[NET]: Set truesize in pskb_copy

Since pskb_copy tacks on the non-linear bits from the original
skb, it needs to count them in the truesize field of the new skb.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

net/core/skbuff.c

@@ -582,6 +582,7 @@ struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask)
 	n->csum	     = skb->csum;
 	n->ip_summed = skb->ip_summed;
 
+	n->truesize += skb->data_len;
 	n->data_len  = skb->data_len;
 	n->len	     = skb->len;