1 files changed, 43 insertions, 20 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index ae16f80..6afb6d8 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1254,6 +1254,39 @@ static void tcp_prequeue_process(struct sock *sk)
 	tp->ucopy.memory = 0;
 }
 
+#ifdef CONFIG_NET_DMA
+static void tcp_service_net_dma(struct sock *sk, bool wait)
+{
+	dma_cookie_t done, used;
+	dma_cookie_t last_issued;
+	struct tcp_sock *tp = tcp_sk(sk);
+
+	if (!tp->ucopy.dma_chan)
+		return;
+
+	last_issued = tp->ucopy.dma_cookie;
+	dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
+
+	do {
+		if (dma_async_memcpy_complete(tp->ucopy.dma_chan,
+					      last_issued, &done,
+					      &used) == DMA_SUCCESS) {
+			/* Safe to free early-copied skbs now */
+			__skb_queue_purge(&sk->sk_async_wait_queue);
+			break;
+		} else {
+			struct sk_buff *skb;
+			while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
+			       (dma_async_is_complete(skb->dma_cookie, done,
+						      used) == DMA_SUCCESS)) {
+				__skb_dequeue(&sk->sk_async_wait_queue);
+				kfree_skb(skb);
+			}
+		}
+	} while (wait);
+}
+#endif
+
 static inline struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
 {
 	struct sk_buff *skb;
@@ -1546,6 +1579,10 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 			/* __ Set realtime policy in scheduler __ */
 		}
 
+#ifdef CONFIG_NET_DMA
+		if (tp->ucopy.dma_chan)
+			dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
+#endif
 		if (copied >= target) {
 			/* Do not sleep, just process backlog. */
 			release_sock(sk);
@@ -1554,6 +1591,7 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 			sk_wait_data(sk, &timeo);
 
 #ifdef CONFIG_NET_DMA
+		tcp_service_net_dma(sk, false);  /* Don't block */
 		tp->ucopy.wakeup = 0;
 #endif
 
@@ -1633,6 +1671,9 @@ do_prequeue:
 						copied = -EFAULT;
 					break;
 				}
+
+				dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
+
 				if ((offset + used) == skb->len)
 					copied_early = 1;
 
@@ -1702,27 +1743,9 @@ skip_copy:
 	}
 
 #ifdef CONFIG_NET_DMA
-	if (tp->ucopy.dma_chan) {
-		dma_cookie_t done, used;
-
-		dma_async_memcpy_issue_pending(tp->ucopy.dma_chan);
-
-		while (dma_async_memcpy_complete(tp->ucopy.dma_chan,
-						 tp->ucopy.dma_cookie, &done,
-						 &used) == DMA_IN_PROGRESS) {
-			/* do partial cleanup of sk_async_wait_queue */
-			while ((skb = skb_peek(&sk->sk_async_wait_queue)) &&
-			       (dma_async_is_complete(skb->dma_cookie, done,
-						      used) == DMA_SUCCESS)) {
-				__skb_dequeue(&sk->sk_async_wait_queue);
-				kfree_skb(skb);
-			}
-		}
+	tcp_service_net_dma(sk, true);  /* Wait for queue to drain */
+	tp->ucopy.dma_chan = NULL;
 
-		/* Safe to free early-copied skbs now */
-		__skb_queue_purge(&sk->sk_async_wait_queue);
-		tp->ucopy.dma_chan = NULL;
-	}
 	if (tp->ucopy.pinned_list) {
 		dma_unpin_iovec_pages(tp->ucopy.pinned_list);
 		tp->ucopy.pinned_list = NULL;