Re: [PATCH-v3 5/9] vhost/scsi: Add ANY_LAYOUT vhost_virtqueue callback

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Feb 04, 2015 at 01:40:25AM -0800, Nicholas A. Bellinger wrote:
> > > +		/*
> > > +		 * Any associated T10_PI bytes for the outgoing / incoming
> > > +		 * payloads are included in calculation of exp_data_len here.
> > > +		 */
> > > +		if (out_size > req_size) {
> > > +			data_direction = DMA_TO_DEVICE;
> > > +			exp_data_len = out_size - req_size;
> > > +		} else if (in_size > rsp_size) {
> > > +			data_direction = DMA_FROM_DEVICE;
> > > +			exp_data_len = in_size - rsp_size;
> > > +		} else {
> > > +			data_direction = DMA_NONE;
> > > +			exp_data_len = 0;
> > > +		}
> > 
> > We must validate this doesn't cause exp_data_len to be negative.
> > 
> 
> AFAICT, exp_data_len is always >= 0 here.

What guarantees out_size > req_size and in_size > rsp_size,
respectively?

-- 
MST