1 files changed, 11 insertions, 9 deletions

diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c
index 12166ec9b7e7..7628c3fc37ca 100644
--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -250,16 +250,18 @@ EXPORT_SYMBOL(rwsem_down_read_failed);
 
 static inline bool rwsem_try_write_lock(long count, struct rw_semaphore *sem)
 {
-        if (!(count & RWSEM_ACTIVE_MASK)) {
-                /* try acquiring the write lock */
-                if (sem->count == RWSEM_WAITING_BIAS &&
-                    cmpxchg(&sem->count, RWSEM_WAITING_BIAS,
-                            RWSEM_ACTIVE_WRITE_BIAS) == RWSEM_WAITING_BIAS) {
-                        if (!list_is_singular(&sem->wait_list))
-                                rwsem_atomic_update(RWSEM_WAITING_BIAS, sem);
-                        return true;
-                }
+        /*
+         * Try acquiring the write lock. Check count first in order
+         * to reduce unnecessary expensive cmpxchg() operations.
+         */
+        if (count == RWSEM_WAITING_BIAS &&
+            cmpxchg(&sem->count, RWSEM_WAITING_BIAS,
+                    RWSEM_ACTIVE_WRITE_BIAS) == RWSEM_WAITING_BIAS) {
+                if (!list_is_singular(&sem->wait_list))
+                        rwsem_atomic_update(RWSEM_WAITING_BIAS, sem);
+                return true;
         }
+
         return false;
 }