mac80211: fix recalc_radar hwconf sync problem

local->hw.conf maybe not be synced when recalcing whether radar is
enabled, sometimes leaving radar enabled even if it's not neccesary
anymore.

Fix this by:
 * setting radar_enabled when creating the chanctx
 * turning radar_enabled off before destroying the last channel context

Reported-by: Zefir Kurtisi <zefir.kurtisi@neratec.com>
Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 33 insertions, 10 deletions

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 8024874ba95d..166165efd8e2 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -57,6 +57,22 @@ ieee80211_find_chanctx(struct ieee80211_local *local,
         return NULL;
 }
 
+static bool ieee80211_is_radar_required(struct ieee80211_local *local)
+{
+        struct ieee80211_sub_if_data *sdata;
+
+        rcu_read_lock();
+        list_for_each_entry_rcu(sdata, &local->interfaces, list) {
+                if (sdata->radar_required) {
+                        rcu_read_unlock();
+                        return true;
+                }
+        }
+        rcu_read_unlock();
+
+        return false;
+}
+
 static struct ieee80211_chanctx *
 ieee80211_new_chanctx(struct ieee80211_local *local,
                       const struct cfg80211_chan_def *chandef,
@@ -75,6 +91,9 @@ ieee80211_new_chanctx(struct ieee80211_local *local,
         ctx->conf.rx_chains_static = 1;
         ctx->conf.rx_chains_dynamic = 1;
         ctx->mode = mode;
+        ctx->conf.radar_enabled = ieee80211_is_radar_required(local);
+        if (!local->use_chanctx)
+                local->hw.conf.radar_enabled = ctx->conf.radar_enabled;
 
         if (!local->use_chanctx) {
                 local->_oper_chandef = *chandef;
@@ -99,6 +118,7 @@ ieee80211_new_chanctx(struct ieee80211_local *local,
 static void ieee80211_free_chanctx(struct ieee80211_local *local,
                                    struct ieee80211_chanctx *ctx)
 {
+        bool check_single_channel = false;
         lockdep_assert_held(&local->chanctx_mtx);
 
         WARN_ON_ONCE(ctx->refcount != 0);
@@ -108,6 +128,14 @@ static void ieee80211_free_chanctx(struct ieee80211_local *local,
                 chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
                 chandef->center_freq1 = chandef->chan->center_freq;
                 chandef->center_freq2 = 0;
+
+                /* NOTE: Disabling radar is only valid here for
+                 * single channel context. To be sure, check it ...
+                 */
+                if (local->hw.conf.radar_enabled)
+                        check_single_channel = true;
+                local->hw.conf.radar_enabled = false;
+
                 ieee80211_hw_config(local, 0);
         } else {
                 drv_remove_chanctx(local, ctx);
@@ -116,6 +144,9 @@ static void ieee80211_free_chanctx(struct ieee80211_local *local,
         list_del_rcu(&ctx->list);
         kfree_rcu(ctx, rcu_head);
 
+        /* throw a warning if this wasn't the only channel context. */
+        WARN_ON(check_single_channel && !list_empty(&local->chanctx_list));
+
         mutex_lock(&local->mtx);
         ieee80211_recalc_idle(local);
         mutex_unlock(&local->mtx);
@@ -227,19 +258,11 @@ static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
 void ieee80211_recalc_radar_chanctx(struct ieee80211_local *local,
                                     struct ieee80211_chanctx *chanctx)
 {
-        struct ieee80211_sub_if_data *sdata;
-        bool radar_enabled = false;
+        bool radar_enabled;
 
         lockdep_assert_held(&local->chanctx_mtx);
 
-        rcu_read_lock();
-        list_for_each_entry_rcu(sdata, &local->interfaces, list) {
-                if (sdata->radar_required) {
-                        radar_enabled = true;
-                        break;
-                }
-        }
-        rcu_read_unlock();
+        radar_enabled = ieee80211_is_radar_required(local);
 
         if (radar_enabled == chanctx->conf.radar_enabled)
                 return;