Revert "ipc/sem.c: optimize sem_lock()"

This reverts commit 901f6fedc5340d66e2ca67c70dfee926cb5a1ea0
(upstream commit 6d07b68ce16ae9535955ba2059dedba5309c3ca1).

As suggested in commit 5864a2fd3088db73d47942370d0f7210a807b9bc
(ipc/sem.c: fix complex_count vs. simple op race) since it introduces
a regression and the candidate fix requires too many changes for 3.10.

Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/ipc/sem.c b/ipc/sem.c
index 47a15192b8b879c76e618b3b2088b4d76ef3b1a7..3b968a028ccf1ae02e08a23f3db048b1c107b067 100644 (file)
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -267,20 +267,12 @@ static void sem_rcu_free(struct rcu_head *head)
  * Caller must own sem_perm.lock.
  * New simple ops cannot start, because simple ops first check
  * that sem_perm.lock is free.
- * that a) sem_perm.lock is free and b) complex_count is 0.
  */
 static void sem_wait_array(struct sem_array *sma)
 {
        int i;
        struct sem *sem;
 
-       if (sma->complex_count)  {
-               /* The thread that increased sma->complex_count waited on
-                * all sem->lock locks. Thus we don't need to wait again.
-                */
-               return;
-       }
-
        for (i = 0; i < sma->sem_nsems; i++) {
                sem = sma->sem_base + i;
                spin_unlock_wait(&sem->lock);