[PATCH 4/4] Do not call flush_cache_user_range with mmap_sem held

[Russell King - ARM Linux]

On Tue, Dec 14, 2010 at 05:51:36PM +0000, Catalin Marinas wrote:
> But what's the problem if such mapping disappears? The
> flush_cache_user_range code should just skip such pages.

That's only half the story.

What if someone remaps something over that range before the cache
maintainence has completed.