Re: [PATCH 6/8] i386: bitops: Don't mark memory as clobberedunnecessarily

[Benjamin Herrenschmidt]

On Tue, 2007-07-24 at 11:13 -0700, Linus Torvalds wrote:
> 
> IOW, if you do a spinlock with the bitops, the locking side should be
> able 
> to use a "test_and_set_bit()" on its own, but the unlocking side
> should be
> 
>         smp_mb__before_clear_bit();
>         clear_bit();
> 
> because the ones that don't return a value also don't imply a memory 
> barrier.

Yup. But I much prefer Nick's clear_bit_unlock() :-)

Ben.


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