Merge: net/sched: phase-2 backports for RHEL-9.2

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/1924

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2162634
Upstream Status: All mainline in net.git.
Tested: boot tested only
Conflicts: None

Signed-off-by: Davide Caratti <dcaratti@redhat.com>

Approved-by: Marcelo Ricardo Leitner <mleitner@redhat.com>
Approved-by: Xin Long <lxin@redhat.com>

Signed-off-by: Herton R. Krzesinski <herton@redhat.com>

Author: Herton R. Krzesinski

include/net/sch_generic.h

@@ -1298,4 +1298,11 @@ void mq_change_real_num_tx(struct Qdisc *sch, unsigned int new_real_tx);
 
 int sch_frag_xmit_hook(struct sk_buff *skb, int (*xmit)(struct sk_buff *skb));
 
+/* Make sure qdisc is no longer in SCHED state. */
+static inline void qdisc_synchronize(const struct Qdisc *q)
+{
+	while (test_bit(__QDISC_STATE_SCHED, &q->state))
+		msleep(1);
+}
+
 #endif

net/sched/cls_tcindex.c

@@ -332,7 +332,7 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
 		  struct tcindex_filter_result *r, struct nlattr **tb,
 		  struct nlattr *est, u32 flags, struct netlink_ext_ack *extack)
 {
-	struct tcindex_filter_result new_filter_result, *old_r = r;
+	struct tcindex_filter_result new_filter_result;
 	struct tcindex_data *cp = NULL, *oldp;
 	struct tcindex_filter *f = NULL; /* make gcc behave */
 	struct tcf_result cr = {};
@@ -401,7 +401,7 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
 	err = tcindex_filter_result_init(&new_filter_result, cp, net);
 	if (err < 0)
 		goto errout_alloc;
-	if (old_r)
+	if (r)
 		cr = r->res;
 
 	err = -EBUSY;
@@ -478,14 +478,6 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
 		tcf_bind_filter(tp, &cr, base);
 	}
 
-	if (old_r && old_r != r) {
-		err = tcindex_filter_result_init(old_r, cp, net);
-		if (err < 0) {
-			kfree(f);
-			goto errout_alloc;
-		}
-	}
-
 	oldp = p;
 	r->res = cr;
 	tcf_exts_change(&r->exts, &e);

net/sched/sch_api.c

@@ -1113,6 +1113,11 @@ static int qdisc_graft(struct net_device *dev, struct Qdisc *parent,
 			return -ENOENT;
 		}
 
+		if (new && new->ops == &noqueue_qdisc_ops) {
+			NL_SET_ERR_MSG(extack, "Cannot assign noqueue to a class");
+			return -EINVAL;
+		}
+
 		err = cops->graft(parent, cl, new, &old, extack);
 		if (err)
 			return err;

net/sched/sch_cake.c

@@ -2224,8 +2224,12 @@ static struct sk_buff *cake_dequeue(struct Qdisc *sch)
 
 static void cake_reset(struct Qdisc *sch)
 {
+	struct cake_sched_data *q = qdisc_priv(sch);
 	u32 c;
 
+	if (!q->tins)
+		return;
+
 	for (c = 0; c < CAKE_MAX_TINS; c++)
 		cake_clear_tin(sch, c);
 }

net/sched/sch_gred.c

@@ -377,6 +377,7 @@ static int gred_offload_dump_stats(struct Qdisc *sch)
 	/* Even if driver returns failure adjust the stats - in case offload
 	 * ended but driver still wants to adjust the values.
 	 */
+	sch_tree_lock(sch);
 	for (i = 0; i < MAX_DPs; i++) {
 		if (!table->tab[i])
 			continue;
@@ -393,6 +394,7 @@ static int gred_offload_dump_stats(struct Qdisc *sch)
 		sch->qstats.overlimits += hw_stats->stats.qstats[i].overlimits;
 	}
 	_bstats_update(&sch->bstats, bytes, packets);
+	sch_tree_unlock(sch);
 
 	kfree(hw_stats);
 	return ret;

net/sched/sch_htb.c

@@ -1566,22 +1566,25 @@ static int htb_destroy_class_offload(struct Qdisc *sch, struct htb_class *cl,
 	struct tc_htb_qopt_offload offload_opt;
 	struct netdev_queue *dev_queue;
 	struct Qdisc *q = cl->leaf.q;
-	struct Qdisc *old = NULL;
+	struct Qdisc *old;
 	int err;
 
 	if (cl->level)
 		return -EINVAL;
 
 	WARN_ON(!q);
 	dev_queue = htb_offload_get_queue(cl);
-	old = htb_graft_helper(dev_queue, NULL);
-	if (destroying)
-		/* Before HTB is destroyed, the kernel grafts noop_qdisc to
-		 * all queues.
+	/* When destroying, caller qdisc_graft grafts the new qdisc and invokes
+	 * qdisc_put for the qdisc being destroyed. htb_destroy_class_offload
+	 * does not need to graft or qdisc_put the qdisc being destroyed.
+	 */
+	if (!destroying) {
+		old = htb_graft_helper(dev_queue, NULL);
+		/* Last qdisc grafted should be the same as cl->leaf.q when
+		 * calling htb_delete.
 		 */
-		WARN_ON(!(old->flags & TCQ_F_BUILTIN));
-	else
 		WARN_ON(old != q);
+	}
 
 	if (cl->parent) {
 		_bstats_update(&cl->parent->bstats_bias,
@@ -1598,10 +1601,12 @@ static int htb_destroy_class_offload(struct Qdisc *sch, struct htb_class *cl,
 	};
 	err = htb_offload(qdisc_dev(sch), &offload_opt);
 
-	if (!err || destroying)
-		qdisc_put(old);
-	else
-		htb_graft_helper(dev_queue, old);
+	if (!destroying) {
+		if (!err)
+			qdisc_put(old);
+		else
+			htb_graft_helper(dev_queue, old);
+	}
 
 	if (last_child)
 		return err;

net/sched/sch_taprio.c

@@ -1633,6 +1633,7 @@ static void taprio_reset(struct Qdisc *sch)
 	int i;
 
 	hrtimer_cancel(&q->advance_timer);
+
 	if (q->qdiscs) {
 		for (i = 0; i < dev->num_tx_queues; i++)
 			if (q->qdiscs[i])
@@ -1656,6 +1657,7 @@ static void taprio_destroy(struct Qdisc *sch)
 	 * happens in qdisc_create(), after taprio_init() has been called.
 	 */
 	hrtimer_cancel(&q->advance_timer);
+	qdisc_synchronize(sch);
 
 	taprio_disable_offload(dev, q, NULL);