNIX_SCM + bool + depends on UNIX + default y + config UNIX_DIAG tristate "UNIX: socket monitoring interface" depends on UNIX diff --git a/net/unix/Makefile b/net/unix/Makefile index ffd0a275c3a7..54e58cc4f945 100644 --- a/net/unix/Makefile +++ b/net/unix/Makefile @@ -10,3 +10,5 @@ unix-$(CONFIG_SYSCTL) += sysctl_net_unix.o obj-$(CONFIG_UNIX_DIAG) += unix_diag.o unix_diag-y := diag.o + +obj-$(CONFIG_UNIX_SCM) += scm.o diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 74d1eed7cbd4..2ce32dbb2feb 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -119,6 +119,8 @@ #include #include +#include "scm.h" + struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE]; EXPORT_SYMBOL_GPL(unix_socket_table); DEFINE_SPINLOCK(unix_table_lock); @@ -1486,67 +1488,6 @@ static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer) return err; } -static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb) -{ - int i; - - scm->fp = UNIXCB(skb).fp; - UNIXCB(skb).fp = NULL; - - for (i = scm->fp->count-1; i >= 0; i--) - unix_notinflight(scm->fp->user, scm->fp->fp[i]); -} - -static void unix_destruct_scm(struct sk_buff *skb) -{ - struct scm_cookie scm; - memset(&scm, 0, sizeof(scm)); - scm.pid = UNIXCB(skb).pid; - if (UNIXCB(skb).fp) - unix_detach_fds(&scm, skb); - - /* Alas, it calls VFS */ - /* So fscking what? fput() had been SMP-safe since the last Summer */ - scm_destroy(&scm); - sock_wfree(skb); -} - -/* - * The "user->unix_inflight" variable is protected by the garbage - * collection lock, and we just read it locklessly here. If you go - * over the limit, there might be a tiny race in actually noticing - * it across threads. Tough. - */ -static inline bool too_many_unix_fds(struct task_struct *p) -{ - struct user_struct *user = current_user(); - - if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE))) - return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN); - return false; -} - -static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) -{ - int i; - - if (too_many_unix_fds(current)) - return -ETOOMANYREFS; - - /* - * Need to duplicate file references for the sake of garbage - * collection. Otherwise a socket in the fps might become a - * candidate for GC while the skb is not yet queued. - */ - UNIXCB(skb).fp = scm_fp_dup(scm->fp); - if (!UNIXCB(skb).fp) - return -ENOMEM; - - for (i = scm->fp->count - 1; i >= 0; i--) - unix_inflight(scm->fp->user, scm->fp->fp[i]); - return 0; -} - static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds) { int err = 0; diff --git a/net/unix/garbage.c b/net/unix/garbage.c index f81854d74c7d..8bbe1b8e4ff7 100644 --- a/net/unix/garbage.c +++ b/net/unix/garbage.c @@ -86,80 +86,13 @@ #include #include +#include "scm.h" + /* Internal data structures and random procedures: */ -static LIST_HEAD(gc_inflight_list); static LIST_HEAD(gc_candidates); -static DEFINE_SPINLOCK(unix_gc_lock); static DECLARE_WAIT_QUEUE_HEAD(unix_gc_wait); -unsigned int unix_tot_inflight; - -struct sock *unix_get_socket(struct file *filp) -{ - struct sock *u_sock = NULL; - struct inode *inode = file_inode(filp); - - /* Socket ? */ - if (S_ISSOCK(inode->i_mode) && !(filp->f_mode & FMODE_PATH)) { - struct socket *sock = SOCKET_I(inode); - struct sock *s = sock->sk; - - /* PF_UNIX ? */ - if (s && sock->ops && sock->ops->family == PF_UNIX) - u_sock = s; - } else { - /* Could be an io_uring instance */ - u_sock = io_uring_get_socket(filp); - } - return u_sock; -} - -/* Keep the number of times in flight count for the file - * descriptor if it is for an AF_UNIX socket. - */ - -void unix_inflight(struct user_struct *user, struct file *fp) -{ - struct sock *s = unix_get_socket(fp); - - spin_lock(&unix_gc_lock); - - if (s) { - struct unix_sock *u = unix_sk(s); - - if (atomic_long_inc_return(&u->inflight) == 1) { - BUG_ON(!list_empty(&u->link)); - list_add_tail(&u->link, &gc_inflight_list); - } else { - BUG_ON(list_empty(&u->link)); - } - unix_tot_inflight++; - } - user->unix_inflight++; - spin_unlock(&unix_gc_lock); -} - -void unix_notinflight(struct user_struct *user, struct file *fp) -{ - struct sock *s = unix_get_socket(fp); - - spin_lock(&unix_gc_lock); - - if (s) { - struct unix_sock *u = unix_sk(s); - - BUG_ON(!atomic_long_read(&u->inflight)); - BUG_ON(list_empty(&u->link)); - - if (atomic_long_dec_and_test(&u->inflight)) - list_del_init(&u->link); - unix_tot_inflight--; - } - user->unix_inflight--; - spin_unlock(&unix_gc_lock); -} - static void scan_inflight(struct sock *x, void (*func)(struct unix_sock *), struct sk_buff_head *hitlist) { diff --git a/net/unix/scm.c b/net/unix/scm.c new file mode 100644 index 000000000000..ed1624588934 --- /dev/null +++ b/net/unix/scm.c @@ -0,0 +1,146 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "scm.h" + +unsigned int unix_tot_inflight; + +LIST_HEAD(gc_inflight_list); +DEFINE_SPINLOCK(unix_gc_lock); + +struct sock *unix_get_socket(struct file *filp) +{ + struct sock *u_sock = NULL; + struct inode *inode = file_inode(filp); + + /* Socket ? */ + if (S_ISSOCK(inode->i_mode) && !(filp->f_mode & FMODE_PATH)) { + struct socket *sock = SOCKET_I(inode); + struct sock *s = sock->sk; + + /* PF_UNIX ? */ + if (s && sock->ops && sock->ops->family == PF_UNIX) + u_sock = s; + } else { + /* Could be an io_uring instance */ + u_sock = io_uring_get_socket(filp); + } + return u_sock; +} +EXPORT_SYMBOL(unix_get_socket); + +/* Keep the number of times in flight count for the file + * descriptor if it is for an AF_UNIX socket. + */ +void unix_inflight(struct user_struct *user, struct file *fp) +{ + struct sock *s = unix_get_socket(fp); + + spin_lock(&unix_gc_lock); + + if (s) { + struct unix_sock *u = unix_sk(s); + + if (atomic_long_inc_return(&u->inflight) == 1) { + BUG_ON(!list_empty(&u->link)); + list_add_tail(&u->link, &gc_inflight_list); + } else { + BUG_ON(list_empty(&u->link)); + } + unix_tot_inflight++; + } + user->unix_inflight++; + spin_unlock(&unix_gc_lock); +} + +void unix_notinflight(struct user_struct *user, struct file *fp) +{ + struct sock *s = unix_get_socket(fp); + + spin_lock(&unix_gc_lock); + + if (s) { + struct unix_sock *u = unix_sk(s); + + BUG_ON(!atomic_long_read(&u->inflight)); + BUG_ON(list_empty(&u->link)); + + if (atomic_long_dec_and_test(&u->inflight)) + list_del_init(&u->link); + unix_tot_inflight--; + } + user->unix_inflight--; + spin_unlock(&unix_gc_lock); +} + +/* + * The "user->unix_inflight" variable is protected by the garbage + * collection lock, and we just read it locklessly here. If you go + * over the limit, there might be a tiny race in actually noticing + * it across threads. Tough. + */ +static inline bool too_many_unix_fds(struct task_struct *p) +{ + struct user_struct *user = current_user(); + + if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE))) + return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN); + return false; +} + +int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) +{ + int i; + + if (too_many_unix_fds(current)) + return -ETOOMANYREFS; + + /* + * Need to duplicate file references for the sake of garbage + * collection. Otherwise a socket in the fps might become a + * candidate for GC while the skb is not yet queued. + */ + UNIXCB(skb).fp = scm_fp_dup(scm->fp); + if (!UNIXCB(skb).fp) + return -ENOMEM; + + for (i = scm->fp->count - 1; i >= 0; i--) + unix_inflight(scm->fp->user, scm->fp->fp[i]); + return 0; +} +EXPORT_SYMBOL(unix_attach_fds); + +void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb) +{ + int i; + + scm->fp = UNIXCB(skb).fp; + UNIXCB(skb).fp = NULL; + + for (i = scm->fp->count-1; i >= 0; i--) + unix_notinflight(scm->fp->user, scm->fp->fp[i]); +} +EXPORT_SYMBOL(unix_detach_fds); + +void