From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756935Ab2GEQmz (ORCPT ); Thu, 5 Jul 2012 12:42:55 -0400 Received: from g6t0184.atlanta.hp.com ([15.193.32.61]:30328 "EHLO g6t0184.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751785Ab2GEQmx (ORCPT ); Thu, 5 Jul 2012 12:42:53 -0400 Message-ID: <1341506570.2605.6.camel@lorien2> Subject: Re: [PATCH 21/25] leds: convert transient 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 10:42:50 -0600 In-Reply-To: <1341378617-10386-22-git-send-email-bryan.wu@canonical.com> References: <1341378617-10386-1-git-send-email-bryan.wu@canonical.com> <1341378617-10386-22-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: Shuah Khan > Signed-off-by: Bryan Wu > --- > drivers/leds/ledtrig-transient.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/leds/ledtrig-transient.c b/drivers/leds/ledtrig-transient.c > index 398f104..8e30b0df 100644 > --- a/drivers/leds/ledtrig-transient.c > +++ b/drivers/leds/ledtrig-transient.c > @@ -161,7 +161,8 @@ static void transient_trig_activate(struct led_classdev *led_cdev) > int rc; > struct transient_trig_data *tdata; > > - tdata = kzalloc(sizeof(struct transient_trig_data), GFP_KERNEL); > + tdata = devm_kzalloc(led_cdev->dev, > + sizeof(struct transient_trig_data), GFP_KERNEL); > if (!tdata) { > dev_err(led_cdev->dev, > "unable to allocate transient trigger\n"); > @@ -194,7 +195,6 @@ err_out_duration: > err_out: > dev_err(led_cdev->dev, "unable to register transient trigger\n"); > led_cdev->trigger_data = NULL; > - kfree(tdata); > } > > static void transient_trig_deactivate(struct led_classdev *led_cdev) > @@ -209,7 +209,6 @@ static void transient_trig_deactivate(struct led_classdev *led_cdev) > device_remove_file(led_cdev->dev, &dev_attr_state); > led_cdev->trigger_data = NULL; > led_cdev->activated = false; > - kfree(transient_data); > } > } > 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 appicable to all led triggers, not just this one. Thanks, -- Shuah