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

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

[gregkh]

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 cf6a2eacbcb2593b5b91d0817915c4f0464bb534 Mon Sep 17 00:00:00 2001
From: "K. Y. Srinivasan" <kys@microsoft.com>
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).

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/hv/vmbus_drv.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 7d3bccb3..40956d1 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;
 }
 
-- 
1.7.7.3