Re: [patch] IA64: suppress return value of down_trylock() in salinfo_work_to_do()

[Matthew Wilcox <matthew@wil.cx>]

On Sun, Aug 03, 2008 at 12:08:08PM +1000, Keith Owens wrote:
> >task A acquires sem
> >
> >task B tries to acquire the sem, fails
> >task B releases the sem that it didn't acquire
> >
> >task A releases the sem, falls down, goes boom?
> 
> Cannot happen.  See the comment above the function:
> 
>   This routine must be called with data_saved_lock held, to make the down/up
>   operation atomic

... that requres one to know that salinfo_work_to_do() is the only place
which calls up() (and it always calls down_trylock first).  This is a
really creative misuse of semaphores.

-- 
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