Re: Usage of Semaphore with a workqueue

[Devesh Sharma <devesh28@xxxxxxxxx>]

Hello mulyadi,

Thanks for replying, sorry for late response comments are inline below

On Wed, Apr 1, 2009 at 10:14 PM, Mulyadi Santosa
<mulyadi.santosa@xxxxxxxxx> wrote:
> Hi
>
> On Wed, Apr 1, 2009 at 10:12 PM, Devesh Sharma <devesh28@xxxxxxxxx> wrote:
>> Hello list,
>>
>> Consider a case where I have a workqueue, a work is submitted to a it
>> from some interrupt handler
>> Lets say, some where in a code, it tries to get some semaphore to
>> enter into a critical section,
>> and fails to get it, sholud I still return from the work function by
>> returning ERESTARTSYS?
>> Kindly somebody clarify this to me
>
> To the best I know, when you fail to get semaphore, your code path
> will be blocked. Since you use workqueue which is able to sleep
> safely, I think you don't need to return ERESTARTSYS. The workqueue
> will sleep and try to reacquire the semaphore.
Do you mean there will not be any difference if I use
down_interruptible() or down() because
in workqueue context there is no way to send signal hence both will be
equivalant? So one must be careful
while designing semaphore/mutexs+workqueue because it can lead it to
infinite sleep?
>
> regards,
>
> Mulyadi.
>

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