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-rw-r--r--drivers/hv/vmbus_drv.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 0c048dd8013..d3b0b4fba4d 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -62,6 +62,14 @@ struct hv_device_info {
struct hv_dev_port_info outbound;
};
+static int vmbus_exists(void)
+{
+ if (hv_acpi_dev == NULL)
+ return -ENODEV;
+
+ return 0;
+}
+
static void get_channel_info(struct hv_device *device,
struct hv_device_info *info)
@@ -590,6 +598,10 @@ int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, c
pr_info("registering driver %s\n", hv_driver->name);
+ ret = vmbus_exists();
+ if (ret < 0)
+ return ret;
+
hv_driver->driver.name = hv_driver->name;
hv_driver->driver.owner = owner;
hv_driver->driver.mod_name = mod_name;
@@ -614,6 +626,9 @@ void vmbus_driver_unregister(struct hv_driver *hv_driver)
{
pr_info("unregistering driver %s\n", hv_driver->name);
+ if (!vmbus_exists())
+ return;
+
driver_unregister(&hv_driver->driver);
}
@@ -776,6 +791,7 @@ static int __init hv_acpi_init(void)
cleanup:
acpi_bus_unregister_driver(&vmbus_acpi_driver);
+ hv_acpi_dev = NULL;
return ret;
}