[RFC] ethtool: Support ETHTOOL_GSTATS2 command.

[Ben Greear]

On 03/20/2018 11:24 AM, Michal Kubecek wrote:
> On Tue, Mar 20, 2018 at 08:39:33AM -0700, Ben Greear wrote:
>> On 03/20/2018 03:37 AM, Michal Kubecek wrote:
>>>
>>> IMHO it would be more practical to set "0 means same as GSTATS" as a
>>> rule and make ethtool_get_stats() a wrapper for ethtool_get_stats2() to
>>> avoid code duplication (or perhaps a use fall-through in the switch). It
>>> would also allow drivers to provide only one of the callbacks.
>>
>> Yes, but that would require changing all drivers at once, and would make backporting
>> and out-of-tree drivers harder to manage.  I had low hopes that this feature would
>> make it upstream, so I didn't want to propose any large changes up front.
>
> I don't think so. What I mean is:
>
> (a) driver implements ->get_ethtool_stats2() callback; then we use it
>     for GSTATS2
> (b) driver does not implement get_ethtool_stats2() but implements
>     ->get_ethtool_stats(); then we call for GSTATS2 if level is zero,
>     otherwise GSTATS2 returns -EINVAL
>
> and GSTATS is always translated to GSTATS2 with level 0, either by
> defining ethtool_get_stats() as a wrapper or by fall-through in the
> switch statement.
>
> This way, most drivers could be left untouched and only those which
> would implement non-default levels would provide ->get_ethtool_stats2()
> callback instead of ->get_ethtool_stats().

OK, that makes sense.  I'll wait on feedback from the flags or #defined levels
and re-spin the patch accordingly.

Thanks,
Ben


-- 
Ben Greear <greearb at candelatech.com>
Candela Technologies Inc  http://www.candelatech.com