1 files changed, 90 insertions, 44 deletions

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 5a7872ac3566..055222bae6e4 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1287,7 +1287,7 @@ static irqreturn_t xennet_rx_interrupt(int irq, void *dev_id)
 
         if (likely(netif_carrier_ok(dev) &&
                    RING_HAS_UNCONSUMED_RESPONSES(&queue->rx)))
-                        napi_schedule(&queue->napi);
+                napi_schedule(&queue->napi);
 
         return IRQ_HANDLED;
 }
@@ -1437,16 +1437,12 @@ static void xennet_end_access(int ref, void *page)
 static void xennet_disconnect_backend(struct netfront_info *info)
 {
         unsigned int i = 0;
-        struct netfront_queue *queue = NULL;
         unsigned int num_queues = info->netdev->real_num_tx_queues;
 
+        netif_carrier_off(info->netdev);
+
         for (i = 0; i < num_queues; ++i) {
-                /* Stop old i/f to prevent errors whilst we rebuild the state. */
-                spin_lock_bh(&queue->rx_lock);
-                spin_lock_irq(&queue->tx_lock);
-                netif_carrier_off(queue->info->netdev);
-                spin_unlock_irq(&queue->tx_lock);
-                spin_unlock_bh(&queue->rx_lock);
+                struct netfront_queue *queue = &info->queues[i];
 
                 if (queue->tx_irq && (queue->tx_irq == queue->rx_irq))
                         unbind_from_irqhandler(queue->tx_irq, queue);
@@ -1457,6 +1453,8 @@ static void xennet_disconnect_backend(struct netfront_info *info)
                 queue->tx_evtchn = queue->rx_evtchn = 0;
                 queue->tx_irq = queue->rx_irq = 0;
 
+                napi_synchronize(&queue->napi);
+
                 /* End access and free the pages */
                 xennet_end_access(queue->tx_ring_ref, queue->tx.sring);
                 xennet_end_access(queue->rx_ring_ref, queue->rx.sring);
@@ -1698,8 +1696,6 @@ static int xennet_init_queue(struct netfront_queue *queue)
                 goto exit_free_tx;
         }
 
-        netif_napi_add(queue->info->netdev, &queue->napi, xennet_poll, 64);
-
         return 0;
 
  exit_free_tx:
@@ -1790,6 +1786,70 @@ error:
         return err;
 }
 
+static void xennet_destroy_queues(struct netfront_info *info)
+{
+        unsigned int i;
+
+        rtnl_lock();
+
+        for (i = 0; i < info->netdev->real_num_tx_queues; i++) {
+                struct netfront_queue *queue = &info->queues[i];
+
+                if (netif_running(info->netdev))
+                        napi_disable(&queue->napi);
+                netif_napi_del(&queue->napi);
+        }
+
+        rtnl_unlock();
+
+        kfree(info->queues);
+        info->queues = NULL;
+}
+
+static int xennet_create_queues(struct netfront_info *info,
+                                unsigned int num_queues)
+{
+        unsigned int i;
+        int ret;
+
+        info->queues = kcalloc(num_queues, sizeof(struct netfront_queue),
+                               GFP_KERNEL);
+        if (!info->queues)
+                return -ENOMEM;
+
+        rtnl_lock();
+
+        for (i = 0; i < num_queues; i++) {
+                struct netfront_queue *queue = &info->queues[i];
+
+                queue->id = i;
+                queue->info = info;
+
+                ret = xennet_init_queue(queue);
+                if (ret < 0) {
+                        dev_warn(&info->netdev->dev, "only created %d queues\n",
+                                 num_queues);
+                        num_queues = i;
+                        break;
+                }
+
+                netif_napi_add(queue->info->netdev, &queue->napi,
+                               xennet_poll, 64);
+                if (netif_running(info->netdev))
+                        napi_enable(&queue->napi);
+        }
+
+        netif_set_real_num_tx_queues(info->netdev, num_queues);
+
+        rtnl_unlock();
+
+        if (num_queues == 0) {
+                dev_err(&info->netdev->dev, "no queues\n");
+                return -EINVAL;
+        }
+        return 0;
+}
+
 /* Common code used when first setting up, and when resuming. */
 static int talk_to_netback(struct xenbus_device *dev,
                            struct netfront_info *info)
@@ -1826,42 +1886,20 @@ static int talk_to_netback(struct xenbus_device *dev,
                 goto out;
         }
 
