ipv6: move np->repflow to atomic flags

Move np->repflow to inet->inet_flags to fix data-races.

Signed-off-by: Eric Dumazet <[e-mail]>
Reviewed-by: David Ahern <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/ipv6.h

···
 
 	/* sockopt flags */
 	__u16			sndflow:1,
-				repflow:1,
 				pmtudisc:3,
 				padding:1,	/* 1 bit hole */
 				srcprefs:3,	/* 001: prefer temporary address

include/net/inet_sock.h

···
 	INET_FLAGS_AUTOFLOWLABEL = 24,
 	INET_FLAGS_DONTFRAG	= 25,
 	INET_FLAGS_RECVERR6	= 26,
+	INET_FLAGS_REPFLOW	= 27,
 };
 
 /* cmsg flags for inet */

net/dccp/ipv6.c

···
 			WRITE_ONCE(np->mcast_hops, ipv6_hdr(opt_skb)->hop_limit);
 		if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
 			np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
-		if (np->repflow)
+		if (inet6_test_bit(REPFLOW, sk))
 			np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
 		if (ipv6_opt_accepted(sk, opt_skb,
 				      &DCCP_SKB_CB(opt_skb)->header.h6)) {

net/ipv6/af_inet6.c

···
 	inet6_set_bit(MC6_LOOP, sk);
 	inet6_set_bit(MC6_ALL, sk);
 	np->pmtudisc	= IPV6_PMTUDISC_WANT;
-	np->repflow	= net->ipv6.sysctl.flowlabel_reflect & FLOWLABEL_REFLECT_ESTABLISHED;
+	inet6_assign_bit(REPFLOW, sk, net->ipv6.sysctl.flowlabel_reflect &
+				     FLOWLABEL_REFLECT_ESTABLISHED);
 	sk->sk_ipv6only	= net->ipv6.sysctl.bindv6only;
 	sk->sk_txrehash = READ_ONCE(net->core.sysctl_txrehash);
 

net/ipv6/ip6_flowlabel.c

···
 		return 0;
 	}
 
-	if (np->repflow) {
+	if (inet6_test_bit(REPFLOW, sk)) {
 		freq->flr_label = np->flow_label;
 		return 0;
 	}
···
 	if (freq->flr_flags & IPV6_FL_F_REFLECT) {
 		if (sk->sk_protocol != IPPROTO_TCP)
 			return -ENOPROTOOPT;
-		if (!np->repflow)
+		if (!inet6_test_bit(REPFLOW, sk))
 			return -ESRCH;
 		np->flow_label = 0;
-		np->repflow = 0;
+		inet6_clear_bit(REPFLOW, sk);
 		return 0;
 	}
 
···
 
 		if (sk->sk_protocol != IPPROTO_TCP)
 			return -ENOPROTOOPT;
-		np->repflow = 1;
+		inet6_set_bit(REPFLOW, sk);
 		return 0;
 	}
 

net/ipv6/tcp_ipv6.c

···
 				    &ireq->ir_v6_rmt_addr);
 
 		fl6->daddr = ireq->ir_v6_rmt_addr;
-		if (np->repflow && ireq->pktopts)
+		if (inet6_test_bit(REPFLOW, sk) && ireq->pktopts)
 			fl6->flowlabel = ip6_flowlabel(ipv6_hdr(ireq->pktopts));
 
 		tclass = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reflect_tos) ?
···
 	    (ipv6_opt_accepted(sk_listener, skb, &TCP_SKB_CB(skb)->header.h6) ||
 	     np->rxopt.bits.rxinfo ||
 	     np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim ||
-	     np->rxopt.bits.rxohlim || np->repflow)) {
+	     np->rxopt.bits.rxohlim || inet6_test_bit(REPFLOW, sk_listener))) {
 		refcount_inc(&skb->users);
 		ireq->pktopts = skb;
 	}
···
 	if (sk) {
 		oif = sk->sk_bound_dev_if;
 		if (sk_fullsock(sk)) {
-			const struct ipv6_pinfo *np = tcp_inet6_sk(sk);
-
 			trace_tcp_send_reset(sk, skb);
-			if (np->repflow)
+			if (inet6_test_bit(REPFLOW, sk))
 				label = ip6_flowlabel(ipv6h);
 			priority = sk->sk_priority;
 			txhash = sk->sk_txhash;
···
 		newnp->mcast_oif   = inet_iif(skb);
 		newnp->mcast_hops  = ip_hdr(skb)->ttl;
 		newnp->rcv_flowinfo = 0;
-		if (np->repflow)
+		if (inet6_test_bit(REPFLOW, sk))
 			newnp->flow_label = 0;
 
 		/*
···
 	newnp->mcast_oif  = tcp_v6_iif(skb);
 	newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
 	newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
-	if (np->repflow)
+	if (inet6_test_bit(REPFLOW, sk))
 		newnp->flow_label = ip6_flowlabel(ipv6_hdr(skb));
 
 	/* Set ToS of the new socket based upon the value of incoming SYN.
···
 				   ipv6_hdr(opt_skb)->hop_limit);
 		if (np->rxopt.bits.rxflow || np->rxopt.bits.rxtclass)
 			np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
-		if (np->repflow)
+		if (inet6_test_bit(REPFLOW, sk))
 			np->flow_label = ip6_flowlabel(ipv6_hdr(opt_skb));
 		if (ipv6_opt_accepted(sk, opt_skb, &TCP_SKB_CB(opt_skb)->header.h6)) {
 			tcp_v6_restore_cb(opt_skb);