unix_destruct_scm(struct sk_buff *skb) +{ + struct scm_cookie scm; + + memset(&scm, 0, sizeof(scm)); + scm.pid = UNIXCB(skb).pid; + if (UNIXCB(skb).fp) + unix_detach_fds(&scm, skb); + + /* Alas, it calls VFS */ + /* So fscking what? fput() had been SMP-safe since the last Summer */ + scm_destroy(&scm); + sock_wfree(skb); +} diff --git a/net/unix/scm.h b/net/unix/scm.h new file mode 100644 index 000000000000..5a255a477f16 --- /dev/null +++ b/net/unix/scm.h @@ -0,0 +1,10 @@ +#ifndef NET_UNIX_SCM_H +#define NET_UNIX_SCM_H + +extern struct list_head gc_inflight_list; +extern spinlock_t unix_gc_lock; + +int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb); +void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb); + +#endif From patchwork Fri Feb 8 17:34:18 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10803507 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B093B1390 for ; Fri, 8 Feb 2019 17:35:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A125A2DCD6 for ; Fri, 8 Feb 2019 17:35:05 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9503D2DCDD; Fri, 8 Feb 2019 17:35:05 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B05A42DCE1 for ; 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Fri, 08 Feb 2019 09:35:00 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 14/19] io_uring: add file set registration Date: Fri, 8 Feb 2019 10:34:18 -0700 Message-Id: <20190208173423.27014-15-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We normally have to fget/fput for each IO we do on a file. Even with the batching we do, the cost of the atomic inc/dec of the file usage count adds up. This adds IORING_REGISTER_FILES, and IORING_UNREGISTER_FILES opcodes for the io_uring_register(2) system call. The arguments passed in must be an array of __s32 holding file descriptors, and nr_args should hold the number of file descriptors the application wishes to pin for the duration of the io_uring instance (or until IORING_UNREGISTER_FILES is called). When used, the application must set IOSQE_FIXED_FILE in the sqe->flags member. Then, instead of setting sqe->fd to the real fd, it sets sqe->fd to the index in the array passed in to IORING_REGISTER_FILES. Files are automatically unregistered when the io_uring instance is torn down. An application need only unregister if it wishes to register a new set of fds. Signed-off-by: Jens Axboe Reviewed-by: Hannes Reinecke --- fs/io_uring.c | 256 ++++++++++++++++++++++++++++++---- include/uapi/linux/io_uring.h | 9 +- 2 files changed, 235 insertions(+), 30 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 50c48e43d56e..244fb71e3424 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include #include @@ -41,6 +42,7 @@ #include "internal.h" #define IORING_MAX_ENTRIES 4096 +#define IORING_MAX_FIXED_FILES 1024 struct io_uring { u32 head ____cacheline_aligned_in_smp; @@ -102,6 +104,14 @@ struct io_ring_ctx { struct fasync_struct *cq_fasync; } ____cacheline_aligned_in_smp; + /* + * If used, fixed file set. Writers must ensure that ->refs is dead, + * readers must ensure that ->refs is alive as long as the file* is + * used. Only updated through io_uring_register(2). + */ + struct file **user_files; + unsigned nr_user_files; + /* if used, fixed mapped user buffers */ unsigned nr_user_bufs; struct io_mapped_ubuf *user_bufs; @@ -149,6 +159,7 @@ struct io_kiocb { unsigned int flags; #define REQ_F_FORCE_NONBLOCK 1 /* inline submission attempt */ #define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */ +#define REQ_F_FIXED_FILE 4 /* ctx owns file */ u64 user_data; u64 error; @@ -376,15 +387,17 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events, * Batched puts of the same file, to avoid dirtying the * file usage count multiple times, if avoidable. */ - if (!file) { - file = req->rw.ki_filp; - file_count = 1; - } else if (file == req->rw.ki_filp) { - file_count++; - } else { - fput_many(file, file_count); - file = req->rw.ki_filp; - file_count = 1; + if (!(req->flags & REQ_F_FIXED_FILE)) { + if (!file) { + file = req->rw.ki_filp; + file_count = 1; + } else if (file == req->rw.ki_filp) { + file_count++; + } else { + fput_many(file, file_count); + file = req->rw.ki_filp; + file_count = 1; + } } if (to_free == ARRAY_SIZE(reqs)) @@ -516,13 +529,19 @@ static void kiocb_end_write(struct kiocb *kiocb) } } +static void io_fput(struct io_kiocb *req) +{ + if (!(req->flags & REQ_F_FIXED_FILE)) + fput(req->rw.ki_filp); +} + static void io_complete_rw(struct kiocb *kiocb, long res, long res2) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw); kiocb_end_write(kiocb); - fput(kiocb->ki_filp); + io_fput(req); io_cqring_add_event(req->ctx, req->user_data, res, 0); io_free_req(req); } @@ -638,19 +657,29 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, { struct io_ring_ctx *ctx = req->ctx; struct kiocb *kiocb = &req->rw; - unsigned ioprio; + unsigned ioprio, flags; int fd, ret; /* For -EAGAIN retry, everything is already prepped */ if (kiocb->ki_filp) return 0; + flags = READ_ONCE(sqe->flags); fd = READ_ONCE(sqe->fd); - kiocb->ki_filp = io_file_get(state, fd); - if (unlikely(!kiocb->ki_filp)) - return -EBADF; - if (force_nonblock && !io_file_supports_async(kiocb->ki_filp)) - force_nonblock = false; + + if (flags & IOSQE_FIXED_FILE) { + if (unlikely(!ctx->user_files || + (unsigned) fd >= ctx->nr_user_files)) + return -EBADF; + kiocb->ki_filp = ctx->user_files[fd]; + req->flags |= REQ_F_FIXED_FILE; + } else { + kiocb->ki_filp = io_file_get(state, fd); + if (unlikely(!kiocb->ki_filp)) + return -EBADF; + if (force_nonblock && !io_file_supports_async(kiocb->ki_filp)) + force_nonblock = false; + } kiocb->ki_pos = READ_ONCE(sqe->off); kiocb->ki_flags = iocb_flags(kiocb->ki_filp); kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp)); @@ -690,10 +719,14 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, } return 0; out_fput: - /* in case of error, we didn't use this file reference. drop it. */ - if (state) - state->used_refs--; - io_file_put(state, kiocb->ki_filp); + if (!(flags & IOSQE_FIXED_FILE)) { + /* + * in case of error, we didn't use this file reference. drop it. + */ + if (state) + state->used_refs--; + io_file_put(state, kiocb->ki_filp); + } return ret; } @@ -825,7 +858,7 @@ static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s, out_fput: /* Hold on to the file for -EAGAIN */ if (unlikely(ret && ret != -EAGAIN)) - fput(file); + io_fput(req); return ret; } @@ -879,7 +912,7 @@ static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s, kfree(iovec); out_fput: if (unlikely(ret)) - fput(file); + io_fput(req); return ret; } @@ -905,7 +938,7 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe, loff_t sqe_off = READ_ONCE(sqe->off); loff_t sqe_len = READ_ONCE(sqe->len); loff_t end = sqe_off + sqe_len; - unsigned fsync_flags; + unsigned fsync_flags, flags; struct file *file; int ret, fd; @@ -923,14 +956,23 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe, return -EINVAL; fd = READ_ONCE(sqe->fd); - file = fget(fd); + flags = READ_ONCE(sqe->flags); + + if (flags & IOSQE_FIXED_FILE) { + if (unlikely(!ctx->user_files || fd >= ctx->nr_user_files)) + return -EBADF; + file = ctx->user_files[fd]; + } else { + file = fget(fd); + } if (unlikely(!file)) return -EBADF; ret = vfs_fsync_range(file, sqe_off, end > 0 ? end : LLONG_MAX, fsync_flags & IORING_FSYNC_DATASYNC); - fput(file); + if (!