RE: [PATCH V1 7/7] Drivers: scsi: storvsc: Increase the value ofSTORVSC_MAX_IO_REQUESTS

From: KY Srinivasan
Date: Thu May 16 2013 - 10:02:13 EST




> -----Original Message-----
> From: Dan Carpenter [mailto:dan.carpenter@xxxxxxxxxx]
> Sent: Thursday, May 16, 2013 9:55 AM
> To: KY Srinivasan
> Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> devel@xxxxxxxxxxxxxxxxxxxxxx; ohering@xxxxxxxx; jbottomley@xxxxxxxxxxxxx;
> hch@xxxxxxxxxxxxx; linux-scsi@xxxxxxxxxxxxxxx; apw@xxxxxxxxxxxxx;
> jasowang@xxxxxxxxxx
> Subject: Re: [PATCH V1 7/7] Drivers: scsi: storvsc: Increase the value of
> STORVSC_MAX_IO_REQUESTS
>
> On Thu, May 16, 2013 at 01:37:41PM +0000, KY Srinivasan wrote:
> >
> >
> > > -----Original Message-----
> > > From: Dan Carpenter [mailto:dan.carpenter@xxxxxxxxxx]
> > > Sent: Thursday, May 16, 2013 8:02 AM
> > > To: KY Srinivasan
> > > Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > > devel@xxxxxxxxxxxxxxxxxxxxxx; ohering@xxxxxxxx;
> jbottomley@xxxxxxxxxxxxx;
> > > hch@xxxxxxxxxxxxx; linux-scsi@xxxxxxxxxxxxxxx; apw@xxxxxxxxxxxxx;
> > > jasowang@xxxxxxxxxx
> > > Subject: Re: [PATCH V1 7/7] Drivers: scsi: storvsc: Increase the value of
> > > STORVSC_MAX_IO_REQUESTS
> > >
> > > On Thu, May 16, 2013 at 05:21:19AM -0700, K. Y. Srinivasan wrote:
> > > > Increase the value of STORVSC_MAX_IO_REQUESTS to 200 requests. The
> > > current
> > > > ringbuffer size can support this higher value.
> > > >
> > >
> > > The ringbuffer size is a module parameter so it's odd to talk about
> > > the "current" size.
> >
> > While the ringbuffer size is a module parameter; there is a default value. The
> current size refers to the default.
> > Your comment applies to the current value (of 128) as well in that it is possible
> for somebody to load this
> > driver with a ringbuffer size that could not support the value of 128. If this is
> the case, we fail the load.
> > This safety check continues to exist.
>
> The issue is there in the original code, true.
>
> Would the right fix be to add some sanity checks in module_init()?

The check is already there (as I noted above). Look at the function:
storvsc_drv_init(). If the ring size is picked incorrectly, the load is failed.

Regards,

K. Y
>
> regards,
> dan carpenter
>
>


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