---

yaml --- r: 373753 b: refs/heads/master c: 9b0fc9c h: refs/heads/master i: 373751: 933598b v: v3
git-mirror · May 7, 2013 · 514a0b3 · 514a0b3
1 parent 7724925
commit 514a0b3
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Showing 2 changed files with 10 additions and 9 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: a7d2c573ae7fad1b2c877d1a1342fa5bb0d6478c
+refs/heads/master: 9b0fc9c09f1b262b7fe697eba6b05095d78850e5
diff --git a/trunk/lib/rwsem.c b/trunk/lib/rwsem.c
@@ -216,22 +216,23 @@ struct rw_semaphore __sched *rwsem_down_write_failed(struct rw_semaphore *sem)
 	/* wait until we successfully acquire the lock */
 	set_task_state(tsk, TASK_UNINTERRUPTIBLE);
 	while (true) {
-
-		/* Try acquiring the write lock. */
-		count = RWSEM_ACTIVE_WRITE_BIAS;
-		if (!list_is_singular(&sem->wait_list))
-			count += RWSEM_WAITING_BIAS;
-		if (cmpxchg(&sem->count, RWSEM_WAITING_BIAS, count) ==
+		if (!(count & RWSEM_ACTIVE_MASK)) {
+			/* Try acquiring the write lock. */
+			count = RWSEM_ACTIVE_WRITE_BIAS;
+			if (!list_is_singular(&sem->wait_list))
+				count += RWSEM_WAITING_BIAS;
+			if (cmpxchg(&sem->count, RWSEM_WAITING_BIAS, count) ==
 							RWSEM_WAITING_BIAS)
-			break;
+				break;
+		}
 
 		raw_spin_unlock_irq(&sem->wait_lock);
 
 		/* Block until there are no active lockers. */
 		do {
 			schedule();
 			set_task_state(tsk, TASK_UNINTERRUPTIBLE);
-		} while (sem->count & RWSEM_ACTIVE_MASK);
+		} while ((count = sem->count) & RWSEM_ACTIVE_MASK);
 
 		raw_spin_lock_irq(&sem->wait_lock);
 	}