Re: [RFC net-next 1/2] ethtool: add support for controling the type of adaptive coalescing

Andrew Lunn
2020-11-20T13:40:03Z

On Fri, Nov 20, 2020 at 08:23:22AM +0100, Michal Kubecek wrote:
> On Fri, Nov 20, 2020 at 10:59:59AM +0800, tanhuazhong wrote:
> > On 2020/11/20 6:02, Michal Kubecek wrote:
> > >
> > > We could use a similar approach as struct ethtool_link_ksettings, e.g.
> > >
> > > struct kernel_ethtool_coalesce {
> > > struct ethtool_coalesce base;
> > > /* new members which are not part of UAPI */
> > > }
> > >
> > > get_coalesce() and set_coalesce() would get pointer to struct
> > > kernel_ethtool_coalesce and ioctl code would be modified to only touch
> > > the base (legacy?) part.
> > > > While already changing the ops arguments, we could also add extack
> > > pointer, either as a separate argument or as struct member (I slightly
> > > prefer the former).
> >
> > If changing the ops arguments, each driver who implement
> > set_coalesce/get_coalesce of ethtool_ops need to be updated. Is it
> > acceptable adding two new ops to get/set ext_coalesce info (like
> > ecc31c60240b ("ethtool: Add link extended state") does)? Maybe i can send V2
> > in this way, and then could you help to see which one is more suitable?
>
> If it were just this one case, adding an extra op would be perfectly
> fine. But from long term point of view, we should expect extending also
> other existing ethtool requests and going this way for all of them would
> essentially double the number of callbacks in struct ethtool_ops.

coccinella might be useful here.

Andrew