From: Shuah Khan <shuahkhan@gmail.com>
To: Fabio Baltieri <fabio.baltieri@gmail.com>
Cc: shuahkhan@gmail.com, Bryan Wu <bryan.wu@canonical.com>,
linux-leds@vger.kernel.org, rpurdie@rpsys.net,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 25/25] leds: convert One-shot LED trigger driver to devm_kzalloc() and cleanup error exit path
Date: Thu, 05 Jul 2012 14:35:28 -0600 [thread overview]
Message-ID: <1341520528.3076.3.camel@lorien2> (raw)
In-Reply-To: <20120705194828.GA1563@gmail.com>
On Thu, 2012-07-05 at 21:48 +0200, Fabio Baltieri wrote:
> > >
> > 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.
>
> Shuah,
>
> I'm as the same opinion - as triggers are not really "driver", in the
> sense that they are not using the driver structures, using devm_
> functions doesn't seems to be really appropriate.
>
Correct. Each driver could support multiple triggers and triggers are
not at the same level as the device.
> Specifically:
>
> > > + oneshot_data = devm_kzalloc(led_cdev->dev, sizeof(*oneshot_data),
> > > + GFP_KERNEL);
>
> this one is registering the data on the relative LED's resources, so
> that they are not freed until you unload the LED's driver itself.
> I also think that this leads to memory leak if you keep activating
> triggers, as the deactivate function is not actually freeing the
> resources, so in that case the correct procedure should be the usual
> kalloc/kfree.
>
> Is this consistent with what your conclusions, Shuah?
Correct. Using devm_ in triggers is not the correct and there is no need
to change from using kalloc()/kfree().
-- Shuah
>
> Fabio
>
> > 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
> >
> > --
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next prev parent reply other threads:[~2012-07-05 20:35 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-04 5:09 [PATCH 00/25] leds: convert all kzalloc() to devm_kzalloc() Bryan Wu
2012-07-04 5:09 ` [PATCH 01/25] leds: convert Big Networks LED driver " Bryan Wu
2012-07-04 5:09 ` [PATCH 02/25] leds: convert HTC ASIC3 LED driver to devm_kzalloc() and cleanup error exit path Bryan Wu
2012-07-04 5:09 ` [PATCH 03/25] leds: convert Atmel PWM LED driver to devm_kzalloc() Bryan Wu
2012-07-04 5:09 ` [PATCH 04/25] leds: convert LP3944 " Bryan Wu
2012-07-04 7:34 ` Bryan Wu
2012-07-04 5:09 ` [PATCH 05/25] leds: convert DA9030/DA9034 LED driver to devm_kzalloc() and cleanup error exit path Bryan Wu
2012-07-04 5:09 ` [PATCH 06/25] leds: convert LP5521 " Bryan Wu
2012-07-04 7:35 ` Bryan Wu
2012-07-04 5:09 ` [PATCH 07/25] leds: convert BD2802 RGB " Bryan Wu
2012-07-04 5:10 ` [PATCH 08/25] leds: convert PCA9633 LED driver to devm_kzalloc() Bryan Wu
2012-07-04 5:10 ` [PATCH 09/25] leds: convert LP5523 LED driver to devm_kzalloc() and cleanup error exit path Bryan Wu
2012-07-04 5:10 ` [PATCH 10/25] leds: convert Renesas TPU " Bryan Wu
2012-07-04 5:10 ` [PATCH 11/25] leds: convert LT3593 LED driver to devm_kzalloc() Bryan Wu
2012-07-04 5:10 ` [PATCH 12/25] leds: convert PCA9532 " Bryan Wu
2012-07-04 5:10 ` [PATCH 13/25] leds: convert Sun Fire LED driver to devm_kzalloc() and cleanup error exit path Bryan Wu
2012-07-04 5:10 ` [PATCH 14/25] leds: convert PCA955x " Bryan Wu
2012-07-04 5:10 ` [PATCH 15/25] leds: convert ADP5520 " Bryan Wu
2012-07-04 7:40 ` Bryan Wu
2012-07-04 5:10 ` [PATCH 16/25] leds: convert Freescale MC13783 " Bryan Wu
2012-07-04 5:10 ` [PATCH 17/25] leds: convert TCA6507 LED driver to devm_kzalloc() Bryan Wu
2012-07-04 5:10 ` [PATCH 18/25] leds: convert LM3530 LED driver to devm_kzalloc() and cleanup error exit path Bryan Wu
2012-07-05 0:01 ` Linus Walleij
2012-07-04 5:10 ` [PATCH 19/25] leds: convert DAC124S085 LED driver to devm_kzalloc() Bryan Wu
2012-07-04 5:10 ` [PATCH 20/25] leds: convert Network Space v2 LED driver to devm_kzalloc() and cleanup error exit path Bryan Wu
2012-07-04 5:10 ` [PATCH 21/25] leds: convert transient LED trigger driver to devm_kzalloc() Bryan Wu
2012-07-05 16:42 ` Shuah Khan
2012-07-04 5:10 ` [PATCH 22/25] leds: convert GPIO LED trigger driver to devm_kzalloc() and cleanup error exit path Bryan Wu
2012-07-05 16:45 ` Shuah Khan
2012-07-04 5:10 ` [PATCH 23/25] leds: convert Backlight emulation " Bryan Wu
2012-07-05 16:46 ` Shuah Khan
2012-07-04 5:10 ` [PATCH 24/25] leds: convert Heartbeat LED trigger driver to devm_kzalloc() Bryan Wu
2012-07-05 16:46 ` Shuah Khan
2012-07-04 5:10 ` [PATCH 25/25] leds: convert One-shot LED trigger driver to devm_kzalloc() and cleanup error exit path Bryan Wu
2012-07-05 16:47 ` Shuah Khan
2012-07-05 19:48 ` Fabio Baltieri
2012-07-05 20:35 ` Shuah Khan [this message]
2012-07-06 4:02 ` Bryan Wu
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