1 files changed, 34 insertions, 20 deletions

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index f7a31d2cb3f1..4de46aa61d95 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -96,6 +96,7 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
 static void make_tx_response(struct xenvif_queue *queue,
 			     struct xen_netif_tx_request *txp,
 			     s8       st);
+static void push_tx_responses(struct xenvif_queue *queue);
 
 static inline int tx_work_todo(struct xenvif_queue *queue);
 
@@ -641,7 +642,7 @@ static void tx_add_credit(struct xenvif_queue *queue)
 	queue->remaining_credit = min(max_credit, max_burst);
 }
 
-static void tx_credit_callback(unsigned long data)
+void xenvif_tx_credit_callback(unsigned long data)
 {
 	struct xenvif_queue *queue = (struct xenvif_queue *)data;
 	tx_add_credit(queue);
@@ -657,6 +658,7 @@ static void xenvif_tx_err(struct xenvif_queue *queue,
 	do {
 		spin_lock_irqsave(&queue->response_lock, flags);
 		make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR);
+		push_tx_responses(queue);
 		spin_unlock_irqrestore(&queue->response_lock, flags);
 		if (cons == end)
 			break;
@@ -1163,8 +1165,6 @@ static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
 	if (size > queue->remaining_credit) {
 		queue->credit_timeout.data     =
 			(unsigned long)queue;
-		queue->credit_timeout.function =
-			tx_credit_callback;
 		mod_timer(&queue->credit_timeout,
 			  next_credit);
 		queue->credit_window_start = next_credit;
@@ -1343,7 +1343,7 @@ static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *s
 {
 	unsigned int offset = skb_headlen(skb);
 	skb_frag_t frags[MAX_SKB_FRAGS];
-	int i;
+	int i, f;
 	struct ubuf_info *uarg;
 	struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
 
@@ -1383,23 +1383,25 @@ static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *s
 		frags[i].page_offset = 0;
 		skb_frag_size_set(&frags[i], len);
 	}
-	/* swap out with old one */
-	memcpy(skb_shinfo(skb)->frags,
-	       frags,
-	       i * sizeof(skb_frag_t));
-	skb_shinfo(skb)->nr_frags = i;
-	skb->truesize += i * PAGE_SIZE;
 
-	/* remove traces of mapped pages and frag_list */
+	/* Copied all the bits from the frag list -- free it. */
 	skb_frag_list_init(skb);
+	xenvif_skb_zerocopy_prepare(queue, nskb);
+	kfree_skb(nskb);
+
+	/* Release all the original (foreign) frags. */
+	for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
+		skb_frag_unref(skb, f);
 	uarg = skb_shinfo(skb)->destructor_arg;
 	/* increase inflight counter to offset decrement in callback */
 	atomic_inc(&queue->inflight_packets);
 	uarg->callback(uarg, true);
 	skb_shinfo(skb)->destructor_arg = NULL;
 
-	xenvif_skb_zerocopy_prepare(queue, nskb);
-	kfree_skb(nskb);
+	/* Fill the skb with the new (local) frags. */
+	memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
+	skb_shinfo(skb)->nr_frags = i;
+	skb->truesize += i * PAGE_SIZE;
 
 	return 0;
 }
@@ -1652,13 +1654,20 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
 	unsigned long flags;
 
 	pending_tx_info = &queue->pending_tx_info[pending_idx];
+
 	spin_lock_irqsave(&queue->response_lock, flags);
+
 	make_tx_response(queue, &pending_tx_info->req, status);
-	index = pending_index(queue->pending_prod);
+
+	/* Release the pending index before pusing the Tx response so
+	 * its available before a new Tx request is pushed by the
+	 * frontend.
+	 */
+	index = pending_index(queue->pending_prod++);
 	queue->pending_ring[index] = pending_idx;
-	/* TX shouldn't use the index before we give it back here */
-	mb();
-	queue->pending_prod++;
+
+	push_tx_responses(queue);
+
 	spin_unlock_irqrestore(&queue->response_lock, flags);
 }
 
@@ -1669,7 +1678,6 @@ static void make_tx_response(struct xenvif_queue *queue,
 {
 	RING_IDX i = queue->tx.rsp_prod_pvt;
 	struct xen_netif_tx_response *resp;
-	int notify;
 
 	resp = RING_GET_RESPONSE(&queue->tx, i);
 	resp->id     = txp->id;
@@ -1679,6 +1687,12 @@ static void make_tx_response(struct xenvif_queue *queue,
 		RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
 
 	queue->tx.rsp_prod_pvt = ++i;
+}
+
+static void push_tx_responses(struct xenvif_queue *queue)
+{
+	int notify;
+
 	RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
 	if (notify)
 		notify_remote_via_irq(queue->tx_irq);
@@ -1766,7 +1780,7 @@ int xenvif_map_frontend_rings(struct xenvif_queue *queue,
 	int err = -ENOMEM;
 
 	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
-				     tx_ring_ref, &addr);
+				     &tx_ring_ref, 1, &addr);
 	if (err)
 		goto err;
 
@@ -1774,7 +1788,7 @@ int xenvif_map_frontend_rings(struct xenvif_queue *queue,
 	BACK_RING_INIT(&queue->tx, txs, PAGE_SIZE);
 
 	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
-				     rx_ring_ref, &addr);
+				     &rx_ring_ref, 1, &addr);
 	if (err)
 		goto err;