Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753156Ab0KVJ7g (ORCPT ); Mon, 22 Nov 2010 04:59:36 -0500 Received: from 93-97-173-237.zone5.bethere.co.uk ([93.97.173.237]:64798 "EHLO tim.rpsys.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752750Ab0KVJ7f (ORCPT ); Mon, 22 Nov 2010 04:59:35 -0500 Subject: Re: [PATCH] backlight: grab ops_lock before testing bd->ops From: Richard Purdie To: Uwe =?ISO-8859-1?Q?Kleine-K=F6nig?= , akpm Cc: linux-kernel@vger.kernel.org, kernel@pengutronix.de In-Reply-To: <1290418989-27653-1-git-send-email-u.kleine-koenig@pengutronix.de> References: <1290418989-27653-1-git-send-email-u.kleine-koenig@pengutronix.de> Content-Type: text/plain; charset="UTF-8" Date: Mon, 22 Nov 2010 09:59:07 +0000 Message-ID: <1290419947.1272.16677.camel@rex> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1974 Lines: 56 On Mon, 2010-11-22 at 10:43 +0100, Uwe Kleine-König wrote: > According to the comment describing ops_lock in the definition of > struct backlight_device and when comparing with other functions in > backlight.c the mutex must be hold when checking ops to be non-NULL. > > Signed-off-by: Uwe Kleine-König Acked-by: Richard Purdie > --- > drivers/video/backlight/backlight.c | 12 ++++++------ > 1 files changed, 6 insertions(+), 6 deletions(-) > > diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c > index e207810..0870329 100644 > --- a/drivers/video/backlight/backlight.c > +++ b/drivers/video/backlight/backlight.c > @@ -197,12 +197,12 @@ static int backlight_suspend(struct device *dev, pm_message_t state) > { > struct backlight_device *bd = to_backlight_device(dev); > > - if (bd->ops->options & BL_CORE_SUSPENDRESUME) { > - mutex_lock(&bd->ops_lock); > + mutex_lock(&bd->ops_lock); > + if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) { > bd->props.state |= BL_CORE_SUSPENDED; > backlight_update_status(bd); > - mutex_unlock(&bd->ops_lock); > } > + mutex_unlock(&bd->ops_lock); > > return 0; > } > @@ -211,12 +211,12 @@ static int backlight_resume(struct device *dev) > { > struct backlight_device *bd = to_backlight_device(dev); > > - if (bd->ops->options & BL_CORE_SUSPENDRESUME) { > - mutex_lock(&bd->ops_lock); > + mutex_lock(&bd->ops_lock); > + if (bd->ops && bd->ops->options & BL_CORE_SUSPENDRESUME) { > bd->props.state &= ~BL_CORE_SUSPENDED; > backlight_update_status(bd); > - mutex_unlock(&bd->ops_lock); > } > + mutex_unlock(&bd->ops_lock); > > return 0; > } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/