(flags & IOSQE_FIXED_FILE)) + fput(file); io_cqring_add_event(ctx, sqe->user_data, ret, 0); io_free_req(req); return 0; @@ -1067,7 +1109,7 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s, ssize_t ret; /* enforce forwards compatibility on users */ - if (unlikely(s->sqe->flags)) + if (unlikely(s->sqe->flags & ~IOSQE_FIXED_FILE)) return -EINVAL; req = io_get_req(ctx, state); @@ -1255,6 +1297,151 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, return ring->r.head == ring->r.tail ? ret : 0; } +static void __io_sqe_files_unregister(struct io_ring_ctx *ctx) +{ +#if defined(CONFIG_UNIX) + if (ctx->ring_sock) { + struct sock *sock = ctx->ring_sock->sk; + struct sk_buff *skb; + + while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL) + kfree_skb(skb); + } +#else + int i; + + for (i = 0; i < ctx->nr_user_files; i++) + fput(ctx->user_files[i]); +#endif +} + +static int io_sqe_files_unregister(struct io_ring_ctx *ctx) +{ + if (!ctx->user_files) + return -ENXIO; + + __io_sqe_files_unregister(ctx); + kfree(ctx->user_files); + ctx->user_files = NULL; + return 0; +} + +#if defined(CONFIG_UNIX) +static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int nr, int offset) +{ + struct scm_fp_list *fpl; + struct sk_buff *skb; + int i; + + fpl = kzalloc(sizeof(*fpl), GFP_KERNEL); + if (!fpl) + return -ENOMEM; + + skb = alloc_skb(0, GFP_KERNEL); + if (!skb) { + kfree(fpl); + return -ENOMEM; + } + + skb->sk = ctx->ring_sock->sk; + skb->destructor = unix_destruct_scm; + + fpl->user = get_uid(ctx->user); + for (i = 0; i < nr; i++) { + fpl->fp[i] = get_file(ctx->user_files[i + offset]); + unix_inflight(fpl->user, fpl->fp[i]); + fput(fpl->fp[i]); + } + + fpl->max = fpl->count = nr; + UNIXCB(skb).fp = fpl; + skb_queue_head(&ctx->ring_sock->sk->sk_receive_queue, skb); + return 0; +} + +/* + * If UNIX sockets are enabled, fd passing can cause a reference cycle which + * causes regular reference counting to break down. We rely on the UNIX + * garbage collection to take care of this problem for us. + */ +static int io_sqe_files_scm(struct io_ring_ctx *ctx) +{ + unsigned left, total; + int ret = 0; + + total = 0; + left = ctx->nr_user_files; + while (left) { + unsigned this_files = min_t(unsigned, left, SCM_MAX_FD); + int ret; + + ret = __io_sqe_files_scm(ctx, this_files, total); + if (ret) + break; + left -= this_files; + total += this_files; + } + + return ret; +} +#else +static int io_sqe_files_scm(struct io_ring_ctx *ctx) +{ + return 0; +} +#endif + +static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, + unsigned nr_args) +{ + __s32 __user *fds = (__s32 __user *) arg; + int fd, ret = 0; + unsigned i; + + if (ctx->user_files) + return -EBUSY; + if (!nr_args) + return -EINVAL; + if (nr_args > IORING_MAX_FIXED_FILES) + return -EMFILE; + + ctx->user_files = kcalloc(nr_args, sizeof(struct file *), GFP_KERNEL); + if (!ctx->user_files) + return -ENOMEM; + + for (i = 0; i < nr_args; i++) { + ret = -EFAULT; + if (copy_from_user(&fd, &fds[i], sizeof(fd))) + break; + + ctx->user_files[i] = fget(fd); + + ret = -EBADF; + if (!ctx->user_files[i]) + break; + /* + * Don't allow io_uring instances to be registered. If UNIX + * isn't enabled, then this causes a reference cycle and this + * instance can never get freed. If UNIX is enabled we'll + * handle it just fine, but there's still no point in allowing + * a ring fd as it doesn't suppor regular read/write anyway. + */ + if (ctx->user_files[i]->f_op == &io_uring_fops) { + fput(ctx->user_files[i]); + break; + } + ctx->nr_user_files++; + ret = 0; + } + + if (!ret) + ret = io_sqe_files_scm(ctx); + if (ret) + io_sqe_files_unregister(ctx); + + return ret; +} + static int io_sq_offload_start(struct io_ring_ctx *ctx) { int ret; @@ -1521,14 +1708,16 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx) destroy_workqueue(ctx->sqo_wq); if (ctx->sqo_mm) mmdrop(ctx->sqo_mm); + + io_iopoll_reap_events(ctx); + io_sqe_buffer_unregister(ctx); + io_sqe_files_unregister(ctx); + #if defined(CONFIG_UNIX) if (ctx->ring_sock) sock_release(ctx->ring_sock); #endif - io_iopoll_reap_events(ctx); - io_sqe_buffer_unregister(ctx); - io_mem_free(ctx->sq_ring); io_mem_free(ctx->sq_sqes); io_mem_free(ctx->cq_ring); @@ -1886,6 +2075,15 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, break; ret = io_sqe_buffer_unregister(ctx); break; + case IORING_REGISTER_FILES: + ret = io_sqe_files_register(ctx, arg, nr_args); + break; + case IORING_UNREGISTER_FILES: + ret = -EINVAL; + if (arg || nr_args) + break; + ret = io_sqe_files_unregister(ctx); + break; default: ret = -EINVAL; break; diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index cf28f7a11f12..6257478d55e9 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -16,7 +16,7 @@ */ struct io_uring_sqe { __u8 opcode; /* type of operation for this sqe */ - __u8 flags; /* as of now unused */ + __u8 flags; /* IOSQE_ flags */ __u16 ioprio; /* ioprio for the request */ __s32 fd; /* file descriptor to do IO on */ __u64 off; /* offset into file */ @@ -33,6 +33,11 @@ struct io_uring_sqe { }; }; +/* + * sqe->flags + */ +#define IOSQE_FIXED_FILE (1U << 0) /* use fixed fileset */ + /* * io_uring_setup() flags */ @@ -113,5 +118,7 @@ struct io_uring_params { */ #define IORING_REGISTER_BUFFERS 0 #define IORING_UNREGISTER_BUFFERS 1 +#define IORING_REGISTER_FILES 2 +#define IORING_UNREGISTER_FILES 3 #endif From patchwork Fri Feb 8 17:34:19 2019 Content-Type: text/plain; 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Fri, 08 Feb 2019 09:35:02 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 15/19] io_uring: add submission polling Date: Fri, 8 Feb 2019 10:34:19 -0700 Message-Id: <20190208173423.27014-16-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This enables an application to do IO, without ever entering the kernel. By using the SQ ring to fill in new sqes and watching for completions on the CQ ring, we can submit and reap IOs without doing a single system call. The kernel side thread will poll for new submissions, and in case of HIPRI/polled IO, it'll also poll for completions. By default, we allow 1 second of active spinning. This can by changed by passing in a different grace period at io_uring_register(2) time. If the thread exceeds this idle time without having any work to do, it will set: sq_ring->flags |= IORING_SQ_NEED_WAKEUP. The application will have to call io_uring_enter() to start things back up again. If IO is kept busy, that will never be needed. Basically an application that has this feature enabled will guard it's io_uring_enter(2) call with: read_barrier(); if (*sq_ring->flags & IORING_SQ_NEED_WAKEUP) io_uring_enter(fd, 0, 0, IORING_ENTER_SQ_WAKEUP); instead of calling it unconditionally. It's mandatory to use fixed files with this feature. Failure to do so will result in the application getting an -EBADF CQ entry when submitting IO. Signed-off-by: Jens Axboe Reviewed-by: Hannes Reinecke --- fs/io_uring.c | 249 +++++++++++++++++++++++++++++++++- include/uapi/linux/io_uring.h | 12 +- 2 files changed, 253 insertions(+), 8 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 244fb71e3424..e6b9cef4665d 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include @@ -87,12 +88,16 @@ struct io_ring_ctx { unsigned cached_sq_head; unsigned sq_entries; unsigned sq_mask; + unsigned sq_thread_idle; struct io_uring_sqe *sq_sqes; } ____cacheline_aligned_in_smp; /* IO offload */ struct workqueue_struct *sqo_wq; + struct task_struct *sqo_thread; /* if using sq thread polling */ struct mm_struct *sqo_mm; + wait_queue_head_t sqo_wait; + unsigned sqo_stop; struct { /* CQ ring */ @@ -147,6 +152,7 @@ struct sqe_submit { unsigned short index; bool has_user; bool needs_lock; + bool needs_fixed_file; }; struct io_kiocb { @@ -299,6 +305,8 @@ static void io_cqring_add_event(struct io_ring_ctx *ctx, u64 ki_user_data, if (waitqueue_active(&ctx->wait)) wake_up(&ctx->wait); + if (waitqueue_active(&ctx->sqo_wait)) + wake_up(&ctx->sqo_wait); } static void