btrfs: add separate helper for unlock_extent_cached with GFP_ATOMIC

There's only one instance where we pass different gfp mask to
unlock_extent_cached. Add a separate helper for that and then we can
drop the gfp parameter from unlock_extent_cached.
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent_io.c

@@ -2493,7 +2493,7 @@ endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64 len,
 
 	if (uptodate && tree->track_uptodate)
 		set_extent_uptodate(tree, start, end, &cached, GFP_ATOMIC);
-	unlock_extent_cached(tree, start, end, &cached, GFP_ATOMIC);
+	unlock_extent_cached_atomic(tree, start, end, &cached);
 }
 
 /*

fs/btrfs/extent_io.h

@@ -318,6 +318,13 @@ static inline int unlock_extent_cached(struct extent_io_tree *tree, u64 start,
 				mask, NULL);
 }
 
+static inline int unlock_extent_cached_atomic(struct extent_io_tree *tree,
+		u64 start, u64 end, struct extent_state **cached)
+{
+	return __clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
+				GFP_ATOMIC, NULL);
+}
+
 static inline int clear_extent_bits(struct extent_io_tree *tree, u64 start,
 		u64 end, unsigned bits)
 {