guaranteed progress for NVME commands?

[Keith Busch]

On Tue, Mar 22, 2016 at 02:46:16PM +0000, Keith Busch wrote:
> I'm not sure why the driver is even considering that.
> The transfer size doesn't matter; only nr_phys_segments should determine how
> many elements the nvme_iod sgl needs to have.

err, scratch that. The size has to be accounted for when considering
PRP lists, which are unnamed fields in struct nvme_iod.