pkt_sched: Manage qdisc list inside of root qdisc.

Idea is from Patrick McHardy.

Instead of managing the list of qdiscs on the device level, manage it
in the root qdisc of a netdev_queue.  This solves all kinds of
visibility issues during qdisc destruction.

The way to iterate over all qdiscs of a netdev_queue is to visit
the netdev_queue->qdisc, and then traverse it's list.

The only special case is to ignore builting qdiscs at the root when
dumping or doing a qdisc_lookup().  That was not needed previously
because builtin qdiscs were not added to the device's qdisc_list.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 2 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 9c5a68850114..812bcd8b4363 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -636,8 +636,6 @@ struct net_device
         unsigned int            real_num_tx_queues;
 
         unsigned long           tx_queue_len;   /* Max frames per queue allowed */
-        spinlock_t              qdisc_list_lock;
-        struct list_head        qdisc_list;
 
 /*
  * One part is mostly used on xmit path (device)