From 750e991ce9cf04af982bb11e6058c133d205d879 Mon Sep 17 00:00:00 2001
From: mtk31095 <michael-cy.lee@mediatek.com>
Date: Fri, 16 Dec 2022 10:37:53 +0800
Subject: [PATCH 12/14] mac80211: mtk: check the control channel before
 downgrading the bandwidth

Signed-off-by: mtk31095 <michael-cy.lee@mediatek.com>
---
 net/mac80211/mlme.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index f97bf2b..8ee325a 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -5019,6 +5019,26 @@ ieee80211_verify_sta_he_mcs_support(struct ieee80211_sub_if_data *sdata,
 	return false;
 }
 
+static bool ieee80211_check_same_ctrl_channel(struct ieee80211_sub_if_data *sdata,
+					      const struct cfg80211_chan_def *chandef)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_chanctx *ctx;
+
+	mutex_lock(&local->chanctx_mtx);
+	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		if (ctx->replace_state == IEEE80211_CHANCTX_WILL_BE_REPLACED)
+			continue;
+		if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
+			continue;
+		if (chandef->chan == ctx->conf.def.chan)
+			return true;
+	}
+
+	mutex_unlock(&local->chanctx_mtx);
+	return false;
+}
+
 static int ieee80211_prep_channel(struct ieee80211_sub_if_data *sdata,
 				  struct cfg80211_bss *cbss)
 {
@@ -5179,6 +5199,9 @@ static int ieee80211_prep_channel(struct ieee80211_sub_if_data *sdata,
 	    chandef.width == NL80211_CHAN_WIDTH_10)
 		goto out;
 
+	if (!ret || !ieee80211_check_same_ctrl_channel(sdata, &chandef))
+		goto out;
+
 	while (ret && chandef.width != NL80211_CHAN_WIDTH_20_NOHT) {
 		ifmgd->flags |= ieee80211_chandef_downgrade(&chandef);
 		ret = ieee80211_vif_use_channel(sdata, &chandef,
-- 
2.18.0