RE: [PATCH RESEND V2 3/7] scsi: storvsc: Untangle the storage protocol negotiation from the vmbus protocol negotiation.

[KY Srinivasan <kys@microsoft.com>]

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> -----Original Message-----
> From: Johannes Thumshirn [mailto:jthumshirn@suse.de]
> Sent: Thursday, August 13, 2015 7:34 AM
> To: KY Srinivasan <kys@microsoft.com>; Keith Mange
> <Keith.Mange@microsoft.com>
> Cc: gregkh@linuxfoundation.org; linux-kernel@vger.kernel.org;
> devel@linuxdriverproject.org; ohering@suse.com;
> jbottomley@parallels.com; hch@infradead.org; linux-scsi@vger.kernel.org;
> apw@canonical.com; vkuznets@redhat.com; jasowang@redhat.com
> Subject: Re: [PATCH RESEND V2 3/7] scsi: storvsc: Untangle the storage
> protocol negotiation from the vmbus protocol negotiation.
> 
> "K. Y. Srinivasan" <kys@microsoft.com> writes:
> 
> > From: Keith Mange <keith.mange@microsoft.com>
> >
> > Currently we are making decisions based on vmbus protocol versions
> > that have been negotiated; use storage potocol versions instead.
> >
> > Tested-by: Alex Ng <alexng@microsoft.com>
> > Signed-off-by: Keith Mange <keith.mange@microsoft.com>
> > Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
> > ---
> >  drivers/scsi/storvsc_drv.c |  109
> +++++++++++++++++++++++++++++++++++---------
> >  1 files changed, 87 insertions(+), 22 deletions(-)
> >
> > diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
> > index 5f9d133..f29871e 100644
> > --- a/drivers/scsi/storvsc_drv.c
> > +++ b/drivers/scsi/storvsc_drv.c
> > @@ -56,14 +56,18 @@
> >   * V1 RC > 2008/1/31:  2.0
> >   * Win7: 4.2
> >   * Win8: 5.1
> > + * Win8.1: 6.0
> > + * Win10: 6.2
> >   */
> >
> >  #define VMSTOR_PROTO_VERSION(MAJOR_, MINOR_)	((((MAJOR_)
> & 0xff) << 8) | \
> >  						(((MINOR_) & 0xff)))
> >
> > +#define VMSTOR_PROTO_VERSION_WIN6
> 	VMSTOR_PROTO_VERSION(2, 0)
> >  #define VMSTOR_PROTO_VERSION_WIN7
> 	VMSTOR_PROTO_VERSION(4, 2)
> >  #define VMSTOR_PROTO_VERSION_WIN8
> 	VMSTOR_PROTO_VERSION(5, 1)
> > -
> > +#define VMSTOR_PROTO_VERSION_WIN8_1
> 	VMSTOR_PROTO_VERSION(6, 0)
> > +#define VMSTOR_PROTO_VERSION_WIN10
> 	VMSTOR_PROTO_VERSION(6, 2)
> >
> >  /*  Packet structure describing virtual storage requests. */
> >  enum vstor_packet_operation {
> > @@ -205,6 +209,46 @@ struct vmscsi_request {
> >
> >
> >  /*
> > + * The list of storage protocols in order of preference.
> > + */
> > +struct vmstor_protocol {
> > +	int protocol_version;
> > +	int sense_buffer_size;
> > +	int vmscsi_size_delta;
> > +};
> > +
> > +#define VMSTOR_NUM_PROTOCOLS    5
> 
> can't you just use ARRAY_SIZE() here, so you don't have to touch the
> constant every time a new protocol is appended to the list?

Certainly. These patches have been floating around for more than a month now and if it is ok
with you, I will submit a patch on top of this current series to address the concern you have raised.
James, please let me know.

Regards,

K. Y 
> 
> > +
> > +const struct vmstor_protocol
> vmstor_protocols[VMSTOR_NUM_PROTOCOLS] = {
> > +	{
> > +		VMSTOR_PROTO_VERSION_WIN10,
> > +		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
> > +		0
> > +	},
> > +	{
> > +		VMSTOR_PROTO_VERSION_WIN8_1,
> > +		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
> > +		0
> > +	},
> > +	{
> > +		VMSTOR_PROTO_VERSION_WIN8,
> > +		POST_WIN7_STORVSC_SENSE_BUFFER_SIZE,
> > +		0
> > +	},
> > +	{
> > +		VMSTOR_PROTO_VERSION_WIN7,
> > +		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
> > +		sizeof(struct vmscsi_win8_extension),
> > +	},
> > +	{
> > +		VMSTOR_PROTO_VERSION_WIN6,
> > +		PRE_WIN8_STORVSC_SENSE_BUFFER_SIZE,
> > +		sizeof(struct vmscsi_win8_extension),
> > +	}
> > +};
> > +
> 
> Thanks,
>         Johannes
> --
> Johannes Thumshirn                                           Storage
> jthumshirn@suse.de                                 +49 911 74053 689
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