Michael Ellerman 78e05b1421 powerpc: Add smp_mb()s to arch_spin_unlock_wait()
Similar to the previous commit which described why we need to add a
barrier to arch_spin_is_locked(), we have a similar problem with
spin_unlock_wait().

We need a barrier on entry to ensure any spinlock we have previously
taken is visibly locked prior to the load of lock->slock.

It's also not clear if spin_unlock_wait() is intended to have ACQUIRE
semantics. For now be conservative and add a barrier on exit to give it
ACQUIRE semantics.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-08-13 15:13:27 +10:00
..
2012-03-28 18:30:02 +01:00
2014-07-22 15:56:04 +10:00
2014-07-22 15:55:51 +10:00
2012-07-03 14:14:41 +10:00