Re: [PATCH RFC] fs/aio: fix sleeping while TASK_INTERRUPTIBLE

[Chris Mason <clm@fb.com>]

On Tue, Jan 13, 2015 at 11:06 AM, Benjamin LaHaise <bcrl@kvack.org> 
wrote:
> Hi Chris,
> 
> On Mon, Dec 22, 2014 at 07:16:25PM -0500, Chris Mason wrote:
>>  The 3.19 merge window brought in a great new warning to catch 
>> someone
>>  calling might_sleep with their state != TASK_RUNNING.  The idea was 
>> to
>>  find buggy code locking mutexes after calling prepare_to_wait(), 
>> kind
>>  of like this:
> ...
>>  This has been lightly tested and hasn't been benchmarked, so RFC for
>>  now.
>> 
>>  Signed-off-by: Chris Mason <clm@fb.com>
>>  Reported-by: The code of Peter Zijlstra <peterz@infradead.org>
> 
> After mulling this over, I think your patch is probably the safest 
> for us
> to apply at present as it is also the most amenable to backporting.  
> Are
> you okay with removing the RFC status?  I still have my concerns about
> possible task wakeups causing problems with filesystem code if the
> copy_to_user() takes a page fault, but those can be addressed 
> separately.
> Kent's closures are an option for the future, but I think it would be
> more appropriate for that new code to be introduced in the next merge
> window.

I'll resend the patch with improved comments, and get perf tests done 
on fast storage.

-chris

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