On 2022-01-11 3:57 p.m., Jason Gunthorpe wrote:

On Tue, Jan 11, 2022 at 03:09:13PM -0700, Logan Gunthorpe wrote:

quoted

Either that, or we need a wrapper that allocates an appropriately
sized SGL to pass to any dma_map implementation that doesn't support
the new structures.

This is what I think we should do. If we start with RDMA then we can
motivate the 4 main server IOMMU drivers to get updated ASAP, then it
can acceptably start to spread to other users.

I suspect the preferred path forward is for the IOMMU drivers that don't
use dma-iommu should be converted to use it. Then anything we do to
dma-iommu will be applicable to the IOMMU drivers. Better than expecting
them to implement a bunch of new functionality themselves.

Logan