Drivers: hv: Make the vmbus driver unloadable

It turns out that the vmbus driver can be made unloadable. Make it
unloadable.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/hv/channel_mgmt.c

@@ -223,6 +223,17 @@ static void vmbus_process_rescind_offer(struct work_struct *work)
 	vmbus_device_unregister(channel->device_obj);
 }
 
+void vmbus_free_channels(void)
+{
+	struct vmbus_channel *channel;
+
+	list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
+		vmbus_device_unregister(channel->device_obj);
+		kfree(channel->device_obj);
+		free_channel(channel);
+	}
+}
+
 /*
  * vmbus_process_offer - Process the offer by creating a channel/device
  * associated with this offer

drivers/hv/hv.c

@@ -237,6 +237,9 @@ void hv_cleanup(void)
 {
 	union hv_x64_msr_hypercall_contents hypercall_msr;
 
+	/* Reset our OS id */
+	wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
+
 	kfree(hv_context.signal_event_buffer);
 	hv_context.signal_event_buffer = NULL;
 	hv_context.signal_event_param = NULL;

drivers/hv/hyperv_vmbus.h

@@ -611,6 +611,7 @@ void vmbus_device_unregister(struct hv_device *device_obj);
 
 struct vmbus_channel *relid2channel(u32 relid);
 
+void vmbus_free_channels(void);
 
 /* Connection interface */
 

drivers/hv/vmbus_drv.c

@@ -795,8 +795,19 @@ cleanup:
 	return ret;
 }
 
+static void __exit vmbus_exit(void)
+{
+
+	free_irq(irq, hv_acpi_dev);
+	vmbus_free_channels();
+	bus_unregister(&hv_bus);
+	hv_cleanup();
+	acpi_bus_unregister_driver(&vmbus_acpi_driver);
+}
+
 
 MODULE_LICENSE("GPL");
 MODULE_VERSION(HV_DRV_VERSION);
 
 subsys_initcall(hv_acpi_init);
+module_exit(vmbus_exit);