diff options
Diffstat (limited to 'drivers/net/xen-netback/xenbus.c')
| -rw-r--r-- | drivers/net/xen-netback/xenbus.c | 151 |
1 files changed, 123 insertions, 28 deletions
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c index 1fe48fe364e..b45bce20ad7 100644 --- a/drivers/net/xen-netback/xenbus.c +++ b/drivers/net/xen-netback/xenbus.c @@ -24,6 +24,12 @@ struct backend_info { struct xenbus_device *dev; struct xenvif *vif; + + /* This is the state that will be reflected in xenstore when any + * active hotplug script completes. + */ + enum xenbus_state state; + enum xenbus_state frontend_state; struct xenbus_watch hotplug_status_watch; u8 have_hotplug_status_watch:1; @@ -42,7 +48,7 @@ static int netback_remove(struct xenbus_device *dev) if (be->vif) { kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE); xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status"); - xenvif_disconnect(be->vif); + xenvif_free(be->vif); be->vif = NULL; } kfree(be); @@ -136,6 +142,8 @@ static int netback_probe(struct xenbus_device *dev, if (err) goto fail; + be->state = XenbusStateInitWait; + /* This kicks hotplug scripts, so do it immediately. */ backend_create_xenvif(be); @@ -208,15 +216,113 @@ static void backend_create_xenvif(struct backend_info *be) kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE); } +static void backend_disconnect(struct backend_info *be) +{ + if (be->vif) + xenvif_disconnect(be->vif); +} -static void disconnect_backend(struct xenbus_device *dev) +static void backend_connect(struct backend_info *be) { - struct backend_info *be = dev_get_drvdata(&dev->dev); + if (be->vif) + connect(be); +} - if (be->vif) { - xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status"); - xenvif_disconnect(be->vif); - be->vif = NULL; +static inline void backend_switch_state(struct backend_info *be, + enum xenbus_state state) +{ + struct xenbus_device *dev = be->dev; + + pr_debug("%s -> %s\n", dev->nodename, xenbus_strstate(state)); + be->state = state; + + /* If we are waiting for a hotplug script then defer the + * actual xenbus state change. + */ + if (!be->have_hotplug_status_watch) + xenbus_switch_state(dev, state); +} + +/* Handle backend state transitions: + * + * The backend state starts in InitWait and the following transitions are + * allowed. + * + * InitWait -> Connected + * + * ^ \ | + * | \ | + * | \ | + * | \ | + * | \ | + * | \ | + * | V V + * + * Closed <-> Closing + * + * The state argument specifies the eventual state of the backend and the + * function transitions to that state via the shortest path. + */ +static void set_backend_state(struct backend_info *be, + enum xenbus_state state) +{ + while (be->state != state) { + switch (be->state) { + case XenbusStateClosed: + switch (state) { + case XenbusStateInitWait: + case XenbusStateConnected: + pr_info("%s: prepare for reconnect\n", + be->dev->nodename); + backend_switch_state(be, XenbusStateInitWait); + break; + case XenbusStateClosing: + backend_switch_state(be, XenbusStateClosing); + break; + default: + BUG(); + } + break; + case XenbusStateInitWait: + switch (state) { + case XenbusStateConnected: + backend_connect(be); + backend_switch_state(be, XenbusStateConnected); + break; + case XenbusStateClosing: + case XenbusStateClosed: + backend_switch_state(be, XenbusStateClosing); + break; + default: + BUG(); + } + break; + case XenbusStateConnected: + switch (state) { + case XenbusStateInitWait: + case XenbusStateClosing: + case XenbusStateClosed: + backend_disconnect(be); + backend_switch_state(be, XenbusStateClosing); + break; + default: + BUG(); + } + break; + case XenbusStateClosing: + switch (state) { + case XenbusStateInitWait: + case XenbusStateConnected: + case XenbusStateClosed: + backend_switch_state(be, XenbusStateClosed); + break; + default: + BUG(); + } + break; + default: + BUG(); + } } } @@ -228,42 +334,33 @@ static void frontend_changed(struct xenbus_device *dev, { struct backend_info *be = dev_get_drvdata(&dev->dev); - pr_debug("frontend state %s\n", xenbus_strstate(frontend_state)); + pr_debug("%s -> %s\n", dev->otherend, xenbus_strstate(frontend_state)); be->frontend_state = frontend_state; switch (frontend_state) { case XenbusStateInitialising: - if (dev->state == XenbusStateClosed) { - pr_info("%s: prepare for reconnect\n", dev->nodename); - xenbus_switch_state(dev, XenbusStateInitWait); - } + set_backend_state(be, XenbusStateInitWait); break; case XenbusStateInitialised: break; case XenbusStateConnected: - if (dev->state == XenbusStateConnected) - break; - backend_create_xenvif(be); - if (be->vif) - connect(be); + set_backend_state(be, XenbusStateConnected); break; case XenbusStateClosing: - if (be->vif) - kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE); - disconnect_backend(dev); - xenbus_switch_state(dev, XenbusStateClosing); + set_backend_state(be, XenbusStateClosing); break; case XenbusStateClosed: - xenbus_switch_state(dev, XenbusStateClosed); + set_backend_state(be, XenbusStateClosed); if (xenbus_dev_is_online(dev)) break; /* fall through if not online */ case XenbusStateUnknown: + set_backend_state(be, XenbusStateClosed); device_unregister(&dev->dev); break; @@ -356,7 +453,9 @@ static void hotplug_status_changed(struct xenbus_watch *watch, if (IS_ERR(str)) return; if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) { - xenbus_switch_state(be->dev, XenbusStateConnected); + /* Complete any pending state change */ + xenbus_switch_state(be->dev, be->state); + /* Not interested in this watch anymore. */ unregister_hotplug_status_watch(be); } @@ -386,12 +485,8 @@ static void connect(struct backend_info *be) err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch, hotplug_status_changed, "%s/%s", dev->nodename, "hotplug-status"); - if (err) { - /* Switch now, since we can't do a watch. */ - xenbus_switch_state(dev, XenbusStateConnected); - } else { + if (!err) be->have_hotplug_status_watch = 1; - } netif_wake_queue(be->vif->dev); } |