From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753204AbZGRPYC (ORCPT ); Sat, 18 Jul 2009 11:24:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753102AbZGRPYB (ORCPT ); Sat, 18 Jul 2009 11:24:01 -0400 Received: from mgw1.diku.dk ([130.225.96.91]:50594 "EHLO mgw1.diku.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752922AbZGRPYA (ORCPT ); Sat, 18 Jul 2009 11:24:00 -0400 Date: Sat, 18 Jul 2009 17:23:57 +0200 (CEST) From: Julia Lawall To: holt@sgi.com, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [PATCH 3/6] drivers/misc/sgi-xp: 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 --- drivers/misc/sgi-xp/xpc_uv.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/misc/sgi-xp/xpc_uv.c b/drivers/misc/sgi-xp/xpc_uv.c index c76677a..d0052ad 100644 --- a/drivers/misc/sgi-xp/xpc_uv.c +++ b/drivers/misc/sgi-xp/xpc_uv.c @@ -443,9 +443,9 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part, if (msg->activate_gru_mq_desc_gpa != part_uv->activate_gru_mq_desc_gpa) { - spin_lock_irqsave(&part_uv->flags_lock, irq_flags); + spin_lock(&part_uv->flags_lock); part_uv->flags &= ~XPC_P_CACHED_ACTIVATE_GRU_MQ_DESC_UV; - spin_unlock_irqrestore(&part_uv->flags_lock, irq_flags); + spin_unlock(&part_uv->flags_lock); part_uv->activate_gru_mq_desc_gpa = msg->activate_gru_mq_desc_gpa; }