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Commit fb344389 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull a mutex fix from Ingo Molnar.

Fix the fastpath_lock failure contention flag for xchg-based mutexes.

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  mutex: Place lock in contended state after fastpath_lock failure
parents 0e665d5d 0bce9c46

include/asm-generic/mutex-xchg.h

+9 −2
Original line number Diff line number Diff line
@@ -26,6 +26,12 @@ static inline void 
__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))

{

	if (unlikely(atomic_xchg(count, 0) != 1))

		/*

		 * We failed to acquire the lock, so mark it contended

		 * to ensure that any waiting tasks are woken up by the

		 * unlock slow path.

		 */

		if (likely(atomic_xchg(count, -1) != 1))

			fail_fn(count);

}
@@ -43,6 +49,7 @@ static inline int 
__mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *))

{

	if (unlikely(atomic_xchg(count, 0) != 1))

		if (likely(atomic_xchg(count, -1) != 1))

			return fail_fn(count);

	return 0;

}