-----Original Message-----
From: Greg KH [mailto:greg@kroah.com]
Sent: Thursday, August 25, 2011 5:00 PM
To: KY Srinivasan
Cc: gregkh@suse.de; linux-kernel@vger.kernel.org;
devel@linuxdriverproject.org; virtualization@lists.osdl.org; Haiyang Zhang
Subject: Re: [PATCH 12/59] Staging: hv: vmbus: Cleanup vmbus_uevent() code

On Thu, Aug 25, 2011 at 09:48:38AM -0700, K. Y. Srinivasan wrote:

quoted

Now generate appropriate uevent based on the modalias string. As part of this,
cleanup the existing uevent code.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
---
 drivers/staging/hv/vmbus_drv.c |   60 ++++++++--------------------------------
 1 files changed, 12 insertions(+), 48 deletions(-)

diff --git a/drivers/staging/hv/vmbus_drv.c b/drivers/staging/hv/vmbus_drv.c
index b651968..a6e7dc5 100644
--- a/drivers/staging/hv/vmbus_drv.c
+++ b/drivers/staging/hv/vmbus_drv.c

@@ -237,58 +237,22 @@ static struct device_attribute vmbus_device_attrs[] =

{

quoted

  * This routine is invoked when a device is added or removed on the vmbus to
  * generate a uevent to udev in the userspace. The udev will then look at its
  * rule and the uevent generated here to load the appropriate driver
+ *
+ * The alias string will be of the form vmbus:guid where guid is the string
+ * representation of the device guid (each byte of the guid will be
+ * represented with two hex characters.
  */
 static int vmbus_uevent(struct device *device, struct kobj_uevent_env *env)
 {
 	struct hv_device *dev = device_to_hv_device(device);
-	int ret;
-
-	ret = add_uevent_var(env, "VMBUS_DEVICE_CLASS_GUID={"
-			     "%02x%02x%02x%02x-%02x%02x-%02x%02x-"
-			     "%02x%02x%02x%02x%02x%02x%02x%02x}",
-			     dev->dev_type.b[3],
-			     dev->dev_type.b[2],
-			     dev->dev_type.b[1],
-			     dev->dev_type.b[0],
-			     dev->dev_type.b[5],
-			     dev->dev_type.b[4],
-			     dev->dev_type.b[7],
-			     dev->dev_type.b[6],
-			     dev->dev_type.b[8],
-			     dev->dev_type.b[9],
-			     dev->dev_type.b[10],
-			     dev->dev_type.b[11],
-			     dev->dev_type.b[12],
-			     dev->dev_type.b[13],
-			     dev->dev_type.b[14],
-			     dev->dev_type.b[15]);
-
-	if (ret)
-		return ret;
+	int i, ret;
+	char alias_name[((sizeof(struct hv_vmbus_device_id) + 1)) * 2];

-	ret = add_uevent_var(env, "VMBUS_DEVICE_DEVICE_GUID={"
-			     "%02x%02x%02x%02x-%02x%02x-%02x%02x-"
-			     "%02x%02x%02x%02x%02x%02x%02x%02x}",
-			     dev->dev_instance.b[3],
-			     dev->dev_instance.b[2],
-			     dev->dev_instance.b[1],
-			     dev->dev_instance.b[0],
-			     dev->dev_instance.b[5],
-			     dev->dev_instance.b[4],
-			     dev->dev_instance.b[7],
-			     dev->dev_instance.b[6],
-			     dev->dev_instance.b[8],
-			     dev->dev_instance.b[9],
-			     dev->dev_instance.b[10],
-			     dev->dev_instance.b[11],
-			     dev->dev_instance.b[12],
-			     dev->dev_instance.b[13],
-			     dev->dev_instance.b[14],
-			     dev->dev_instance.b[15]);
-	if (ret)
-		return ret;
+	for (i = 0; i < (sizeof(struct hv_vmbus_device_id) * 2); i += 2)
+		sprintf(&alias_name[i], "%02x", dev->dev_type.b[i/2]);

I have to edit this to get it to work properly with the fact that I
added the driver_data field to hv_vmbus_device_id.

Arguably, one could say that this patch was always broken as you were
assuming the size of an individual field was the same size as the whole
structure, which I don't think is always the case, or at least it's not
a safe thing to assume :)

Perhaps I could have sized it based on guid size since that is what is going
to be the alias. 

Regards,

K. Y