Re: [Xen-devel] [PATCH] mini-os: fix bit ops comments and memory clobbers.

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2014-06-18 at 10:29 +0200, Samuel Thibault wrote:
> This fixes comments about test_and_clear_bit, set_bit and clear_bit,
> which are actually not atomic, can be reordered and are not memory
> barriers.
> 
> This also drops the empty LOCK and LOCK_PREFIX macros which bring to the
> confusion.

It took me a little while to work out that the reason these aren't
needed is that you have synch_set_bit for the cases where the lock is
actually needed.

> This also adds missing memory clobbers to set_bit and clear_bit.
> 
> Signed-off-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>

Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>




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