Re: [PATCH net] net: Allow non parent devices to be used for ZC DMA

On Wed, 9 Jul 2025 15:40:57 +0300 Dragos Tatulea wrote:

For zerocopy (io_uring, devmem), there is an assumption that the
parent device can do DMA. However that is not always the case:
ScalableFunction devices have the DMA device in the grandparent.

This patch adds a helper for getting the DMA device for a netdev from
its parent or grandparent if necessary. The NULL case is handled in the
callers.

devmem and io_uring are updated accordingly to use this helper instead
of directly using the parent.

Sorry for the silence. I'll reply to Parav on the RFC, I don't think
the question I was asking was answered there.