1 files changed, 54 insertions, 18 deletions

diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c
index 3159a37d966d..6ed8a9df4472 100644
--- a/drivers/xen/xenbus/xenbus_probe_frontend.c
+++ b/drivers/xen/xenbus/xenbus_probe_frontend.c
@@ -1,6 +1,8 @@
-#define DPRINTK(fmt, args...)				\
-	pr_debug("xenbus_probe (%s:%d) " fmt ".\n",	\
-		 __func__, __LINE__, ##args)
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#define DPRINTK(fmt, ...)				\
+	pr_debug("(%s:%d) " fmt "\n",			\
+		 __func__, __LINE__, ##__VA_ARGS__)
 
 #include <linux/kernel.h>
 #include <linux/err.h>
@@ -29,18 +31,20 @@
 #include "xenbus_probe.h"
 
 
+static struct workqueue_struct *xenbus_frontend_wq;
+
 /* device/<type>/<id> => <type>-<id> */
 static int frontend_bus_id(char bus_id[XEN_BUS_ID_SIZE], const char *nodename)
 {
 	nodename = strchr(nodename, '/');
 	if (!nodename || strlen(nodename + 1) >= XEN_BUS_ID_SIZE) {
-		printk(KERN_WARNING "XENBUS: bad frontend %s\n", nodename);
+		pr_warn("bad frontend %s\n", nodename);
 		return -EINVAL;
 	}
 
 	strlcpy(bus_id, nodename + 1, XEN_BUS_ID_SIZE);
 	if (!strchr(bus_id, '/')) {
-		printk(KERN_WARNING "XENBUS: bus_id %s no slash\n", bus_id);
+		pr_warn("bus_id %s no slash\n", bus_id);
 		return -EINVAL;
 	}
 	*strchr(bus_id, '/') = '-';
@@ -89,9 +93,40 @@ static void backend_changed(struct xenbus_watch *watch,
 	xenbus_otherend_changed(watch, vec, len, 1);
 }
 
+static void xenbus_frontend_delayed_resume(struct work_struct *w)
+{
+	struct xenbus_device *xdev = container_of(w, struct xenbus_device, work);
+
+	xenbus_dev_resume(&xdev->dev);
+}
+
+static int xenbus_frontend_dev_resume(struct device *dev)
+{
+	/*
+	 * If xenstored is running in this domain, we cannot access the backend
+	 * state at the moment, so we need to defer xenbus_dev_resume
+	 */
+	if (xen_store_domain_type == XS_LOCAL) {
+		struct xenbus_device *xdev = to_xenbus_device(dev);
+
+		if (!xenbus_frontend_wq) {
+			pr_err("%s: no workqueue to process delayed resume\n",
+			       xdev->nodename);
+			return -EFAULT;
+		}
+
+		INIT_WORK(&xdev->work, xenbus_frontend_delayed_resume);
+		queue_work(xenbus_frontend_wq, &xdev->work);
+
+		return 0;
+	}
+
+	return xenbus_dev_resume(dev);
+}
+
 static const struct dev_pm_ops xenbus_pm_ops = {
 	.suspend	= xenbus_dev_suspend,
-	.resume		= xenbus_dev_resume,
+	.resume		= xenbus_frontend_dev_resume,
 	.freeze		= xenbus_dev_suspend,
 	.thaw		= xenbus_dev_cancel,
 	.restore	= xenbus_dev_resume,
@@ -201,15 +236,13 @@ static int print_device_status(struct device *dev, void *data)
 
 	if (!dev->driver) {
 		/* Information only: is this too noisy? */
-		printk(KERN_INFO "XENBUS: Device with no driver: %s\n",
-		       xendev->nodename);
+		pr_info("Device with no driver: %s\n", xendev->nodename);
 	} else if (xendev->state < XenbusStateConnected) {
 		enum xenbus_state rstate = XenbusStateUnknown;
 		if (xendev->otherend)
 			rstate = xenbus_read_driver_state(xendev->otherend);
-		printk(KERN_WARNING "XENBUS: Timeout connecting "
-		       "to device: %s (local state %d, remote state %d)\n",
-		       xendev->nodename, xendev->state, rstate);
+		pr_warn("Timeout connecting to device: %s (local state %d, remote state %d)\n",
+			xendev->nodename, xendev->state, rstate);
 	}
 
 	return 0;
@@ -223,12 +256,13 @@ static bool wait_loop(unsigned long start, unsigned int max_delay,
 {
 	if (time_after(jiffies, start + (*seconds_waited+5)*HZ)) {
 		if (!*seconds_waited)
-			printk(KERN_WARNING "XENBUS: Waiting for "
-			       "devices to initialise: ");
+			pr_warn("Waiting for devices to initialise: ");
 		*seconds_waited += 5;
-		printk("%us...", max_delay - *seconds_waited);
-		if (*seconds_waited == max_delay)
+		pr_cont("%us...", max_delay - *seconds_waited);
+		if (*seconds_waited == max_delay) {
+			pr_cont("\n");
 			return true;
+		}
 	}
 
 	schedule_timeout_interruptible(HZ/10);
@@ -309,7 +343,7 @@ static void xenbus_reset_wait_for_backend(char *be, int expected)
 	timeout = wait_event_interruptible_timeout(backend_state_wq,
 			backend_state == expected, 5 * HZ);
 	if (timeout <= 0)
-		printk(KERN_INFO "XENBUS: backend %s timed out.\n", be);
+		pr_info("backend %s timed out\n", be);
 }
 
 /*
@@ -332,7 +366,7 @@ static void xenbus_reset_frontend(char *fe, char *be, int be_state)
 	be_watch.callback = xenbus_reset_backend_state_changed;
 	backend_state = XenbusStateUnknown;
 
-	printk(KERN_INFO "XENBUS: triggering reconnect on %s\n", be);
+	pr_info("triggering reconnect on %s\n", be);
 	register_xenbus_watch(&be_watch);
 
 	/* fall through to forward backend to state XenbusStateInitialising */
@@ -351,7 +385,7 @@ static void xenbus_reset_frontend(char *fe, char *be, int be_state)
 	}
 
 	unregister_xenbus_watch(&be_watch);
-	printk(KERN_INFO "XENBUS: reconnect done on %s\n", be);
+	pr_info("reconnect done on %s\n", be);
 	kfree(be_watch.node);
 }
 
@@ -440,6 +474,8 @@ static int __init xenbus_probe_frontend_init(void)
 
 	register_xenstore_notifier(&xenstore_notifier);
 
+	xenbus_frontend_wq = create_workqueue("xenbus_frontend");
+
 	return 0;
 }
 subsys_initcall(xenbus_probe_frontend_init);