From patchwork Tue Jan 8 16:56:41 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10752539 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 992BC17E1 for ; Tue, 8 Jan 2019 16:57:19 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 836E128F9F for ; Tue, 8 Jan 2019 16:57:19 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 818E728FBA; Tue, 8 Jan 2019 16:57:19 +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 EDD5028F9F for ; Tue, 8 Jan 2019 16:57:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729235AbfAHQ5S (ORCPT ); Tue, 8 Jan 2019 11:57:18 -0500 Received: from mail-io1-f66.google.com ([209.85.166.66]:35066 "EHLO mail-io1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729219AbfAHQ5Q (ORCPT ); Tue, 8 Jan 2019 11:57:16 -0500 Received: by mail-io1-f66.google.com with SMTP id f4so3688931ion.2 for ; Tue, 08 Jan 2019 08:57:15 -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=Lz/3jHz1x36txQZ/D99mDx/1sUz8ZTGETsX8P4ZemoU=; b=GTw9t09Sg1AxtJ5+L7hLtOSEycum9LC9wgqFCHQ9uF75Dqqv442Kk5IWnZrDu00Yi0 7lyXBSzesZXeo5NpHfoRuNr1ndCPc+pedh3RljiZS/2VPEfC7xGYvJJWHKbCRu51NCsZ irRZq/pGVj79I22DkV6AU4wWKr9QgeRWF7cJkDOKUUNhwx5OiqXVNn8TX8pONZkmCF76 ds/P7H+Q6wgWz6bwxN7eSIIWnRvKFbL2vhewVKweNH9wkZxPeumRbsn8KyQxbdKTd7Fa +7iSPYIFhij2fOb8hNj8O8wNSHsRdXw/GtaFQY4UUDK3SFr5ob4IAeC+JLOy6GiNnk/V 7WLw== 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=Lz/3jHz1x36txQZ/D99mDx/1sUz8ZTGETsX8P4ZemoU=; b=SbQceyNuaqlgcYVXc/Ue5bXQ6fuZxsygKNCxmt3n+atxHSkCqurGGn4/HKCx5VBHYo Wmt5nUvSUktJGay+zgAz1Oe++uqj8PNG/BZ0ismlrqxcQAYRE7GeF8dAc5Yxhlmt+Fl1 XYTxeGG9hxt29cJ8laCTPTEfgcZuSi8iWl+ewZidRMx/HNkGj5EqHGxkV55gxYoyz2ZE vdNm9ZCCfYMiiFVSOnjLGIlVtZCYUA6WFfL+63MF2griQg4Vd9tajw+h+A9P4sl5Wa2/ lwtD+0Tfpy0QT9muhTA2bR0toXnKgUS3fC71xDUO/vr/7tgz5kG6Zm1LlDNsXth0Ghmy OyTw== X-Gm-Message-State: AJcUukeY98wKySjHnxjY8WeAEJT0jOJIHc228ut9+DBN5d9DxWfjBq4m Ri5J3H3gQzXANpyFN5cALlahuGu70Q9zog== X-Google-Smtp-Source: ALg8bN4GaweI0iaMptEgJJ71xKVQKMRUtVLv45mHwX1U8C/cBBILXlgWDeHxCpbxHZlUhxCxIg00pA== X-Received: by 2002:a6b:dd0b:: with SMTP id f11mr1588813ioc.45.1546966634597; Tue, 08 Jan 2019 08:57:14 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id m10sm17563442ioq.25.2019.01.08.08.57.12 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 08 Jan 2019 08:57:13 -0800 (PST) From: Jens Axboe To: linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-block@vger.kernel.org, linux-arch@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 12/16] block: implement bio helper to add iter bvec pages to bio Date: Tue, 8 Jan 2019 09:56:41 -0700 Message-Id: <20190108165645.19311-13-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190108165645.19311-1-axboe@kernel.dk> References: <20190108165645.19311-1-axboe@kernel.dk> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@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_HOLD_PAGES 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. Signed-off-by: Jens Axboe --- 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..7af4f45d2ed6 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_HOLD_PAGES 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_HOLD_PAGES); + 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_HOLD_PAGES)) + 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_HOLD_PAGES)) + bio_release_pages(bio); bio_put(bio); return; defer: diff --git a/fs/block_dev.c b/fs/block_dev.c index 2ebd2a0d7789..b7742014c9de 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -324,8 +324,9 @@ 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_HOLD_PAGES)) + 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 4ee50b76b4a1..0a64c9c51203 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -1582,8 +1582,9 @@ 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_HOLD_PAGES)) + 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 5c7e7f859a24..97e206855cd3 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -215,6 +215,7 @@ struct bio { /* * bio flags */ +#define BIO_HOLD_PAGES 0 /* don't put O_DIRECT 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 */