fs: rename buffer trylock

Like the page lock change, this also requires name change, so convert the
raw test_and_set bitop to a trylock.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 50cfe8c..eadaab4 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -115,7 +115,6 @@
 BUFFER_FNS(Dirty, dirty)
 TAS_BUFFER_FNS(Dirty, dirty)
 BUFFER_FNS(Lock, locked)
-TAS_BUFFER_FNS(Lock, locked)
 BUFFER_FNS(Req, req)
 TAS_BUFFER_FNS(Req, req)
 BUFFER_FNS(Mapped, mapped)
@@ -321,10 +320,15 @@
 		__wait_on_buffer(bh);
 }
 
+static inline int trylock_buffer(struct buffer_head *bh)
+{
+	return likely(!test_and_set_bit(BH_Lock, &bh->b_state));
+}
+
 static inline void lock_buffer(struct buffer_head *bh)
 {
 	might_sleep();
-	if (test_set_buffer_locked(bh))
+	if (!trylock_buffer(bh))
 		__lock_buffer(bh);
 }