btrfs: add specific helper for range bit test exists

The existing helper test_range_bit works in two ways, checks if the whole
range contains all the bits, or stop on the first occurrence.  By adding
a specific helper for the latter case, the inner loop can be simplified
and contains fewer conditionals, making it a bit faster.

There's no caller that uses the cached state pointer so this reduces the
argument count further.

Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/fs/btrfs/extent-io-tree.c b/fs/btrfs/extent-io-tree.c
index ff8e117a1ace..02414cc86def 100644
--- a/fs/btrfs/extent-io-tree.c
+++ b/fs/btrfs/extent-io-tree.c
@@ -1640,6 +1640,37 @@ search:
 }
 
 /*
+ * Check if the single @bit exists in the given range.
+ */
+bool test_range_bit_exists(struct extent_io_tree *tree, u64 start, u64 end, u32 bit)
+{
+	struct extent_state *state = NULL;
+	bool bitset = false;
+
+	ASSERT(is_power_of_2(bit));
+
+	spin_lock(&tree->lock);
+	state = tree_search(tree, start);
+	while (state && start <= end) {
+		if (state->start > end)
+			break;
+
+		if (state->state & bit) {
+			bitset = true;
+			break;
+		}
+
+		/* If state->end is (u64)-1, start will overflow to 0 */
+		start = state->end + 1;
+		if (start > end || start == 0)
+			break;
+		state = next_state(state);
+	}
+	spin_unlock(&tree->lock);
+	return bitset;
+}
+
+/*
  * Search a range in the state tree for a given mask.  If 'filled' == 1, this
  * returns 1 only if every extent in the tree has the bits set.  Otherwise, 1
  * is returned if any bit in the range is found set.