mutex: Fix/document access-once assumption in mutex_can_spin_on_owner()

mutex_can_spin_on_owner() is technically broken in that it would
in theory allow the compiler to load lock->owner twice, seeing a
pointer first time and a NULL pointer the second time.

Linus pointed out that a compiler has to be seriously broken to
not compile this correctly - but nevertheless this change
is correct as it will better document the implementation.

Signed-off-by: Peter Zijlstra <[email protected]>
Acked-by: Davidlohr Bueso <[email protected]>
Acked-by: Waiman Long <[email protected]>
Acked-by: Linus Torvalds <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: David Howells <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions