Re: [RFC 0/8] Copy Offload with Peer-to-Peer PCI Memory

Benjamin Herrenschmidt
2017-04-16T22:32:38Z

On Sun, 2017-04-16 at 10:47 -0600, Logan Gunthorpe wrote:
> > I think you need to give other archs a chance to support this with a
> > design that considers the offset case as a first class citizen rather
> > than an afterthought.
>
> I'll consider this. Given the fact I can use your existing
> get_dev_pagemap infrastructure to look up the p2pmem device this
> probably isn't as hard as I thought it would be anyway (we probably
> don't even need a page flag). We'd just have lookup the dev_pagemap,
> test if it's a p2pmem device, and if so, call a p2pmem_dma_map function
> which could apply the offset or do any other arch specific logic (if
> necessary).

I'm still not 100% why do you need a "p2mem device" mind you ...

Cheers,
Ben.