Re: [PATCH 09/12] nvme-pci: Use PCI p2pmem subsystem to manage the CMB

[Logan Gunthorpe]

On 05/01/18 08:30 AM, Marta Rybczynska wrote:
> > @@ -429,10 +429,7 @@ static void __nvme_submit_cmd(struct nvme_queue *nvmeq,
> > {
> > 	u16 tail = nvmeq->sq_tail;
> >
> > -	if (nvmeq->sq_cmds_io)
> > -		memcpy_toio(&nvmeq->sq_cmds_io[tail], cmd, sizeof(*cmd));
> > -	else
> > -		memcpy(&nvmeq->sq_cmds[tail], cmd, sizeof(*cmd));
> > +	memcpy(&nvmeq->sq_cmds[tail], cmd, sizeof(*cmd));
>
> Why is it always memcpy() and not memcpy_toio()? I'd expect something like
> if (nvmeq->sq_cmds_is_io)
> 	memcpy_toio(&nvmeq->sq_cmds_io[tail], cmd, sizeof(*cmd));
> else
> 	memcpy(&nvmeq->sq_cmds[tail], cmd, sizeof(*cmd));

We're going on the assumption that memory mapped with 
devm_memremap_pages() can be treated as regular memory. So memcpy_toio 
is not necessary for P2P memory.

Logan