1 files changed, 104 insertions, 56 deletions

diff --git a/sys/dev/xen/blkback/blkback.c b/sys/dev/xen/blkback/blkback.c
index 8729b456b7de..6ca8c007614f 100644
--- a/sys/dev/xen/blkback/blkback.c
+++ b/sys/dev/xen/blkback/blkback.c
@@ -802,6 +802,9 @@ struct xbb_softc {
 
 	/** How many times we have run out of request structures */
 	uint64_t		  request_shortages;
+
+	/** Watch to wait for hotplug script execution */
+	struct xs_watch		  hotplug_watch;
 };
 
 /*---------------------------- Request Processing ----------------------------*/
@@ -3306,7 +3309,7 @@ xbb_connect(struct xbb_softc *xbb)
 {
 	int error;
 
-	if (xenbus_get_state(xbb->dev) == XenbusStateConnected)
+	if (xenbus_get_state(xbb->dev) != XenbusStateInitialised)
 		return;
 
 	if (xbb_collect_frontend_info(xbb) != 0)
@@ -3403,6 +3406,12 @@ xbb_shutdown(struct xbb_softc *xbb)
 	xbb->flags |= XBBF_IN_SHUTDOWN;
 	mtx_unlock(&xbb->lock);
 
+	if (xbb->hotplug_watch.node != NULL) {
+		xs_unregister_watch(&xbb->hotplug_watch);
+		free(xbb->hotplug_watch.node, M_XENBLOCKBACK);
+		xbb->hotplug_watch.node = NULL;
+	}
+
 	if (xenbus_get_state(xbb->dev) < XenbusStateClosing)
 		xenbus_set_state(xbb->dev, XenbusStateClosing);
 
@@ -3583,61 +3592,24 @@ xbb_setup_sysctl(struct xbb_softc *xbb)
 		        "communication channel pages (negotiated)");
 }
 
-/**
- * Attach to a XenBus device that has been claimed by our probe routine.
- *
- * \param dev  NewBus device object representing this Xen Block Back instance.
- *
- * \return  0 for success, errno codes for failure.
- */
-static int
-xbb_attach(device_t dev)
+static void
+xbb_attach_disk(struct xs_watch *watch, const char **vec, unsigned int len)
 {
+	device_t		 dev;
 	struct xbb_softc	*xbb;
 	int			 error;
-	u_int			 max_ring_page_order;
-
-	DPRINTF("Attaching to %s\n", xenbus_get_node(dev));
 
-	/*
-	 * Basic initialization.
-	 * After this block it is safe to call xbb_detach()
-	 * to clean up any allocated data for this instance.
-	 */
+	dev = (device_t) watch->callback_data;
 	xbb = device_get_softc(dev);
-	xbb->dev = dev;
-	xbb->otherend_id = xenbus_get_otherend_id(dev);
-	TASK_INIT(&xbb->io_task, /*priority*/0, xbb_run_queue, xbb);
-	mtx_init(&xbb->lock, device_get_nameunit(dev), NULL, MTX_DEF);
 
-	/*
-	 * Publish protocol capabilities for consumption by the
-	 * front-end.
-	 */
-	error = xs_printf(XST_NIL, xenbus_get_node(xbb->dev),
-			  "feature-barrier", "1");
-	if (error) {
-		xbb_attach_failed(xbb, error, "writing %s/feature-barrier",
-				  xenbus_get_node(xbb->dev));
-		return (error);
-	}
+	error = xs_gather(XST_NIL, xenbus_get_node(dev), "physical-device-path",
+	    NULL, &xbb->dev_name, NULL);
+	if (error != 0)
+		return;
 
-	error = xs_printf(XST_NIL, xenbus_get_node(xbb->dev),
-			  "feature-flush-cache", "1");
-	if (error) {
-		xbb_attach_failed(xbb, error, "writing %s/feature-flush-cache",
-				  xenbus_get_node(xbb->dev));
-		return (error);
-	}
-
-	max_ring_page_order = flsl(XBB_MAX_RING_PAGES) - 1;
-	error = xs_printf(XST_NIL, xenbus_get_node(xbb->dev),
-			  "max-ring-page-order", "%u", max_ring_page_order);
-	if (error) {
-		xbb_attach_failed(xbb, error, "writing %s/max-ring-page-order",
-				  xenbus_get_node(xbb->dev));
-		return (error);
-	}
+	xs_unregister_watch(watch);
+	free(watch->node, M_XENBLOCKBACK);
+	watch->node = NULL;
 
 	/* Collect physical device information. */
 	error = xs_gather(XST_NIL, xenbus_get_otherend_path(xbb->dev),
@@ -3648,12 +3620,11 @@ xbb_attach(device_t dev)
 
 	error = xs_gather(XST_NIL, xenbus_get_node(dev),
                           "mode", NULL, &xbb->dev_mode,
-			  "params", NULL, &xbb->dev_name,
                           NULL);
 	if (error != 0) {
 		xbb_attach_failed(xbb, error, "reading backend fields at %s",
 				  xenbus_get_node(dev));
-                return (ENXIO);
+                return;
         }
 
