From: Dmitry Torokhov <dtor@insightbb.com>
To: "Yin,Fengwei" <yfw.kernel@gmail.com>
Subject: Re: Is this a preempt issue in drivers/input/evdev.c
Date: Sat, 12 May 2007 01:05:40 -0400
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Hi,

On Friday 11 May 2007 23:18, Yin,Fengwei wrote:
> 
> So if the evdev_release() is preempted at the point marked by another
> process which will open the evdev, which will make operation sequence
> like:
> 
>    --evdev->open in evdev_release()
>          -----> preempted
> 	                            evdev->open++ and input_open_devie()
> 	 <----- reschedule 
> 	input_close_device()
> 
> Should we introduce a mutex here? Or do I miss something? Thanks.
> 

Locking is completely absent in evdev. There was a patch introducing
locking in recent -mm's but it got dropped. I need to refresh it.

-- 
Dmitry
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