From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030183Ab2GEQq6 (ORCPT ); Thu, 5 Jul 2012 12:46:58 -0400 Received: from g5t0007.atlanta.hp.com ([15.192.0.44]:2181 "EHLO g5t0007.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932090Ab2GEQq5 (ORCPT ); Thu, 5 Jul 2012 12:46:57 -0400 Message-ID: <1341506814.2605.10.camel@lorien2> Subject: Re: [PATCH 24/25] leds: convert Heartbeat LED trigger driver to devm_kzalloc() 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 10:46:54 -0600 In-Reply-To: <1341378617-10386-25-git-send-email-bryan.wu@canonical.com> References: <1341378617-10386-1-git-send-email-bryan.wu@canonical.com> <1341378617-10386-25-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: Atsushi Nemoto > Signed-off-by: Bryan Wu > --- > drivers/leds/ledtrig-heartbeat.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/leds/ledtrig-heartbeat.c b/drivers/leds/ledtrig-heartbeat.c > index d3039f2..5caa01b 100644 > --- a/drivers/leds/ledtrig-heartbeat.c > +++ b/drivers/leds/ledtrig-heartbeat.c > @@ -75,7 +75,8 @@ static void heartbeat_trig_activate(struct led_classdev *led_cdev) > { > struct heartbeat_trig_data *heartbeat_data; > > - heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL); > + heartbeat_data = devm_kzalloc(led_cdev->dev, sizeof(*heartbeat_data), > + GFP_KERNEL); > if (!heartbeat_data) > return; > > @@ -93,7 +94,6 @@ static void heartbeat_trig_deactivate(struct led_classdev *led_cdev) > > if (led_cdev->activated) { > del_timer_sync(&heartbeat_data->timer); > - kfree(heartbeat_data); > led_cdev->activated = false; > } > } Bryan, 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