Re: [PATCH v1 2/2] dma: Add IOMMU static calls with clear default ops

Christoph Hellwig
2024-07-17T08:56:56Z

On Wed, Jul 17, 2024 at 11:47:13AM +0300, Leon Romanovsky wrote:
> It will cause to the situation where "struct device" memory footprint
> will increase, while we still need to keep dma_ops for archs that don't
> want to use default IOMMU.

It won't. Even with the new bit we still have 28 more spare bits next
to it :)

> Because dma_ops pointer exists anyway and has already specific flags. I
> decided to take evolutive approach and add a new flag to it, instead of
> revolutionary approach and add a new field to struct device.

The point is that with a little more work we can actually kill that
for common configuration. For non-Xen setups that basically just means
removing the dummy ops, so it's a pretty big quick win.