Commit 734b05b1 authored Sep 26, 2008 by Peter Zijlstra Committed by Ingo Molnar Sep 30, 2008

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>

parent 61270708

kernel/futex.c

+1 −3

Original line number	Diff line number	Diff line
		@@ -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;