various vmbus review comments

[KY Srinivasan]

> -----Original Message-----
> From: Greg KH [mailto:greg at kroah.com]
> Sent: Wednesday, May 04, 2011 12:32 PM
> To: KY Srinivasan
> Cc: gregkh at suse.de; linux-kernel at vger.kernel.org;
> devel at linuxdriverproject.org; virtualization at lists.osdl.org
> Subject: Re: various vmbus review comments
> 
> On Wed, May 04, 2011 at 04:20:11PM +0000, KY Srinivasan wrote:
> >
> >
> > > -----Original Message-----
> > > From: Greg KH [mailto:greg at kroah.com]
> > > Sent: Tuesday, May 03, 2011 4:47 PM
> > > To: KY Srinivasan
> > > Cc: gregkh at suse.de; linux-kernel at vger.kernel.org;
> > > devel at linuxdriverproject.org; virtualization at lists.osdl.org
> > > Subject: various vmbus review comments
> > >
> > > I just took a quick look at the vmbus code, and have the following
> >
> > I have currently consolidated all the header files as follows:
> >
> > 1) hyperv.h - this will have all the vmbus related definitions
> > needed to build drivers that attach to the bus (as you have suggested).
> 
> Great.
> 
> > 2) hyperv_storage.h - this has all the definitions needed to build storage
> > drivers for Hyper-V. Storage drivers will include hyperv.h and
> > hyperv_storage.h.
> >
> > 3) hyperv_net.h - this has all the definitions needed to build the network
> > driver for Hyper-V. The netvsc driver will include hyperv.h and hyperv_net.h.
> >
> > 4) hyperv_utils.h - this has all the definitions needed to build the util driver.
> > The util driver would include hyperv.h and hyperv_utils.h.
> 
> No for all 3 of these.  Why would a simple driver need a .h file at all?
> Just include the structures within the .c file, making it nice and
> self-contained.  There's no need to clutter things up, and individual
> driver .h files should _never_ be in include/linux.

Agreed - we don't need to clutter up  include/linux directory with individual
driver.h files. However, including all the definitions in the .c file would also be
ugly. For instance there are multiple *.c files for the storage drivers and we don't
want to replicate the contents of  hyperv_storage.h in each of these .c files.
The same is true for the netvsc driver - there are multiple .c files where we would need
to replicate the contents of hyperv_net.h. 

How about I keep these driver specific header files; but these could be local to the 
directory where these drivers land.
 
> >
> > > 	- the instances of hv_driver structures need to be static and
> > > 	  not programatically defined, like all other USB and PCI
> > > 	  drivers are handled.
> > > 	- module reference counting.  Are you sure you got it all right
> > > 	  for the individual modules that attach to the bus?  I don't
> > > 	  see any reference counting happening, is that correct?
> >
> > For this round, I want to concentrate on just the vmbus driver. So,
> > module reference counting is I don't think an issue for the vmbus driver
> > given that the driver is not unlodable. Once I am done with the vmbus driver
> > I will address the module reference counting issues for other drivers.
> 
> No, I am referring to the module reference counting of the bus drivers
> that register with the vmbus core.  You aren't doing that at all, and
> you probably need to make sure that this isn't needed.  That is
> concentrating on the vmbus driver.

Ok; I will look into this.

> 
> > I will also address your comment on static initialization hv_driver instances
> > as part of other driver cleanup.
> 
> No, please do this now as it will show how to properly interact with the
> vmbus core code in the correct manner.  Hopefully that will be correct,
> but I have a feeling that it will show you some places in the API that
> need to be changed...

Will do.

Regards,

K. Y