+ /*
+ * If we are established, and we have used up our receive buffer
+ * memory, think about droping the frame.
+ * Note that we have an opportunity to improve performance here.
+ * If we accept one chunk from an skbuff, we have to keep all the
+ * memory of that skbuff around until the chunk is read into user
+ * space. Therefore, once we accept 1 chunk we may as well accept all
+ * remaining chunks in the skbuff. The data_accepted flag helps us do
+ * that.
+ */
+ if ((asoc->state == SCTP_STATE_ESTABLISHED) && (!chunk->data_accepted)) {
+ /*
+ * If the receive buffer policy is 1, then each
+ * association can allocate up to sk_rcvbuf bytes
+ * otherwise, all the associations in aggregate
+ * may allocate up to sk_rcvbuf bytes
+ */
+ if (asoc->ep->rcvbuf_policy)
+ account_value = atomic_read(&asoc->rmem_alloc);
+ else
+ account_value = atomic_read(&sk->sk_rmem_alloc);
+ if (account_value > sk->sk_rcvbuf) {
+ /*
+ * We need to make forward progress, even when we are
+ * under memory pressure, so we always allow the
+ * next tsn after the ctsn ack point to be accepted.
+ * This lets us avoid deadlocks in which we have to
+ * drop frames that would otherwise let us drain the
+ * receive queue.
+ */
+ if ((sctp_tsnmap_get_ctsn(map) + 1) != tsn)
+ return SCTP_IERROR_IGNORE_TSN;
+
+ /*
+ * We're going to accept the frame but we should renege
+ * to make space for it. This will send us down that
+ * path later in this function.
+ */
+ rcvbuf_over = 1;
+ }
+ }
+