On Mon, Nov 10, 2014 at 09:47:27PM +0800, Herbert Xu wrote:

On Mon, Nov 03, 2014 at 11:56:24PM +0800, Amos Kong wrote:

quoted

@@ -98,6 +99,8 @@ static inline void cleanup_rng(struct kref *kref)
 
 	if (rng->cleanup)
 		rng->cleanup(rng);

You need a compiler barrier here to prevent reordering.

Michael Büsch pointed out that we should actually have a memory
barrier here.  I thought we didn't need it because I was only
worried about the code in my original complaint.  However, expecting
driver writers to use correct synchronisation primitives is surely
asking too much.

So let's add an smp_wmb() here to ensure all side-effects of
cleanup is visible.

Thanks,
-- 
Email: Herbert Xu [off-list ref]
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