Re: [RFC v3 4/8] wifi: mac80211: add support for DFS with multiple radios

[Felix Fietkau <nbd@nbd.name>]

On 07.06.24 06:54, Karthikeyan Periyasamy wrote:
> 
> 
> On 6/7/2024 10:05 AM, Felix Fietkau wrote:
>> On 07.06.24 06:25, Karthikeyan Periyasamy wrote:
>>>
>>>
>>> On 6/6/2024 11:37 PM, Felix Fietkau wrote:
>>>> DFS can be supported with multi-channel combinations, as long as each 
>>>> DFS
>>>> capable radio only supports one channel.
>>>>
>>>> Signed-off-by: Felix Fietkau <nbd@nbd.name>
>>>> ---
>>>>   net/mac80211/main.c | 32 ++++++++++++++++++++++++--------
>>>>   1 file changed, 24 insertions(+), 8 deletions(-)
>>>>
>>>> diff --git a/net/mac80211/main.c b/net/mac80211/main.c
>>>> index 40fbf397ce74..e9c4cf611e94 100644
>>>> --- a/net/mac80211/main.c
>>>> +++ b/net/mac80211/main.c
>>>
>>> ...
>>>
>>>>   int ieee80211_register_hw(struct ieee80211_hw *hw)
>>>>   {
>>>>       struct ieee80211_local *local = hw_to_local(hw);
>>>> @@ -1173,17 +1188,18 @@ int ieee80211_register_hw(struct ieee80211_hw 
>>>> *hw)
>>>>               if (comb->num_different_channels > 1)
>>>>                   return -EINVAL;
>>>>           }
>>>> -    } else {
>>>> -        /* DFS is not supported with multi-channel combinations yet */
>>>> -        for (i = 0; i < local->hw.wiphy->n_iface_combinations; i++) {
>>>> -            const struct ieee80211_iface_combination *comb;
>>>> -
>>>> -            comb = &local->hw.wiphy->iface_combinations[i];
>>>> +    } else if (hw->wiphy->n_radio) {
>>>> +        for (i = 0; i < hw->wiphy->n_radio; i++) {
>>>> +            const struct wiphy_radio *radio = &hw->wiphy->radio[i];
>>>> -            if (comb->radar_detect_widths &&
>>>> -                comb->num_different_channels > 1)
>>>> +            if 
>>>> (!ieee80211_ifcomb_check_radar(radio->iface_combinations,
>>>> +                              radio->n_iface_combinations))
>>>>                   return -EINVAL;
>>>>           }
>>>> +    } else {
>>>> +        if 
>>>> (!ieee80211_ifcomb_check_radar(hw->wiphy->iface_combinations,
>>>> +                          hw->wiphy->n_iface_combinations))
>>>> +            return -EINVAL;
>>>>       }
>>>>       /* Only HW csum features are currently compatible with mac80211 */
>>>
>>> Are we omitting the "wiphy->iface_combinations" if the radio specific
>>> iface combination advertised ?
>>>
>>> If so, it looks like unused "wiphy->iface_combinations" for radio
>>> specific combination advertised.
>> 
>> This patch series assumes that you have both wiphy->iface_combinations 
>> and radio->iface_combinations set. wiphy->iface_combinations applies to 
>> the full wiphy, whereas radio->iface_combinations only applies to vifs 
>> assigned to the radio.
> 
> 
> If radio->iface_combinations is set then always vifs assigned to the
> radio. so wiphy->iface_combinations get avoid for all the use cases.
> 
> Ultimately either of one combination only get used by this proposal.
> 
> or I am missing something here ?

The functions that perform interface combination checks are called both 
with -1 as radio_idx (meaning per-wiphy), as well as with the assigned 
radio id. That way, both kinds of combinations/limits are checked and 
enforced.

- Felix