xen-netback: release pending index before pushing Tx responses

[linux-2.6-block.git] / drivers / net / xen-netback / netback.c

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index f7a31d2cb3f1819fdf7ebdeb40e0f6bf44aabe0a..c4d68d7684087f6ec66400047be4991c5e51cfe6 100644 (file)
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -655,9 +655,15 @@ static void xenvif_tx_err(struct xenvif_queue *queue,
        unsigned long flags;
 
        do {
+               int notify;
+
                spin_lock_irqsave(&queue->response_lock, flags);
                make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR);
+               RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
                spin_unlock_irqrestore(&queue->response_lock, flags);
+               if (notify)
+                       notify_remote_via_irq(queue->tx_irq);
+
                if (cons == end)
                        break;
                txp = RING_GET_REQUEST(&queue->tx, cons++);
@@ -1649,17 +1655,28 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
 {
        struct pending_tx_info *pending_tx_info;
        pending_ring_idx_t index;
+       int notify;
        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++;
+
+       RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
+
        spin_unlock_irqrestore(&queue->response_lock, flags);
+
+       if (notify)
+               notify_remote_via_irq(queue->tx_irq);
 }
 
 
@@ -1669,7 +1686,6 @@ 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;
@@ -1679,9 +1695,6 @@ 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;
-       RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
-       if (notify)
-               notify_remote_via_irq(queue->tx_irq);
 }
 
 static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,