patch "drivers: hv: Don't OOPS when you cannot init vmbus" added to driver-core tree

This is a note to let you know that I've just added the patch titled

drivers: hv: Don't OOPS when you cannot init vmbus

to my driver-core git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git
in the driver-core-next branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will be merged to Linus's tree in the next big merge window after the next kernel is released.

If you have any questions about this process, please let me know.

From: "K. Y. Srinivasan" <[email protected]>
Date: Thu, 1 Dec 2011 09:59:34 -0800
Subject: drivers: hv: Don't OOPS when you cannot init vmbus

The hv vmbus driver was causing an OOPS since it was trying to register drivers on top of the bus even if initialization of the bus has failed for some reason (such as the odd chance someone would run a hv enabled kernel in a non-hv environment).

---
 drivers/hv/vmbus_drv.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

index 7d3bccb3..40956d1 100644
@@ -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;
 }
 

1.7.7.3