fix ACK processing after netlink_dump_start

index 98e313e..44a8b41 100644
@@ -1565,7 +1565,10 @@ int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
 
 	netlink_dump(sk);
 	sock_put(sk);
-	return 0;
+
+	/* We successfully started a dump, by returning -EINTR we
+	 * signal not to send ACK even if it was requested */
+	return -EINTR;
 }
 
 void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err)

@@ -1619,17 +1622,21 @@ int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *,
 
 		/* Only requests are handled by the kernel */
 		if (!(nlh->nlmsg_flags & NLM_F_REQUEST))
-			goto skip;
+			goto ack;
 
 		/* Skip control messages */
 		if (nlh->nlmsg_type < NLMSG_MIN_TYPE)
-			goto skip;
+			goto ack;
 
 		err = cb(skb, nlh);
-skip:
+		if (err == -EINTR)
+			goto skip;
+
+ack:
 		if (nlh->nlmsg_flags & NLM_F_ACK || err)
 			netlink_ack(skb, nlh, err);
 
+skip:
 	        msglen = NLMSG_ALIGN(nlh->nlmsg_len);
 		if (msglen > skb->len)
 			msglen = skb->len;