 	/* Parse fopen style mode flags. */
@@ -3664,13 +3635,11 @@ xbb_attach(device_t dev)
 	 * Verify the physical device is present and can support
 	 * the desired I/O mode.
 	 */
-	DROP_GIANT();
 	error = xbb_open_backend(xbb);
-	PICKUP_GIANT();
 	if (error != 0) {
 		xbb_attach_failed(xbb, error, "Unable to open %s",
 				  xbb->dev_name);
-		return (ENXIO);
+		return;
 	}
 
 	/* Use devstat(9) for recording statistics. */
@@ -3702,7 +3671,7 @@ xbb_attach(device_t dev)
 						  /*contxt*/&xbb->io_taskqueue);
 	if (xbb->io_taskqueue == NULL) {
 		xbb_attach_failed(xbb, error, "Unable to create taskqueue");
-		return (ENOMEM);
+		return;
 	}
 
 	taskqueue_start_threads(&xbb->io_taskqueue,
@@ -3717,10 +3686,89 @@ xbb_attach(device_t dev)
 	if (error) {
 		xbb_attach_failed(xbb, error, "writing %s/hotplug-status",
 				  xenbus_get_node(xbb->dev));
-		return (error);
+		return;
 	}
 
 	/* Tell the front end that we are ready to connect. */
+	xenbus_set_state(dev, XenbusStateInitialised);
+}
+
+/**
+ * Attach to a XenBus device that has been claimed by our probe routine.
+ *
+ * \param dev  NewBus device object representing this Xen Block Back instance.
+ *
+ * \return  0 for success, errno codes for failure.
+ */
+static int
+xbb_attach(device_t dev)
+{
+	struct xbb_softc	*xbb;
+	int			 error;
+	u_int			 max_ring_page_order;
+	struct sbuf		*watch_path;
+
+	DPRINTF("Attaching to %s\n", xenbus_get_node(dev));
+
+	/*
+	 * Basic initialization.
+	 * After this block it is safe to call xbb_detach()
+	 * to clean up any allocated data for this instance.
+	 */
+	xbb = device_get_softc(dev);
+	xbb->dev = dev;
+	xbb->otherend_id = xenbus_get_otherend_id(dev);
+	TASK_INIT(&xbb->io_task, /*priority*/0, xbb_run_queue, xbb);
+	mtx_init(&xbb->lock, device_get_nameunit(dev), NULL, MTX_DEF);
+
+	/*
+	 * Publish protocol capabilities for consumption by the
+	 * front-end.
+	 */
+	error = xs_printf(XST_NIL, xenbus_get_node(xbb->dev),
+			  "feature-barrier", "1");
+	if (error) {
+		xbb_attach_failed(xbb, error, "writing %s/feature-barrier",
+				  xenbus_get_node(xbb->dev));
+		return (error);
+	}
+
+	error = xs_printf(XST_NIL, xenbus_get_node(xbb->dev),
+			  "feature-flush-cache", "1");
+	if (error) {
+		xbb_attach_failed(xbb, error, "writing %s/feature-flush-cache",
+				  xenbus_get_node(xbb->dev));
+		return (error);
+	}
+
+	max_ring_page_order = flsl(XBB_MAX_RING_PAGES) - 1;
+	error = xs_printf(XST_NIL, xenbus_get_node(xbb->dev),
+			  "max-ring-page-order", "%u", max_ring_page_order);
+	if (error) {
+		xbb_attach_failed(xbb, error, "writing %s/max-ring-page-order",
+				  xenbus_get_node(xbb->dev));
+		return (error);
+	}
+
+	/*
+	 * We need to wait for hotplug script execution before
+	 * moving forward.
+	 */
+	watch_path = xs_join(xenbus_get_node(xbb->dev), "physical-device-path");
+	xbb->hotplug_watch.callback_data = (uintptr_t)dev;
+	xbb->hotplug_watch.callback = xbb_attach_disk;
+	KASSERT(xbb->hotplug_watch.node == NULL, ("watch node already setup"));
+	xbb->hotplug_watch.node = strdup(sbuf_data(watch_path), M_XENBLOCKBACK);
+	sbuf_delete(watch_path);
+	error = xs_register_watch(&xbb->hotplug_watch);
+	if (error != 0) {
+		xbb_attach_failed(xbb, error, "failed to create watch on %s",
+		    xbb->hotplug_watch.node);
+		free(xbb->hotplug_watch.node, M_XENBLOCKBACK);
+		return (error);
+	}
+
+	/* Tell the toolstack blkback has attached. */
 	xenbus_set_state(dev, XenbusStateInitWait);
 
 	return (0);