xref: /linux/include/net/sch_generic.h (revision a38a98821c939e67e5906bddbed1d15af5ca860d)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __NET_SCHED_GENERIC_H
3 #define __NET_SCHED_GENERIC_H
4 
5 #include <linux/netdevice.h>
6 #include <linux/types.h>
7 #include <linux/rcupdate.h>
8 #include <linux/pkt_sched.h>
9 #include <linux/pkt_cls.h>
10 #include <linux/percpu.h>
11 #include <linux/dynamic_queue_limits.h>
12 #include <linux/list.h>
13 #include <linux/refcount.h>
14 #include <linux/workqueue.h>
15 #include <net/gen_stats.h>
16 #include <net/rtnetlink.h>
17 
18 struct Qdisc_ops;
19 struct qdisc_walker;
20 struct tcf_walker;
21 struct module;
22 
23 struct qdisc_rate_table {
24 	struct tc_ratespec rate;
25 	u32		data[256];
26 	struct qdisc_rate_table *next;
27 	int		refcnt;
28 };
29 
30 enum qdisc_state_t {
31 	__QDISC_STATE_SCHED,
32 	__QDISC_STATE_DEACTIVATED,
33 };
34 
35 struct qdisc_size_table {
36 	struct rcu_head		rcu;
37 	struct list_head	list;
38 	struct tc_sizespec	szopts;
39 	int			refcnt;
40 	u16			data[];
41 };
42 
43 /* similar to sk_buff_head, but skb->prev pointer is undefined. */
44 struct qdisc_skb_head {
45 	struct sk_buff	*head;
46 	struct sk_buff	*tail;
47 	__u32		qlen;
48 	spinlock_t	lock;
49 };
50 
51 struct Qdisc {
52 	int 			(*enqueue)(struct sk_buff *skb,
53 					   struct Qdisc *sch,
54 					   struct sk_buff **to_free);
55 	struct sk_buff *	(*dequeue)(struct Qdisc *sch);
56 	unsigned int		flags;
57 #define TCQ_F_BUILTIN		1
58 #define TCQ_F_INGRESS		2
59 #define TCQ_F_CAN_BYPASS	4
60 #define TCQ_F_MQROOT		8
61 #define TCQ_F_ONETXQUEUE	0x10 /* dequeue_skb() can assume all skbs are for
62 				      * q->dev_queue : It can test
63 				      * netif_xmit_frozen_or_stopped() before
64 				      * dequeueing next packet.
65 				      * Its true for MQ/MQPRIO slaves, or non
66 				      * multiqueue device.
67 				      */
68 #define TCQ_F_WARN_NONWC	(1 << 16)
69 #define TCQ_F_CPUSTATS		0x20 /* run using percpu statistics */
70 #define TCQ_F_NOPARENT		0x40 /* root of its hierarchy :
71 				      * qdisc_tree_decrease_qlen() should stop.
72 				      */
73 #define TCQ_F_INVISIBLE		0x80 /* invisible by default in dump */
74 #define TCQ_F_NOLOCK		0x100 /* qdisc does not require locking */
75 #define TCQ_F_OFFLOADED		0x200 /* qdisc is offloaded to HW */
76 	u32			limit;
77 	const struct Qdisc_ops	*ops;
78 	struct qdisc_size_table	__rcu *stab;
79 	struct hlist_node       hash;
80 	u32			handle;
81 	u32			parent;
82 
83 	struct netdev_queue	*dev_queue;
84 
85 	struct net_rate_estimator __rcu *rate_est;
86 	struct gnet_stats_basic_cpu __percpu *cpu_bstats;
87 	struct gnet_stats_queue	__percpu *cpu_qstats;
88 
89 	/*
90 	 * For performance sake on SMP, we put highly modified fields at the end
91 	 */
92 	struct sk_buff_head	gso_skb ____cacheline_aligned_in_smp;
93 	struct qdisc_skb_head	q;
94 	struct gnet_stats_basic_packed bstats;
95 	seqcount_t		running;
96 	struct gnet_stats_queue	qstats;
97 	unsigned long		state;
98 	struct Qdisc            *next_sched;
99 	struct sk_buff_head	skb_bad_txq;
100 	int			padded;
101 	refcount_t		refcnt;
102 
103 	spinlock_t		busylock ____cacheline_aligned_in_smp;
104 };
105 
106 static inline void qdisc_refcount_inc(struct Qdisc *qdisc)
107 {
108 	if (qdisc->flags & TCQ_F_BUILTIN)
109 		return;
110 	refcount_inc(&qdisc->refcnt);
111 }
112 
113 static inline bool qdisc_is_running(const struct Qdisc *qdisc)
114 {
115 	return (raw_read_seqcount(&qdisc->running) & 1) ? true : false;
116 }
117 
118 static inline bool qdisc_run_begin(struct Qdisc *qdisc)
119 {
120 	if (qdisc_is_running(qdisc))
121 		return false;
122 	/* Variant of write_seqcount_begin() telling lockdep a trylock
123 	 * was attempted.
