Subject: [PATCH 1/3] wireless extensions: make netns aware

From: Johannes Berg <[email-masked]>
Date: Wed, 24 Jun 2009 13:34:48 +0200

This makes wireless extensions netns aware. The
tasklet sending the events is converted to a work
struct so that we can rtnl_lock() in it.

Signed-off-by: Johannes Berg <[email-masked]>
---
 include/net/net_namespace.h |    3 ++
 net/wireless/wext.c         |   61 ++++++++++++++++++++------------------------
 2 files changed, 32 insertions(+), 32 deletions(-)

--- wireless-testing.orig/include/net/net_namespace.h	2009-06-22 14:44:06.000000000 +0200
+++ wireless-testing/include/net/net_namespace.h	2009-06-22 14:46:22.000000000 +0200
@@ -78,6 +78,9 @@ struct net {
 #ifdef CONFIG_XFRM
 	struct netns_xfrm	xfrm;
 #endif
+#ifdef CONFIG_WIRELESS_EXT
+	struct sk_buff_head	wext_nlevents;
+#endif
 	struct net_generic	*gen;
 };
 
--- wireless-testing.orig/net/wireless/wext.c	2009-06-22 14:44:06.000000000 +0200
+++ wireless-testing/net/wireless/wext.c	2009-06-22 14:46:22.000000000 +0200
@@ -1250,48 +1250,48 @@ int compat_wext_handle_ioctl(struct net 
 }
 #endif
 
-/************************* EVENT PROCESSING *************************/
-/*
- * Process events generated by the wireless layer or the driver.
- * Most often, the event will be propagated through rtnetlink
- */
+static int __net_init wext_pernet_init(struct net *net)
+{
+	skb_queue_head_init(&net->wext_nlevents);
+	return 0;
+}
 
-/* ---------------------------------------------------------------- */
-/*
- * Locking...
- * ----------
- *
- * Thanks to Herbert Xu <[email-masked]> for fixing
- * the locking issue in here and implementing this code !
- *
- * The issue : wireless_send_event() is often called in interrupt context,
- * while the Netlink layer can never be called in interrupt context.
- * The fully formed RtNetlink events are queued, and then a tasklet is run
- * to feed those to Netlink.
- * The skb_queue is interrupt safe, and its lock is not held while calling
- * Netlink, so there is no possibility of dealock.
- * Jean II
- */
+static void __net_exit wext_pernet_exit(struct net *net)
+{
+	skb_queue_purge(&net->wext_nlevents);
+}
 
-static struct sk_buff_head wireless_nlevent_queue;
+static struct pernet_operations wext_pernet_ops = {
+	.init = wext_pernet_init,
+	.exit = wext_pernet_exit,
+};
 
 static int __init wireless_nlevent_init(void)
 {
-	skb_queue_head_init(&wireless_nlevent_queue);
+	return register_pernet_subsys(&wext_pernet_ops);
 	return 0;
 }
 
 subsys_initcall(wireless_nlevent_init);
 
-static void wireless_nlevent_process(unsigned long data)
+/* Process events generated by the wireless layer or the driver. */
+static void wireless_nlevent_process(struct work_struct *work)
 {
 	struct sk_buff *skb;
+	struct net *net;
 
-	while ((skb = skb_dequeue(&wireless_nlevent_queue)))
-		rtnl_notify(skb, &init_net, 0, RTNLGRP_LINK, NULL, GFP_ATOMIC);
+	rtnl_lock();
+
+	for_each_net(net) {
+		while ((skb = skb_dequeue(&net->wext_nlevents)))
+			rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL,
+				    GFP_KERNEL);
+	}
+
+	rtnl_unlock();
 }
 
-static DECLARE_TASKLET(wireless_nlevent_tasklet, wireless_nlevent_process, 0);
+static DECLARE_WORK(wireless_nlevent_work, wireless_nlevent_process);
 
 /* ---------------------------------------------------------------- */
 /*
@@ -1341,9 +1341,6 @@ static void rtmsg_iwinfo(struct net_devi
 	struct sk_buff *skb;
 	int err;
 
-	if (!net_eq(dev_net(dev), &init_net))
-		return;
-
 	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
 	if (!skb)
 		return;
@@ -1356,8 +1353,8 @@ static void rtmsg_iwinfo(struct net_devi
 	}
 
 	NETLINK_CB(skb).dst_group = RTNLGRP_LINK;
-	skb_queue_tail(&wireless_nlevent_queue, skb);
-	tasklet_schedule(&wireless_nlevent_tasklet);
+	skb_queue_tail(&dev_net(dev)->wext_nlevents, skb);
+	schedule_work(&wireless_nlevent_work);
 }
 
 /* ---------------------------------------------------------------- */

--