mac80211: move interface shutdown out of wiphy lock

When reconfiguration fails, we shut down everything, but we
cannot call cfg80211_shutdown_all_interfaces() with the wiphy
mutex held. Since cfg80211 now calls it on resume errors, we
only need to do likewise for where we call reconfig (whether
directly or indirectly), but not under the wiphy lock.

Cc: stable@vger.kernel.org
Fixes: 2fe8ef1 ("cfg80211: change netdev registration/unregistration semantics")
Link: https://lore.kernel.org/r/20210608113226.78233c80f548.Iecc104aceb89f0568f50e9670a9cb191a1c8887b@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/debugfs.c

@@ -387,12 +387,17 @@ static ssize_t reset_write(struct file *file, const char __user *user_buf,
 			   size_t count, loff_t *ppos)
 {
 	struct ieee80211_local *local = file->private_data;
+	int ret;
 
 	rtnl_lock();
 	wiphy_lock(local->hw.wiphy);
 	__ieee80211_suspend(&local->hw, NULL);
-	__ieee80211_resume(&local->hw);
+	ret = __ieee80211_resume(&local->hw);
 	wiphy_unlock(local->hw.wiphy);
+
+	if (ret)
+		cfg80211_shutdown_all_interfaces(local->hw.wiphy);
+
 	rtnl_unlock();
 
 	return count;

net/mac80211/main.c

@@ -252,6 +252,7 @@ static void ieee80211_restart_work(struct work_struct *work)
 	struct ieee80211_local *local =
 		container_of(work, struct ieee80211_local, restart_work);
 	struct ieee80211_sub_if_data *sdata;
+	int ret;
 
 	/* wait for scan work complete */
 	flush_workqueue(local->workqueue);
@@ -301,8 +302,12 @@ static void ieee80211_restart_work(struct work_struct *work)
 	/* wait for all packet processing to be done */
 	synchronize_net();
 
-	ieee80211_reconfig(local);
+	ret = ieee80211_reconfig(local);
 	wiphy_unlock(local->hw.wiphy);
+
+	if (ret)
+		cfg80211_shutdown_all_interfaces(local->hw.wiphy);
+
 	rtnl_unlock();
 }
 

net/mac80211/util.c

@@ -2178,8 +2178,6 @@ static void ieee80211_handle_reconfig_failure(struct ieee80211_local *local)
 	list_for_each_entry(ctx, &local->chanctx_list, list)
 		ctx->driver_present = false;
 	mutex_unlock(&local->chanctx_mtx);
-
-	cfg80211_shutdown_all_interfaces(local->hw.wiphy);
 }
 
 static void ieee80211_assign_chanctx(struct ieee80211_local *local,