mac80211: make check_combinations() aware of chanctx reservation

The ieee80211_check_combinations() computes
radar_detect accordingly depending on chanctx
reservation status.

This makes it possible to use the function for
channel_switch validation.
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/util.c

@@ -2933,6 +2933,35 @@ void ieee80211_recalc_dtim(struct ieee80211_local *local,
 	ps->dtim_count = dtim_count;
 }
 
+static u8 ieee80211_chanctx_radar_detect(struct ieee80211_local *local,
+					 struct ieee80211_chanctx *ctx)
+{
+	struct ieee80211_sub_if_data *sdata;
+	u8 radar_detect = 0;
+
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	if (WARN_ON(ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED))
+		return 0;
+
+	list_for_each_entry(sdata, &ctx->reserved_vifs, reserved_chanctx_list)
+		if (sdata->reserved_radar_required)
+			radar_detect |= BIT(sdata->reserved_chandef.width);
+
+	/*
+	 * An in-place reservation context should not have any assigned vifs
+	 * until it replaces the other context.
+	 */
+	WARN_ON(ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER &&
+		!list_empty(&ctx->assigned_vifs));
+
+	list_for_each_entry(sdata, &ctx->assigned_vifs, assigned_chanctx_list)
+		if (sdata->radar_required)
+			radar_detect |= BIT(sdata->vif.bss_conf.chandef.width);
+
+	return radar_detect;
+}
+
 int ieee80211_check_combinations(struct ieee80211_sub_if_data *sdata,
 				 const struct cfg80211_chan_def *chandef,
 				 enum ieee80211_chanctx_mode chanmode,
@@ -2976,8 +3005,7 @@ int ieee80211_check_combinations(struct ieee80211_sub_if_data *sdata,
 	list_for_each_entry(ctx, &local->chanctx_list, list) {
 		if (ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED)
 			continue;
-		if (ctx->conf.radar_enabled)
-			radar_detect |= BIT(ctx->conf.def.width);
+		radar_detect |= ieee80211_chanctx_radar_detect(local, ctx);
 		if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE) {
 			num_different_channels++;
 			continue;
@@ -3039,8 +3067,7 @@ int ieee80211_max_num_channels(struct ieee80211_local *local)
 
 		num_different_channels++;
 
-		if (ctx->conf.radar_enabled)
-			radar_detect |= BIT(ctx->conf.def.width);
+		radar_detect |= ieee80211_chanctx_radar_detect(local, ctx);
 	}
 
 	list_for_each_entry_rcu(sdata, &local->interfaces, list)