4 files changed, 29 insertions, 18 deletions

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 083ecc93fe5e..5f1fda44882b 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -230,6 +230,8 @@ struct xenvif {
          */
         bool disabled;
         unsigned long status;
+        unsigned long drain_timeout;
+        unsigned long stall_timeout;
 
         /* Queues */
         struct xenvif_queue *queues;
@@ -328,7 +330,7 @@ irqreturn_t xenvif_interrupt(int irq, void *dev_id);
 extern bool separate_tx_rx_irq;
 
 extern unsigned int rx_drain_timeout_msecs;
-extern unsigned int rx_drain_timeout_jiffies;
+extern unsigned int rx_stall_timeout_msecs;
 extern unsigned int xenvif_max_queues;
 
 #ifdef CONFIG_DEBUG_FS
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index a6a32d337bbb..9259a732e8a4 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -166,7 +166,7 @@ static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
                 goto drop;
 
         cb = XENVIF_RX_CB(skb);
-        cb->expires = jiffies + rx_drain_timeout_jiffies;
+        cb->expires = jiffies + vif->drain_timeout;
 
         xenvif_rx_queue_tail(queue, skb);
         xenvif_kick_thread(queue);
@@ -414,6 +414,8 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
         vif->ip_csum = 1;
         vif->dev = dev;
         vif->disabled = false;
+        vif->drain_timeout = msecs_to_jiffies(rx_drain_timeout_msecs);
+        vif->stall_timeout = msecs_to_jiffies(rx_stall_timeout_msecs);
 
         /* Start out with no queues. */
         vif->queues = NULL;
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 4a509f715fe8..908e65e9b821 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -60,14 +60,12 @@ module_param(separate_tx_rx_irq, bool, 0644);
  */
 unsigned int rx_drain_timeout_msecs = 10000;
 module_param(rx_drain_timeout_msecs, uint, 0444);
-unsigned int rx_drain_timeout_jiffies;
 
 /* The length of time before the frontend is considered unresponsive
  * because it isn't providing Rx slots.
  */
-static unsigned int rx_stall_timeout_msecs = 60000;
+unsigned int rx_stall_timeout_msecs = 60000;
 module_param(rx_stall_timeout_msecs, uint, 0444);
-static unsigned int rx_stall_timeout_jiffies;
 
 unsigned int xenvif_max_queues;
 module_param_named(max_queues, xenvif_max_queues, uint, 0644);
@@ -2020,7 +2018,7 @@ static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue)
         return !queue->stalled
                 && prod - cons < XEN_NETBK_RX_SLOTS_MAX
                 && time_after(jiffies,
-                              queue->last_rx_time + rx_stall_timeout_jiffies);
+                              queue->last_rx_time + queue->vif->stall_timeout);
 }
 
 static bool xenvif_rx_queue_ready(struct xenvif_queue *queue)
@@ -2038,8 +2036,9 @@ static bool xenvif_have_rx_work(struct xenvif_queue *queue)
 {
         return (!skb_queue_empty(&queue->rx_queue)
                 && xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX))
-                || xenvif_rx_queue_stalled(queue)
-                || xenvif_rx_queue_ready(queue)
+                || (queue->vif->stall_timeout &&
+                    (xenvif_rx_queue_stalled(queue)
+                     || xenvif_rx_queue_ready(queue)))
                 || kthread_should_stop()
                 || queue->vif->disabled;
 }
@@ -2092,6 +2091,9 @@ int xenvif_kthread_guest_rx(void *data)
         struct xenvif_queue *queue = data;
         struct xenvif *vif = queue->vif;
 
+        if (!vif->stall_timeout)
+                xenvif_queue_carrier_on(queue);
+
         for (;;) {
                 xenvif_wait_for_rx_work(queue);
 
@@ -2118,10 +2120,12 @@ int xenvif_kthread_guest_rx(void *data)
                  * while it's probably not responsive, drop the
                  * carrier so packets are dropped earlier.
                  */
-                if (xenvif_rx_queue_stalled(queue))
-                        xenvif_queue_carrier_off(queue);
-                else if (xenvif_rx_queue_ready(queue))
-                        xenvif_queue_carrier_on(queue);
+                if (vif->stall_timeout) {
+                        if (xenvif_rx_queue_stalled(queue))
+                                xenvif_queue_carrier_off(queue);
+                        else if (xenvif_rx_queue_ready(queue))
+                                xenvif_queue_carrier_on(queue);
+                }
 
                 /* Queued packets may have foreign pages from other
                  * domains.  These cannot be queued indefinitely as
@@ -2192,9 +2196,6 @@ static int __init netback_init(void)
         if (rc)
                 goto failed_init;
 
-        rx_drain_timeout_jiffies = msecs_to_jiffies(rx_drain_timeout_msecs);
-        rx_stall_timeout_jiffies = msecs_to_jiffies(rx_stall_timeout_msecs);
-
 #ifdef CONFIG_DEBUG_FS
         xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
         if (IS_ERR_OR_NULL(xen_netback_dbg_root))
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index d44cd19169bd..efbaf2ae1999 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -887,9 +887,15 @@ static int read_xenbus_vif_flags(struct backend_info *be)
                 return -EOPNOTSUPP;
 
         if (xenbus_scanf(XBT_NIL, dev->otherend,
-                         "feature-rx-notify", "%d", &val) < 0 || val == 0) {
-                xenbus_dev_fatal(dev, -EINVAL, "feature-rx-notify is mandatory");
-                return -EINVAL;
+                         "feature-rx-notify", "%d", &val) < 0)
+                val = 0;
+        if (!val) {
+                /* - Reduce drain timeout to poll more frequently for
+                 *   Rx requests.
+                 * - Disable Rx stall detection.
+                 */
+                be->vif->drain_timeout = msecs_to_jiffies(30);
+                be->vif->stall_timeout = 0;
         }
 
         if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg",