cfg80211: move offchan_cac_event to a dedicated work

In order to make cfg80211_offchan_cac_abort() (renamed from
cfg80211_offchan_cac_event) callable in other contexts and
without so much locking restrictions, make it trigger a new
work instead of operating directly.

Do some other renames while at it to clarify.
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/6145c3d0f30400a568023f67981981d24c7c6133.1635325205.git.lorenzo@kernel.org
[rewrite commit log]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -7645,19 +7645,13 @@ void cfg80211_cac_event(struct net_device *netdev,
 			enum nl80211_radar_event event, gfp_t gfp);
 
 /**
- * cfg80211_offchan_cac_event - Channel Availability Check (CAC) offchan event
+ * cfg80211_offchan_cac_abort - Channel Availability Check offchan abort event
  * @wiphy: the wiphy
- * @chandef: chandef for the current channel
- * @event: type of event
- *
- * This function is called when a Channel Availability Check (CAC) is finished,
- * started or aborted by a offchannel dedicated chain.
  *
- * Note that this acquires the wiphy lock.
+ * This function is called by the driver when a Channel Availability Check
+ * (CAC) is aborted by a offchannel dedicated chain.
  */
-void cfg80211_offchan_cac_event(struct wiphy *wiphy,
-				const struct cfg80211_chan_def *chandef,
-				enum nl80211_radar_event event);
+void cfg80211_offchan_cac_abort(struct wiphy *wiphy);
 
 /**
  * cfg80211_gtk_rekey_notify - notify userspace about driver rekeying

net/wireless/core.c

@@ -545,7 +545,9 @@ struct wiphy *wiphy_new_nm(const struct cfg80211_ops *ops, int sizeof_priv,
 	INIT_WORK(&rdev->rfkill_block, cfg80211_rfkill_block_work);
 	INIT_WORK(&rdev->conn_work, cfg80211_conn_work);
 	INIT_WORK(&rdev->event_work, cfg80211_event_work);
-	INIT_DELAYED_WORK(&rdev->offchan_cac_work, cfg80211_offchan_cac_work);
+	INIT_WORK(&rdev->offchan_cac_abort_wk, cfg80211_offchan_cac_abort_wk);
+	INIT_DELAYED_WORK(&rdev->offchan_cac_done_wk,
+			  cfg80211_offchan_cac_done_wk);
 
 	init_waitqueue_head(&rdev->dev_wait);
 
@@ -1055,11 +1057,13 @@ void wiphy_unregister(struct wiphy *wiphy)
 	cancel_work_sync(&rdev->conn_work);
 	flush_work(&rdev->event_work);
 	cancel_delayed_work_sync(&rdev->dfs_update_channels_wk);
+	cancel_delayed_work_sync(&rdev->offchan_cac_done_wk);
 	flush_work(&rdev->destroy_work);
 	flush_work(&rdev->sched_scan_stop_wk);
 	flush_work(&rdev->propagate_radar_detect_wk);
 	flush_work(&rdev->propagate_cac_done_wk);
 	flush_work(&rdev->mgmt_registrations_update_wk);
+	flush_work(&rdev->offchan_cac_abort_wk);
 
 #ifdef CONFIG_PM
 	if (rdev->wiphy.wowlan_config && rdev->ops->set_wakeup)

net/wireless/core.h

@@ -86,7 +86,8 @@ struct cfg80211_registered_device {
 
 	struct wireless_dev *offchan_radar_wdev;
 	struct cfg80211_chan_def offchan_radar_chandef;
-	struct delayed_work offchan_cac_work;
+	struct delayed_work offchan_cac_done_wk;
+	struct work_struct offchan_cac_abort_wk;
 
 	/* netlink port which started critical protocol (0 means not started) */
 	u32 crit_proto_nlportid;
@@ -502,7 +503,9 @@ cfg80211_start_offchan_radar_detection(struct cfg80211_registered_device *rdev,
 
 void cfg80211_stop_offchan_radar_detection(struct wireless_dev *wdev);
 
-void cfg80211_offchan_cac_work(struct work_struct *work);
+void cfg80211_offchan_cac_done_wk(struct work_struct *work);
+
+void cfg80211_offchan_cac_abort_wk(struct work_struct *work);
 
 bool cfg80211_any_wiphy_oper_chan(struct wiphy *wiphy,
 				  struct ieee80211_channel *chan);

net/wireless/mlme.c

@@ -971,17 +971,6 @@ void cfg80211_cac_event(struct net_device *netdev,
 }
 EXPORT_SYMBOL(cfg80211_cac_event);
 
