futex: use fast_gup()

Change the get_user_pages() call with fast_gup() which doesn't require holding
the mmap_sem thereby removing the mmap_sem from all fast paths.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2008-09-26 19:32:22 +02:00 committed by Ingo Molnar
parent 61270708ec
commit 734b05b10e

View file

@ -232,9 +232,7 @@ static int get_futex_key(u32 __user *uaddr, struct rw_semaphore *fshared,
}
again:
down_read(&mm->mmap_sem);
err = get_user_pages(current, mm, address, 1, 0, 0, &page, NULL);
up_read(&mm->mmap_sem);
err = get_user_pages_fast(address, 1, 0, &page);
if (err < 0)
return err;