Re: wait_event_interruptible() seems non-atomic

[Manfred Spraul <manfred@colorfullife.com>]

Jan Engelhardt wrote:

>>For example the use of down_interruptible() looks wrong to me, I'd use
>>plain down().
>>    
>>
>
>I'd like to be able to hit Ctrl+C (in the userspace application) whenever
>possible. If that's not a reason, blame the book
>http://www.xml.com/ldd/chapter/book/ch03.html#t8 ("the read method" a further
>down below)
>
>  
>
As far as I can see BufferLock is only held for tiny sections - the 
longest thing is a copy_to_user(), i.e. at worst a swap in. I my opinion 
the delay for handling Ctrl+C is therefore negligible and not worth the 
added code for handling down_interruptible().
You have already written the code, so I'd leave it as it is and I'll 
blame the book. They probably started from an older version of 
fs/pipe.c, which contained _interruptible calls. There are gone now, 
this allowed some cleanup.

--
    Manfred