From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753349AbZGRPZ5 (ORCPT ); Sat, 18 Jul 2009 11:25:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752481AbZGRPZ5 (ORCPT ); Sat, 18 Jul 2009 11:25:57 -0400 Received: from mgw2.diku.dk ([130.225.96.92]:40072 "EHLO mgw2.diku.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751305AbZGRPZz (ORCPT ); Sat, 18 Jul 2009 11:25:55 -0400 Date: Sat, 18 Jul 2009 17:25:53 +0200 (CEST) From: Julia Lawall To: chris.mason@oracle.com, linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [PATCH 5/6] fs/btrfs: convert nested spin_lock_irqsave to spin_lock Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Julia Lawall If spin_lock_irqsave is called twice in a row with the same second argument, the interrupt state at the point of the second call overwrites the value saved by the first call. Indeed, the second call does not need to save the interrupt state, so it is changed to a simple spin_lock. The semantic match that finds this problem is as follows: (http://www.emn.fr/x-info/coccinelle/) // @@ expression lock1,lock2; expression flags; @@ *spin_lock_irqsave(lock1,flags) ... when != flags *spin_lock_irqsave(lock2,flags) // Signed-off-by: Julia Lawall --- fs/btrfs/async-thread.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c index 6e4f6c5..019e8af 100644 --- a/fs/btrfs/async-thread.c +++ b/fs/btrfs/async-thread.c @@ -424,11 +424,11 @@ int btrfs_requeue_work(struct btrfs_work *work) * list */ if (worker->idle) { - spin_lock_irqsave(&worker->workers->lock, flags); + spin_lock(&worker->workers->lock); worker->idle = 0; list_move_tail(&worker->worker_list, &worker->workers->worker_list); - spin_unlock_irqrestore(&worker->workers->lock, flags); + spin_unlock(&worker->workers->lock); } if (!worker->working) { wake = 1;