Re: [PATCH net-next] net: ethtool: Don't check if RSS context exists in case of context 0

[Gal Pressman <gal@nvidia.com>]

On 27/02/2025 4:27, Jakub Kicinski wrote:
> On Wed, 26 Feb 2025 08:08:40 +0200 Gal Pressman wrote:
>> On 26/02/2025 3:01, Jakub Kicinski wrote:
>>> On Tue, 25 Feb 2025 09:13:48 +0200 Gal Pressman wrote:  
>>>> Context 0 (default context) always exists, there is no need to check
>>>> whether it exists or not when adding a flow steering rule.
>>>>
>>>> The existing check fails when creating a flow steering rule for context
>>>> 0 as it is not stored in the rss_ctx xarray.  
>>>
>>> But what is the use case for redirecting to context 0?  
>>
>> I can think of something like redirecting all TCP traffic to context 1,
>> and then a specific TCP 5-tuple to the default context.
> 
> The ordering guarantees of ntuple filters are a bit unclear.
> My understanding was that first match terminates the search,
> actually, so your example wouldn't work :S

The ordering should be done according to the rule location.
 * @location: Location of rule in the table.  Locations must be
 *	numbered such that a flow matching multiple rules will be
 *	classified according to the first (lowest numbered) rule.

The cited patch is a regression from user's perspective. Surely, not an
intended one?