io_ring_drop_ctx_refs(struct io_ring_ctx *ctx, unsigned refs) @@ -652,9 +660,10 @@ static bool io_file_supports_async(struct file *file) return false; } -static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, +static int io_prep_rw(struct io_kiocb *req, const struct sqe_submit *s, bool force_nonblock, struct io_submit_state *state) { + const struct io_uring_sqe *sqe = s->sqe; struct io_ring_ctx *ctx = req->ctx; struct kiocb *kiocb = &req->rw; unsigned ioprio, flags; @@ -674,6 +683,8 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, kiocb->ki_filp = ctx->user_files[fd]; req->flags |= REQ_F_FIXED_FILE; } else { + if (s->needs_fixed_file) + return -EBADF; kiocb->ki_filp = io_file_get(state, fd); if (unlikely(!kiocb->ki_filp)) return -EBADF; @@ -827,7 +838,7 @@ static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s, struct file *file; ssize_t ret; - ret = io_prep_rw(req, s->sqe, force_nonblock, state); + ret = io_prep_rw(req, s, force_nonblock, state); if (ret) return ret; file = kiocb->ki_filp; @@ -871,7 +882,7 @@ static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s, struct file *file; ssize_t ret; - ret = io_prep_rw(req, s->sqe, force_nonblock, state); + ret = io_prep_rw(req, s, force_nonblock, state); if (ret) return ret; /* Hold on to the file for -EAGAIN */ @@ -1061,6 +1072,7 @@ static void io_sq_wq_submit_work(struct work_struct *work) user_data = READ_ONCE(s->sqe->user_data); s->needs_lock = true; s->has_user = false; + s->needs_fixed_file = false; /* * If we're doing IO to fixed buffers, we don't need to get/set @@ -1215,6 +1227,170 @@ static bool io_get_sqring(struct io_ring_ctx *ctx, struct sqe_submit *s) return false; } +static int io_submit_sqes(struct io_ring_ctx *ctx, struct sqe_submit *sqes, + unsigned int nr, bool has_user, bool mm_fault) +{ + struct io_submit_state state, *statep = NULL; + int ret, i, submitted = 0; + + if (nr > IO_PLUG_THRESHOLD) { + io_submit_state_start(&state, ctx, nr); + statep = &state; + } + + for (i = 0; i < nr; i++) { + if (unlikely(mm_fault)) { + ret = -EFAULT; + } else { + sqes[i].has_user = has_user; + sqes[i].needs_lock = true; + sqes[i].needs_fixed_file = true; + ret = io_submit_sqe(ctx, &sqes[i], statep); + } + if (!ret) { + submitted++; + continue; + } + + io_cqring_add_event(ctx, sqes[i].sqe->user_data, ret, 0); + } + + if (statep) + io_submit_state_end(&state); + + return submitted; +} + +static int io_sq_thread(void *data) +{ + struct sqe_submit sqes[IO_IOPOLL_BATCH]; + struct io_ring_ctx *ctx = data; + struct mm_struct *cur_mm = NULL; + mm_segment_t old_fs; + DEFINE_WAIT(wait); + unsigned inflight; + unsigned long timeout; + + old_fs = get_fs(); + set_fs(USER_DS); + + timeout = inflight = 0; + while (!kthread_should_stop() && !ctx->sqo_stop) { + bool all_fixed, mm_fault = false; + int i; + + if (inflight) { + unsigned nr_events = 0; + + if (ctx->flags & IORING_SETUP_IOPOLL) { + /* + * We disallow the app entering submit/complete + * with polling, but we still need to lock the + * ring to prevent racing with polled issue + * that got punted to a workqueue. + */ + mutex_lock(&ctx->uring_lock); + io_iopoll_check(ctx, &nr_events, 0); + mutex_unlock(&ctx->uring_lock); + } else { + /* + * Normal IO, just pretend everything completed. + * We don't have to poll completions for that. + */ + nr_events = inflight; + } + + inflight -= nr_events; + if (!inflight) + timeout = jiffies + ctx->sq_thread_idle; + } + + if (!io_get_sqring(ctx, &sqes[0])) { + /* + * We're polling. If we're within the defined idle + * period, then let us spin without work before going + * to sleep. + */ + if (inflight || !time_after(jiffies, timeout)) { + cpu_relax(); + continue; + } + + /* + * Drop cur_mm before scheduling, we can't hold it for + * long periods (or over schedule()). Do this before + * adding ourselves to the waitqueue, as the unuse/drop + * may sleep. + */ + if (cur_mm) { + unuse_mm(cur_mm); + mmput(cur_mm); + cur_mm = NULL; + } + + prepare_to_wait(&ctx->sqo_wait, &wait, + TASK_INTERRUPTIBLE); + + /* Tell userspace we may need a wakeup call */ + ctx->sq_ring->flags |= IORING_SQ_NEED_WAKEUP; + smp_wmb(); + + if (!io_get_sqring(ctx, &sqes[0])) { + if (kthread_should_stop()) { + finish_wait(&ctx->sqo_wait, &wait); + break; + } + if (signal_pending(current)) + flush_signals(current); + schedule(); + finish_wait(&ctx->sqo_wait, &wait); + + ctx->sq_ring->flags &= ~IORING_SQ_NEED_WAKEUP; + smp_wmb(); + continue; + } + finish_wait(&ctx->sqo_wait, &wait); + + ctx->sq_ring->flags &= ~IORING_SQ_NEED_WAKEUP; + smp_wmb(); + } + + i = 0; + all_fixed = true; + do { + if (all_fixed && io_sqe_needs_user(sqes[i].sqe)) + all_fixed = false; + + i++; + if (i == ARRAY_SIZE(sqes)) + break; + } while (io_get_sqring(ctx, &sqes[i])); + + io_commit_sqring(ctx); + + /* Unless all new commands are FIXED regions, grab mm */ + if (!all_fixed && !cur_mm) { + mm_fault = !mmget_not_zero(ctx->sqo_mm); + if (!mm_fault) { + use_mm(ctx->sqo_mm); + cur_mm = ctx->sqo_mm; + } + } + + inflight += io_submit_sqes(ctx, sqes, i, cur_mm != NULL, + mm_fault); + } + + io_iopoll_reap_events(ctx); + + set_fs(old_fs); + if (cur_mm) { + unuse_mm(cur_mm); + mmput(cur_mm); + } + return 0; +} + static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit) { struct io_submit_state state, *statep = NULL; @@ -1233,6 +1409,7 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit) s.has_user = true; s.needs_lock = false; + s.needs_fixed_file = false; ret = io_submit_sqe(ctx, &s, statep); if (ret) { @@ -1442,13 +1619,47 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, return ret; } -static int io_sq_offload_start(struct io_ring_ctx *ctx) +static int io_sq_offload_start(struct io_ring_ctx *ctx, + struct io_uring_params *p) { int ret; + init_waitqueue_head(&ctx->sqo_wait); mmgrab(current->mm); ctx->sqo_mm = current->mm; + ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle); + if (!ctx->sq_thread_idle) + ctx->sq_thread_idle = HZ; + + ret = -EINVAL; + if (!cpu_possible(p->sq_thread_cpu)) + goto err; + + if (ctx->flags & IORING_SETUP_SQPOLL) { + if (p->flags & IORING_SETUP_SQ_AFF) { + int cpu; + + cpu = array_index_nospec(p->sq_thread_cpu, NR_CPUS); + ctx->sqo_thread = kthread_create_on_cpu(io_sq_thread, + ctx, cpu, + "io_uring-sq"); + } else { + ctx->sqo_thread = kthread_create(io_sq_thread, ctx, + "io_uring-sq"); + } + if (IS_ERR(ctx->sqo_thread)) { + ret = PTR_ERR(ctx->sqo_thread); + ctx->sqo_thread = NULL; + goto err; + } + wake_up_process(ctx->sqo_thread); + } else if (p->flags & IORING_SETUP_SQ_AFF) { + /* Can't have SQ_AFF without SQPOLL */ + ret = -EINVAL; + goto err; + } + /* Do QD, or 2 * CPUS, whatever is smallest */ ctx->sqo_wq = alloc_workqueue("io_ring-wq", WQ_UNBOUND | WQ_FREEZABLE, min(ctx->sq_entries - 1, 2 * num_online_cpus())); @@ -1459,6 +1670,12 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx) return 0; err: + if (ctx->sqo_thread) { + ctx->sqo_stop = 1; + mb(); + kthread_stop(ctx->sqo_thread); + ctx->sqo_thread = NULL; + } mmdrop(ctx->sqo_mm); ctx->sqo_mm = NULL; return ret; @@ -1704,6 +1921,11 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg, static void io_ring_ctx_free(struct io_ring_ctx *ctx) { + if (ctx->sqo_thread) { + ctx->sqo_stop = 1; + mb(); + kthread_stop(ctx->sqo_thread); + } if (ctx->sqo_wq) destroy_workqueue(ctx->sqo_wq); if (ctx->sqo_mm) @@ -1811,7 +2033,7 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, int submitted = 0; struct fd f; - if (flags & ~IORING_ENTER_GETEVENTS) + if (flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP)) return -EINVAL; f = fdget(fd); @@ -1827,6 +2049,18 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, if (!percpu_ref_tryget(&ctx->refs)) goto out_fput; + /* + * For SQ polling, the thread will do all submissions and completions. + * Just return the requested submit count, and wake the thread if + * we were asked to. + */ + if (ctx->flags & IORING_SETUP_SQPOLL) { + if (flags & IORING_ENTER_SQ_WAKEUP) + wake_up(&ctx->sqo_wait); + submitted = to_submit; + goto out_ctx; + } + if (to_submit) { to_submit = min(to_submit, ctx->sq_entries); @@ -1990,7 +2224,7 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p) if (ret) goto err; - ret = io_sq_offload_start(ctx); + ret = io_sq_offload_start(ctx, p); if (ret) goto err; @@ -2038,7 +2272,8 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params) return -EINVAL; } - if (p.flags & ~IORING_SETUP_IOPOLL) + if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL | + IORING_SETUP_SQ_AFF)) return -EINVAL; ret = io_uring_create(entries, &p); diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 6257478d55e9..0ec74bab8dbe 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -42,6 +42,8 @@ struct io_uring_sqe { * io_uring_setup() flags */ #define IORING_SETUP_IOPOLL (1U << 0) /* io_context is polled */ +#define IORING_SETUP_SQPOLL (1U << 1) /* SQ poll thread */ +#define IORING_SETUP_SQ_AFF (1U << 2) /* sq_thread_cpu is valid */ #define IORING_OP_NOP 0 #define IORING_OP_READV 1 @@ -86,6 +88,11 @@ struct io_sqring_offsets { __u64 resv2; }; +/* + * sq_ring->flags + */ +#define IORING_SQ_NEED_WAKEUP (1U << 0) /* needs io_uring_enter wakeup */ + struct io_cqring_offsets { __u32 head; __u32 tail; @@ -100,6 +107,7 @@ struct io_cqring_offsets { * io_uring_enter(2) flags */ #define IORING_ENTER_GETEVENTS (1U << 0) +#define IORING_ENTER_SQ_WAKEUP (1U << 1) /* * Passed in for io_uring_setup(2). Copied back with updated info on success @@ -108,7 +116,9 @@ struct io_uring_params { __u32 sq_entries; __u32 cq_entries; __u32 flags; - __u32 resv[7]; + __u32 sq_thread_cpu; + __u32 sq_thread_idle; + __u32 resv[5]; struct io_sqring_offsets sq_off; struct io_cqring_offsets cq_off; }; From patchwork Fri Feb 8 17:34:20 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10803511 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CFC6A1390 for ; Fri, 8 Feb 2019 17:35:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BFEE62DCD6 for ; Fri, 8 Feb 2019 17:35:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B44762DCE0; Fri, 8 Feb 2019 17:35:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5AD982DCD6 for ; Fri, 8 Feb 2019 17:35:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727970AbfBHRfI (ORCPT ); Fri, 8 Feb 2019 12:35:08 -0500 Received: from mail-it1-f195.google.com ([209.85.166.195]:55181 "EHLO mail-it1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727944AbfBHRfG (ORCPT ); Fri, 8 Feb 2019 12:35:06 -0500 Received: by mail-it1-f195.google.com with SMTP id i145so10657806ita.4 for ; Fri, 08 Feb 2019 09:35:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=8zkyREBIrKQ0HvbZ1wj0qlZpaBpErgZ9IGppgDbR9QY=; b=TMgJCzez4idSxsrC8s5C4LEXrJ9jsC4a4q/C/MS9EPg46Ynua1ToGQqzL9iO7zA5Aa noUFGdrV0MOCn65jDGDwHp9lP+kDRWbGFNQMjI0OnIirJsS5h05gkU+nvwl4iz5u704A f69v9+qqFRYnn544sdcq14JwGT+b8pJHdaW5S4YCjEKfB1m+dBe5Kr3BlL0L0460kN5j FRjuPORQNaJQ3ge+b8LCjuxBPLyrzSSRHmXhX+9orTDc4smIC3lUJPlgvM6CkVjXA9Ky Aj6Z2dLM2Yzt5hjnLC6uctCDX3zJdZIxQcUQt/9LvqWWIY/ZXvL/z5nMcOOQZFnfg1YJ 2wlA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=8zkyREBIrKQ0HvbZ1wj0qlZpaBpErgZ9IGppgDbR9QY=; b=lCy6yB9yJ7cME1jN5vviMs0eveMngwslvxXuXbD6nsYcdv0vMvLb2mK56/QzAtcyz4 lCiLg8+YMO3ZG07O3xoLfy5vgI1bnXTJCF8WFngpD/CU2XCRjIgcLFsCedQmLTw/I1Ck y8jqAd7ST7Oh4Rydewght57yzH+p+33eCVQwtC7FpWtmP7YoHWcQiIdvsgxiHjUflIbx Pu8S/MHjNOV+elY8dbRn17XilGxGm0/6PxNBVER6HVkHsiM3dYaPO6NKKOu3UOgILynO NAc5Jmi/vVRyM7S+z6VZPFq2hKCYSxmcF8plfz7o0AzboK9DLjVJ+jReXgyzT9l4LiQq MZsg== X-Gm-Message-State: AHQUAuaSO6b4Jjq3BKSirzYQMNm1PyiL4hnObvWCWBnJ9sQRZMVEK1XJ X+kHefftN1M3pcTRnJ+DEGNCyQ== X-Google-Smtp-Source: AHgI3Ibe8NUVbMFgNZrDH8sa0QfYhwVnElSiBoALnDeJuorCZe92zmTlZWTuKhRBfomuMBzxLKAaHw== X-Received: by 2002:a24:4d05:: with SMTP id l5mr9381301itb.147.1549647305683; Fri, 08 Feb 2019 09:35:05 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id f142sm1522627itc.15.2019.02.08.09.35.03 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Feb 2019 09:35:04 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 16/19] io_uring: add io_kiocb ref count Date: Fri, 8 Feb 2019 10:34:20 -0700 Message-Id: <20190208173423.27014-17-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We'll use this for the POLL implementation. Regular requests will NOT be using references, so initialize it to 0. Any real use of the io_kiocb ref will initialize it to at least 2. Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe --- fs/io_uring.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index e6b9cef4665d..9b28f2cd29db 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -163,6 +163,7 @@ struct io_kiocb { struct io_ring_ctx *ctx; struct list_head list; unsigned int flags; + refcount_t refs; #define REQ_F_FORCE_NONBLOCK 1 /* inline submission attempt */ #define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */ #define REQ_F_FIXED_FILE 4 /* ctx owns file */ @@ -349,6 +350,7 @@ static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx, req->ctx = ctx; req->flags = 0; + refcount_set(&req->refs, 0); return req; out: io_ring_drop_ctx_refs(ctx, 1); @@ -366,8 +368,10 @@ static void io_free_req_many(struct io_ring_ctx *ctx, void **reqs, int *nr) static void io_free_req(struct io_kiocb *req) { - io_ring_drop_ctx_refs(req->ctx, 1); - kmem_cache_free(req_cachep, req); + if (!refcount_read(&req->refs) || refcount_dec_and_test(&req->refs)) { + io_ring_drop_ctx_refs(req->ctx, 1); + kmem_cache_free(req_cachep, req); + } } /* From patchwork Fri Feb 8 17:34:21 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10803543 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0E87E1390 for ; Fri, 8 Feb 2019 17:38:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7C9CC20881 for ; Fri, 8 Feb 2019 17:38:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6C4BE22A68; Fri, 8 Feb 2019 17:38:50 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EC2DC2DCDD for ; 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Fri, 08 Feb 2019 09:35:06 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 17/19] io_uring: add support for IORING_OP_POLL Date: Fri, 8 Feb 2019 10:34:21 -0700 Message-Id: <20190208173423.27014-18-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This is basically a direct port of bfe4037e722e, which implements a one-shot poll command through aio. Description below is based on that commit as well. However, instead of adding a POLL command and relying on io_cancel(2) to remove it, we mimic the epoll(2) interface of having a command to add a poll notification, IORING_OP_POLL_ADD, and one to remove it again, IORING_OP_POLL_REMOVE. To poll for a file descriptor the application should submit an sqe of type IORING_OP_POLL. It will poll the fd for the events specified in the poll_events field. Unlike poll or epoll without EPOLLONESHOT this interface always works in one shot mode, that is once the sqe is completed, it will have to be resubmitted. Based-on-code-from: Christoph Hellwig Signed-off-by: Jens Axboe --- fs/io_uring.c | 261 +++++++++++++++++++++++++++++++++- include/uapi/linux/io_uring.h | 3 + 2 files changed, 263 insertions(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 9b28f2cd29db..c014dbc29c77 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -140,6 +140,7 @@ struct io_ring_ctx { * manipulate the list, hence no extra locking is needed there. */ struct list_head poll_list; + struct list_head