[PATCH] fs: jfs: use the correct value to do sanity check

[Dongliang Mu]

The previous commit 920f4b7e923b ("fs: jfs: fix shift-out-of-bounds
in dbAllocAG") incorrectly uses MAXMAPSIZE - L2MAXAG as upper bound to
limit bmp->db_agl2size. The right value should be L2MAXL2SIZE - L2MAXAG,
i.e., 13 + 10*3 - 7 = 36, according to Dave Kleikamp.

Fix this by modifying the upper bound to the correct value.

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Fixes: 920f4b7e923b ("fs: jfs: fix shift-out-of-bounds in dbAllocAG")
Signed-off-by: Dongliang Mu <dzm91@xxxxxxxxxxx>
---
 fs/jfs/jfs_dmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index 962c855631cb..e1cbfbb60303 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -193,7 +193,7 @@ int dbMount(struct inode *ipbmap)
 	bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
 	bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
 	bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
-	if (bmp->db_agl2size > MAXMAPSIZE - L2MAXAG) {
+	if (bmp->db_agl2size > L2MAXL2SIZE - L2MAXAG) {
 		err = -EINVAL;
 		goto err_release_metapage;
 	}
-- 
2.35.1