mac80211: add max channel calculation utility function

The utility function has no uses yet. It is aimed
at future chanctx reservation management and
channel switching.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 42 insertions, 0 deletions

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 5a6cc3382ae9..7a376f826cf8 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2873,3 +2873,45 @@ int ieee80211_check_combinations(struct ieee80211_sub_if_data *sdata,
                                            num_different_channels,
                                            radar_detect, num);
 }
+
+static void
+ieee80211_iter_max_chans(const struct ieee80211_iface_combination *c,
+                         void *data)
+{
+        u32 *max_num_different_channels = data;
+
+        *max_num_different_channels = max(*max_num_different_channels,
+                                          c->num_different_channels);
+}
+
+int ieee80211_max_num_channels(struct ieee80211_local *local)
+{
+        struct ieee80211_sub_if_data *sdata;
+        int num[NUM_NL80211_IFTYPES] = {};
+        struct ieee80211_chanctx *ctx;
+        int num_different_channels = 0;
+        u8 radar_detect = 0;
+        u32 max_num_different_channels = 1;
+        int err;
+
+        lockdep_assert_held(&local->chanctx_mtx);
+
+        list_for_each_entry(ctx, &local->chanctx_list, list) {
+                num_different_channels++;
+
+                if (ctx->conf.radar_enabled)
+                        radar_detect |= BIT(ctx->conf.def.width);
+        }
+
+        list_for_each_entry_rcu(sdata, &local->interfaces, list)
+                num[sdata->wdev.iftype]++;
+
+        err = cfg80211_iter_combinations(local->hw.wiphy,
+                                         num_different_channels, radar_detect,
+                                         num, ieee80211_iter_max_chans,
+                                         &max_num_different_channels);
+        if (err < 0)
+                return err;
+
+        return max_num_different_channels;
+}