[1/2] wifi: mac80211: Add non-atomic station iterator.

Commit Message

Rory Little Aug. 6, 2024, 12:40 a.m. UTC

Drivers may at times want to iterate their stations with a function
which requires some non-atomic operations.

ieee80211_iterate_stations_mtx() introduces an API to iterate stations
while holding that wiphy's mutex. This allows the iterating function to
do non-atomic operations safely.

Signed-off-by: Rory Little <[e-mail]>
---
 include/net/mac80211.h | 18 ++++++++++++++++++
 net/mac80211/util.c    | 30 ++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

Patch

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index e1580360e099..6c8a2dd53243 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -6313,6 +6313,24 @@  void ieee80211_iterate_stations_atomic(struct ieee80211_hw *hw,
 				       void (*iterator)(void *data,
 						struct ieee80211_sta *sta),
 				       void *data);
+
+/**
+ * ieee80211_iterate_stations_mtx - iterate stations
+ *
+ * This function iterates over all stations associated with a given
+ * hardware that are currently uploaded to the driver and calls the callback
+ * function for them. This version can only be used while holding the wiphy
+ * mutex.
+ *
+ * @hw: the hardware struct of which the interfaces should be iterated over
+ * @iterator: the iterator function to call
+ * @data: first argument of the iterator function
+ */
+void ieee80211_iterate_stations_mtx(struct ieee80211_hw *hw,
+				    void (*iterator)(void *data,
+						     struct ieee80211_sta *sta),
+				    void *data);
+
 /**
  * ieee80211_queue_work - add work onto the mac80211 workqueue
  *
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index ef7133ac13f0..e12c871f0477 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -940,6 +940,23 @@  static void __iterate_stations(struct ieee80211_local *local,
 	}
 }
 
+static void __iterate_stations_safe(struct ieee80211_local *local,
+				    void (*iterator)(void *data,
+						     struct ieee80211_sta *sta),
+				    void *data)
+{
+	struct sta_info *sta, *sta_temp;
+
+	lockdep_assert_wiphy(local->hw.wiphy);
+
+	list_for_each_entry_safe(sta, sta_temp, &local->sta_list, list) {
+		if (!sta->uploaded)
+			continue;
+
+		iterator(data, &sta->sta);
+	}
+}
+
 void ieee80211_iterate_stations_atomic(struct ieee80211_hw *hw,
 			void (*iterator)(void *data,
 					 struct ieee80211_sta *sta),
@@ -953,6 +970,19 @@  void ieee80211_iterate_stations_atomic(struct ieee80211_hw *hw,
 }
 EXPORT_SYMBOL_GPL(ieee80211_iterate_stations_atomic);
 
+void ieee80211_iterate_stations_mtx(struct ieee80211_hw *hw,
+				    void (*iterator)(void *data,
+						     struct ieee80211_sta *sta),
+				    void *data)
+{
+	struct ieee80211_local *local = hw_to_local(hw);
+
+	lockdep_assert_wiphy(local->hw.wiphy);
+
+	__iterate_stations_safe(local, iterator, data);
+}
+EXPORT_SYMBOL_GPL(ieee80211_iterate_stations_mtx);
+
 struct ieee80211_vif *wdev_to_ieee80211_vif(struct wireless_dev *wdev)
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);