Re: [PATCH 12/59] Staging: hv: vmbus: Cleanup vmbus_uevent() code

Greg KH
2011-08-25T22:27:08Z

On Thu, Aug 25, 2011 at 10:14:05PM +0000, KY Srinivasan wrote:
>
>
> > -----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:
> > > 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[] =
> > {
> > > * 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.

That's what I ended up doing :)

greg k-h