Messages in this thread Patch in this message | | | From | Waiman Long <> | Subject | [PATCH v2 3/7] locking/rwsem: rwsem_can_spin_on_owner can be called with preemption enabled | Date | Thu, 7 Aug 2014 18:26:44 -0400 |
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The rwsem_can_spin_on_owner() function can be called with preemption enabled. This patch moves it before preempt_disable() so that it won't do unnecessary preemption operations when spinning is not possible.
Signed-off-by: Waiman Long <Waiman.Long@hp.com> --- kernel/locking/rwsem-xadd.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c index ddd56d2..c8887ba 100644 --- a/kernel/locking/rwsem-xadd.c +++ b/kernel/locking/rwsem-xadd.c @@ -404,11 +404,11 @@ static bool rwsem_optimistic_spin(struct rw_semaphore *sem) bool taken = false; int spincnt = 0; - preempt_disable(); - /* sem->wait_lock should not be held when doing optimistic spinning */ if (!rwsem_can_spin_on_owner(sem)) - goto done; + return false; + + preempt_disable(); if (!osq_lock(&sem->osq)) goto done; -- 1.7.1
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