cancel_list; } ____cacheline_aligned_in_smp; #if defined(CONFIG_UNIX) @@ -155,8 +156,20 @@ struct sqe_submit { bool needs_fixed_file; }; +struct io_poll_iocb { + struct file *file; + struct wait_queue_head *head; + __poll_t events; + bool woken; + bool canceled; + struct wait_queue_entry wait; +}; + struct io_kiocb { - struct kiocb rw; + union { + struct kiocb rw; + struct io_poll_iocb poll; + }; struct sqe_submit submit; @@ -240,6 +253,7 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) init_waitqueue_head(&ctx->wait); spin_lock_init(&ctx->completion_lock); INIT_LIST_HEAD(&ctx->poll_list); + INIT_LIST_HEAD(&ctx->cancel_list); return ctx; } @@ -993,6 +1007,244 @@ static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe, return 0; } +static void io_poll_remove_one(struct io_kiocb *req) +{ + struct io_poll_iocb *poll = &req->poll; + + spin_lock(&poll->head->lock); + WRITE_ONCE(poll->canceled, true); + if (!list_empty(&poll->wait.entry)) { + list_del_init(&poll->wait.entry); + queue_work(req->ctx->sqo_wq, &req->work); + } + spin_unlock(&poll->head->lock); + + list_del_init(&req->list); +} + +static void io_poll_remove_all(struct io_ring_ctx *ctx) +{ + struct io_kiocb *req; + + spin_lock_irq(&ctx->completion_lock); + while (!list_empty(&ctx->cancel_list)) { + req = list_first_entry(&ctx->cancel_list, struct io_kiocb,list); + io_poll_remove_one(req); + } + spin_unlock_irq(&ctx->completion_lock); +} + +/* + * Find a running poll command that matches one specified in sqe->addr, + * and remove it if found. + */ +static int io_poll_remove(struct io_kiocb *req, const struct io_uring_sqe *sqe) +{ + struct io_ring_ctx *ctx = req->ctx; + struct io_kiocb *poll_req, *next; + int ret = -ENOENT; + + if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) + return -EINVAL; + if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index || + sqe->poll_events) + return -EINVAL; + + spin_lock_irq(&ctx->completion_lock); + list_for_each_entry_safe(poll_req, next, &ctx->cancel_list, list) { + if (READ_ONCE(sqe->addr) == poll_req->user_data) { + io_poll_remove_one(poll_req); + ret = 0; + break; + } + } + spin_unlock_irq(&ctx->completion_lock); + + io_cqring_add_event(req->ctx, sqe->user_data, ret, 0); + io_free_req(req); + return 0; +} + +static void io_poll_complete(struct io_kiocb *req, __poll_t mask) +{ + io_cqring_add_event(req->ctx, req->user_data, mangle_poll(mask), 0); + io_fput(req); + io_free_req(req); +} + +static void io_poll_complete_work(struct work_struct *work) +{ + struct io_kiocb *req = container_of(work, struct io_kiocb, work); + struct io_poll_iocb *poll = &req->poll; + struct poll_table_struct pt = { ._key = poll->events }; + struct io_ring_ctx *ctx = req->ctx; + __poll_t mask = 0; + + if (!READ_ONCE(poll->canceled)) + mask = vfs_poll(poll->file, &pt) & poll->events; + + /* + * Note that ->ki_cancel callers also delete iocb from active_reqs after + * calling ->ki_cancel. We need the ctx_lock roundtrip here to + * synchronize with them. In the cancellation case the list_del_init + * itself is not actually needed, but harmless so we keep it in to + * avoid further branches in the fast path. + */ + spin_lock_irq(&ctx->completion_lock); + if (!mask && !READ_ONCE(poll->canceled)) { + add_wait_queue(poll->head, &poll->wait); + spin_unlock_irq(&ctx->completion_lock); + return; + } + list_del_init(&req->list); + spin_unlock_irq(&ctx->completion_lock); + + io_poll_complete(req, mask); +} + +static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, + void *key) +{ + struct io_poll_iocb *poll = container_of(wait, struct io_poll_iocb, + wait); + struct io_kiocb *req = container_of(poll, struct io_kiocb, poll); + struct io_ring_ctx *ctx = req->ctx; + __poll_t mask = key_to_poll(key); + + poll->woken = true; + + /* for instances that support it check for an event match first: */ + if (mask) { + if (!(mask & poll->events)) + return 0; + + /* try to complete the iocb inline if we can: */ + if (spin_trylock(&ctx->completion_lock)) { + list_del(&req->list); + spin_unlock(&ctx->completion_lock); + + list_del_init(&poll->wait.entry); + io_poll_complete(req, mask); + return 1; + } + } + + list_del_init(&poll->wait.entry); + queue_work(ctx->sqo_wq, &req->work); + return 1; +} + +struct io_poll_table { + struct poll_table_struct pt; + struct io_kiocb *req; + int error; +}; + +static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head, + struct poll_table_struct *p) +{ + struct io_poll_table *pt = container_of(p, struct io_poll_table, pt); + + if (unlikely(pt->req->poll.head)) { + pt->error = -EINVAL; + return; + } + + pt->error = 0; + pt->req->poll.head = head; + add_wait_queue(head, &pt->req->poll.wait); +} + +static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe) +{ + struct io_poll_iocb *poll = &req->poll; + struct io_ring_ctx *ctx = req->ctx; + struct io_poll_table ipt; + unsigned flags; + __poll_t mask; + u16 events; + int fd; + + if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) + return -EINVAL; + if (sqe->addr || sqe->ioprio || sqe->off || sqe->len || sqe->buf_index) + return -EINVAL; + + INIT_WORK(&req->work, io_poll_complete_work); + events = READ_ONCE(sqe->poll_events); + poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP; + + flags = READ_ONCE(sqe->flags); + fd = READ_ONCE(sqe->fd); + + if (flags & IOSQE_FIXED_FILE) { + if (unlikely(!ctx->user_files || fd >= ctx->nr_user_files)) + return -EBADF; + poll->file = ctx->user_files[fd]; + req->flags |= REQ_F_FIXED_FILE; + } else { + poll->file = fget(fd); + } + if (unlikely(!poll->file)) + return -EBADF; + + poll->head = NULL; + poll->woken = false; + poll->canceled = false; + + ipt.pt._qproc = io_poll_queue_proc; + ipt.pt._key = poll->events; + ipt.req = req; + ipt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */ + + /* initialized the list so that we can do list_empty checks */ + INIT_LIST_HEAD(&poll->wait.entry); + init_waitqueue_func_entry(&poll->wait, io_poll_wake); + + /* one for removal from waitqueue, one for this function */ + refcount_set(&req->refs, 2); + + mask = vfs_poll(poll->file, &ipt.pt) & poll->events; + if (unlikely(!poll->head)) { + /* we did not manage to set up a waitqueue, done */ + goto out; + } + + spin_lock_irq(&ctx->completion_lock); + spin_lock(&poll->head->lock); + if (poll->woken) { + /* wake_up context handles the rest */ + mask = 0; + ipt.error = 0; + } else if (mask || ipt.error) { + /* if we get an error or a mask we are done */ + WARN_ON_ONCE(list_empty(&poll->wait.entry)); + list_del_init(&poll->wait.entry); + } else { + /* actually waiting for an event */ + list_add_tail(&req->list, &ctx->cancel_list); + } + spin_unlock(&poll->head->lock); + spin_unlock_irq(&ctx->completion_lock); + +out: + if (unlikely(ipt.error)) { + if (!