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>
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 9a90759..5e65bf2 100644
--- a/include/net/ipv6.h
+++ b/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 */