dm: optimize max_io_len() by inlining max_io_len_target_boundary()

Saves redundant dm_target_offset() math.

Also, reverse argument order for max_io_len() to be consistent with
other similar functions.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm.c

@@ -1041,16 +1041,16 @@ static void clone_endio(struct bio *bio)
  * Return maximum size of I/O possible at the supplied sector up to the current
  * target boundary.
  */
-static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti)
+static inline sector_t max_io_len_target_boundary(struct dm_target *ti,
+						  sector_t target_offset)
 {
-	sector_t target_offset = dm_target_offset(ti, sector);
-
 	return ti->len - target_offset;
 }
 
-static sector_t max_io_len(sector_t sector, struct dm_target *ti)
+static sector_t max_io_len(struct dm_target *ti, sector_t sector)
 {
-	sector_t len = max_io_len_target_boundary(sector, ti);
+	sector_t target_offset = dm_target_offset(ti, sector);
+	sector_t len = max_io_len_target_boundary(ti, target_offset);
 	sector_t max_len;
 
 	/*
@@ -1060,7 +1060,7 @@ static sector_t max_io_len(sector_t sector, struct dm_target *ti)
 	 * - blk_max_size_offset() also respects q->limits.max_sectors
 	 */
 	max_len = blk_max_size_offset(dm_table_get_md(ti->table)->queue,
-				      dm_target_offset(ti, sector));
+				      target_offset);
 	if (len > max_len)
 		len = max_len;
 
@@ -1115,7 +1115,7 @@ static long dm_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
 		goto out;
 	if (!ti->type->direct_access)
 		goto out;
-	len = max_io_len(sector, ti) / PAGE_SECTORS;
+	len = max_io_len(ti, sector) / PAGE_SECTORS;
 	if (len < 1)
 		goto out;
 	nr_pages = min(len, nr_pages);
@@ -1497,7 +1497,8 @@ static int __send_changing_extent_only(struct clone_info *ci, struct dm_target *
 	if (!num_bios)
 		return -EOPNOTSUPP;
 
-	len = min((sector_t)ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
+	len = min_t(sector_t, ci->sector_count,
+		    max_io_len_target_boundary(ti, dm_target_offset(ti, ci->sector)));
 
 	__send_duplicate_bios(ci, ti, num_bios, &len);
 
@@ -1578,7 +1579,7 @@ static int __split_and_process_non_flush(struct clone_info *ci)
 	if (__process_abnormal_io(ci, ti, &r))
 		return r;
 
-	len = min_t(sector_t, max_io_len(ci->sector, ti), ci->sector_count);
+	len = min_t(sector_t, max_io_len(ti, ci->sector), ci->sector_count);
 
 	r = __clone_and_map_data_bio(ci, ti, ci->sector, &len);
 	if (r < 0)