[PATCH net-next v5 5/5] net: sched: sch_dualpi2: use qdisc_dequeue_drop() for dequeue drops
From: Jesper Dangaard Brouer <hawk@kernel.org>
Date: 2026-02-26 13:45:24
Also in:
bpf
Subsystem:
networking [general], tc subsystem, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Jamal Hadi Salim, Jiri Pirko, Linus Torvalds
DualPI2 drops packets during dequeue but was using kfree_skb_reason() directly, bypassing trace_qdisc_drop. Convert to qdisc_dequeue_drop() and add QDISC_DROP_L4S_STEP_NON_ECN to the qdisc drop reason enum. - Set TCQ_F_DEQUEUE_DROPS flag in dualpi2_init() - Use enum qdisc_drop_reason in drop_and_retry() - Replace kfree_skb_reason() with qdisc_dequeue_drop() Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org> Reviewed-by: Toke Høiland-Jørgensen <redacted> --- include/net/dropreason-core.h | 6 ------ include/net/dropreason-qdisc.h | 8 ++++++++ net/sched/sch_dualpi2.c | 12 ++++++------ 3 files changed, 14 insertions(+), 12 deletions(-)
diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h
index 3d8d284e05c8..5c8c2eb3d2c5 100644
--- a/include/net/dropreason-core.h
+++ b/include/net/dropreason-core.h@@ -121,7 +121,6 @@ FN(CANFD_RX_INVALID_FRAME) \ FN(CANXL_RX_INVALID_FRAME) \ FN(PFMEMALLOC) \ - FN(DUALPI2_STEP_DROP) \ FN(PSP_INPUT) \ FN(PSP_OUTPUT) \ FNe(MAX)
@@ -579,11 +578,6 @@ enum skb_drop_reason { * reached a path or socket not eligible for use of memory reserves */ SKB_DROP_REASON_PFMEMALLOC, - /** - * @SKB_DROP_REASON_DUALPI2_STEP_DROP: dropped by the step drop - * threshold of DualPI2 qdisc. - */ - SKB_DROP_REASON_DUALPI2_STEP_DROP, /** @SKB_DROP_REASON_PSP_INPUT: PSP input checks failed */ SKB_DROP_REASON_PSP_INPUT, /** @SKB_DROP_REASON_PSP_OUTPUT: PSP output checks failed */
diff --git a/include/net/dropreason-qdisc.h b/include/net/dropreason-qdisc.h
index 84f19a51382c..fb151cd31751 100644
--- a/include/net/dropreason-qdisc.h
+++ b/include/net/dropreason-qdisc.h@@ -14,6 +14,7 @@ FN(BAND_LIMIT) \ FN(HORIZON_LIMIT) \ FN(FLOW_LIMIT) \ + FN(L4S_STEP_NON_ECN) \ FNe(MAX) #undef FN
@@ -93,6 +94,13 @@ enum qdisc_drop_reason { * monopolizing queue resources. */ QDISC_DROP_FLOW_LIMIT, + /** + * @QDISC_DROP_L4S_STEP_NON_ECN: DualPI2 qdisc dropped a non-ECN-capable + * packet because the L4S queue delay exceeded the step threshold. + * Since the packet cannot be ECN-marked, it must be dropped to signal + * congestion. See RFC 9332 for the DualQ Coupled AQM step mechanism. + */ + QDISC_DROP_L4S_STEP_NON_ECN, /** * @QDISC_DROP_MAX: the maximum of qdisc drop reasons, which * shouldn't be used as a real 'reason' - only for tracing code gen
diff --git a/net/sched/sch_dualpi2.c b/net/sched/sch_dualpi2.c
index 020cc20c6b56..fe6f5e889625 100644
--- a/net/sched/sch_dualpi2.c
+++ b/net/sched/sch_dualpi2.c@@ -571,11 +571,11 @@ static int do_step_aqm(struct dualpi2_sched_data *q, struct sk_buff *skb, } static void drop_and_retry(struct dualpi2_sched_data *q, struct sk_buff *skb, - struct Qdisc *sch, enum skb_drop_reason reason) + struct Qdisc *sch, enum qdisc_drop_reason reason) { ++q->deferred_drops_cnt; q->deferred_drops_len += qdisc_pkt_len(skb); - kfree_skb_reason(skb, reason); + qdisc_dequeue_drop(sch, skb, reason); qdisc_qstats_drop(sch); }
@@ -590,15 +590,13 @@ static struct sk_buff *dualpi2_qdisc_dequeue(struct Qdisc *sch) while ((skb = dequeue_packet(sch, q, &credit_change, now))) { if (!q->drop_early && must_drop(sch, q, skb)) { - drop_and_retry(q, skb, sch, - SKB_DROP_REASON_QDISC_DROP); + drop_and_retry(q, skb, sch, QDISC_DROP_CONGESTED); continue; } if (skb_in_l_queue(skb) && do_step_aqm(q, skb, now)) { qdisc_qstats_drop(q->l_queue); - drop_and_retry(q, skb, sch, - SKB_DROP_REASON_DUALPI2_STEP_DROP); + drop_and_retry(q, skb, sch, QDISC_DROP_L4S_STEP_NON_ECN); continue; }
@@ -915,6 +913,8 @@ static int dualpi2_init(struct Qdisc *sch, struct nlattr *opt, struct dualpi2_sched_data *q = qdisc_priv(sch); int err; + sch->flags |= TCQ_F_DEQUEUE_DROPS; + q->l_queue = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, TC_H_MAKE(sch->handle, 1), extack); if (!q->l_queue)