cipso: Relax too much careful cipso hash function.

The cipso_v4_cache is allocated to contain CIPSO_V4_CACHE_BUCKETS
buckets. The CIPSO_V4_CACHE_BUCKETS = 1 << CIPSO_V4_CACHE_BUCKETBITS,
where CIPSO_V4_CACHE_BUCKETBITS = 7.

The bucket-selection function for this hash is calculated like this:

  bkt = hash & (CIPSO_V4_CACHE_BUCKETBITS - 1);
                                     ^^^

i.e. picking only 4 buckets of possible 128 :)
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Acked-by: NPaul Moore <paul.moore@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/cipso_ipv4.c

@@ -338,7 +338,7 @@ static int cipso_v4_cache_check(const unsigned char *key,
 		return -ENOENT;
 
 	hash = cipso_v4_map_cache_hash(key, key_len);
-	bkt = hash & (CIPSO_V4_CACHE_BUCKETBITS - 1);
+	bkt = hash & (CIPSO_V4_CACHE_BUCKETS - 1);
 	spin_lock_bh(&cipso_v4_cache[bkt].lock);
 	list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) {
 		if (entry->hash == hash &&
@@ -417,7 +417,7 @@ int cipso_v4_cache_add(const struct sk_buff *skb,
 	atomic_inc(&secattr->cache->refcount);
 	entry->lsm_data = secattr->cache;
 
-	bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETBITS - 1);
+	bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETS - 1);
 	spin_lock_bh(&cipso_v4_cache[bkt].lock);
 	if (cipso_v4_cache[bkt].size < cipso_v4_cache_bucketsize) {
 		list_add(&entry->list, &cipso_v4_cache[bkt].list);