(flags & IOSQE_FIXED_FILE)) + fput(poll->file); + /* + * Drop one of our refs to this req, __io_submit_sqe() will + * drop the other one since we're returning an error. + */ + io_free_req(req); + return ipt.error; + } + + if (mask) + io_poll_complete(req, mask); + io_free_req(req); + return 0; +} + static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, const struct sqe_submit *s, bool force_nonblock, struct io_submit_state *state) @@ -1028,6 +1280,12 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, case IORING_OP_FSYNC: ret = io_fsync(req, s->sqe, force_nonblock); break; + case IORING_OP_POLL_ADD: + ret = io_poll_add(req, s->sqe); + break; + case IORING_OP_POLL_REMOVE: + ret = io_poll_remove(req, s->sqe); + break; default: ret = -EINVAL; break; @@ -1983,6 +2241,7 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) percpu_ref_kill(&ctx->refs); mutex_unlock(&ctx->uring_lock); + io_poll_remove_all(ctx); io_iopoll_reap_events(ctx); wait_for_completion(&ctx->ctx_done); io_ring_ctx_free(ctx); diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 0ec74bab8dbe..e23408692118 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -25,6 +25,7 @@ struct io_uring_sqe { union { __kernel_rwf_t rw_flags; __u32 fsync_flags; + __u16 poll_events; }; __u64 user_data; /* data to be passed back at completion time */ union { @@ -51,6 +52,8 @@ struct io_uring_sqe { #define IORING_OP_FSYNC 3 #define IORING_OP_READ_FIXED 4 #define IORING_OP_WRITE_FIXED 5 +#define IORING_OP_POLL_ADD 6 +#define IORING_OP_POLL_REMOVE 7 /* * sqe->fsync_flags From patchwork Fri Feb 8 17:34:22 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10803545 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6A2BD1823 for ; Fri, 8 Feb 2019 17:38:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5660A28C0C for ; Fri, 8 Feb 2019 17:38:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4920028B05; 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Fri, 08 Feb 2019 09:35:10 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id f142sm1522627itc.15.2019.02.08.09.35.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Feb 2019 09:35:09 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 18/19] io_uring: allow workqueue item to handle multiple buffered requests Date: Fri, 8 Feb 2019 10:34:22 -0700 Message-Id: <20190208173423.27014-19-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Right now we punt any buffered request that ends up triggering an -EAGAIN to an async workqueue. This works fine in terms of providing async execution of them, but it also can create quite a lot of work queue items. For sequentially buffered IO, it's advantageous to serialize the issue of them. For reads, the first one will trigger a read-ahead, and subsequent request merely end up waiting on later pages to complete. For writes, devices usually respond better to streamed sequential writes. Add state to track the last buffered request we punted to a work queue, and if the next one is sequential to the previous, attempt to get the previous work item to handle it. We limit the number of sequential add-ons to the a multiple (8) of the max read-ahead size of the file. This should be a good number for both reads and wries, as it defines the max IO size the device can do directly. This drastically cuts down on the number of context switches we need to handle buffered sequential IO, and a basic test case of copying a big file with io_uring sees a 5x speedup. Signed-off-by: Jens Axboe --- fs/io_uring.c | 267 ++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 216 insertions(+), 51 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index c014dbc29c77..175dac00eb47 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -74,6 +74,16 @@ struct io_mapped_ubuf { unsigned int nr_bvecs; }; +struct async_list { + spinlock_t lock; + atomic_t cnt; + struct list_head list; + + struct file *file; + off_t io_end; + size_t io_pages; +}; + struct io_ring_ctx { struct { struct percpu_ref refs; @@ -143,6 +153,8 @@ struct io_ring_ctx { struct list_head cancel_list; } ____cacheline_aligned_in_smp; + struct async_list pending_async[2]; + #if defined(CONFIG_UNIX) struct socket *ring_sock; #endif @@ -180,6 +192,7 @@ struct io_kiocb { #define REQ_F_FORCE_NONBLOCK 1 /* inline submission attempt */ #define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */ #define REQ_F_FIXED_FILE 4 /* ctx owns file */ +#define REQ_F_SEQ_PREV 8 /* sequential with previous */ u64 user_data; u64 error; @@ -236,6 +249,7 @@ static void io_ring_ctx_ref_free(struct percpu_ref *ref) static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) { struct io_ring_ctx *ctx; + int i; ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) @@ -251,6 +265,11 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) init_completion(&ctx->ctx_done); mutex_init(&ctx->uring_lock); init_waitqueue_head(&ctx->wait); + for (i = 0; i < ARRAY_SIZE(ctx->pending_async); i++) { + spin_lock_init(&ctx->pending_async[i].lock); + INIT_LIST_HEAD(&ctx->pending_async[i].list); + atomic_set(&ctx->pending_async[i].cnt, 0); + } spin_lock_init(&ctx->completion_lock); INIT_LIST_HEAD(&ctx->poll_list); INIT_LIST_HEAD(&ctx->cancel_list); @@ -847,6 +866,39 @@ static int io_import_iovec(struct io_ring_ctx *ctx, int rw, return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter); } +static void io_async_list_note(int rw, struct io_kiocb *req, size_t len) +{ + struct async_list *async_list = &req->ctx->pending_async[rw]; + struct kiocb *kiocb = &req->rw; + struct file *filp = kiocb->ki_filp; + off_t io_end = kiocb->ki_pos + len; + + if (filp == async_list->file && kiocb->ki_pos == async_list->io_end) { + unsigned long max_pages; + + /* Use 8x RA size as a decent limiter for both reads/writes */ + max_pages = filp->f_ra.ra_pages; + if (!max_pages) + max_pages = VM_MAX_READAHEAD >> (PAGE_SHIFT - 10); + max_pages *= 8; + + len >>= PAGE_SHIFT; + if (async_list->io_pages + len <= max_pages) { + req->flags |= REQ_F_SEQ_PREV; + async_list->io_pages += len; + } else { + io_end = 0; + async_list->io_pages = 0; + } + } + + if (async_list->file != filp) { + async_list->io_pages = 0; + async_list->file = filp; + } + async_list->io_end = io_end; +} + static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s, bool force_nonblock, struct io_submit_state *state) { @@ -854,6 +906,7 @@ static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s, struct kiocb *kiocb = &req->rw; struct iov_iter iter; struct file *file; + size_t iov_count; ssize_t ret; ret = io_prep_rw(req, s, force_nonblock, state); @@ -872,16 +925,24 @@ static ssize_t io_read(struct io_kiocb *req, const struct sqe_submit *s, if (ret) goto out_fput; - ret = rw_verify_area(READ, file, &kiocb->ki_pos, iov_iter_count(&iter)); + iov_count = iov_iter_count(&iter); + ret = rw_verify_area(READ, file, &kiocb->ki_pos, iov_count); if (!ret) { ssize_t ret2; /* Catch -EAGAIN return for forced non-blocking submission */ ret2 = call_read_iter(file, kiocb, &iter); - if (!force_nonblock || ret2 != -EAGAIN) + if (!force_nonblock || ret2 != -EAGAIN) { io_rw_done(kiocb, ret2); - else + } else { + /* + * If ->needs_lock is true, we're already in async + * context. + */ + if (!s->needs_lock) + io_async_list_note(READ, req, iov_count); ret = -EAGAIN; + } } kfree(iovec); out_fput: @@ -898,14 +959,12 @@ static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s, struct kiocb *kiocb = &req->rw; struct iov_iter iter; struct file *file; + size_t iov_count; ssize_t ret; ret = io_prep_rw(req, s, force_nonblock, state); if (ret) return ret; - /* Hold on to the file for -EAGAIN */ - if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT)) - return -EAGAIN; ret = -EBADF; file = kiocb->ki_filp; @@ -919,8 +978,17 @@ static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s, if (ret) goto out_fput; - ret = rw_verify_area(WRITE, file, &kiocb->ki_pos, - iov_iter_count(&iter)); + iov_count = iov_iter_count(&iter); + + ret = -EAGAIN; + if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT)) { + /* If ->needs_lock is true, we're already in async context. */ + if (!s->needs_lock) + io_async_list_note(WRITE, req, iov_count); + goto out_free; + } + + ret = rw_verify_area(WRITE, file, &kiocb->ki_pos, iov_count); if (!ret) { /* * Open-code file_start_write here to grab freeze protection, @@ -938,9 +1006,11 @@ static ssize_t io_write(struct io_kiocb *req, const struct sqe_submit *s, kiocb->ki_flags |= IOCB_WRITE; io_rw_done(kiocb, call_write_iter(file, kiocb, &iter)); } +out_free: kfree(iovec); out_fput: - if (unlikely(ret)) + /* Hold