wifi: iwlwifi: mld: only create debugfs symlink if it does not exist

When mac80211 switches between non-MLO and MLO it will recreate the
debugfs directories. This results in the add_if_debugfs handler being
called multiple times. As the convenience symlink is created in the mld
debugfs directory and not the vif, it will not be removed by mac80211
when this happens and still exists.

Add a check and only create the convenience symlink if we have not yet
done so.

Fixes: d1e879e ("wifi: iwlwifi: add iwlmld sub-driver")
Signed-off-by: Benjamin Berg <[email protected]>
Signed-off-by: Miri Korenblit <[email protected]>
Link: https://patch.msgid.link/20250420095642.2490696f032a.I74319c7cf18f7e16a3d331cb96e38504b9fbab66@changeid
Signed-off-by: Johannes Berg <[email protected]>

Author: benzea

drivers/net/wireless/intel/iwlwifi/mld/debugfs.c

@@ -949,8 +949,9 @@ void iwl_mld_add_vif_debugfs(struct ieee80211_hw *hw,
 	snprintf(name, sizeof(name), "%pd", vif->debugfs_dir);
 	snprintf(target, sizeof(target), "../../../%pd3/iwlmld",
 		 vif->debugfs_dir);
-	mld_vif->dbgfs_slink =
-		debugfs_create_symlink(name, mld->debugfs_dir, target);
+	if (!mld_vif->dbgfs_slink)
+		mld_vif->dbgfs_slink =
+			debugfs_create_symlink(name, mld->debugfs_dir, target);
 
 	if (iwlmld_mod_params.power_scheme != IWL_POWER_SCHEME_CAM &&
 	    vif->type == NL80211_IFTYPE_STATION) {

drivers/net/wireless/intel/iwlwifi/mld/mac80211.c

@@ -651,6 +651,7 @@ void iwl_mld_mac80211_remove_interface(struct ieee80211_hw *hw,
 
 #ifdef CONFIG_IWLWIFI_DEBUGFS
 	debugfs_remove(iwl_mld_vif_from_mac80211(vif)->dbgfs_slink);
+	iwl_mld_vif_from_mac80211(vif)->dbgfs_slink = NULL;
 #endif
 
 	iwl_mld_rm_vif(mld, vif);