Re: [PATCH net-next] ethtool: add netlink support for rss set

[Jakub Kicinski <kuba@kernel.org>]

On Mon, 13 Mar 2023 22:34:17 +0000 Mogilappagari, Sudheer wrote:
> > RSS contexts are somewhat under-defined, so I'd prefer to wait until we
> > actually need to extend the API before going to netlink.
> > I think I told you as much when you posted initial code for RSS?
> 
> Hi Jakub, we are making these changes based on below discussion:
> https://lore.kernel.org/netdev/0402fc4f-21c9-eded-bed7-fd82a069ca70@intel.com/
> Our thinking was to move existing functionality to netlink first and then
> add new parameter (inline-flow-steering). Hence the reason for sending RSS_GET 
> first and now RSS_SET. Are you suggesting that new parameter changes be sent
> together with this patch-set ? 

Ah, so you do have a feature. Yes, it would be somewhat helpful but my
larger concern remains. We skipped the dump implementation when
implementing GET. The admin still has no way of knowing what / how many
RSS contexts had been created. With the context ID being an unbounded
integer just going from 0 until ENOENT is not even an option.

So we need to start tracking the contexts. Add a pointer to struct
netdevice to hold an "ethtool_settings" struct. In the ethtool settings
struct add a list head. Put an object for each created RSS context on
that list.

Then implement dump, then the netlink SET. (All one series.)