1 files changed, 24 insertions, 38 deletions

diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 48a55cda979b..e29e15dca86e 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -43,6 +43,23 @@
 #define XENVIF_QUEUE_LENGTH 32
 #define XENVIF_NAPI_WEIGHT  64
 
+/* This function is used to set SKBTX_DEV_ZEROCOPY as well as
+ * increasing the inflight counter. We need to increase the inflight
+ * counter because core driver calls into xenvif_zerocopy_callback
+ * which calls xenvif_skb_zerocopy_complete.
+ */
+void xenvif_skb_zerocopy_prepare(struct xenvif_queue *queue,
+                                 struct sk_buff *skb)
+{
+        skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
+        atomic_inc(&queue->inflight_packets);
+}
+
+void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue)
+{
+        atomic_dec(&queue->inflight_packets);
+}
+
 static inline void xenvif_stop_queue(struct xenvif_queue *queue)
 {
         struct net_device *dev = queue->vif->dev;
@@ -78,12 +95,8 @@ int xenvif_poll(struct napi_struct *napi, int budget)
         /* This vif is rogue, we pretend we've there is nothing to do
          * for this vif to deschedule it from NAPI. But this interface
          * will be turned off in thread context later.
-         * Also, if a guest doesn't post enough slots to receive data on one of
-         * its queues, the carrier goes down and NAPI is descheduled here so
-         * the guest can't send more packets until it's ready to receive.
          */
-        if (unlikely(queue->vif->disabled ||
-                     !netif_carrier_ok(queue->vif->dev))) {
+        if (unlikely(queue->vif->disabled)) {
                 napi_complete(napi);
                 return 0;
         }
@@ -528,9 +541,6 @@ int xenvif_init_queue(struct xenvif_queue *queue)
 
         init_timer(&queue->rx_stalled);
 
-        netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll,
-                        XENVIF_NAPI_WEIGHT);
-
         return 0;
 }
 
@@ -564,6 +574,7 @@ int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
 
         init_waitqueue_head(&queue->wq);
         init_waitqueue_head(&queue->dealloc_wq);
+        atomic_set(&queue->inflight_packets, 0);
 
         if (tx_evtchn == rx_evtchn) {
                 /* feature-split-event-channels == 0 */
@@ -618,6 +629,9 @@ int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
         wake_up_process(queue->task);
         wake_up_process(queue->dealloc_task);
 
+        netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll,
+                        XENVIF_NAPI_WEIGHT);
+
         return 0;
 
 err_rx_unbind:
@@ -646,25 +660,6 @@ void xenvif_carrier_off(struct xenvif *vif)
         rtnl_unlock();
 }
 
-static void xenvif_wait_unmap_timeout(struct xenvif_queue *queue,
-                                      unsigned int worst_case_skb_lifetime)
-{
-        int i, unmap_timeout = 0;
-
-        for (i = 0; i < MAX_PENDING_REQS; ++i) {
-                if (queue->grant_tx_handle[i] != NETBACK_INVALID_HANDLE) {
-                        unmap_timeout++;
-                        schedule_timeout(msecs_to_jiffies(1000));
-                        if (unmap_timeout > worst_case_skb_lifetime &&
-                            net_ratelimit())
-                                netdev_err(queue->vif->dev,
-                                           "Page still granted! Index: %x\n",
-                                           i);
-                        i = -1;
-                }
-        }
-}
-
 void xenvif_disconnect(struct xenvif *vif)
 {
         struct xenvif_queue *queue = NULL;
@@ -676,6 +671,8 @@ void xenvif_disconnect(struct xenvif *vif)
         for (queue_index = 0; queue_index < num_queues; ++queue_index) {
                 queue = &vif->queues[queue_index];
 
+                netif_napi_del(&queue->napi);
+
                 if (queue->task) {
                         del_timer_sync(&queue->rx_stalled);
                         kthread_stop(queue->task);
@@ -708,7 +705,6 @@ void xenvif_disconnect(struct xenvif *vif)
 void xenvif_deinit_queue(struct xenvif_queue *queue)
 {
         free_xenballooned_pages(MAX_PENDING_REQS, queue->mmap_pages);
-        netif_napi_del(&queue->napi);
 }
 
 void xenvif_free(struct xenvif *vif)
@@ -716,21 +712,11 @@ void xenvif_free(struct xenvif *vif)
         struct xenvif_queue *queue = NULL;
         unsigned int num_queues = vif->num_queues;
         unsigned int queue_index;
-        /* Here we want to avoid timeout messages if an skb can be legitimately
-         * stuck somewhere else. Realistically this could be an another vif's
-         * internal or QDisc queue. That another vif also has this
-         * rx_drain_timeout_msecs timeout, so give it time to drain out.
-         * Although if that other guest wakes up just before its timeout happens
-         * and takes only one skb from QDisc, it can hold onto other skbs for a
-         * longer period.
-         */
-        unsigned int worst_case_skb_lifetime = (rx_drain_timeout_msecs/1000);
 
         unregister_netdev(vif->dev);
 
         for (queue_index = 0; queue_index < num_queues; ++queue_index) {
                 queue = &vif->queues[queue_index];
-                xenvif_wait_unmap_timeout(queue, worst_case_skb_lifetime);
                 xenvif_deinit_queue(queue);
         }