linux-kernel - Re: [PATCH v2 4/4] platform/x86: ideapad-laptop: add a mutex to synchronize VPC commands

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Message-ID: <53b247e1-62cf-4289-8ad6-2138a1757e06@redhat.com>
Date: Thu, 18 Jul 2024 10:12:06 +0200
From: Hans de Goede <hdegoede@...hat.com>
To: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
 Gergo Koteles <soyer@....hu>
Cc: Ike Panhc <ike.pan@...onical.com>, platform-driver-x86@...r.kernel.org,
 LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 4/4] platform/x86: ideapad-laptop: add a mutex to
 synchronize VPC commands

Hi,

On 7/18/24 10:06 AM, Ilpo Järvinen wrote:
> On Thu, 18 Jul 2024, Gergo Koteles wrote:
> 
>> Calling VPC commands consists of several VPCW and VPCR ACPI calls.
>> These calls and their results can get mixed up if they are called
>> simultaneously from different threads, like acpi notify handler,
>> sysfs, debugfs, notification chain.
>>
>> Add a mutex to synchronize VPC commands.
>>
>> Signed-off-by: Gergo Koteles <soyer@....hu>
>> ---
> 
>> @@ -2027,6 +2053,8 @@ static int ideapad_acpi_add(struct platform_device *pdev)
>>  	priv->adev = adev;
>>  	priv->platform_device = pdev;
>>  
>> +	mutex_init(&priv->vpc_mutex);
>> +
>>  	ideapad_check_features(priv);
>>  
>>  	err = ideapad_sysfs_init(priv);
> 
> mutex_destroy() missing from rollback and ideapad_acpi_remove().

Right, note the easiest way to fix this is to use the new devm_mutex_init()
instead of plain mutex_init() that will also take care of destroying the mutex
on any exit-on-error cases from probe().

Regards,

Hans