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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-06-29 12:59:32 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-08-17 08:08:57 -0700
commite0892e086aae8d86e33dc8fb87f3d36c901df574 (patch)
tree6a480513ccaa1bb3e2427bddf8f452994bc3d901 /ipc/sem.c
parentexit: Replace spin_unlock_wait() with lock/unlock pair (diff)
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ipc: Replace spin_unlock_wait() with lock/unlock pair
There is no agreed-upon definition of spin_unlock_wait()'s semantics, and it appears that all callers could do just as well with a lock/unlock pair. This commit therefore replaces the spin_unlock_wait() call in exit_sem() with spin_lock() followed immediately by spin_unlock(). This should be safe from a performance perspective because exit_sem() is rarely invoked in production. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Will Deacon <will.deacon@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Andrea Parri <parri.andrea@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Manfred Spraul <manfred@colorfullife.com>
Diffstat (limited to 'ipc/sem.c')
-rw-r--r--ipc/sem.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/ipc/sem.c b/ipc/sem.c
index 9e70cd7a17da..2570830e29fc 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -2091,7 +2091,8 @@ void exit_sem(struct task_struct *tsk)
* possibility where we exit while freeary() didn't
* finish unlocking sem_undo_list.
*/
- spin_unlock_wait(&ulp->lock);
+ spin_lock(&ulp->lock);
+ spin_unlock(&ulp->lock);
rcu_read_unlock();
break;
}