[PATCH 3/3] md: reuse sb length-checking logic

[Christopher Unkel <cunkel@drivescale.com>]

The logic in super_1_load() to check the length of the superblock
against (new_)data_offset has the same purpose as the newly-created
super_1_sb_length_ok().  The latter is also more complete in that it
check for overlap between the superblock write and the bitmap.

Signed-off-by: Christopher Unkel <cunkel@drivescale.com>
---
This series replaces the first patch of the previous series
(https://lkml.org/lkml/2020/10/22/1058), with the following changes:

1. Creates a helper function super_1_sb_length_ok().
2. Fixes operator placement style violation.
3. Covers case in super_1_sync().
4. Refactors duplicate logic.
5. Covers a case in existing code where aligned superblock could
   run into bitmap.

 drivers/md/md.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 802a9a256fe5..3b7bf14922ac 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1768,13 +1768,8 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
 	atomic_set(&rdev->corrected_errors, le32_to_cpu(sb->cnt_corrected_read));
 
 	super_1_set_rdev_sb_size(rdev, le32_to_cpu(sb->max_dev), minor_version);
-
-	if (minor_version
-	    && rdev->data_offset < sb_start + (rdev->sb_size/512))
-		return -EINVAL;
-	if (minor_version
-	    && rdev->new_data_offset < sb_start + (rdev->sb_size/512))
-		return -EINVAL;
+	if (!super_1_sb_length_ok(rdev, minor_version, rdev->sb_size))
+	    return -EINVAL;
 
 	if (sb->level == cpu_to_le32(LEVEL_MULTIPATH))
 		rdev->desc_nr = -1;
-- 
2.17.1