Re: [PATCH 2.4] Use double-linked list for dev->qdisc_list

Tomasz Paszkowski wrote:

This patch changes dev->qdisc_list to a double-linked list. This solves
the performance problems when destroying qdiscs with large number of inner
qdiscs.

This is backported version of Patrick McHardy patch (03-qdisc_list-list_h.diff)
or 2.6 kernels.
 

Looks good, except for the last hunk, the BUG_TRAP is valid in 2.4 because
it doesn't use RCU. Change it to BUG_TRAP(list_empty(&dev->qdisc_list)).

 

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

#endif
-	BUG_TRAP(dev->qdisc_list == NULL);
	BUG_TRAP(!timer_pending(&dev->watchdog_timer));
-	dev->qdisc_list = NULL;
	spin_unlock_bh(&dev->queue_lock);
	write_unlock(&qdisc_tree_lock);
}