124 	 */
125 	raw_write_seqcount_begin(&qdisc->running);
126 	seqcount_acquire(&qdisc->running.dep_map, 0, 1, _RET_IP_);
127 	return true;
128 }
129 
130 static inline void qdisc_run_end(struct Qdisc *qdisc)
131 {
132 	write_seqcount_end(&qdisc->running);
133 }
134 
135 static inline bool qdisc_may_bulk(const struct Qdisc *qdisc)
136 {
137 	return qdisc->flags & TCQ_F_ONETXQUEUE;
138 }
139 
140 static inline int qdisc_avail_bulklimit(const struct netdev_queue *txq)
141 {
142 #ifdef CONFIG_BQL
143 	/* Non-BQL migrated drivers will return 0, too. */
144 	return dql_avail(&txq->dql);
145 #else
146 	return 0;
147 #endif
148 }
149 
150 struct Qdisc_class_ops {
151 	/* Child qdisc manipulation */
152 	struct netdev_queue *	(*select_queue)(struct Qdisc *, struct tcmsg *);
153 	int			(*graft)(struct Qdisc *, unsigned long cl,
154 					struct Qdisc *, struct Qdisc **,
155 					struct netlink_ext_ack *extack);
156 	struct Qdisc *		(*leaf)(struct Qdisc *, unsigned long cl);
157 	void			(*qlen_notify)(struct Qdisc *, unsigned long);
158 
159 	/* Class manipulation routines */
160 	unsigned long		(*find)(struct Qdisc *, u32 classid);
161 	int			(*change)(struct Qdisc *, u32, u32,
162 					struct nlattr **, unsigned long *,
163 					struct netlink_ext_ack *);
164 	int			(*delete)(struct Qdisc *, unsigned long);
165 	void			(*walk)(struct Qdisc *, struct qdisc_walker * arg);
166 
167 	/* Filter manipulation */
168 	struct tcf_block *	(*tcf_block)(struct Qdisc *sch,
169 					     unsigned long arg,
170 					     struct netlink_ext_ack *extack);
171 	unsigned long		(*bind_tcf)(struct Qdisc *, unsigned long,
172 					u32 classid);
173 	void			(*unbind_tcf)(struct Qdisc *, unsigned long);
174 
175 	/* rtnetlink specific */
176 	int			(*dump)(struct Qdisc *, unsigned long,
177 					struct sk_buff *skb, struct tcmsg*);
178 	int			(*dump_stats)(struct Qdisc *, unsigned long,
179 					struct gnet_dump *);
180 };
181 
182 struct Qdisc_ops {
183 	struct Qdisc_ops	*next;
184 	const struct Qdisc_class_ops	*cl_ops;
185 	char			id[IFNAMSIZ];
186 	int			priv_size;
187 	unsigned int		static_flags;
188 
189 	int 			(*enqueue)(struct sk_buff *skb,
190 					   struct Qdisc *sch,
191 					   struct sk_buff **to_free);
192 	struct sk_buff *	(*dequeue)(struct Qdisc *);
193 	struct sk_buff *	(*peek)(struct Qdisc *);
194 
195 	int			(*init)(struct Qdisc *sch, struct nlattr *arg,
196 					struct netlink_ext_ack *extack);
197 	void			(*reset)(struct Qdisc *);
198 	void			(*destroy)(struct Qdisc *);
199 	int			(*change)(struct Qdisc *sch,
200 					  struct nlattr *arg,
201 					  struct netlink_ext_ack *extack);
202 	void			(*attach)(struct Qdisc *sch);
203 
204 	int			(*dump)(struct Qdisc *, struct sk_buff *);
205 	int			(*dump_stats)(struct Qdisc *, struct gnet_dump *);
206 
207 	struct module		*owner;
208 };
209 
210 
211 struct tcf_result {
212 	union {
213 		struct {
214 			unsigned long	class;
215 			u32		classid;
216 		};
217 		const struct tcf_proto *goto_tp;
218 	};
219 };
220 
221 struct tcf_proto_ops {
222 	struct list_head	head;
223 	char			kind[IFNAMSIZ];
224 
225 	int			(*classify)(struct sk_buff *,
226 					    const struct tcf_proto *,
227 					    struct tcf_result *);
228 	int			(*init)(struct tcf_proto*);
229 	void			(*destroy)(struct tcf_proto*);
230 
231 	void*			(*get)(struct tcf_proto*, u32 handle);
232 	int			(*change)(struct net *net, struct sk_buff *,
233 					struct tcf_proto*, unsigned long,
