@@ -3010,14 +3010,21 @@ static int sctp_setsockopt_fragment_interleave(struct sock *sk,
- * 7.1.25. Set or Get the sctp partial delivery point
+ * 8.1.21. Set or Get the SCTP Partial Delivery Point
* This option will set or get the SCTP partial delivery point. This
* point is the size of a message where the partial delivery API will be
* invoked to help free up rwnd space for the peer. Setting this to a
- * lower value will cause partial delivery's to happen more often. The
+ * lower value will cause partial deliveries to happen more often. The
* calls argument is an integer that sets or gets the partial delivery
- * point.
+ * point. Note also that the call will fail if the user attempts to set
+ * this value larger than the socket receive buffer size.
+ * Note that any single message having a length smaller than or equal to
+ * the SCTP partial delivery point will be delivered in one single read
+ * 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,
@@ -3030,6 +3037,12 @@ static int sctp_setsockopt_partial_delivery_point(struct sock *sk,
if (get_user(val, (int __user *)optval))
+ /* 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))
+ return -EINVAL;
sctp_sk(sk)->pd_point = val;
return 0; /* is this the right error code? */