6 files changed, 69 insertions, 29 deletions

diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index 61786be9138b..ec097d6f964d 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -534,7 +534,7 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
 
         err = xenbus_map_ring(dev, gnt_ref, &node->handle, addr);
         if (err)
-                goto out_err;
+                goto out_err_free_ballooned_pages;
 
         spin_lock(&xenbus_valloc_lock);
         list_add(&node->next, &xenbus_valloc_pages);
@@ -543,8 +543,9 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
         *vaddr = addr;
         return 0;
 
- out_err:
+ out_err_free_ballooned_pages:
         free_xenballooned_pages(1, &node->page);
+ out_err:
         kfree(node);
         return err;
 }
diff --git a/drivers/xen/xenbus/xenbus_comms.h b/drivers/xen/xenbus/xenbus_comms.h
index c8abd3b8a6c4..e74f9c1fbd80 100644
--- a/drivers/xen/xenbus/xenbus_comms.h
+++ b/drivers/xen/xenbus/xenbus_comms.h
@@ -45,6 +45,7 @@ int xb_wait_for_data_to_read(void);
 int xs_input_avail(void);
 extern struct xenstore_domain_interface *xen_store_interface;
 extern int xen_store_evtchn;
+extern enum xenstore_init xen_store_domain_type;
 
 extern const struct file_operations xen_xenbus_fops;
 
diff --git a/drivers/xen/xenbus/xenbus_dev_backend.c b/drivers/xen/xenbus/xenbus_dev_backend.c
index d73000800762..a6f42fc01407 100644
--- a/drivers/xen/xenbus/xenbus_dev_backend.c
+++ b/drivers/xen/xenbus/xenbus_dev_backend.c
@@ -70,22 +70,21 @@ static long xenbus_alloc(domid_t domid)
         return err;
 }
 
-static long xenbus_backend_ioctl(struct file *file, unsigned int cmd, unsigned long data)
+static long xenbus_backend_ioctl(struct file *file, unsigned int cmd,
+                                 unsigned long data)
 {
         if (!capable(CAP_SYS_ADMIN))
                 return -EPERM;
 
         switch (cmd) {
-                case IOCTL_XENBUS_BACKEND_EVTCHN:
-                        if (xen_store_evtchn > 0)
-                                return xen_store_evtchn;
-                        return -ENODEV;
-
-                case IOCTL_XENBUS_BACKEND_SETUP:
-                        return xenbus_alloc(data);
-
-                default:
-                        return -ENOTTY;
+        case IOCTL_XENBUS_BACKEND_EVTCHN:
+                if (xen_store_evtchn > 0)
+                        return xen_store_evtchn;
+                return -ENODEV;
+        case IOCTL_XENBUS_BACKEND_SETUP:
+                return xenbus_alloc(data);
+        default:
+                return -ENOTTY;
         }
 }
 
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 3325884c693f..56cfaaa9d006 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -69,6 +69,9 @@ EXPORT_SYMBOL_GPL(xen_store_evtchn);
 struct xenstore_domain_interface *xen_store_interface;
 EXPORT_SYMBOL_GPL(xen_store_interface);
 
+enum xenstore_init xen_store_domain_type;
+EXPORT_SYMBOL_GPL(xen_store_domain_type);
+
 static unsigned long xen_store_mfn;
 
 static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
@@ -719,17 +722,11 @@ static int __init xenstored_local_init(void)
         return err;
 }
 
-enum xenstore_init {
-        UNKNOWN,
-        PV,
-        HVM,
-        LOCAL,
-};
 static int __init xenbus_init(void)
 {
         int err = 0;
-        enum xenstore_init usage = UNKNOWN;
         uint64_t v = 0;
+        xen_store_domain_type = XS_UNKNOWN;
 
         if (!xen_domain())
                 return -ENODEV;
@@ -737,29 +734,29 @@ static int __init xenbus_init(void)
         xenbus_ring_ops_init();
 
         if (xen_pv_domain())
-                usage = PV;
+                xen_store_domain_type = XS_PV;
         if (xen_hvm_domain())
-                usage = HVM;
+                xen_store_domain_type = XS_HVM;
         if (xen_hvm_domain() && xen_initial_domain())
-                usage = LOCAL;
+                xen_store_domain_type = XS_LOCAL;
         if (xen_pv_domain() && !xen_start_info->store_evtchn)
-                usage = LOCAL;
+                xen_store_domain_type = XS_LOCAL;
         if (xen_pv_domain() && xen_start_info->store_evtchn)
                 xenstored_ready = 1;
 
-        switch (usage) {
-        case LOCAL:
+        switch (xen_store_domain_type) {
+        case XS_LOCAL:
                 err = xenstored_local_init();
                 if (err)
                         goto out_error;
                 xen_store_interface = mfn_to_virt(xen_store_mfn);
                 break;
-        case PV:
+        case XS_PV:
                 xen_store_evtchn = xen_start_info->store_evtchn;
                 xen_store_mfn = xen_start_info->store_mfn;
                 xen_store_interface = mfn_to_virt(xen_store_mfn);
                 break;
-        case HVM:
+        case XS_HVM:
                 err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
                 if (err)
                         goto out_error;
diff --git a/drivers/xen/xenbus/xenbus_probe.h b/drivers/xen/xenbus/xenbus_probe.h
index bb4f92ed8730..146f857a36f8 100644
--- a/drivers/xen/xenbus/xenbus_probe.h
+++ b/drivers/xen/xenbus/xenbus_probe.h
@@ -47,6 +47,13 @@ struct xen_bus_type {
         struct bus_type bus;
 };
 
+enum xenstore_init {
+        XS_UNKNOWN,
+        XS_PV,
+        XS_HVM,
+        XS_LOCAL,
+};
+
 extern struct device_attribute xenbus_dev_attrs[];
 
 extern int xenbus_match(struct device *_dev, struct device_driver *_drv);
diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c
index 3159a37d966d..a7e25073de19 100644
--- a/drivers/xen/xenbus/xenbus_probe_frontend.c
+++ b/drivers/xen/xenbus/xenbus_probe_frontend.c
@@ -29,6 +29,8 @@
 #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)
 {
@@ -89,9 +91,40 @@ 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,
@@ -440,6 +473,8 @@ 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);