From patchwork Mon Jan 28 21:35:28 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 10784869 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 156EB1390 for ; Mon, 28 Jan 2019 21:36:02 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 032AF2B363 for ; Mon, 28 Jan 2019 21:36:02 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EBA3C2B52C; Mon, 28 Jan 2019 21:36:01 +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 76DE82B363 for ; Mon, 28 Jan 2019 21:36:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728233AbfA1VgA (ORCPT ); Mon, 28 Jan 2019 16:36:00 -0500 Received: from mail-io1-f67.google.com ([209.85.166.67]:41522 "EHLO mail-io1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728153AbfA1VgA (ORCPT ); Mon, 28 Jan 2019 16:36:00 -0500 Received: by mail-io1-f67.google.com with SMTP id s22so14830099ioc.8 for ; Mon, 28 Jan 2019 13:35:59 -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=G8T35uShc/XUaofaPvfFcDkbFt1ms1TuRNJTOihxJHM=; b=yy3mu54Fhd8QJPS+6wdw2+/rgn7hGj1wRfYgeMG50/QXevDFNNpp5fEYbtyP229GVQ pXnRR8RZassVpIrGx8N6PJ9rimx9RInVeLM8YnHq6LBGvnzRYjjiJgavGBrleYFPliGE c0mLxvyTVbyC779dZnt5Ud1+xp9rwBW12qk3lMCrxP+dFBvimRmAHsv6GURQ8lAg+Krs /gCiVdc1RVYY/PiO6Ofytg6VWPKNEeRqPaGgbEOXTxyOo1vY2/73Y8QmR1lqrvUPFztM NSHT8j5hUR+vF8e8iCFSrjn3yLEeSZL9BhllHEquMgOIdzU3e9fsxm1pBu669Zz0pXYW i6CA== 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=G8T35uShc/XUaofaPvfFcDkbFt1ms1TuRNJTOihxJHM=; b=qxjS0YMobMce3rReN54xsCbLHBmHjuDesjKnfsf3nvUfg2E9A9whyDmdykCds0jTT1 PxWNpGLAXBSq21/4gi0eFlVL9+4j2aya8sNjm+hIt3ffcz6WhcL2LRf6v5nuVrfl88gt vLk/D9OaHNYdWIrsdMBlD+f+YGXixOrsjNyVD2kG6TN4ttb34hFSJHbxjNxPeJ57NiRa WZwW/c8MrTD5EM7gf8hh5Muyg/FduXGT9dJeEmo46F5+eN+UpENyN/ZnYkNRg+h7s+HL zunuLHQgtBxL6X7z9F+AyzdX+EKl8Iom/CCA0JUBdRYUeeJp9PVut9R/aVeG2LjGolww tbtg== X-Gm-Message-State: AHQUAuaDS50EMrSws1jEUNIZPQIzgkJ5zinkLPrSR8VkKDU17bd2xOg8 BKEqUqlcvpU2cvaGfFuH/Zes+g== X-Google-Smtp-Source: ALg8bN4Q1NfwTS9vXRFtmlXIGbid0KjJZesm/qZI9dsB2UCGIs6whysNtqVmiM4SXsiCJcnvqBAfNg== X-Received: by 2002:a6b:3a45:: with SMTP id h66mr13185409ioa.156.1548711359049; Mon, 28 Jan 2019 13:35:59 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id u25sm13782077iob.23.2019.01.28.13.35.57 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Jan 2019 13:35:58 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe Subject: [PATCH 08/18] fs: add fget_many() and fput_many() Date: Mon, 28 Jan 2019 14:35:28 -0700 Message-Id: <20190128213538.13486-9-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> References: <20190128213538.13486-1-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 --- 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 ccb0b7a63aa5..acaad78b6781 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)