[PATCH 00/40] Staging: hv: Driver cleanup

KY Srinivasan kys at microsoft.com
Thu Jun 30 23:28:27 UTC 2011



> -----Original Message-----
> From: Christoph Hellwig [mailto:hch at infradead.org]
> Sent: Thursday, June 30, 2011 3:34 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: [PATCH 00/40] Staging: hv: Driver cleanup
> 
> On Wed, Jun 29, 2011 at 07:38:21AM -0700, K. Y. Srinivasan wrote:
> > Further cleanup of the hv drivers:
> >
> > 	1) Cleanup the reference counting mess for both stor and net devices.
> 
> I really don't understand the need for reference counting on the storage
> side, especially now that you only have a SCSI driver.  The SCSI
> midlayer does proper counting on it's objects (Scsi_Host, scsi_device,
> scsi_cmnd), so you'll get that for free given that SCSI drivers just
> piggyback on the midlayer lifetime rules.

The reference counting allows us to properly deal with messages coming back from the host
to the guest with a racing remove of the device. I am told these messages could potentially be
not a response to a message sent from the guest.

> 
> For now your patches should probably go in as-is, but mid-term you
> should be able to completely remove that code on the storage side.
> 

Thanks. Sure, we will always try to simplify the code.

Regards,

K. Y



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