pkt_sched: Add 'deactivated' state.

This new state lets dev_deactivate() mark a qdisc as having been
deactivated.

dev_queue_xmit() and ing_filter() check for this bit and do not
try to process the qdisc if the bit is set.

dev_deactivate() polls the qdisc after setting the bit, waiting
for both __QDISC_STATE_RUNNING and __QDISC_STATE_SCHED to clear.

This isn't perfect yet, but subsequent changesets will make it so.
This part is just one piece of the puzzle.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2008-08-17 21:51:03 -07:00
parent 08013fa353
commit a9312ae893
3 changed files with 15 additions and 1 deletions

View file

@ -27,6 +27,7 @@ enum qdisc_state_t
{
__QDISC_STATE_RUNNING,
__QDISC_STATE_SCHED,
__QDISC_STATE_DEACTIVATED,
};
struct qdisc_size_table {

View file

@ -1800,6 +1800,12 @@ gso:
spin_lock(root_lock);
if (unlikely(test_bit(__QDISC_STATE_DEACTIVATED, &q->state))) {
spin_unlock(root_lock);
rc = NET_XMIT_DROP;
goto out_kfree_skb;
}
rc = qdisc_enqueue_root(skb, q);
qdisc_run(q);
@ -2084,7 +2090,8 @@ static int ing_filter(struct sk_buff *skb)
q = rxq->qdisc;
if (q != &noop_qdisc) {
spin_lock(qdisc_lock(q));
result = qdisc_enqueue_root(skb, q);
if (likely(!test_bit(__QDISC_STATE_DEACTIVATED, &q->state)))
result = qdisc_enqueue_root(skb, q);
spin_unlock(qdisc_lock(q));
}

View file

@ -597,6 +597,9 @@ static void transition_one_qdisc(struct net_device *dev,
struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
int *need_watchdog_p = _need_watchdog;
if (!(new_qdisc->flags & TCQ_F_BUILTIN))
clear_bit(__QDISC_STATE_DEACTIVATED, &new_qdisc->state);
rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
if (need_watchdog_p && new_qdisc != &noqueue_qdisc)
*need_watchdog_p = 1;
@ -640,6 +643,9 @@ static void dev_deactivate_queue(struct net_device *dev,
if (qdisc) {
spin_lock_bh(qdisc_lock(qdisc));
if (!(qdisc->flags & TCQ_F_BUILTIN))
set_bit(__QDISC_STATE_DEACTIVATED, &qdisc->state);
dev_queue->qdisc = qdisc_default;
qdisc_reset(qdisc);