memcg: ipv6/sit: account and don't WARN on ip_tunnel_prl structs allocation

Author: Andrey Ryabinin <aryabinin@virtuozzo.com>

The size of the ip_tunnel_prl structs allocation is controllable from
user-space, thus it's better to avoid spam in dmesg if allocation failed.
Also add __GFP_ACCOUNT as this is a good candidate for per-memcg
accounting. Allocation is temporary and limited by 4GB.
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/sit.c

@@ -321,7 +321,7 @@ static int ipip6_tunnel_get_prl(struct net_device *dev, struct ifreq *ifr)
 	 * we try harder to allocate.
 	 */
 	kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
-		kcalloc(cmax, sizeof(*kp), GFP_KERNEL | __GFP_NOWARN) :
+		kcalloc(cmax, sizeof(*kp), GFP_KERNEL_ACCOUNT | __GFP_NOWARN) :
 		NULL;
 
 	rcu_read_lock();
@@ -334,7 +334,8 @@ static int ipip6_tunnel_get_prl(struct net_device *dev, struct ifreq *ifr)
 		 * For root users, retry allocating enough memory for
 		 * the answer.
 		 */
-		kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
+		kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC | __GFP_ACCOUNT |
+					      __GFP_NOWARN);
 		if (!kp) {
 			ret = -ENOMEM;
 			goto out;