ipv6: add ip6_sock_set_recvpktinfo

Add a helper to directly set the IPV6_RECVPKTINFO sockopt from kernel
space without going through a fake uaccess.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ipv6.h

@@ -1262,4 +1262,11 @@ static inline int ip6_sock_set_addr_preferences(struct sock *sk, bool val)
 	return ret;
 }
 
+static inline void ip6_sock_set_recvpktinfo(struct sock *sk)
+{
+	lock_sock(sk);
+	inet6_sk(sk)->rxopt.bits.rxinfo = true;
+	release_sock(sk);
+}
+
 #endif /* _NET_IPV6_H */

net/sunrpc/svcsock.c

@@ -595,8 +595,6 @@ static struct svc_xprt_class svc_udp_class = {
 
 static void svc_udp_init(struct svc_sock *svsk, struct svc_serv *serv)
 {
-	int err, level, optname, one = 1;
-
 	svc_xprt_init(sock_net(svsk->sk_sock->sk), &svc_udp_class,
 		      &svsk->sk_xprt, serv);
 	clear_bit(XPT_CACHE_AUTH, &svsk->sk_xprt.xpt_flags);
@@ -617,17 +615,13 @@ static void svc_udp_init(struct svc_sock *svsk, struct svc_serv *serv)
 	switch (svsk->sk_sk->sk_family) {
 	case AF_INET:
 		ip_sock_set_pktinfo(svsk->sk_sock->sk);
-		return;
+		break;
 	case AF_INET6:
-		level = SOL_IPV6;
-		optname = IPV6_RECVPKTINFO;
+		ip6_sock_set_recvpktinfo(svsk->sk_sock->sk);
 		break;
 	default:
 		BUG();
 	}
-	err = kernel_setsockopt(svsk->sk_sock, level, optname,
-					(char *)&one, sizeof(one));
-	dprintk("svc: kernel_setsockopt returned %d\n", err);
 }
 
 /*