4 files changed, 63 insertions, 3 deletions

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 589fa256256b..8a495b318b6f 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -238,6 +238,8 @@ struct xenvif {
         unsigned int num_queues; /* active queues, resource allocated */
         unsigned int stalled_queues;
 
+        struct xenbus_watch credit_watch;
+
         spinlock_t lock;
 
 #ifdef CONFIG_DEBUG_FS
@@ -260,6 +262,8 @@ static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
         return to_xenbus_device(vif->dev->dev.parent);
 }
 
+void xenvif_tx_credit_callback(unsigned long data);
+
 struct xenvif *xenvif_alloc(struct device *parent,
                             domid_t domid,
                             unsigned int handle);
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index d2ada7cda97a..1a83e190fc15 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -463,6 +463,7 @@ int xenvif_init_queue(struct xenvif_queue *queue)
         queue->credit_bytes = queue->remaining_credit = ~0UL;
         queue->credit_usec  = 0UL;
         init_timer(&queue->credit_timeout);
+        queue->credit_timeout.function = xenvif_tx_credit_callback;
         queue->credit_window_start = get_jiffies_64();
 
         queue->rx_queue_max = XENVIF_RX_QUEUE_BYTES;
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index cab9f5257f57..2c25e8e1a91e 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -641,7 +641,7 @@ 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);
@@ -1169,8 +1169,6 @@ 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;
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 794204e34fba..3d8dbf5f2d39 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -41,6 +41,7 @@ static void connect(struct backend_info *be);
 static int read_xenbus_vif_flags(struct backend_info *be);
 static int backend_create_xenvif(struct backend_info *be);
 static void unregister_hotplug_status_watch(struct backend_info *be);
+static void xen_unregister_watchers(struct xenvif *vif);
 static void set_backend_state(struct backend_info *be,
                               enum xenbus_state state);
 
@@ -232,6 +233,7 @@ static int netback_remove(struct xenbus_device *dev)
         unregister_hotplug_status_watch(be);
         if (be->vif) {
                 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
+                xen_unregister_watchers(be->vif);
                 xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
                 xenvif_free(be->vif);
                 be->vif = NULL;
@@ -430,6 +432,7 @@ static int backend_create_xenvif(struct backend_info *be)
 static void backend_disconnect(struct backend_info *be)
 {
         if (be->vif) {
+                xen_unregister_watchers(be->vif);
 #ifdef CONFIG_DEBUG_FS
                 xenvif_debugfs_delif(be->vif);
 #endif /* CONFIG_DEBUG_FS */
@@ -645,6 +648,59 @@ static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
         return 0;
 }
 
+static void xen_net_rate_changed(struct xenbus_watch *watch,
+                                const char **vec, unsigned int len)
+{
+        struct xenvif *vif = container_of(watch, struct xenvif, credit_watch);
+        struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
+        unsigned long   credit_bytes;
+        unsigned long   credit_usec;
+        unsigned int queue_index;
+
+        xen_net_read_rate(dev, &credit_bytes, &credit_usec);
+        for (queue_index = 0; queue_index < vif->num_queues; queue_index++) {
+                struct xenvif_queue *queue = &vif->queues[queue_index];
+
+                queue->credit_bytes = credit_bytes;
+                queue->credit_usec = credit_usec;
+                if (!mod_timer_pending(&queue->credit_timeout, jiffies) &&
+                        queue->remaining_credit > queue->credit_bytes) {
+                        queue->remaining_credit = queue->credit_bytes;
+                }
+        }
+}
+
+static int xen_register_watchers(struct xenbus_device *dev, struct xenvif *vif)
+{
+        int err = 0;
+        char *node;
+        unsigned maxlen = strlen(dev->nodename) + sizeof("/rate");
+
+        node = kmalloc(maxlen, GFP_KERNEL);
+        if (!node)
+                return -ENOMEM;
+        snprintf(node, maxlen, "%s/rate", dev->nodename);
+        vif->credit_watch.node = node;
+        vif->credit_watch.callback = xen_net_rate_changed;
+        err = register_xenbus_watch(&vif->credit_watch);
+        if (err) {
+                pr_err("Failed to set watcher %s\n", vif->credit_watch.node);
+                kfree(node);
+                vif->credit_watch.node = NULL;
+                vif->credit_watch.callback = NULL;
+        }
+        return err;
+}
+
+static void xen_unregister_watchers(struct xenvif *vif)
+{
+        if (vif->credit_watch.node) {
+                unregister_xenbus_watch(&vif->credit_watch);
+                kfree(vif->credit_watch.node);
+                vif->credit_watch.node = NULL;
+        }
+}
+
 static void unregister_hotplug_status_watch(struct backend_info *be)
 {
         if (be->have_hotplug_status_watch) {
@@ -709,6 +765,7 @@ static void connect(struct backend_info *be)
         }
 
         xen_net_read_rate(dev, &credit_bytes, &credit_usec);
+        xen_register_watchers(dev, be->vif);
         read_xenbus_vif_flags(be);
 
         /* Use the number of queues requested by the frontend */