From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx3.wp.pl ([212.77.101.10]:52768 "EHLO mx3.wp.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750985AbaBHWXH (ORCPT ); Sat, 8 Feb 2014 17:23:07 -0500 Received: from ip-94-112-189-223.net.upcbroadband.cz (HELO localhost) (stf_xl@wp.pl@[94.112.189.223]) (envelope-sender ) by smtp.wp.pl (WP-SMTPD) with AES128-SHA encrypted SMTP for ; 8 Feb 2014 23:16:24 +0100 Date: Sat, 8 Feb 2014 23:18:43 +0100 From: Stanislaw Gruszka To: linux-btrfs@vger.kernel.org Subject: [PATCH] btrfs: always choose work from prio_head first Message-ID: <20140208221843.GA12866@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-btrfs-owner@vger.kernel.org List-ID: In case we do not refill, we can overwrite cur pointer from prio_head by one from not prioritized head, what looks as something that was not intended. This change make we always take works from prio_head first until it's not empty. Signed-off-by: Stanislaw Gruszka --- I found this by reading code, not sure if change is correct. Patch is only compile tested. fs/btrfs/async-thread.c | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c index c1e0b0c..0b78bf2 100644 --- a/fs/btrfs/async-thread.c +++ b/fs/btrfs/async-thread.c @@ -262,18 +262,19 @@ static struct btrfs_work *get_next_work(struct btrfs_worker_thread *worker, struct btrfs_work *work = NULL; struct list_head *cur = NULL; - if (!list_empty(prio_head)) + if (!list_empty(prio_head)) { cur = prio_head->next; + goto out; + } smp_mb(); if (!list_empty(&worker->prio_pending)) goto refill; - if (!list_empty(head)) + if (!list_empty(head)) { cur = head->next; - - if (cur) goto out; + } refill: spin_lock_irq(&worker->lock); -- 1.7.4.4