xfs: refactor data device extent validation

Refactor all the open-coded validation of non-static data device extents
into a single helper.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
diff --git a/fs/xfs/xfs_rmap_item.c b/fs/xfs/xfs_rmap_item.c
index 9b84017..4fa8752 100644
--- a/fs/xfs/xfs_rmap_item.c
+++ b/fs/xfs/xfs_rmap_item.c
@@ -493,16 +493,7 @@ xfs_rui_validate_map(
 	if (rmap->me_startoff + rmap->me_len <= rmap->me_startoff)
 		return false;
 
-	if (rmap->me_startblock + rmap->me_len <= rmap->me_startblock)
-		return false;
-
-	if (!xfs_verify_fsbno(mp, rmap->me_startblock))
-		return false;
-
-	if (!xfs_verify_fsbno(mp, rmap->me_startblock + rmap->me_len - 1))
-		return false;
-
-	return true;
+	return xfs_verify_fsbext(mp, rmap->me_startblock, rmap->me_len);
 }
 
 /*