mac80211: add vif debugfs driver callbacks

Add debugfs driver callbacks so drivers can add
debugfs entries for interfaces. Note that they
_must_ remove the entries again as add/remove in
the driver doesn't correspond to add/remove in
debugfs; the former is up/down while the latter
is netdev create/destroy.

Signed-off-by: Alexander Bondar <alexander.bondar@intel.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

3 files changed, 59 insertions, 0 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 7da11211825d..46e08ba92b97 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2167,6 +2167,18 @@ enum ieee80211_rate_control_changed {
  *      MAC address of the device going away.
  *      Hence, this callback must be implemented. It can sleep.
  *
+ * @add_interface_debugfs: Drivers can use this callback to add debugfs files
+ *      when a vif is added to mac80211. This callback and
+ *      @remove_interface_debugfs should be within a CONFIG_MAC80211_DEBUGFS
+ *      conditional. @remove_interface_debugfs must be provided for cleanup.
+ *      This callback can sleep.
+ *
+ * @remove_interface_debugfs: Remove the debugfs files which were added using
+ *      @add_interface_debugfs. This callback must remove all debugfs entries
+ *      that were added because mac80211 only removes interface debugfs when the
+ *      interface is destroyed, not when it is removed from the driver.
+ *      This callback can sleep.
+ *
  * @config: Handler for configuration requests. IEEE 802.11 code calls this
  *      function to change hardware configuration, e.g., channel.
  *      This function should never fail but returns a negative error code
@@ -2580,6 +2592,12 @@ struct ieee80211_ops {
                                    struct ieee80211_vif *vif,
                                    struct ieee80211_sta *sta,
                                    struct dentry *dir);
+        void (*add_interface_debugfs)(struct ieee80211_hw *hw,
+                                      struct ieee80211_vif *vif,
+                                      struct dentry *dir);
+        void (*remove_interface_debugfs)(struct ieee80211_hw *hw,
+                                         struct ieee80211_vif *vif,
+                                         struct dentry *dir);
 #endif
         void (*sta_notify)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
                         enum sta_notify_cmd, struct ieee80211_sta *sta);
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index 434b3c4f31b5..2b08b9982d06 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -528,6 +528,43 @@ static inline void drv_sta_remove_debugfs(struct ieee80211_local *local,
                 local->ops->sta_remove_debugfs(&local->hw, &sdata->vif,
                                                sta, dir);
 }
+
+static inline
+void drv_add_interface_debugfs(struct ieee80211_local *local,
+                               struct ieee80211_sub_if_data *sdata)
+{
+        might_sleep();
+
+        check_sdata_in_driver(sdata);
+
+        if (!local->ops->add_interface_debugfs)
+                return;
+
+        local->ops->add_interface_debugfs(&local->hw, &sdata->vif,
+                                          sdata->debugfs.dir);
+}
+
+static inline
+void drv_remove_interface_debugfs(struct ieee80211_local *local,
+                                  struct ieee80211_sub_if_data *sdata)
+{
+        might_sleep();
+
+        check_sdata_in_driver(sdata);
+
+        if (!local->ops->remove_interface_debugfs)
+                return;
+
+        local->ops->remove_interface_debugfs(&local->hw, &sdata->vif,
+                                             sdata->debugfs.dir);
+}
+#else
+static inline
+void drv_add_interface_debugfs(struct ieee80211_local *local,
+                               struct ieee80211_sub_if_data *sdata) {}
+static inline
+void drv_remove_interface_debugfs(struct ieee80211_local *local,
+                                  struct ieee80211_sub_if_data *sdata) {}
 #endif
 
 static inline __must_check
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 0a36dc6346bb..deb78e864af6 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -621,6 +621,8 @@ int ieee80211_do_open(struct wireless_dev *wdev, bool coming_up)
                                 goto err_del_interface;
                 }
 
+                drv_add_interface_debugfs(local, sdata);
+
                 if (sdata->vif.type == NL80211_IFTYPE_AP) {
                         local->fif_pspoll++;
                         local->fif_probe_req++;
@@ -882,6 +884,8 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
                  */
                 ieee80211_free_keys(sdata);
 
+                drv_remove_interface_debugfs(local, sdata);
+
                 if (going_down)
                         drv_remove_interface(local, sdata);
         }