From: Davide Caratti dcaratti@redhat.com
[ Upstream commit 454d3e1ae057a1e09a15905b06b860f60d6c14d0 ]
leaf classes of ETS qdiscs are served in strict priority or deficit round robin (DRR), depending on the value of 'nstrict'. Since this value can be changed while traffic is running, we need to be sure that the active list of DRR classes can be updated at any time, so:
1) call INIT_LIST_HEAD(&alist) on all leaf classes in .init(), before the first packet hits any of them. 2) ensure that 'alist' is not overwritten with zeros when a leaf class is no more strict priority nor DRR (i.e. array elements beyond 'nbands').
Link: https://lore.kernel.org/netdev/YS%2FoZ+f0Nr8eQkzH@dcaratti.users.ipa.redhat.... Suggested-by: Cong Wang cong.wang@bytedance.com Signed-off-by: Davide Caratti dcaratti@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Stable-dep-of: 87c6efc5ce9c ("net/sched: ets: use old 'nbands' while purging unused classes") Signed-off-by: Sasha Levin sashal@kernel.org --- net/sched/sch_ets.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/net/sched/sch_ets.c b/net/sched/sch_ets.c index b49e1a977586..7bf6be69b3ee 100644 --- a/net/sched/sch_ets.c +++ b/net/sched/sch_ets.c @@ -666,7 +666,6 @@ static int ets_qdisc_change(struct Qdisc *sch, struct nlattr *opt,
q->nbands = nbands; for (i = nstrict; i < q->nstrict; i++) { - INIT_LIST_HEAD(&q->classes[i].alist); if (q->classes[i].qdisc->q.qlen) { list_add_tail(&q->classes[i].alist, &q->active); q->classes[i].deficit = quanta[i]; @@ -694,7 +693,11 @@ static int ets_qdisc_change(struct Qdisc *sch, struct nlattr *opt, ets_offload_change(sch); for (i = q->nbands; i < oldbands; i++) { qdisc_put(q->classes[i].qdisc); - memset(&q->classes[i], 0, sizeof(q->classes[i])); + q->classes[i].qdisc = NULL; + q->classes[i].quantum = 0; + q->classes[i].deficit = 0; + memset(&q->classes[i].bstats, 0, sizeof(q->classes[i].bstats)); + memset(&q->classes[i].qstats, 0, sizeof(q->classes[i].qstats)); } return 0; } @@ -703,7 +706,7 @@ static int ets_qdisc_init(struct Qdisc *sch, struct nlattr *opt, struct netlink_ext_ack *extack) { struct ets_sched *q = qdisc_priv(sch); - int err; + int err, i;
if (!opt) return -EINVAL; @@ -713,6 +716,9 @@ static int ets_qdisc_init(struct Qdisc *sch, struct nlattr *opt, return err;
INIT_LIST_HEAD(&q->active); + for (i = 0; i < TCQ_ETS_MAX_BANDS; i++) + INIT_LIST_HEAD(&q->classes[i].alist); + return ets_qdisc_change(sch, opt, extack); }