+ sem_wait_array(sma);
+ return -1;
+ }
+
+ /*
+ * Only one semaphore affected - try to optimize locking.
+ * The rules are:
+ * - optimized locking is possible if no complex operation
+ * is either enqueued or processed right now.
+ * - The test for enqueued complex ops is simple:
+ * sma->complex_count != 0
+ * - Testing for complex ops that are processed right now is
+ * a bit more difficult. Complex ops acquire the full lock
+ * and first wait that the running simple ops have completed.
+ * (see above)
+ * Thus: If we own a simple lock and the global lock is free
+ * and complex_count is now 0, then it will stay 0 and
+ * thus just locking sem->lock is sufficient.
+ */
+ sem = sma->sem_base + sops->sem_num;