nfsd: avoid undefined signed overflow

In C, signed integer overflow results in undefined behavior, but unsigned
overflow wraps around. So do the subtraction first, then cast to signed.

Reported-by: Joakim Tjernlund <joakim.tjernlund@transmode.se>
Signed-off-by: Jim Rees <rees@umich.edu>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Jim Rees 2013-05-17 17:33:00 -04:00 committed by J. Bruce Fields
parent b6040f9706
commit 1a9357f443

View file

@ -3427,7 +3427,7 @@ grace_disallows_io(struct net *net, struct inode *inode)
/* Returns true iff a is later than b: */
static bool stateid_generation_after(stateid_t *a, stateid_t *b)
{
return (s32)a->si_generation - (s32)b->si_generation > 0;
return (s32)(a->si_generation - b->si_generation) > 0;
}
static __be32 check_stateid_generation(stateid_t *in, stateid_t *ref, bool has_session)