RE: [PATCH V2 2/8] Drivers: scsi: storvsc: Set cmd_per_lun to reflect value supported by the Host

KY Srinivasan
2014-07-10T22:08:23Z

> -----Original Message-----
> From: Christoph Hellwig [mailto:hch@infradead.org]
> Sent: Thursday, July 10, 2014 3:25 AM
> To: KY Srinivasan
> Cc: linux-kernel@vger.kernel.org; devel@linuxdriverproject.org;
> ohering@suse.com; jbottomley@parallels.com; hch@infradead.org;
> jasowang@redhat.com; apw@canonical.com; linux-scsi@vger.kernel.org;
> stable@vger.kernel.org
> Subject: Re: [PATCH V2 2/8] Drivers: scsi: storvsc: Set cmd_per_lun to reflect
> value supported by the Host
>
> > - .cmd_per_lun = 1,
> > + .cmd_per_lun = 255,
> > .can_queue =
> STORVSC_MAX_IO_REQUESTS*STORVSC_MAX_TARGETS,
>
> slave_configure immediately adjusts this down to
> STORVSC_MAX_IO_REQUESTS (250), any reson to start out with the magic
> 255 here?

The number 255 (set for cmd_per_lun) is what the host can support (I recently discovered this in an MSDN document). STORVSC_MAX_IO_REQUESTS is an implementation limitation in this driver.

Regards,

K. Y