on to the file for -EAGAIN */ + if (unlikely(ret && ret != -EAGAIN)) io_fput(req); return ret; } @@ -1309,6 +1379,21 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, return 0; } +static struct async_list *io_async_list_from_sqe(struct io_ring_ctx *ctx, + const struct io_uring_sqe *sqe) +{ + switch (sqe->opcode) { + case IORING_OP_READV: + case IORING_OP_READ_FIXED: + return &ctx->pending_async[READ]; + case IORING_OP_WRITEV: + case IORING_OP_WRITE_FIXED: + return &ctx->pending_async[WRITE]; + default: + return NULL; + } +} + static inline bool io_sqe_needs_user(const struct io_uring_sqe *sqe) { u8 opcode = READ_ONCE(sqe->opcode); @@ -1320,60 +1405,133 @@ static inline bool io_sqe_needs_user(const struct io_uring_sqe *sqe) static void io_sq_wq_submit_work(struct work_struct *work) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); - struct sqe_submit *s = &req->submit; struct io_ring_ctx *ctx = req->ctx; + struct mm_struct *cur_mm = NULL; + struct async_list *async_list; + LIST_HEAD(req_list); mm_segment_t old_fs; - bool needs_user; - u64 user_data; int ret; - /* Ensure we clear previously set forced non-block flag */ - req->flags &= ~REQ_F_FORCE_NONBLOCK; - req->rw.ki_flags &= ~IOCB_NOWAIT; + async_list = io_async_list_from_sqe(ctx, req->submit.sqe); +restart: + do { + struct sqe_submit *s = &req->submit; + u64 user_data = READ_ONCE(s->sqe->user_data); + + /* Ensure we clear previously set forced non-block flag */ + req->flags &= ~REQ_F_FORCE_NONBLOCK; + req->rw.ki_flags &= ~IOCB_NOWAIT; - user_data = READ_ONCE(s->sqe->user_data); - s->needs_lock = true; - s->has_user = false; - s->needs_fixed_file = false; + ret = 0; + if (io_sqe_needs_user(s->sqe) && !cur_mm) { + if (!mmget_not_zero(ctx->sqo_mm)) { + ret = -EFAULT; + } else { + cur_mm = ctx->sqo_mm; + use_mm(ctx->sqo_mm); + old_fs = get_fs(); + set_fs(USER_DS); + } + } + + if (!ret) { + s->has_user = cur_mm != NULL; + s->needs_lock = true; + s->needs_fixed_file = false; + do { + ret = __io_submit_sqe(ctx, req, s, false, NULL); + /* + * We can get EAGAIN for polled IO even though + * we're forcing a sync submission from here, + * since we can't wait for request slots on the + * block side. + */ + if (ret != -EAGAIN) + break; + cond_resched(); + } while (1); + } + if (ret) { + io_cqring_add_event(ctx, user_data, ret, 0); + io_free_req(req); + } + if (!async_list) + break; + if (!list_empty(&req_list)) { + req = list_first_entry(&req_list, struct io_kiocb, + list); + list_del(&req->list); + continue; + } + if (list_empty(&async_list->list)) + break; + + req = NULL; + spin_lock(&async_list->lock); + if (list_empty(&async_list->list)) { + spin_unlock(&async_list->lock); + break; + } + list_splice_init(&async_list->list, &req_list); + spin_unlock(&async_list->lock); + + req = list_first_entry(&req_list, struct io_kiocb, list); + list_del(&req->list); + } while (req); /* - * If we're doing IO to fixed buffers, we don't need to get/set - * user context + * Rare case of racing with a submitter. If we find the count has + * dropped to zero AND we have pending work items, then restart + * the processing. This is a tiny race window. */ - needs_user = io_sqe_needs_user(s->sqe); - if (needs_user) { - if (!mmget_not_zero(ctx->sqo_mm)) { - ret = -EFAULT; - goto err; + ret = atomic_dec_return(&async_list->cnt); + while (!ret && !list_empty(&async_list->list)) { + spin_lock(&async_list->lock); + atomic_inc(&async_list->cnt); + list_splice_init(&async_list->list, &req_list); + spin_unlock(&async_list->lock); + + if (!list_empty(&req_list)) { + req = list_first_entry(&req_list, struct io_kiocb, + list); + list_del(&req->list); + goto restart; } - use_mm(ctx->sqo_mm); - old_fs = get_fs(); - set_fs(USER_DS); - s->has_user = true; + ret = atomic_dec_return(&async_list->cnt); } - do { - ret = __io_submit_sqe(ctx, req, s, false, NULL); - /* - * We can get EAGAIN for polled IO even though we're forcing - * a sync submission from here, since we can't wait for - * request slots on the block side. - */ - if (ret != -EAGAIN) - break; - cond_resched(); - } while (1); - - if (needs_user) { + if (cur_mm) { set_fs(old_fs); - unuse_mm(ctx->sqo_mm); - mmput(ctx->sqo_mm); + unuse_mm(cur_mm); + mmput(cur_mm); } -err: - if (ret) { - io_cqring_add_event(ctx, user_data, ret, 0); - io_free_req(req); +} + +/* + * See if we can piggy back onto previously submitted work, that is still + * running. We currently only allow this if the new request is sequential + * to the previous one we punted. + */ +static bool io_add_to_prev_work(struct async_list *list, struct io_kiocb *req) +{ + bool ret = false; + + if (!list) + return false; + if (!(req->flags & REQ_F_SEQ_PREV)) + return false; + if (!atomic_read(&list->cnt)) + return false; + + ret = true; + spin_lock(&list->lock); + list_add_tail(&req->list, &list->list); + if (!atomic_read(&list->cnt)) { + list_del_init(&req->list); + ret = false; } + spin_unlock(&list->lock); + return ret; } static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s, @@ -1394,9 +1552,16 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, const struct sqe_submit *s, ret = __io_submit_sqe(ctx, req, s, true, state); if (ret == -EAGAIN) { + struct async_list *list; + + list = io_async_list_from_sqe(ctx, s->sqe); memcpy(&req->submit, s, sizeof(*s)); - INIT_WORK(&req->work, io_sq_wq_submit_work); - queue_work(ctx->sqo_wq, &req->work); + if (!io_add_to_prev_work(list, req)) { + if (list) + atomic_inc(&list->cnt); + INIT_WORK(&req->work, io_sq_wq_submit_work); + queue_work(ctx->sqo_wq, &req->work); + } ret = 0; } if (ret) From patchwork Fri Feb 8 17:34:23 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10803539 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B3AEA1390 for ; Fri, 8 Feb 2019 17:38:39 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A1B072DCE1 for ; Fri, 8 Feb 2019 17:38:39 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 94AB22E147; Fri, 8 Feb 2019 17:38:39 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 40D3B2DCE1 for ; 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Fri, 08 Feb 2019 09:35:11 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 19/19] io_uring: add io_uring_event cache hit information Date: Fri, 8 Feb 2019 10:34:23 -0700 Message-Id: <20190208173423.27014-20-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add hint on whether a read was served out of the page cache, or if it hit media. This is useful for buffered async IO, O_DIRECT reads would never have this set (for obvious reasons). If the read hit page cache, cqe->flags will have IOCQE_FLAG_CACHEHIT set. Signed-off-by: Jens Axboe --- fs/io_uring.c | 7 ++++++- include/uapi/linux/io_uring.h | 5 +++++ 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 175dac00eb47..48e864de5dca 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -583,11 +583,16 @@ static void io_fput(struct io_kiocb *req) static void io_complete_rw(struct kiocb *kiocb, long res, long res2) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw); + unsigned ev_flags = 0; kiocb_end_write(kiocb); io_fput(req); - io_cqring_add_event(req->ctx, req->user_data, res, 0); + + if (res > 0 && (req->flags & REQ_F_FORCE_NONBLOCK)) + ev_flags = IOCQE_FLAG_CACHEHIT; + + io_cqring_add_event(req->ctx, req->user_data, res, ev_flags); io_free_req(req); } diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index e23408692118..24906e99fdc7 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -69,6 +69,11 @@ struct io_uring_cqe { __u32 flags; }; +/* + * io_uring_event->flags + */ +#define IOCQE_FLAG_CACHEHIT (1U << 0) /* IO did not hit media */ + /* * Magic offsets for the application to mmap the data it needs */