--- /dev/null
+From: Felix Fietkau <nbd@nbd.name>
+Date: Thu, 14 Sep 2023 13:17:16 +0200
+Subject: [PATCH] cfg80211: allow grace period for DFS available after beacon
+ shutdown
+
+Fixes reconfiguring an AP on a DFS channel in non-ETSI regdomain
+
+Fixes: b35a51c7dd25 ("cfg80211: Make pre-CAC results valid only for ETSI domain")
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/include/net/cfg80211.h
++++ b/include/net/cfg80211.h
+@@ -175,6 +175,8 @@ enum ieee80211_channel_flags {
+ * @dfs_state: current state of this channel. Only relevant if radar is required
+ * on this channel.
+ * @dfs_state_entered: timestamp (jiffies) when the dfs state was entered.
++ * @dfs_state_last_available: timestamp (jiffies) of the last time when the
++ * channel was available.
+ * @dfs_cac_ms: DFS CAC time in milliseconds, this is valid for DFS channels.
+ */
+ struct ieee80211_channel {
+@@ -191,6 +193,7 @@ struct ieee80211_channel {
+ int orig_mag, orig_mpwr;
+ enum nl80211_dfs_state dfs_state;
+ unsigned long dfs_state_entered;
++ unsigned long dfs_state_last_available;
+ unsigned int dfs_cac_ms;
+ };
+
+--- a/net/wireless/ap.c
++++ b/net/wireless/ap.c
+@@ -30,6 +30,9 @@ static int ___cfg80211_stop_ap(struct cf
+ if (!wdev->links[link_id].ap.beacon_interval)
+ return -ENOENT;
+
++ cfg80211_update_last_available(wdev->wiphy,
++ &wdev->links[link_id].ap.chandef);
++
+ err = rdev_stop_ap(rdev, dev, link_id);
+ if (!err) {
+ wdev->conn_owner_nlportid = 0;
+@@ -41,9 +44,6 @@ static int ___cfg80211_stop_ap(struct cf
+ if (notify)
+ nl80211_send_ap_stopped(wdev);
+
+- /* Should we apply the grace period during beaconing interface
+- * shutdown also?
+- */
+ cfg80211_sched_dfs_chan_update(rdev);
+ }
+
+--- a/net/wireless/chan.c
++++ b/net/wireless/chan.c
+@@ -461,6 +461,8 @@ static void cfg80211_set_chans_dfs_state
+
+ c->dfs_state = dfs_state;
+ c->dfs_state_entered = jiffies;
++ if (dfs_state == NL80211_DFS_AVAILABLE)
++ c->dfs_state_last_available = jiffies;
+ }
+ }
+
+@@ -873,6 +875,49 @@ static bool cfg80211_get_chans_dfs_avail
+ return true;
+ }
+
++static void
++__cfg80211_update_last_available(struct wiphy *wiphy,
++ u32 center_freq,
++ u32 bandwidth)
++{
++ struct ieee80211_channel *c;
++ u32 freq, start_freq, end_freq;
++
++ start_freq = cfg80211_get_start_freq(center_freq, bandwidth);
++ end_freq = cfg80211_get_end_freq(center_freq, bandwidth);
++
++ /*
++ * Check entire range of channels for the bandwidth.
++ * If any channel in between is disabled or has not
++ * had gone through CAC return false
++ */
++ for (freq = start_freq; freq <= end_freq; freq += MHZ_TO_KHZ(20)) {
++ c = ieee80211_get_channel_khz(wiphy, freq);
++ if (!c)
++ return;
++
++ c->dfs_state_last_available = jiffies;
++ }
++}
++
++void cfg80211_update_last_available(struct wiphy *wiphy,
++ const struct cfg80211_chan_def *chandef)
++{
++ int width;
++
++ width = cfg80211_chandef_get_width(chandef);
++ if (width < 0)
++ return;
++
++ __cfg80211_update_last_available(wiphy, MHZ_TO_KHZ(chandef->center_freq1),
++ width);
++ if (chandef->width != NL80211_CHAN_WIDTH_80P80)
++ return;
++
++ __cfg80211_update_last_available(wiphy, MHZ_TO_KHZ(chandef->center_freq2),
++ width);
++}
++
+ static bool cfg80211_chandef_dfs_available(struct wiphy *wiphy,
+ const struct cfg80211_chan_def *chandef)
+ {
+--- a/net/wireless/core.h
++++ b/net/wireless/core.h
+@@ -477,6 +477,8 @@ void cfg80211_set_dfs_state(struct wiphy
+ enum nl80211_dfs_state dfs_state);
+
+ void cfg80211_dfs_channels_update_work(struct work_struct *work);
++void cfg80211_update_last_available(struct wiphy *wiphy,
++ const struct cfg80211_chan_def *chandef);
+
+ unsigned int
+ cfg80211_chandef_dfs_cac_time(struct wiphy *wiphy,
+--- a/net/wireless/mlme.c
++++ b/net/wireless/mlme.c
+@@ -891,6 +891,8 @@ void cfg80211_dfs_channels_update_work(s
+ if (c->dfs_state == NL80211_DFS_UNAVAILABLE) {
+ time_dfs_update = IEEE80211_DFS_MIN_NOP_TIME_MS;
+ radar_event = NL80211_RADAR_NOP_FINISHED;
++ timeout = c->dfs_state_entered +
++ msecs_to_jiffies(time_dfs_update);
+ } else {
+ if (regulatory_pre_cac_allowed(wiphy) ||
+ cfg80211_any_wiphy_oper_chan(wiphy, c))
+@@ -898,11 +900,10 @@ void cfg80211_dfs_channels_update_work(s
+
+ time_dfs_update = REG_PRE_CAC_EXPIRY_GRACE_MS;
+ radar_event = NL80211_RADAR_PRE_CAC_EXPIRED;
++ timeout = c->dfs_state_last_available +
++ msecs_to_jiffies(time_dfs_update);
+ }
+
+- timeout = c->dfs_state_entered +
+- msecs_to_jiffies(time_dfs_update);
+-
+ if (time_after_eq(jiffies, timeout)) {
+ c->dfs_state = NL80211_DFS_USABLE;
+ c->dfs_state_entered = jiffies;