[PATCH] btrfs: qgroup: delete unnecessary check in btrfs_qgroup_check_inherit()

[Dan Carpenter]

This check "if (inherit->num_qgroups > PAGE_SIZE)" is confusing and
unnecessary.

The problem with the check is that static checkers flag it as a
potential mixup of between units of bytes vs number of elements.
Fortunately, the check can safely be deleted because the next check is
correct and applies an even stricter limit:

	if (size != struct_size(inherit, qgroups, inherit->num_qgroups))
		return -EINVAL;

The "inherit" struct ends in a variable array of __u64 and
"inherit->num_qgroups" is the number of elements in the array.  At the
start of the function we check that:

	if (size < sizeof(*inherit) || size > PAGE_SIZE)
		return -EINVAL;

Thus, since we verify that the whole struct fits within one page, that
means that the number of elements in the inherit->qgroups[] array must
be less than PAGE_SIZE.

Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
 fs/btrfs/qgroup.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 5f90f0605b12..a8197e25192c 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -3067,9 +3067,6 @@ int btrfs_qgroup_check_inherit(struct btrfs_fs_info *fs_info,
 	if (inherit->num_ref_copies > 0 || inherit->num_excl_copies > 0)
 		return -EINVAL;
 
-	if (inherit->num_qgroups > PAGE_SIZE)
-		return -EINVAL;
-
 	if (size != struct_size(inherit, qgroups, inherit->num_qgroups))
 		return -EINVAL;
 
-- 
2.43.0