-void cfg80211_offchan_cac_work(struct work_struct *work)
-{
-	struct delayed_work *delayed_work = to_delayed_work(work);
-	struct cfg80211_registered_device *rdev;
-
-	rdev = container_of(delayed_work, struct cfg80211_registered_device,
-			    offchan_cac_work);
-	cfg80211_offchan_cac_event(&rdev->wiphy, &rdev->offchan_radar_chandef,
-				   NL80211_RADAR_CAC_FINISHED);
-}
-
 static void
 __cfg80211_offchan_cac_event(struct cfg80211_registered_device *rdev,
 			     struct wireless_dev *wdev,
@@ -1006,7 +995,7 @@ __cfg80211_offchan_cac_event(struct cfg80211_registered_device *rdev,
 		rdev->offchan_radar_wdev = NULL;
 		break;
 	case NL80211_RADAR_CAC_ABORTED:
-		cancel_delayed_work(&rdev->offchan_cac_work);
+		cancel_delayed_work(&rdev->offchan_cac_done_wk);
 		wdev = rdev->offchan_radar_wdev;
 		rdev->offchan_radar_wdev = NULL;
 		break;
@@ -1022,17 +1011,44 @@ __cfg80211_offchan_cac_event(struct cfg80211_registered_device *rdev,
 	nl80211_radar_notify(rdev, chandef, event, netdev, GFP_KERNEL);
 }
 
-void cfg80211_offchan_cac_event(struct wiphy *wiphy,
-				const struct cfg80211_chan_def *chandef,
-				enum nl80211_radar_event event)
+static void
+cfg80211_offchan_cac_event(struct cfg80211_registered_device *rdev,
+			   const struct cfg80211_chan_def *chandef,
+			   enum nl80211_radar_event event)
+{
+	wiphy_lock(&rdev->wiphy);
+	__cfg80211_offchan_cac_event(rdev, NULL, chandef, event);
+	wiphy_unlock(&rdev->wiphy);
+}
+
+void cfg80211_offchan_cac_done_wk(struct work_struct *work)
+{
+	struct delayed_work *delayed_work = to_delayed_work(work);
+	struct cfg80211_registered_device *rdev;
+
+	rdev = container_of(delayed_work, struct cfg80211_registered_device,
+			    offchan_cac_done_wk);
+	cfg80211_offchan_cac_event(rdev, &rdev->offchan_radar_chandef,
+				   NL80211_RADAR_CAC_FINISHED);
+}
+
+void cfg80211_offchan_cac_abort_wk(struct work_struct *work)
+{
+	struct cfg80211_registered_device *rdev;
+
+	rdev = container_of(work, struct cfg80211_registered_device,
+			    offchan_cac_abort_wk);
+	cfg80211_offchan_cac_event(rdev, &rdev->offchan_radar_chandef,
+				   NL80211_RADAR_CAC_ABORTED);
+}
+
+void cfg80211_offchan_cac_abort(struct wiphy *wiphy)
 {
 	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
 
-	wiphy_lock(wiphy);
-	__cfg80211_offchan_cac_event(rdev, NULL, chandef, event);
-	wiphy_unlock(wiphy);
+	queue_work(cfg80211_wq, &rdev->offchan_cac_abort_wk);
 }
-EXPORT_SYMBOL(cfg80211_offchan_cac_event);
+EXPORT_SYMBOL(cfg80211_offchan_cac_abort);
 
 int
 cfg80211_start_offchan_radar_detection(struct cfg80211_registered_device *rdev,
@@ -1062,7 +1078,7 @@ cfg80211_start_offchan_radar_detection(struct cfg80211_registered_device *rdev,
 	rdev->offchan_radar_chandef = *chandef;
 	__cfg80211_offchan_cac_event(rdev, wdev, chandef,
 				     NL80211_RADAR_CAC_STARTED);
-	queue_delayed_work(cfg80211_wq, &rdev->offchan_cac_work,
+	queue_delayed_work(cfg80211_wq, &rdev->offchan_cac_done_wk,
 			   msecs_to_jiffies(cac_time_ms));
 
 	return 0;