linux-kernel - Re: [PATCH] kernel/workqueue.c: need call device_remove_file() when failure occurs after called device_create

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Date:	Fri, 17 May 2013 10:51:49 +0800
From:	Chen Gang <gang.chen@...anux.com>
To:	Tejun Heo <tj@...nel.org>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] kernel/workqueue.c: need call device_remove_file() when
 failure occurs after called device_create_file()

On 05/17/2013 01:50 AM, Tejun Heo wrote:
> Hey,
> 
> On Thu, May 16, 2013 at 12:48:43PM +0800, Chen Gang wrote:
>> __sysfs_remove_dir() remove all related things, but not deref the count.
>>
>> For __sysfs_remove_dir() ->
>>   ...
>>   sysfs_addrm_start()
>>   ...
>>   while() {
>>     ...
>>     sysfs_remove_one()  (not deref the related file)
>>   }
>>   sysfs_addrm_finish()  (will deref current dir)
>>
>> For device_remove_file() ->
>>   sysfs_remove_file() ->
>>     sysfs_hash_and_remove() ->
>>       ...
>>       sysfs_addrm_start()
>>       ...
>>       sysfs_remove_one() (not deref the current file)
>>       sysfs_addrm_finish()  (will deref current file)
>>
>>
>> So if not call device_remove_file() firstly, the all files under the
>> directory are removed, but the related resources are not released which
>> will cause resource leak.
> 
> Can you please be more specific on what gets leaked and if possible
> fix it from sysfs side?
> 

Oh, it is my fault. It is not the correct reason.

But I will continue to analyse why it should be add device_remove_file()
before device_unregister() in all 'drivers/*' and 'arch/*' source files.


Thanks.
-- 
Chen Gang

Asianux Corporation
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