Re: [PATCH 06/12] IB/core: Add optional PCI P2P flag to rdma_rw_ctx_[init|destroy]()

From: Logan Gunthorpe
Date: Mon Jan 08 2018 - 14:06:19 EST




On 08/01/18 11:57 AM, Christoph Hellwig wrote:
It does, sort of - but in a different way then the normal DMA map
ops. And only to work around the fact that we need to map our
P2P space into struct pages. Without that we could just pass the
bus address around, but the Linux stack and VM isn't anywhere near
ready for something that advanced.

Yeah, wouldn't that be nice.

Ok, so if we shouldn't touch the dma_map infrastructure how should the workaround to opt-out HFI and QIB look? I'm not that familiar with the RDMA code.

Thanks,

Logan