Re: [PATCH v5 07/13] block: Add PCI P2P flag for request queue and check support for requests

Jens Axboe
2018-08-30T19:11:22Z

On 8/30/18 12:53 PM, Logan Gunthorpe wrote:
> QUEUE_FLAG_PCI_P2P is introduced meaning a driver's request queue
> supports targeting P2P memory.
>
> When a request is submitted we check if PCI P2PDMA memory is assigned
> to the first page in the bio. If it is, we ensure the queue it's
> submitted to supports it, and enforce REQ_NOMERGE.

I think this belongs in the caller - both the validity check, and
passing in NOMERGE for this type of request. I don't want to impose
this overhead on everything, for a pretty niche case.

--
Jens Axboe