sctp: pass a kernel pointer to sctp_setsockopt_partial_delivery_point

Use the kernel pointer that sctp_setsockopt has available instead of
directly handling the user pointer.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/socket.c

@@ -3487,24 +3487,19 @@ static int sctp_setsockopt_fragment_interleave(struct sock *sk,
  * call as long as the user provided buffer is large enough to hold the
  * message.
  */
-static int sctp_setsockopt_partial_delivery_point(struct sock *sk,
-						  char __user *optval,
+static int sctp_setsockopt_partial_delivery_point(struct sock *sk, u32 *val,
 						  unsigned int optlen)
 {
-	u32 val;
-
 	if (optlen != sizeof(u32))
 		return -EINVAL;
-	if (get_user(val, (int __user *)optval))
-		return -EFAULT;
 
 	/* Note: We double the receive buffer from what the user sets
 	 * it to be, also initial rwnd is based on rcvbuf/2.
 	 */
-	if (val > (sk->sk_rcvbuf >> 1))
+	if (*val > (sk->sk_rcvbuf >> 1))
 		return -EINVAL;
 
-	sctp_sk(sk)->pd_point = val;
+	sctp_sk(sk)->pd_point = *val;
 
 	return 0; /* is this the right error code? */
 }
@@ -4695,7 +4690,7 @@ static int sctp_setsockopt(struct sock *sk, int level, int optname,
 		retval = sctp_setsockopt_delayed_ack(sk, kopt, optlen);
 		break;
 	case SCTP_PARTIAL_DELIVERY_POINT:
-		retval = sctp_setsockopt_partial_delivery_point(sk, optval, optlen);
+		retval = sctp_setsockopt_partial_delivery_point(sk, kopt, optlen);
 		break;
 
 	case SCTP_INITMSG: