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Miller" , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Jamal Hadi Salim , Jiri Pirko , netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet Content-Type: text/plain; charset="UTF-8" hhf_dump_stats() only runs with RTNL held, reading fields that can be changed in qdisc fast path. Add READ_ONCE()/WRITE_ONCE() annotations. Fixes: edb09eb17ed8 ("net: sched: do not acquire qdisc spinlock in qdisc/class stats dump") Signed-off-by: Eric Dumazet Reviewed-by: Jamal Hadi Salim --- net/sched/sch_hhf.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/net/sched/sch_hhf.c b/net/sched/sch_hhf.c index 95e5d9bfd9c8c0cac08e080b8f1e0332e722aa3b..96021f52d835b56339509565ca03fe796593e231 100644 --- a/net/sched/sch_hhf.c +++ b/net/sched/sch_hhf.c @@ -198,7 +198,8 @@ static struct hh_flow_state *seek_list(const u32 hash, return NULL; list_del(&flow->flowchain); kfree(flow); - q->hh_flows_current_cnt--; + WRITE_ONCE(q->hh_flows_current_cnt, + q->hh_flows_current_cnt - 1); } else if (flow->hash_id == hash) { return flow; } @@ -226,7 +227,7 @@ static struct hh_flow_state *alloc_new_hh(struct list_head *head, } if (q->hh_flows_current_cnt >= q->hh_flows_limit) { - q->hh_flows_overlimit++; + WRITE_ONCE(q->hh_flows_overlimit, q->hh_flows_overlimit + 1); return NULL; } /* Create new entry. */ @@ -234,7 +235,7 @@ static struct hh_flow_state *alloc_new_hh(struct list_head *head, if (!flow) return NULL; - q->hh_flows_current_cnt++; + WRITE_ONCE(q->hh_flows_current_cnt, q->hh_flows_current_cnt + 1); INIT_LIST_HEAD(&flow->flowchain); list_add_tail(&flow->flowchain, head); @@ -309,7 +310,7 @@ static enum wdrr_bucket_idx hhf_classify(struct sk_buff *skb, struct Qdisc *sch) return WDRR_BUCKET_FOR_NON_HH; flow->hash_id = hash; flow->hit_timestamp = now; - q->hh_flows_total_cnt++; + WRITE_ONCE(q->hh_flows_total_cnt, q->hh_flows_total_cnt + 1); /* By returning without updating counters in q->hhf_arrays, * we implicitly implement "shielding" (see Optimization O1). @@ -403,7 +404,7 @@ static int hhf_enqueue(struct sk_buff *skb, struct Qdisc *sch, return NET_XMIT_SUCCESS; prev_backlog = sch->qstats.backlog; - q->drop_overlimit++; + WRITE_ONCE(q->drop_overlimit, q->drop_overlimit + 1); /* Return Congestion Notification only if we dropped a packet from this * bucket. */ @@ -686,10 +687,10 @@ static int hhf_dump_stats(struct Qdisc *sch, struct gnet_dump *d) { struct hhf_sched_data *q = qdisc_priv(sch); struct tc_hhf_xstats st = { - .drop_overlimit = q->drop_overlimit, - .hh_overlimit = q->hh_flows_overlimit, - .hh_tot_count = q->hh_flows_total_cnt, - .hh_cur_count = q->hh_flows_current_cnt, + .drop_overlimit = READ_ONCE(q->drop_overlimit), + .hh_overlimit = READ_ONCE(q->hh_flows_overlimit), + .hh_tot_count = READ_ONCE(q->hh_flows_total_cnt), + .hh_cur_count = READ_ONCE(q->hh_flows_current_cnt), }; return gnet_stats_copy_app(d, &st, sizeof(st)); -- 2.54.0.rc2.533.g4f5dca5207-goog