[PATCH] Send wireless netlink events with a clean slate

Drivers expect to be able to call wireless_send_event in arbitrary
contexts.  On the other hand, netlink really doesn't like being
invoked in an IRQ context.  So we need to postpone the sending of
netlink skb's to a tasklet.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/core/wireless.c

@@ -82,6 +82,7 @@
 #include <linux/init.h>			/* for __init */
 #include <linux/if_arp.h>		/* ARPHRD_ETHER */
 #include <linux/etherdevice.h>		/* compare_ether_addr */
+#include <linux/interrupt.h>
 
 #include <linux/wireless.h>		/* Pretty obvious */
 #include <net/iw_handler.h>		/* New driver API */
@@ -1842,6 +1843,18 @@ int wireless_rtnetlink_set(struct net_device *	dev,
  */
 
 #ifdef WE_EVENT_RTNETLINK
+static struct sk_buff_head wireless_nlevent_queue;
+
+static void wireless_nlevent_process(unsigned long data)
+{
+	struct sk_buff *skb;
+
+	while ((skb = skb_dequeue(&wireless_nlevent_queue)))
+		netlink_broadcast(rtnl, skb, 0, RTNLGRP_LINK, GFP_ATOMIC);
+}
+
+static DECLARE_TASKLET(wireless_nlevent_tasklet, wireless_nlevent_process, 0);
+
 /* ---------------------------------------------------------------- */
 /*
  * Fill a rtnetlink message with our event data.
@@ -1904,8 +1917,17 @@ static inline void rtmsg_iwinfo(struct net_device *	dev,
 		return;
 	}
 	NETLINK_CB(skb).dst_group = RTNLGRP_LINK;
-	netlink_broadcast(rtnl, skb, 0, RTNLGRP_LINK, GFP_ATOMIC);
+	skb_queue_tail(&wireless_nlevent_queue, skb);
+	tasklet_schedule(&wireless_nlevent_tasklet);
+}
+
+static int __init wireless_nlevent_init(void)
+{
+	skb_queue_head_init(&wireless_nlevent_queue);
+	return 0;
 }
+
+subsys_initcall(wireless_nlevent_init);
 #endif	/* WE_EVENT_RTNETLINK */
 
 /* ---------------------------------------------------------------- */