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>
diff --git a/net/core/dev.c b/net/core/dev.c
index 600bb23..d9e31f6 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1800,6 +1800,12 @@
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 @@
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));
}
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 4685746..ff1c455 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -597,6 +597,9 @@
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 @@
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);