| Message ID | 20160823202544.14368.44444.stgit@john-Precision-Tower-5810 |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index c8e69a8..112d029 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -813,10 +813,6 @@ struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue, root_lock = qdisc_lock(oqdisc); spin_lock_bh(root_lock); - /* Prune old scheduler */ - if (oqdisc && atomic_read(&oqdisc->refcnt) <= 1) - qdisc_reset(oqdisc); - /* ... and graft new one */ if (qdisc == NULL) qdisc = &noop_qdisc;
In qdisc_graft_qdisc a "new" qdisc is attached and the 'qdisc_destroy' operation is called on the old qdisc. The destroy operation will wait a rcu grace period and call qdisc_rcu_free(). At which point gso_cpu_skb is free'd along with all stats so no need to zero stats and gso_cpu_skb from the graft operation itself. Further after dropping the qdisc locks we can not continue to call qdisc_reset before waiting an rcu grace period so that the qdisc is detached from all cpus. By removing the qdisc_reset() here we get the correct property of waiting an rcu grace period and letting the qdisc_destroy operation clean up the qdisc correctly. Note, a refcnt greater than 1 would cause the destroy operation to be aborted however if this ever happened the reference to the qdisc would be lost and we would have a memory leak. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> --- net/sched/sch_generic.c | 4 ---- 1 file changed, 4 deletions(-)