[PATCH] [72/139] net/dst: dst_dev_event() called after other notifiers

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <eric.dumazet@xxxxxxxxx>

[ Upstream commit 332dd96f7ac15e937088fe11f15cfe0210e8edd1 ]

Followup of commit ef885afbf8a37689 (net: use rcu_barrier() in
rollback_registered_many)

dst_dev_event() scans a garbage dst list that might be feeded by various
network notifiers at device dismantle time.

Its important to call dst_dev_event() after other notifiers, or we might
enter the infamous msleep(250) in netdev_wait_allrefs(), and wait one
second before calling again call_netdevice_notifiers(NETDEV_UNREGISTER,
dev) to properly remove last device references.

Use priority -10 to let dst_dev_notifier be called after other network
notifiers (they have the default 0 priority)

Reported-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Reported-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
Reported-by: Octavian Purdila <opurdila@xxxxxxxxxxx>
Reported-by: Benjamin LaHaise <bcrl@xxxxxxxxx>
Tested-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

---
 net/core/dst.c |    1 +
 1 file changed, 1 insertion(+)

Index: linux-2.6.35.y/net/core/dst.c
===================================================================
--- linux-2.6.35.y.orig/net/core/dst.c
+++ linux-2.6.35.y/net/core/dst.c
@@ -343,6 +343,7 @@ static int dst_dev_event(struct notifier
 
 static struct notifier_block dst_dev_notifier = {
 	.notifier_call	= dst_dev_event,
+	.priority = -10, /* must be called after other network notifiers */
 };
 
 void __init dst_init(void)
--
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