Btrfs: stop spinning on mutex_trylock and let the adaptive code spin for us

Mutexes now spin internally and the btrfs spin is no longer required for
performance.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index 39bae77..40ba8e8 100644 (file)
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -37,16 +37,6 @@
 
 int btrfs_tree_lock(struct extent_buffer *eb)
 {
-       int i;
-
-       if (mutex_trylock(&eb->mutex))
-               return 0;
-       for (i = 0; i < 512; i++) {
-               cpu_relax();
-               if (mutex_trylock(&eb->mutex))
-                       return 0;
-       }
-       cpu_relax();
        mutex_lock_nested(&eb->mutex, BTRFS_MAX_LEVEL - btrfs_header_level(eb));
        return 0;
 }