Re: [PATCH net v3 3/7] net/sched: act_gate: build schedule and RCU-swap

Build a fresh params snapshot and swap it in with rcu_replace_pointer(),
then free the old snapshot via call_rcu(). This is the same publish+defer
pattern used in taprio sched swapping (sch_taprio.c, commit d5c4546062fd6f)
and in act_pedit param updates (act_pedit.c, commit 52cf89f78c01bf).

When REPLACE omits TCA_GATE_ENTRY_LIST, carry forward the old snapshot fields
(basetime/clockid/flags/cycletime/priority) and only override provided attrs,
so partial updates don’t reset unrelated state.

Parse entry lists with GFP_KERNEL and explicit error handling, matching taprio’s
schedule parsing (sch_taprio.c, commit 5a781ccbd19e46).
[...]

@@ -388,32 +416,92 @@ static int tcf_gate_init(struct net *net, struct nlattr *nla,
  
  	gact = to_gate(*a);
  
-	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
-	if (err < 0)
+	p = kzalloc(sizeof(*p), GFP_KERNEL);
+	if (!p) {
+		err = -ENOMEM;
  		goto release_idr;
+	}
+	INIT_LIST_HEAD(&p->entries);

[...]    	if (!cycletime) {

@@ -425,20 +513,26 @@ static int tcf_gate_init(struct net *net, struct nlattr *nla,
  		cycletime = cycle;
  		if (!cycletime) {
  			err = -EINVAL;
-			goto chain_put;
+			goto release_mem;
  		}
  	}
  	p->tcfg_cycletime = cycletime;