1 files changed, 13 insertions, 2 deletions

diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c
index 3064c50e181e..09b180063ee1 100644
--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -180,7 +180,7 @@ static void __rwsem_mark_wake(struct rw_semaphore *sem,
                  * but it gives the spinners an early indication that the
                  * readers now have the lock.
                  */
-                rwsem_set_reader_owned(sem);
+                __rwsem_set_reader_owned(sem, waiter->task);
         }
 
         /*
@@ -233,8 +233,19 @@ __rwsem_down_read_failed_common(struct rw_semaphore *sem, int state)
         waiter.type = RWSEM_WAITING_FOR_READ;
 
         raw_spin_lock_irq(&sem->wait_lock);
-        if (list_empty(&sem->wait_list))
+        if (list_empty(&sem->wait_list)) {
+                /*
+                 * In case the wait queue is empty and the lock isn't owned
+                 * by a writer, this reader can exit the slowpath and return
+                 * immediately as its RWSEM_ACTIVE_READ_BIAS has already
+                 * been set in the count.
+                 */
+                if (atomic_long_read(&sem->count) >= 0) {
+                        raw_spin_unlock_irq(&sem->wait_lock);
+                        return sem;
+                }
                 adjustment += RWSEM_WAITING_BIAS;
+        }
         list_add_tail(&waiter.list, &sem->wait_list);
 
         /* we're now waiting on the lock, but no longer actively locking */