From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933280Ab2GEQqY (ORCPT ); Thu, 5 Jul 2012 12:46:24 -0400 Received: from g6t0184.atlanta.hp.com ([15.193.32.61]:32670 "EHLO g6t0184.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756882Ab2GEQqW (ORCPT ); Thu, 5 Jul 2012 12:46:22 -0400 Message-ID: <1341506780.2605.9.camel@lorien2> Subject: Re: [PATCH 23/25] leds: convert Backlight emulation LED trigger driver to devm_kzalloc() and cleanup error exit path From: Shuah Khan Reply-To: shuahkhan@gmail.com To: Bryan Wu Cc: shuahkhan@gmail.com, linux-leds@vger.kernel.org, rpurdie@rpsys.net, linux-kernel@vger.kernel.org Date: Thu, 05 Jul 2012 10:46:20 -0600 In-Reply-To: <1341378617-10386-24-git-send-email-bryan.wu@canonical.com> References: <1341378617-10386-1-git-send-email-bryan.wu@canonical.com> <1341378617-10386-24-git-send-email-bryan.wu@canonical.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2012-07-04 at 13:10 +0800, Bryan Wu wrote: > Cc: Rodolfo Giometti > Signed-off-by: Bryan Wu > --- > drivers/leds/ledtrig-backlight.c | 10 +++------- > 1 file changed, 3 insertions(+), 7 deletions(-) > > diff --git a/drivers/leds/ledtrig-backlight.c b/drivers/leds/ledtrig-backlight.c > index b941685..3fa20a9 100644 > --- a/drivers/leds/ledtrig-backlight.c > +++ b/drivers/leds/ledtrig-backlight.c > @@ -101,7 +101,8 @@ static void bl_trig_activate(struct led_classdev *led) > > struct bl_trig_notifier *n; > > - n = kzalloc(sizeof(struct bl_trig_notifier), GFP_KERNEL); > + n = devm_kzalloc(led->dev, sizeof(struct bl_trig_notifier), > + GFP_KERNEL); > led->trigger_data = n; > if (!n) { > dev_err(led->dev, "unable to allocate backlight trigger\n"); > @@ -110,7 +111,7 @@ static void bl_trig_activate(struct led_classdev *led) > > ret = device_create_file(led->dev, &dev_attr_inverted); > if (ret) > - goto err_invert; > + led->trigger_data = NULL; > > n->led = led; > n->brightness = led->brightness; > @@ -123,10 +124,6 @@ static void bl_trig_activate(struct led_classdev *led) > led->activated = true; > > return; > - > -err_invert: > - led->trigger_data = NULL; > - kfree(n); > } > > static void bl_trig_deactivate(struct led_classdev *led) > @@ -137,7 +134,6 @@ static void bl_trig_deactivate(struct led_classdev *led) > if (led->activated) { > device_remove_file(led->dev, &dev_attr_inverted); > fb_unregister_client(&n->notifier); > - kfree(n); > led->activated = false; > } > } Bryan, I don't believe memory triggers allocate in their activate routine should be converted to devm_kzalloc(). Based on my understanding, the memory allocated using devm_kzalloc() us free'ed when driver is detached. In the case of led triggers, driver stays registered while the triggers it supports can be activated and deactivated many times. By converting these allocations into devm_kzalloc()s could lead to memory leaks. Please correct me if my understanding is incorrect. If what I am saying makes sense, please take this as comment that is applicable to all led triggers, not just this one. Thanks, -- Shuah