ipv6: add ip6_sock_set_recverr

Add a helper to directly set the IPV6_RECVERR sockopt from kernel space
without going through a fake uaccess.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/ipv6.h

@@ -1188,4 +1188,11 @@ static inline int ip6_sock_set_v6only(struct sock *sk)
 	return 0;
 }
 
+static inline void ip6_sock_set_recverr(struct sock *sk)
+{
+	lock_sock(sk);
+	inet6_sk(sk)->recverr = true;
+	release_sock(sk);
+}
+
 #endif /* _NET_IPV6_H */

net/rxrpc/local_object.c

@@ -107,7 +107,7 @@ static struct rxrpc_local *rxrpc_alloc_local(struct rxrpc_net *rxnet,
 static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net)
 {
 	struct sock *usk;
-	int ret, opt;
+	int ret;
 
 	_enter("%p{%d,%d}",
 	       local, local->srx.transport_type, local->srx.transport.family);
@@ -157,13 +157,7 @@ static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net)
 	switch (local->srx.transport.family) {
 	case AF_INET6:
 		/* we want to receive ICMPv6 errors */
-		opt = 1;
-		ret = kernel_setsockopt(local->socket, SOL_IPV6, IPV6_RECVERR,
-					(char *) &opt, sizeof(opt));
-		if (ret < 0) {
-			_debug("setsockopt failed");
-			goto error;
-		}
+		ip6_sock_set_recverr(local->socket->sk);
 
 		/* Fall through and set IPv4 options too otherwise we don't get
 		 * errors from IPv4 packets sent through the IPv6 socket.