On 7/25/24 6:15 PM, Martin KaFai Lau wrote:
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 5064b6d2d1ec..9fb9375e2793 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1352,6 +1352,13 @@ static struct Qdisc *qdisc_create(struct net_device *dev,
rcu_assign_pointer(sch->stab, stab);
}
+#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_BPF_JIT)
+ if (sch->flags & TCQ_F_BPF) {
I can see the reason why this patch is needed. It is a few line changes and they
are not in the fast path... still weakly not excited about them but I know it
could be a personal preference.
I think at the very least, instead of adding a new TCQ_F_BPF, let see if the
"owner == BPF_MODULE_OWNER" test can be reused like how it is done in the
bpf_try_module_get().
A rough direction I am spinning...
The pre/post is mainly to initialize and cleanup the "struct bpf_sched_data"
before/after calling the bpf prog.
For the pre (init), there is a ".gen_prologue(...., const struct bpf_prog
*prog)" in the "bpf_verifier_ops". Take a look at the tc_cls_act_prologue().
It calls a BPF_FUNC_skb_pull_data helper. It potentially can call a kfunc
bpf_qdisc_watchdog_cancel. However, the gen_prologue is invoked too late in the
typo. The kfunc should be s/qdisc_watchdog_cancel/qdisc_watchdog_init/ for the pre.
verifier for kfunc calling now. This will need some thoughts and works.
For the post (destroy,reset), there is no "gen_epilogue" now. If
bpf_qdisc_watchdog_schedule() is not allowed to be called in the ".reset" and
".destroy" bpf prog. I think it can be changed to pre also? There is a ".filter"
function in the "struct btf_kfunc_id_set" during the kfunc register.
+ err = bpf_qdisc_init_pre_op(sch, tca[TCA_OPTIONS], extack);
+ if (err != 0)
+ goto err_out4;
+ }
