From patchwork Tue Nov 17 11:52:25 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 7635991 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 A25FE9F1D3 for ; Tue, 17 Nov 2015 11:53:33 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B914A204FC for ; Tue, 17 Nov 2015 11:53:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C5AD2204EA for ; Tue, 17 Nov 2015 11:53:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753378AbbKQLxZ (ORCPT ); Tue, 17 Nov 2015 06:53:25 -0500 Received: from mail-qk0-f173.google.com ([209.85.220.173]:36783 "EHLO mail-qk0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753345AbbKQLxV (ORCPT ); Tue, 17 Nov 2015 06:53:21 -0500 Received: by qkda6 with SMTP id a6so1673794qkd.3 for ; Tue, 17 Nov 2015 03:53:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=poochiereds_net.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=fTluOW3aLuu9Xqzk9iCLL55rdQeE3gmc4MiX7Yolljw=; b=yPiSgyroS36NYNvx4HfFM/lkRazrSO1tWc8fwcM0rKrczwFNxi9sbxpk05Er9Jksxx +7n6XzVEv0Evg5UpZnHrt/ovG6Da90qaWZ9y6sHYK9zQxHaey/pWhO4VsLT0KjA4TuDl ylsFwRCU8xeC5IureXZ31LP6PvVyGalmVA9hd8RsQqzcweMRb1HiX0mqv/5GAC7whao4 KbkNCcMKVEIHkGiHu8snKDOBI/FATU357JvFoHl5j/FsaBS7eG67D2GeDAQ2Zl/li8BY rhDx4UQsVS6/pDHYnATmgcUmUHyKotS804cVb7UgV6FJ2uzKZRsE6F9WIIXYuufqgGND be3Q== 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=fTluOW3aLuu9Xqzk9iCLL55rdQeE3gmc4MiX7Yolljw=; b=Rax6i9qrhSObre3IRnFxlTly50wLNKfV7CHgSRTWRhVF+jFOu0MjvuZI/jVYHiy2C/ fGBmQSdVvXpa96j/vGC4UkO6StEYNQ8IJqVC452KuMSV2MNQov7Vr4EVozb/QkL8vil/ BwgB70fXIyn9z6VN08s+qJInjyOLcTfEP1V+TfbXtZPOPNAIlaPVk6Wnkke6GHkJ2vt4 EbzbEFuA4+tPgBc97eYZkxkuzbvoQxlR9vPe2FSLK5mYc78j4692tCMlxHcaq73LvChl 6FrweVOqPu0ZO08aoVJEzsQ/EOD4NwrdQLF2ZH3FyNLT2ZAE2gRBz/eGLatBR1FNhaEk iX+Q== X-Gm-Message-State: ALoCoQn6YmYI+xQ9Bqn+r3majeGgsDXg/jUUrwPzGjNqka74qtLe9xrovVWODPDM1nwhbCzuwehJ X-Received: by 10.55.78.70 with SMTP id c67mr23950271qkb.37.1447761200626; Tue, 17 Nov 2015 03:53:20 -0800 (PST) Received: from tlielax.poochiereds.net ([2606:a000:1125:4075::d5a]) by smtp.googlemail.com with ESMTPSA id w10sm1583910qhc.16.2015.11.17.03.53.19 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 17 Nov 2015 03:53:19 -0800 (PST) From: Jeff Layton X-Google-Original-From: Jeff Layton To: bfields@fieldses.org, trond.myklebust@primarydata.com Cc: linux-nfs@vger.kernel.org, Eric Paris , Alexander Viro , linux-fsdevel@vger.kernel.org Subject: [PATCH v1 03/38] fs: add a kerneldoc header to fput Date: Tue, 17 Nov 2015 06:52:25 -0500 Message-Id: <1447761180-4250-4-git-send-email-jeff.layton@primarydata.com> X-Mailer: git-send-email 2.4.3 In-Reply-To: <1447761180-4250-1-git-send-email-jeff.layton@primarydata.com> References: <1447761180-4250-1-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=-7.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,T_DKIM_INVALID,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. Cc: Al Viro Signed-off-by: Jeff Layton --- fs/file_table.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/fs/file_table.c b/fs/file_table.c index 52cc6803c07a..8cfeaee6323f 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -261,6 +261,25 @@ 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 final cleanup work. + * + * Why not just do it synchronously? __fput can involve taking locks of all + * sorts, and doing it synchronously means that the callers must take extra care + * not to deadlock. That can be very difficult to ensure, so by deferring it + * until just before return to userland or to the workqueue, we sidestep that + * nastiness. Also, __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)) { @@ -281,6 +300,7 @@ 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 @@ -299,7 +319,6 @@ void __fput_sync(struct file *file) } } -EXPORT_SYMBOL(fput); void put_filp(struct file *file) {