From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932201AbZHMUKQ (ORCPT ); Thu, 13 Aug 2009 16:10:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932124AbZHMUKM (ORCPT ); Thu, 13 Aug 2009 16:10:12 -0400 Received: from vena.lwn.net ([206.168.112.25]:46266 "EHLO vena.lwn.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932177AbZHMUKD (ORCPT ); Thu, 13 Aug 2009 16:10:03 -0400 Date: Thu, 13 Aug 2009 14:07:16 -0600 From: Jonathan Corbet To: LKML Cc: Ingo Molnar , Mark Gross , Andrew Morton , Frederic Weisbecker Subject: [PATCH 1/2] pm_qos: remove the BKL Message-ID: <20090813140716.4490ab37@bike.lwn.net> In-Reply-To: <20090813140554.014ce1e0@bike.lwn.net> References: <20090813140554.014ce1e0@bike.lwn.net> Organization: LWN.net X-Mailer: Claws Mail 3.7.2 (GTK+ 2.16.5; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org pm_qos_power_open got its lock_kernel() calls from the open() pushdown. A look at the code shows that the only global resources accessed are pm_qos_array and "name". pm_qos_array doesn't change (things pointed to therein do change, but they are atomics and/or are protected by pm_qos_lock). Accesses to "name" are totally unprotected with or without the BKL; that will be fixed shortly. The BKL is not helpful here; take it out. Signed-off-by: Jonathan Corbet Cc: Mark Gross --- kernel/pm_qos_params.c | 8 +------- 1 files changed, 1 insertions(+), 7 deletions(-) diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c index dfdec52..d96b83e 100644 --- a/kernel/pm_qos_params.c +++ b/kernel/pm_qos_params.c @@ -29,7 +29,6 @@ #include #include -#include #include #include #include @@ -352,20 +351,15 @@ static int pm_qos_power_open(struct inode *inode, struct file *filp) int ret; long pm_qos_class; - lock_kernel(); pm_qos_class = find_pm_qos_object_by_minor(iminor(inode)); if (pm_qos_class >= 0) { filp->private_data = (void *)pm_qos_class; sprintf(name, "process_%d", current->pid); ret = pm_qos_add_requirement(pm_qos_class, name, PM_QOS_DEFAULT_VALUE); - if (ret >= 0) { - unlock_kernel(); + if (ret >= 0) return 0; - } } - unlock_kernel(); - return -EPERM; } -- 1.6.2.5