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

Logan Gunthorpe
2017-04-19T18:19:32Z

On 19/04/17 12:11 PM, Logan Gunthorpe wrote:
>
>
> On 19/04/17 11:41 AM, Dan Williams wrote:
>> No, not quite ;-). I still don't think we should require the non-HMM
>> to pass NULL for all the HMM arguments. What I like about Logan's
>> proposal is to have a separate create and register steps dev_pagemap.
>> That way call paths that don't care about HMM specifics can just turn
>> around and register the vanilla dev_pagemap.
>
> Would you necessarily even need a create step? I was thinking more along
> the lines that struct dev_pagemap _could_ just be a member in another
> structure. The caller would set the attributes they needed and pass it
> to devm_memremap. (Similar to how we commonly do things with struct
> device, et al). Potentially, that could also get rid of the need for the
> *data pointer HMM is using to get back the struct hmm_devmem seeing
> container_of could be used instead.

Also, now that I've thought about it a little more, it _may_ be that
many or all of the hmm specific fields in dev_pagemap could move to a
containing struct too...

Logan