libceph: fix misjudgement of maximum monitor number

num_mon should allow up to CEPH_MAX_MON in ceph_monmap_decode().
Signed-off-by: NChengguang Xu <cgxu519@icloud.com>
Reviewed-by: NIlya Dryomov <idryomov@gmail.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

net/ceph/mon_client.c

@@ -60,7 +60,7 @@ struct ceph_monmap *ceph_monmap_decode(void *p, void *end)
 	num_mon = ceph_decode_32(&p);
 	ceph_decode_need(&p, end, num_mon*sizeof(m->mon_inst[0]), bad);
 
-	if (num_mon >= CEPH_MAX_MON)
+	if (num_mon > CEPH_MAX_MON)
 		goto bad;
 	m = kmalloc(sizeof(*m) + sizeof(m->mon_inst[0])*num_mon, GFP_NOFS);
 	if (m == NULL)