From patchwork Mon Sep 14 13:45:53 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 7176381 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 62E369F314 for ; Mon, 14 Sep 2015 13:51:10 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 4F389205B1 for ; Mon, 14 Sep 2015 13:51:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4945A205DB for ; Mon, 14 Sep 2015 13:51:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753310AbbINNu6 (ORCPT ); Mon, 14 Sep 2015 09:50:58 -0400 Received: from mail-yk0-f173.google.com ([209.85.160.173]:36134 "EHLO mail-yk0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753499AbbINNqD (ORCPT ); Mon, 14 Sep 2015 09:46:03 -0400 Received: by ykdt18 with SMTP id t18so132496904ykd.3 for ; Mon, 14 Sep 2015 06:46:03 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=MMKA+9vKn4JQVFSJOL+UE2mCHh+MZdbKbntJrdPT2zw=; b=h04TyjwbhYpGT+hJU4wL7CrTpp9ddrH7RcVRhWKnWLlgb93SSqNFqkOJBZG0dVVFYa a8DkhOpXEUsFFaYY+GIUibzh7qZPMf+CfwYdujiQUSsynO59bVWtIFdKlljFIIIwoqoN kB0uPn2rP3goxO9OeT8+WP/UZl1nKCp7DHUr66qrbC41ByGmqySa4uYKfumphnDB76h8 PF7oObT22Cw+sexbOYmiHes3FGBrU0blp/w7JfDGnnsMLTJYU2axJryNG9r27OCBlQmL l2/ZfIn9L4pd6RLfcuIPIy2yWFx9dZ26tiWGLKnChKNff3KiUOKK3022IU/VdRrNCoSO qB5A== X-Gm-Message-State: ALoCoQns8G7JIgaO3ILJ2LtW8G4PbJp3il/n+6p6DEnhkaTPzL+UcKNqAo03YtIxTvVGS3JYLlyu X-Received: by 10.129.95.10 with SMTP id t10mr13630365ywb.100.1442238363304; Mon, 14 Sep 2015 06:46:03 -0700 (PDT) Received: from tlielax.poochiereds.net ([2606:a000:1105:8e:3a60:77ff:fe93:a95d]) by smtp.googlemail.com with ESMTPSA id a4sm9601131ywc.15.2015.09.14.06.46.02 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 14 Sep 2015 06:46:02 -0700 (PDT) From: Jeff Layton X-Google-Original-From: Jeff Layton To: Al Viro Cc: bfields@fieldses.org, linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/4] fs: add a kerneldoc header to fput Date: Mon, 14 Sep 2015 09:45:53 -0400 Message-Id: <1442238355-8203-3-git-send-email-jeff.layton@primarydata.com> X-Mailer: git-send-email 2.4.3 In-Reply-To: <1442238355-8203-1-git-send-email-jeff.layton@primarydata.com> References: <1442238355-8203-1-git-send-email-jeff.layton@primarydata.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP ...and move its EXPORT_SYMBOL just below the function. Signed-off-by: Jeff Layton --- fs/file_table.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/fs/file_table.c b/fs/file_table.c index f4833af62eae..d63f4a399d39 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -260,6 +260,21 @@ void flush_delayed_fput(void) flush_delayed_work(&delayed_fput_work); } +/** + * fput - put a struct file reference + * @file: file of which to put the reference + * + * This function decrements the reference count for the struct file reference, + * and queues it up for destruction if the count goes to zero. In the case of + * most tasks we queue it to the task_work infrastructure, which will be run + * just before the task returns back to userspace. kthreads however never + * return to userspace, so for those we add them to a global list and schedule + * a delayed workqueue job to do the work of putting them. + * + * Why not just do it synchronously? __fput can be quite stack intensive, so + * doing a final fput has the possibility of blowing up if we don't take steps + * to ensure that we have enough stack space to make it work. + */ void fput(struct file *file) { if (atomic_long_dec_and_test(&file->f_count)) { @@ -280,6 +295,7 @@ void fput(struct file *file) schedule_delayed_work(&delayed_fput_work, 1); } } +EXPORT_SYMBOL(fput); /* * synchronous analog of fput(); for kernel threads that might be needed @@ -298,7 +314,6 @@ void __fput_sync(struct file *file) } } -EXPORT_SYMBOL(fput); void put_filp(struct file *file) {