xfs: check the flags earlier in xfs_attr_match

Checking the flags match is much cheaper than a memcmp, so do it early
on in xfs_attr_match, and also add a little helper to calculate the
match mask right under the comment explaining the logic for it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

fs/xfs/libxfs/xfs_attr_leaf.c

@@ -507,6 +507,13 @@ xfs_attr3_leaf_read(
  * INCOMPLETE flag will not be set in attr->attr_filter, but rather
  * XFS_DA_OP_RECOVERY will be set in args->op_flags.
  */
+static inline unsigned int xfs_attr_match_mask(const struct xfs_da_args *args)
+{
+	if (args->op_flags & XFS_DA_OP_RECOVERY)
+		return XFS_ATTR_NSP_ONDISK_MASK;
+	return XFS_ATTR_NSP_ONDISK_MASK | XFS_ATTR_INCOMPLETE;
+}
+
 static bool
 xfs_attr_match(
 	struct xfs_da_args	*args,
@@ -514,21 +521,15 @@ xfs_attr_match(
 	const unsigned char	*name,
 	unsigned int		namelen)
 {
+	unsigned int		mask = xfs_attr_match_mask(args);
 
 	if (args->namelen != namelen)
 		return false;
+	if ((args->attr_filter & mask) != (attr_flags & mask))
+		return false;
 	if (memcmp(args->name, name, namelen) != 0)
 		return false;
 
-	/* Recovery ignores the INCOMPLETE flag. */
-	if ((args->op_flags & XFS_DA_OP_RECOVERY) &&
-	    args->attr_filter == (attr_flags & XFS_ATTR_NSP_ONDISK_MASK))
-		return true;
-
-	/* All remaining matches need to be filtered by INCOMPLETE state. */
-	if (args->attr_filter !=
-	    (attr_flags & (XFS_ATTR_NSP_ONDISK_MASK | XFS_ATTR_INCOMPLETE)))
-		return false;
 	return true;
 }