bpf: net_sched: Support updating bstats

Add a kfunc to update Qdisc bstats when an skb is dequeued. The kfunc is
only available in .dequeue programs.

Signed-off-by: Amery Hung <amery.hung@bytedance.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20250409214606.2000194-6-ameryhung@gmail.com

diff --git a/net/sched/bpf_qdisc.c b/net/sched/bpf_qdisc.c
index 0790f1248bd8282051632d6c59f6070034711a18..dcbd1c9276345468d0cffbe40af6630a6a5c902d 100644 (file)
--- a/net/sched/bpf_qdisc.c
+++ b/net/sched/bpf_qdisc.c
@@ -238,6 +238,15 @@ __bpf_kfunc void bpf_qdisc_reset_destroy_epilogue(struct Qdisc *sch)
        qdisc_watchdog_cancel(&q->watchdog);
 }
 
+/* bpf_qdisc_bstats_update - Update Qdisc basic statistics
+ * @sch: The qdisc from which an skb is dequeued.
+ * @skb: The skb to be dequeued.
+ */
+__bpf_kfunc void bpf_qdisc_bstats_update(struct Qdisc *sch, const struct sk_buff *skb)
+{
+       bstats_update(&sch->bstats, skb);
+}
+
 __bpf_kfunc_end_defs();
 
 BTF_KFUNCS_START(qdisc_kfunc_ids)
@@ -248,6 +257,7 @@ BTF_ID_FLAGS(func, bpf_dynptr_from_skb, KF_TRUSTED_ARGS)
 BTF_ID_FLAGS(func, bpf_qdisc_watchdog_schedule, KF_TRUSTED_ARGS)
 BTF_ID_FLAGS(func, bpf_qdisc_init_prologue, KF_TRUSTED_ARGS)
 BTF_ID_FLAGS(func, bpf_qdisc_reset_destroy_epilogue, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_qdisc_bstats_update, KF_TRUSTED_ARGS)
 BTF_KFUNCS_END(qdisc_kfunc_ids)
 
 BTF_SET_START(qdisc_common_kfunc_set)
@@ -263,6 +273,7 @@ BTF_SET_END(qdisc_enqueue_kfunc_set)
 
 BTF_SET_START(qdisc_dequeue_kfunc_set)
 BTF_ID(func, bpf_qdisc_watchdog_schedule)
+BTF_ID(func, bpf_qdisc_bstats_update)
 BTF_SET_END(qdisc_dequeue_kfunc_set)
 
 enum qdisc_ops_kf_flags {