Re: [PATCH for-next v2 06/18] RDMA/rxe: Add rxe_add_frag() to rxe_mr.c

Jason Gunthorpe
2022-12-01T00:41:31Z

On Wed, Nov 30, 2022 at 06:36:56PM -0600, Bob Pearson wrote:
> I'm not looking at my patch you responded to but the one you posted to replace maps
> by xarrays.

I see, I botched that part

> The existing rxe driver assumes that if ibmr->type == IB_MR_TYPE_DMA
> that the iova is just a kernel (virtual) address that is already
> mapped.

No, it is not correct

> Maybe this is not correct but it has always worked this way. These
> are heavily used by storage stacks (e.g. Lustre) which always use
> DMA mr's. Since we don't actually do any DMAs we don't need to setup
> the iommu for these and just do memcpy's without dealing with pages.

You still should be doing the kmap

Jason