-        /* Allocate array of queues */
-        info->queues = kcalloc(num_queues, sizeof(struct netfront_queue), GFP_KERNEL);
-        if (!info->queues) {
-                err = -ENOMEM;
-                goto out;
-        }
-        rtnl_lock();
-        netif_set_real_num_tx_queues(info->netdev, num_queues);
-        rtnl_unlock();
+        if (info->queues)
+                xennet_destroy_queues(info);
+
+        err = xennet_create_queues(info, num_queues);
+        if (err < 0)
+                goto destroy_ring;
 
         /* Create shared ring, alloc event channel -- for each queue */
         for (i = 0; i < num_queues; ++i) {
                 queue = &info->queues[i];
-                queue->id = i;
-                queue->info = info;
-                err = xennet_init_queue(queue);
-                if (err) {
-                        /* xennet_init_queue() cleans up after itself on failure,
-                         * but we still have to clean up any previously initialised
-                         * queues. If i > 0, set num_queues to i, then goto
-                         * destroy_ring, which calls xennet_disconnect_backend()
-                         * to tidy up.
-                         */
-                        if (i > 0) {
-                                rtnl_lock();
-                                netif_set_real_num_tx_queues(info->netdev, i);
-                                rtnl_unlock();
-                                goto destroy_ring;
-                        } else {
-                                goto out;
-                        }
-                }
                 err = setup_netfront(dev, queue, feature_split_evtchn);
                 if (err) {
-                        /* As for xennet_init_queue(), setup_netfront() will tidy
-                         * up the current queue on error, but we need to clean up
+                        /* setup_netfront() will tidy up the current
+                         * queue on error, but we need to clean up
                          * those already allocated.
                          */
                         if (i > 0) {
@@ -2005,13 +2043,15 @@ static int xennet_connect(struct net_device *dev)
         /* By now, the queue structures have been set up */
         for (j = 0; j < num_queues; ++j) {
                 queue = &np->queues[j];
-                spin_lock_bh(&queue->rx_lock);
-                spin_lock_irq(&queue->tx_lock);
 
                 /* Step 1: Discard all pending TX packet fragments. */
+                spin_lock_irq(&queue->tx_lock);
                 xennet_release_tx_bufs(queue);
+                spin_unlock_irq(&queue->tx_lock);
 
                 /* Step 2: Rebuild the RX buffer freelist and the RX ring itself. */
+                spin_lock_bh(&queue->rx_lock);
+
                 for (requeue_idx = 0, i = 0; i < NET_RX_RING_SIZE; i++) {
                         skb_frag_t *frag;
                         const struct page *page;
@@ -2035,6 +2075,8 @@ static int xennet_connect(struct net_device *dev)
                 }
 
                 queue->rx.req_prod_pvt = requeue_idx;
+
+                spin_unlock_bh(&queue->rx_lock);
         }
 
         /*
@@ -2046,13 +2088,17 @@ static int xennet_connect(struct net_device *dev)
         netif_carrier_on(np->netdev);
         for (j = 0; j < num_queues; ++j) {
                 queue = &np->queues[j];
+
                 notify_remote_via_irq(queue->tx_irq);
                 if (queue->tx_irq != queue->rx_irq)
                         notify_remote_via_irq(queue->rx_irq);
-                xennet_tx_buf_gc(queue);
-                xennet_alloc_rx_buffers(queue);
 
+                spin_lock_irq(&queue->tx_lock);
+                xennet_tx_buf_gc(queue);
                 spin_unlock_irq(&queue->tx_lock);
+
+                spin_lock_bh(&queue->rx_lock);
+                xennet_alloc_rx_buffers(queue);
                 spin_unlock_bh(&queue->rx_lock);
         }