xen-netback: add control ring boilerplate

[cascardo/linux.git] / drivers / net / xen-netback / xenbus.c

diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index bd182cd..6a31f26 100644 (file)
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -38,7 +38,8 @@ struct backend_info {
        const char *hotplug_script;
 };
 
-static int connect_rings(struct backend_info *be, struct xenvif_queue *queue);
+static int connect_data_rings(struct backend_info *be,
+                             struct xenvif_queue *queue);
 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);
@@ -367,6 +368,12 @@ static int netback_probe(struct xenbus_device *dev,
        if (err)
                pr_debug("Error writing multi-queue-max-queues\n");
 
+       err = xenbus_printf(XBT_NIL, dev->nodename,
+                           "feature-ctrl-ring",
+                           "%u", true);
+       if (err)
+               pr_debug("Error writing feature-ctrl-ring\n");
+
        script = xenbus_read(XBT_NIL, dev->nodename, "script", NULL);
        if (IS_ERR(script)) {
                err = PTR_ERR(script);
@@ -457,7 +464,8 @@ static void backend_disconnect(struct backend_info *be)
 #ifdef CONFIG_DEBUG_FS
                xenvif_debugfs_delif(be->vif);
 #endif /* CONFIG_DEBUG_FS */
-               xenvif_disconnect(be->vif);
+               xenvif_disconnect_data(be->vif);
+               xenvif_disconnect_ctrl(be->vif);
        }
 }
 
@@ -825,6 +833,48 @@ static void hotplug_status_changed(struct xenbus_watch *watch,
        kfree(str);
 }
 
+static int connect_ctrl_ring(struct backend_info *be)
+{
+       struct xenbus_device *dev = be->dev;
+       struct xenvif *vif = be->vif;
+       unsigned int val;
+       grant_ref_t ring_ref;
+       unsigned int evtchn;
+       int err;
+
+       err = xenbus_gather(XBT_NIL, dev->otherend,
+                           "ctrl-ring-ref", "%u", &val, NULL);
+       if (err)
+               goto done; /* The frontend does not have a control ring */
+
+       ring_ref = val;
+
+       err = xenbus_gather(XBT_NIL, dev->otherend,
+                           "event-channel-ctrl", "%u", &val, NULL);
+       if (err) {
+               xenbus_dev_fatal(dev, err,
+                                "reading %s/event-channel-ctrl",
+                                dev->otherend);
+               goto fail;
+       }
+
+       evtchn = val;
+
+       err = xenvif_connect_ctrl(vif, ring_ref, evtchn);
+       if (err) {
+               xenbus_dev_fatal(dev, err,
+                                "mapping shared-frame %u port %u",
+                                ring_ref, evtchn);
+               goto fail;
+       }
+
+done:
+       return 0;
+
+fail:
+       return err;
+}
+
 static void connect(struct backend_info *be)
 {
        int err;
@@ -861,6 +911,12 @@ static void connect(struct backend_info *be)
        xen_register_watchers(dev, be->vif);
        read_xenbus_vif_flags(be);
 
+       err = connect_ctrl_ring(be);
+       if (err) {
+               xenbus_dev_fatal(dev, err, "connecting control ring");
+               return;
+       }
+
        /* Use the number of queues requested by the frontend */
        be->vif->queues = vzalloc(requested_num_queues *
                                  sizeof(struct xenvif_queue));
@@ -896,11 +952,12 @@ static void connect(struct backend_info *be)
                queue->remaining_credit = credit_bytes;
                queue->credit_usec = credit_usec;
 
-               err = connect_rings(be, queue);
+               err = connect_data_rings(be, queue);
                if (err) {
-                       /* connect_rings() cleans up after itself on failure,
-                        * but we need to clean up after xenvif_init_queue() here,
-                        * and also clean up any previously initialised queues.
+                       /* connect_data_rings() cleans up after itself on
+                        * failure, but we need to clean up after
+                        * xenvif_init_queue() here, and also clean up any
+                        * previously initialised queues.
                         */
                        xenvif_deinit_queue(queue);
                        be->vif->num_queues = queue_index;
@@ -935,15 +992,17 @@ static void connect(struct backend_info *be)
 
 err:
        if (be->vif->num_queues > 0)
-               xenvif_disconnect(be->vif); /* Clean up existing queues */
+               xenvif_disconnect_data(be->vif); /* Clean up existing queues */
        vfree(be->vif->queues);
        be->vif->queues = NULL;
        be->vif->num_queues = 0;
+       xenvif_disconnect_ctrl(be->vif);
        return;
 }
 
 
-static int connect_rings(struct backend_info *be, struct xenvif_queue *queue)
+static int connect_data_rings(struct backend_info *be,
+                             struct xenvif_queue *queue)
 {
        struct xenbus_device *dev = be->dev;
        unsigned int num_queues = queue->vif->num_queues;
@@ -1007,8 +1066,8 @@ static int connect_rings(struct backend_info *be, struct xenvif_queue *queue)
        }
 
        /* Map the shared frame, irq etc. */
-       err = xenvif_connect(queue, tx_ring_ref, rx_ring_ref,
-                            tx_evtchn, rx_evtchn);
+       err = xenvif_connect_data(queue, tx_ring_ref, rx_ring_ref,
+                                 tx_evtchn, rx_evtchn);
        if (err) {
                xenbus_dev_fatal(dev, err,
                                 "mapping shared-frames %lu/%lu port tx %u rx %u",