On Tue, Jan 14, 2014 at 04:33:08PM -0800, Jason Low wrote:
> The mutex_can_spin_on_owner() function should also return false if the
> task needs to be rescheduled.
>
While I was staring at mutex_can_spin_on_owner(); don't we need this?
kernel/locking/mutex.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 4dd6e4c219de..480d2f437964 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -214,8 +214,10 @@ static inline int mutex_can_spin_on_owner(struct mutex
*lock)
rcu_read_lock();
owner = ACCESS_ONCE(lock->owner);
- if (owner)
+ if (owner) {
+ smp_read_barrier_depends();
retval = owner->on_cpu;
+ }
rcu_read_unlock();
/*
* if lock->owner is not set, the mutex owner may have just acquired
--
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