diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-01-09 17:18:50 +0000 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2025-01-14 10:17:53 +0100 |
| commit | 88df16f851ad8473ae89aba36d07e76b11c798ca (patch) | |
| tree | b0cd7903874bdd65fe95e4b6dcae2a5a0ed1299a /net/sched | |
| parent | a833fb852e96c778bff1d14866f1db2c346b3d2e (diff) | |
net: sched: calls synchronize_net() only when needed
dev_deactivate_many() role is to remove the qdiscs
of a network device.
When/if a qdisc is dismantled, an rcu grace period
is needed to make sure all outstanding qdisc enqueue
are done before we proceed with a qdisc reset.
Most virtual devices do not have a qdisc.
We can call the expensive synchronize_net() only
if needed.
Note that dev_deactivate_many() does not have to deal
with qdisc-less dev_queue_xmit, as an old comment
was claiming.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250109171850.2871194-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net/sched')
| -rw-r--r-- | net/sched/sch_generic.c | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index bb7dd351bd65..14ab2f4c190a 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -1277,15 +1277,17 @@ static void qdisc_deactivate(struct Qdisc *qdisc) static void dev_deactivate_queue(struct net_device *dev, struct netdev_queue *dev_queue, - void *_qdisc_default) + void *_sync_needed) { - struct Qdisc *qdisc_default = _qdisc_default; + bool *sync_needed = _sync_needed; struct Qdisc *qdisc; qdisc = rtnl_dereference(dev_queue->qdisc); if (qdisc) { + if (qdisc->enqueue) + *sync_needed = true; qdisc_deactivate(qdisc); - rcu_assign_pointer(dev_queue->qdisc, qdisc_default); + rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc); } } @@ -1352,24 +1354,22 @@ static bool some_qdisc_is_busy(struct net_device *dev) */ void dev_deactivate_many(struct list_head *head) { + bool sync_needed = false; struct net_device *dev; list_for_each_entry(dev, head, close_list) { netdev_for_each_tx_queue(dev, dev_deactivate_queue, - &noop_qdisc); + &sync_needed); if (dev_ingress_queue(dev)) dev_deactivate_queue(dev, dev_ingress_queue(dev), - &noop_qdisc); + &sync_needed); netdev_watchdog_down(dev); } - /* Wait for outstanding qdisc-less dev_queue_xmit calls or - * outstanding qdisc enqueuing calls. - * This is avoided if all devices are in dismantle phase : - * Caller will call synchronize_net() for us - */ - synchronize_net(); + /* Wait for outstanding qdisc enqueuing calls. */ + if (sync_needed) + synchronize_net(); list_for_each_entry(dev, head, close_list) { netdev_for_each_tx_queue(dev, dev_reset_queue, NULL); |