Re: [RFC v3 6/8] wifi: mac80211: extend ifcomb check functions for multi-radio

[Karthikeyan Periyasamy <quic_periyasa@quicinc.com>]

On 6/6/2024 11:37 PM, Felix Fietkau wrote:
> Add support for counting global and per-radio max/current number of
> channels, as well as checking radio-specific interface combinations.
> 
> Signed-off-by: Felix Fietkau <nbd@nbd.name>
> ---
>   net/mac80211/cfg.c         |   7 +-
>   net/mac80211/chan.c        |  17 +++--
>   net/mac80211/ibss.c        |   2 +-
>   net/mac80211/ieee80211_i.h |   6 +-
>   net/mac80211/iface.c       |   2 +-
>   net/mac80211/util.c        | 131 +++++++++++++++++++++++++++-----------
>   6 files changed, 116 insertions(+), 49 deletions(-)
> 
> diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
> index 62119e957cd8..950b7b72f0b8 100644
> --- a/net/mac80211/cfg.c
> +++ b/net/mac80211/cfg.c
> @@ -263,7 +263,7 @@ static int ieee80211_start_p2p_device(struct wiphy *wiphy,
>   
>   	lockdep_assert_wiphy(sdata->local->hw.wiphy);
>   
> -	ret = ieee80211_check_combinations(sdata, NULL, 0, 0);
> +	ret = ieee80211_check_combinations(sdata, NULL, 0, 0, -1);
>   	if (ret < 0)
>   		return ret;
>   
> @@ -285,7 +285,7 @@ static int ieee80211_start_nan(struct wiphy *wiphy,
>   
>   	lockdep_assert_wiphy(sdata->local->hw.wiphy);
>   
> -	ret = ieee80211_check_combinations(sdata, NULL, 0, 0);
> +	ret = ieee80211_check_combinations(sdata, NULL, 0, 0, -1);
>   	if (ret < 0)
>   		return ret;
>   
> @@ -4001,7 +4001,7 @@ __ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
>   		goto out;
>   
>   	/* if reservation is invalid then this will fail */
> -	err = ieee80211_check_combinations(sdata, NULL, chanctx->mode, 0);
> +	err = ieee80211_check_combinations(sdata, NULL, chanctx->mode, 0, -1);

Once we reach the global limit, all the -1 passing caller get fail 
becuase the iface check param (existing and new) is validated against 
the global limit. since global limt as a sort of union of all per-radio 
limits.

Ex:
Global iface = 6 (Radio iface 2GHz:4, 5GHz:4, 6GHz:6)


So far 6 iface created (Radio iface 2GHz:2, 5GHz:3, 6GHz:1)

In this case, new iface creation get fail because caller uses 
ieee80211_check_combinations() with -1 as radio idx, so it checked 
against global limit


-- 
Karthikeyan Periyasamy
--
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