Commit 124f75f8 authored by Al Viro's avatar Al Viro
Browse files

clean overflow checks in count_mounts() a bit 



Wraparound checks in there are redundant (x + y < x and
x + y < y are equivalent when x and y are both unsigned int).

IMO more straightforward code would be better here...

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 90b2433e

fs/namespace.c

+10 −9
Original line number Diff line number Diff line
@@ -2069,22 +2069,23 @@ static int invent_group_ids(struct mount *mnt, bool recurse) 
int count_mounts(struct mnt_namespace *ns, struct mount *mnt)

{

	unsigned int max = READ_ONCE(sysctl_mount_max);

	unsigned int mounts = 0, old, pending, sum;

	unsigned int mounts = 0;

	struct mount *p;



	if (ns->mounts >= max)

		return -ENOSPC;

	max -= ns->mounts;

	if (ns->pending_mounts >= max)

		return -ENOSPC;

	max -= ns->pending_mounts;



	for (p = mnt; p; p = next_mnt(p, mnt))

		mounts++;



	old = ns->mounts;

	pending = ns->pending_mounts;

	sum = old + pending;

	if ((old > sum) ||

	    (pending > sum) ||

	    (max < sum) ||

	    (mounts > (max - sum)))

	if (mounts > max)

		return -ENOSPC;



	ns->pending_mounts = pending + mounts;

	ns->pending_mounts += mounts;

	return 0;

}