cfg80211/wext: fix message ordering

commit cb150b9d23be6ee7f3a0fff29784f1c5b5ac514d upstream.

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.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
[bwh: Backported to 3.2:
 - Add default case in cfg80211_netdev_notifier_call() which bypasses
   the added wireless_nlevent_flush() (added upstream by commit
   6784c7db8d43 "cfg80211: change return value of notifier function")
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/include/net/iw_handler.h b/include/net/iw_handler.h
index 5d5a6a4..1b5984a 100644 (file)
--- a/include/net/iw_handler.h
+++ b/include/net/iw_handler.h
@@ -442,6 +442,12 @@ extern void wireless_send_event(struct net_device *        dev,
                                unsigned int            cmd,
                                union iwreq_data *      wrqu,
                                const char *            extra);
                                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... */
 
 /* 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
index ea93f4b..4043f71 100644 (file)
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -985,8 +985,12 @@ static int cfg80211_netdev_notifier_call(struct notifier_block * nb,
                if (ret)
                        return notifier_from_errno(ret);
                break;
                if (ret)
                        return notifier_from_errno(ret);
                break;

+       default:
+               return NOTIFY_DONE;

        }
 
        }
 

+       wireless_nlevent_flush();
+

        return NOTIFY_DONE;
 }
 
        return NOTIFY_DONE;
 }
 

diff --git a/net/wireless/wext-core.c b/net/wireless/wext-core.c
index 9f63dd7..2894190 100644 (file)
--- 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 */
 
 
 /* IW event code */
 

-static void wireless_nlevent_flush(void)
+void wireless_nlevent_flush(void)

 {
        struct sk_buff *skb;
        struct net *net;
 {
        struct sk_buff *skb;
        struct net *net;


@@ -355,6 +355,7 @@ static void wireless_nlevent_flush(void)
                                    GFP_KERNEL);
        }
 }
                                    GFP_KERNEL);
        }
 }

+EXPORT_SYMBOL_GPL(wireless_nlevent_flush);

 
 static int wext_netdev_notifier_call(struct notifier_block *nb,
                                     unsigned long state, void *ptr)
 
 static int wext_netdev_notifier_call(struct notifier_block *nb,
                                     unsigned long state, void *ptr)