Re: [PATCH v2 net-next] net: Allow SF devices to be used for ZC DMA

[Christoph Hellwig]

On Tue, Jul 15, 2025 at 06:06:49AM -0700, Jakub Kicinski wrote:
> On Mon, 14 Jul 2025 21:39:30 -0700 Christoph Hellwig wrote:
> > > LGTM, but we need a better place for this function. netdevice.h is
> > > included directly by 1.5k files, and indirectly by probably another 5k.
> > > It's not a great place to put random helpers with 2 callers. 
> > > Maybe net/netdev_rx_queue.h and net/core/netdev_rx_queue.c?
> > > I don't think it needs to be a static inline either.  
> > 
> > The whole concept is also buggy.  Trying to get a dma-able device by
> > walking down from an upper level construct like the netdevice can't work
> > reliably.  You'll need to explicitly provide the dma_device using either
> > a method or a pointer to it instead of this guesswork.
> 
> Yeah, I'm pretty sure we'll end up with a method in queue ops.
> But it's not that deep, an easy thing to change.

Why not get this right now instead of adding more of the hacky parent
walking?