From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7FB60C43441 for ; Mon, 26 Nov 2018 16:46:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 48DCB20659 for ; Mon, 26 Nov 2018 16:46:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="TsiE6o8E" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 48DCB20659 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-block-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727140AbeK0DlG (ORCPT ); Mon, 26 Nov 2018 22:41:06 -0500 Received: from mail-it1-f193.google.com ([209.85.166.193]:37833 "EHLO mail-it1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727131AbeK0DlG (ORCPT ); Mon, 26 Nov 2018 22:41:06 -0500 Received: by mail-it1-f193.google.com with SMTP id b5so28759200iti.2 for ; Mon, 26 Nov 2018 08:46:26 -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=14kCfLiACV93AenWhL1xKvUDPabDTnEKBX7DXRr/kpI=; b=TsiE6o8Eb0baO9E/R/9Y+x1GNi8Ll19OJN+fBlr0JSLeQPh2XnDuYYnmupv0xtiIGy wsb0mw2JZkLxf8ZkQAzgQ7YLL12/4pRFYwm4Y4nPgo4jibzhvUeNfcvC0cKsdUYKhRsz CmALeNil06mvEh9rmSE1+xpBZUzhystU5aUncZdfB3tRDrvptSFOgUaEiiYOR/zlvy+y 2llqHNFHKTY4MSoVpgiFfOHvrx5AEfsQ6dsR7Vq9I6jn5y1udh9ECbsoXfUdwVFYOMwm xNx2eNfYJCmORjkGQPEriidigQKdwDNiz+r0dbZkLGhKcwv/AAFFSpV6W+DK0OeTV8SY 5onw== 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=14kCfLiACV93AenWhL1xKvUDPabDTnEKBX7DXRr/kpI=; b=o8CMrtxD+IzXj0xoU/U30dmkeDOZVsn7rWn6ZPkp/8/SsVjIgvzxtoLj4t3Sfx2G4B gdtbnKun/Op06y0bcjQaTxxUK1u7rmKKcj1tWM0YkqvuaaUuUbxfKzXb/H9eM8EOTlHt eK0FjE94dHMwiOhwSPHWRYTsg4+ZH8tSNwvsIuhnnRRgwPqSY++PAfd1I7/ziIdXPuUH 7e56NpWV9WZR+YUYsdfC92QpQ4fEkJuGhwx23RK0K2aW0rpUwSov1PJHhHMQ4bzAZF1O DiNxBUtHfUT4FyrO6XY7wd9NSSXj7m+bMOMdr1et3EqG9a5l14+Lty26hpbdBsn3rabd A4ag== X-Gm-Message-State: AGRZ1gI11JUGHN0NxG+78Z6ERAAsr2+XGBZvXrfR/XUAOePCf9SX6KzH 7+P81D/q7vW8TenVfzr3TQegAeXDTDg= X-Google-Smtp-Source: AFSGD/W0/Ihdfel1+3+1K66f2K+U9pBnmMyGYfrv5GLw2DRIQGsnMawLkeCIlfUSbBEvSDaV5SRrBA== X-Received: by 2002:a02:4352:: with SMTP id s79mr23135746jab.124.1543250785780; Mon, 26 Nov 2018 08:46:25 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id t65-v6sm486801ita.9.2018.11.26.08.46.23 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 26 Nov 2018 08:46:24 -0800 (PST) From: Jens Axboe To: linux-block@vger.kernel.org, linux-aio@kvack.org, linux-fsdevel@vger.kernel.org Cc: Jens Axboe Subject: [PATCH 19/20] fs: add fget_many() and fput_many() Date: Mon, 26 Nov 2018 09:45:43 -0700 Message-Id: <20181126164544.5699-20-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181126164544.5699-1-axboe@kernel.dk> References: <20181126164544.5699-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org 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. Signed-off-by: Jens Axboe --- fs/file.c | 15 ++++++++++----- fs/file_table.c | 10 ++++++++-- include/linux/file.h | 2 ++ include/linux/fs.h | 3 ++- 4 files changed, 22 insertions(+), 8 deletions(-) diff --git a/fs/file.c b/fs/file.c index 7ffd6e9d103d..ad9870edfd51 100644 --- a/fs/file.c +++ b/fs/file.c @@ -676,7 +676,7 @@ 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; @@ -691,7 +691,7 @@ 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(); @@ -699,15 +699,20 @@ 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_many(fd, 1); } EXPORT_SYMBOL(fget); struct file *fget_raw(unsigned int fd) { - return __fget(fd, 0); + return __fget(fd, 0, 1); } EXPORT_SYMBOL(fget_raw); @@ -738,7 +743,7 @@ 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 e49af4caf15d..6a3964df33e4 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 +347,12 @@ 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 6a5f71f8ae06..dc54a65c401a 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -952,7 +952,8 @@ 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) -- 2.17.1