Re: Synchronization mechanism between wait_for_completion_interruptible_timeout() & complete()

From: Naveen Kumar Parna
Date: Fri Mar 06 2015 - 03:34:59 EST


Thanks Michal.

Now I am clearing x->done to zero before
wait_for_completion_interruptible_timeout.

On Thu, Mar 5, 2015 at 6:53 PM, Michal Hocko <mhocko@xxxxxxx> wrote:
> On Wed 04-03-15 18:46:43, Naveen Kumar Parna wrote:
>> Hello,
>>
>> I have a question regarding the synchronization mechanism between
>> wait_for_completion_interruptible_timeout() & complete(). I used
>> complete() API in the ISR Tx interrupt path and
>> wait_for_completion_interruptible_timeout() in struct file_operations
>> .write method.
>>
>> Let assume a scenario in which Tx interrupt occurred and ISR called
>> complete() API before any process actually blocked at write method on
>> wait_for_completion_interruptible_timeout().
>>
>> After a few milli seconds, a process called write() API. Does it gets
>> blocked on wait_for_completion_interruptible_timeout() for completion
>> of a specific task to be signaled from new Tx interrupt?
>
> No, see do_wait_for_common resp. complete and x->done handling.
>
> --
> Michal Hocko
> SUSE Labs
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