1 files changed, 6 insertions, 19 deletions

diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index 870528d87526..3a496b0d3d2b 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -325,24 +325,12 @@ struct extent_buffer *btrfs_try_read_lock_root_node(struct btrfs_root *root)
  * acquire the lock.
  */
 
-int btrfs_drew_lock_init(struct btrfs_drew_lock *lock)
+void btrfs_drew_lock_init(struct btrfs_drew_lock *lock)
 {
-	int ret;
-
-	ret = percpu_counter_init(&lock->writers, 0, GFP_KERNEL);
-	if (ret)
-		return ret;
-
 	atomic_set(&lock->readers, 0);
+	atomic_set(&lock->writers, 0);
 	init_waitqueue_head(&lock->pending_readers);
 	init_waitqueue_head(&lock->pending_writers);
-
-	return 0;
-}
-
-void btrfs_drew_lock_destroy(struct btrfs_drew_lock *lock)
-{
-	percpu_counter_destroy(&lock->writers);
 }
 
 /* Return true if acquisition is successful, false otherwise */
@@ -351,10 +339,10 @@ bool btrfs_drew_try_write_lock(struct btrfs_drew_lock *lock)
 	if (atomic_read(&lock->readers))
 		return false;
 
-	percpu_counter_inc(&lock->writers);
+	atomic_inc(&lock->writers);
 
 	/* Ensure writers count is updated before we check for pending readers */
-	smp_mb();
+	smp_mb__after_atomic();
 	if (atomic_read(&lock->readers)) {
 		btrfs_drew_write_unlock(lock);
 		return false;
@@ -374,7 +362,7 @@ void btrfs_drew_write_lock(struct btrfs_drew_lock *lock)
 
 void btrfs_drew_write_unlock(struct btrfs_drew_lock *lock)
 {
-	percpu_counter_dec(&lock->writers);
+	atomic_dec(&lock->writers);
 	cond_wake_up(&lock->pending_readers);
 }
 
@@ -390,8 +378,7 @@ void btrfs_drew_read_lock(struct btrfs_drew_lock *lock)
 	 */
 	smp_mb__after_atomic();
 
-	wait_event(lock->pending_readers,
-		   percpu_counter_sum(&lock->writers) == 0);
+	wait_event(lock->pending_readers, atomic_read(&lock->writers) == 0);
 }
 
 void btrfs_drew_read_unlock(struct btrfs_drew_lock *lock)