cfg80211/wext: fix message ordering

Since cfg80211 frequently takes actions from its netdev notifier call, wireless extensions messages could still be ordered badly since the wext netdev notifier, since wext is built into the kernel, runs before the cfg80211 netdev notifier. For example, the following can happen: 5: wlan1: <BROADCAST,MULTICAST> mtu 1500 qdisc mq state DOWN group default link/ether 02:00:00:00:01:00 brd ff:ff:ff:ff:ff:ff 5: wlan1: <BROADCAST,MULTICAST,UP> link/ether when setting the interface down causes the wext message. To also fix this, export the wireless_nlevent_flush() function and also call it from the cfg80211 notifier. Cc: [email protected] Signed-off-by: Johannes Berg <[email protected]>
jix · Jan 29, 2016 · cb150b9 · cb150b9
1 parent 8bf8627
commit cb150b9
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Showing 3 changed files with 10 additions and 1 deletion.
diff --git a/include/net/iw_handler.h b/include/net/iw_handler.h
@@ -439,6 +439,12 @@ int dev_get_wireless_info(char *buffer, char **start, off_t offset, int length);
 /* Send a single event to user space */
 void wireless_send_event(struct net_device *dev, unsigned int cmd,
 			 union iwreq_data *wrqu, const char *extra);
+#ifdef CONFIG_WEXT_CORE
+/* flush all previous wext events - if work is done from netdev notifiers */
+void wireless_nlevent_flush(void);
+#else
+static inline void wireless_nlevent_flush(void) {}
+#endif
 
 /* We may need a function to send a stream of events to user space.
  * More on that later... */

diff --git a/net/wireless/core.c b/net/wireless/core.c
@@ -1147,6 +1147,8 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
 		return NOTIFY_DONE;
 	}
 
+	wireless_nlevent_flush();
+
 	return NOTIFY_OK;
 }
 

diff --git a/net/wireless/wext-core.c b/net/wireless/wext-core.c
@@ -342,7 +342,7 @@ static const int compat_event_type_size[] = {
 
 /* IW event code */
 
-static void wireless_nlevent_flush(void)
+void wireless_nlevent_flush(void)
 {
 	struct sk_buff *skb;
 	struct net *net;
@@ -355,6 +355,7 @@ static void wireless_nlevent_flush(void)
 				    GFP_KERNEL);
 	}
 }
+EXPORT_SYMBOL_GPL(wireless_nlevent_flush);
 
 static int wext_netdev_notifier_call(struct notifier_block *nb,
 				     unsigned long state, void *ptr)
-Original file line number
+Diff line change
@@ Expand Up @@
     		return NOTIFY_DONE;
     	}
+    	wireless_nlevent_flush();
     	return NOTIFY_OK;
     }
@@ Expand Down @@