net: pass a sockptr_t into ->setsockopt

Rework the remaining setsockopt code to pass a sockptr_t instead of a
plain user pointer.  This removes the last remaining set_fs(KERNEL_DS)
outside of architecture specific code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org> [ieee802154]
Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index e58fe7e..4389df6 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -1242,7 +1242,7 @@ static int pppol2tp_session_setsockopt(struct sock *sk,
  * session or the special tunnel type.
  */
 static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
-			       char __user *optval, unsigned int optlen)
+			       sockptr_t optval, unsigned int optlen)
 {
 	struct sock *sk = sock->sk;
 	struct l2tp_session *session;
@@ -1256,7 +1256,7 @@ static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
 	if (optlen < sizeof(int))
 		return -EINVAL;
 
-	if (get_user(val, (int __user *)optval))
+	if (copy_from_sockptr(&val, optval, sizeof(int)))
 		return -EFAULT;
 
 	err = -ENOTCONN;