openwrt/target/linux/generic/hack-5.4/662-remove_pfifo_fast.patch

From b531d492d5ef1cf9dba0f4888eb5fd8624a6d762 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@nbd.name>
Date: Fri, 7 Jul 2017 17:23:42 +0200
Subject: net: sched: switch default qdisc from pfifo_fast to fq_codel and remove pfifo_fast

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 net/sched/sch_generic.c | 140 ------------------------------------------------
 1 file changed, 140 deletions(-)

--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -620,230 +620,6 @@ struct Qdisc_ops noqueue_qdisc_ops __rea
 	.owner		=	THIS_MODULE,
 };
 
-static const u8 prio2band[TC_PRIO_MAX + 1] = {
-	1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
-};
-
-/* 3-band FIFO queue: old style, but should be a bit faster than
-   generic prio+fifo combination.
- */
-
-#define PFIFO_FAST_BANDS 3
-
-/*
- * Private data for a pfifo_fast scheduler containing:
- *	- rings for priority bands
- */
-struct pfifo_fast_priv {
-	struct skb_array q[PFIFO_FAST_BANDS];
-};
-
-static inline struct skb_array *band2list(struct pfifo_fast_priv *priv,
-					  int band)
-{
-	return &priv->q[band];
-}
-
-static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
-			      struct sk_buff **to_free)
-{
-	int band = prio2band[skb->priority & TC_PRIO_MAX];
-	struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
-	struct skb_array *q = band2list(priv, band);
-	unsigned int pkt_len = qdisc_pkt_len(skb);
-	int err;
-
-	err = skb_array_produce(q, skb);
-
-	if (unlikely(err)) {
-		if (qdisc_is_percpu_stats(qdisc))
-			return qdisc_drop_cpu(skb, qdisc, to_free);
-		else
-			return qdisc_drop(skb, qdisc, to_free);
-	}
-
-	qdisc_update_stats_at_enqueue(qdisc, pkt_len);
-	return NET_XMIT_SUCCESS;
-}
-
-static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
-{
-	struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
-	struct sk_buff *skb = NULL;
-	bool need_retry = true;
-	int band;
-
-retry:
-	for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
-		struct skb_array *q = band2list(priv, band);
-
-		if (__skb_array_empty(q))
-			continue;
-
-		skb = __skb_array_consume(q);
-	}
-	if (likely(skb)) {
-		qdisc_update_stats_at_dequeue(qdisc, skb);
-	} else if (need_retry &&
-		   test_bit(__QDISC_STATE_MISSED, &qdisc->state)) {
-		/* Delay clearing the STATE_MISSED here to reduce
-		 * the overhead of the second spin_trylock() in
-		 * qdisc_run_begin() and __netif_schedule() calling
-		 * in qdisc_run_end().
-		 */
-		clear_bit(__QDISC_STATE_MISSED, &qdisc->state);
-
-		/* Make sure dequeuing happens after clearing
-		 * STATE_MISSED.
-		 */
-		smp_mb__after_atomic();
-
-		need_retry = false;
-
-		goto retry;
-	} else {
-		WRITE_ONCE(qdisc->empty, true);
-	}
-
-	return skb;
-}
-
-static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
-{
-	struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
-	struct sk_buff *skb = NULL;
-	int band;
-
-	for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
-		struct skb_array *q = band2list(priv, band);
-
-		skb = __skb_array_peek(q);
-	}
-
-	return skb;
-}
-
-static void pfifo_fast_reset(struct Qdisc *qdisc)
-{
-	int i, band;
-	struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
-
-	for (band = 0; band < PFIFO_FAST_BANDS; band++) {
-		struct skb_array *q = band2list(priv, band);
-		struct sk_buff *skb;
-
-		/* NULL ring is possible if destroy path is due to a failed
-		 * skb_array_init() in pfifo_fast_init() case.
-		 */
-		if (!q->ring.queue)
-			continue;
-
-		while ((skb = __skb_array_consume(q)) != NULL)
-			kfree_skb(skb);
-	}
-
-	if (qdisc_is_percpu_stats(qdisc)) {
-		for_each_possible_cpu(i) {
-			struct gnet_stats_queue *q;
-
-			q = per_cpu_ptr(qdisc->cpu_qstats, i);
-			q->backlog = 0;
-			q->qlen = 0;
-		}
-	}
-}
-
-static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
-{
-	struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
-
-	memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1);
-	if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
-		goto nla_put_failure;
-	return skb->len;
-
-nla_put_failure:
-	return -1;
-}
-
-static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt,
-			   struct netlink_ext_ack *extack)
-{
-	unsigned int qlen = qdisc_dev(qdisc)->tx_queue_len;
-	struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
-	int prio;
-
-	/* guard against zero length rings */
-	if (!qlen)
-		return -EINVAL;
-
-	for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
-		struct skb_array *q = band2list(priv, prio);
-		int err;
-
-		err = skb_array_init(q, qlen, GFP_KERNEL);
-		if (err)
-			return -ENOMEM;
-	}
-
-	/* Can by-pass the queue discipline */
-	qdisc->flags |= TCQ_F_CAN_BYPASS;
-	return 0;
-}
-
-static void pfifo_fast_destroy(struct Qdisc *sch)
-{
-	struct pfifo_fast_priv *priv = qdisc_priv(sch);
-	int prio;
-
-	for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
-		struct skb_array *q = band2list(priv, prio);
-
-		/* NULL ring is possible if destroy path is due to a failed
-		 * skb_array_init() in pfifo_fast_init() case.
-		 */
-		if (!q->ring.queue)
-			continue;
-		/* Destroy ring but no need to kfree_skb because a call to
-		 * pfifo_fast_reset() has already done that work.
-		 */
-		ptr_ring_cleanup(&q->ring, NULL);
-	}
-}
-
-static int pfifo_fast_change_tx_queue_len(struct Qdisc *sch,
-					  unsigned int new_len)
-{
-	struct pfifo_fast_priv *priv = qdisc_priv(sch);
-	struct skb_array *bands[PFIFO_FAST_BANDS];
-	int prio;
-
-	for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
-		struct skb_array *q = band2list(priv, prio);
-
-		bands[prio] = q;
-	}
-
-	return skb_array_resize_multiple(bands, PFIFO_FAST_BANDS, new_len,
-					 GFP_KERNEL);
-}
-
-struct Qdisc_ops pfifo_fast_ops __read_mostly = {
-	.id		=	"pfifo_fast",
-	.priv_size	=	sizeof(struct pfifo_fast_priv),
-	.enqueue	=	pfifo_fast_enqueue,
-	.dequeue	=	pfifo_fast_dequeue,
-	.peek		=	pfifo_fast_peek,
-	.init		=	pfifo_fast_init,
-	.destroy	=	pfifo_fast_destroy,
-	.reset		=	pfifo_fast_reset,
-	.dump		=	pfifo_fast_dump,
-	.change_tx_queue_len =  pfifo_fast_change_tx_queue_len,
-	.owner		=	THIS_MODULE,
-	.static_flags	=	TCQ_F_NOLOCK | TCQ_F_CPUSTATS,
-};
-EXPORT_SYMBOL(pfifo_fast_ops);
-
 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 			  const struct Qdisc_ops *ops,
 			  struct netlink_ext_ack *extack)