234 					u32 handle, struct nlattr **,
235 					void **, bool);
236 	int			(*delete)(struct tcf_proto*, void *, bool*);
237 	void			(*walk)(struct tcf_proto*, struct tcf_walker *arg);
238 	void			(*bind_class)(void *, u32, unsigned long);
239 
240 	/* rtnetlink specific */
241 	int			(*dump)(struct net*, struct tcf_proto*, void *,
242 					struct sk_buff *skb, struct tcmsg*);
243 
244 	struct module		*owner;
245 };
246 
247 struct tcf_proto {
248 	/* Fast access part */
249 	struct tcf_proto __rcu	*next;
250 	void __rcu		*root;
251 	int			(*classify)(struct sk_buff *,
252 					    const struct tcf_proto *,
253 					    struct tcf_result *);
254 	__be16			protocol;
255 
256 	/* All the rest */
257 	u32			prio;
258 	u32			classid;
259 	struct Qdisc		*q;
260 	void			*data;
261 	const struct tcf_proto_ops	*ops;
262 	struct tcf_chain	*chain;
263 	struct rcu_head		rcu;
264 };
265 
266 struct qdisc_skb_cb {
267 	unsigned int		pkt_len;
268 	u16			slave_dev_queue_mapping;
269 	u16			tc_classid;
270 #define QDISC_CB_PRIV_LEN 20
271 	unsigned char		data[QDISC_CB_PRIV_LEN];
272 };
273 
274 typedef void tcf_chain_head_change_t(struct tcf_proto *tp_head, void *priv);
275 
276 struct tcf_chain {
277 	struct tcf_proto __rcu *filter_chain;
278 	tcf_chain_head_change_t *chain_head_change;
279 	void *chain_head_change_priv;
280 	struct list_head list;
281 	struct tcf_block *block;
282 	u32 index; /* chain index */
283 	unsigned int refcnt;
284 };
285 
286 struct tcf_block {
287 	struct list_head chain_list;
288 	struct net *net;
289 	struct Qdisc *q;
290 	struct list_head cb_list;
291 };
292 
293 static inline void qdisc_cb_private_validate(const struct sk_buff *skb, int sz)
294 {
295 	struct qdisc_skb_cb *qcb;
296 
297 	BUILD_BUG_ON(sizeof(skb->cb) < offsetof(struct qdisc_skb_cb, data) + sz);
298 	BUILD_BUG_ON(sizeof(qcb->data) < sz);
299 }
300 
301 static inline int qdisc_qlen_cpu(const struct Qdisc *q)
302 {
303 	return this_cpu_ptr(q->cpu_qstats)->qlen;
304 }
305 
306 static inline int qdisc_qlen(const struct Qdisc *q)
307 {
308 	return q->q.qlen;
309 }
310 
311 static inline int qdisc_qlen_sum(const struct Qdisc *q)
312 {
313 	__u32 qlen = 0;
314 	int i;
315 
316 	if (q->flags & TCQ_F_NOLOCK) {
317 		for_each_possible_cpu(i)
318 			qlen += per_cpu_ptr(q->cpu_qstats, i)->qlen;
319 	} else {
320 		qlen = q->q.qlen;
321 	}
322 
323 	return qlen;
324 }
325 
326 static inline struct qdisc_skb_cb *qdisc_skb_cb(const struct sk_buff *skb)
327 {
328 	return (struct qdisc_skb_cb *)skb->cb;
329 }
330 
331 static inline spinlock_t *qdisc_lock(struct Qdisc *qdisc)
332 {
333 	return &qdisc->q.lock;
334 }
335 
336 static inline struct Qdisc *qdisc_root(const struct Qdisc *qdisc)
337 {
338 	struct Qdisc *q = rcu_dereference_rtnl(qdisc->dev_queue->qdisc);
339 
340 	return q;
341 }
342 
343 static inline struct Qdisc *qdisc_root_sleeping(const struct Qdisc *qdisc)
344 {
345 	return qdisc->dev_queue->qdisc_sleeping;
346 }
347 
348 /* The qdisc root lock is a mechanism by which to top level
349  * of a qdisc tree can be locked from any qdisc node in the
350  * forest.  This allows changing the configuration of some
351  * aspect of the qdisc tree while blocking out asynchronous
352  * qdisc access in the packet processing paths.
353  *
354  * It is only legal to do this when the root will not change
355  * on us.  Otherwise we'll potentially lock the wrong qdisc
356  * root.  This is enforced by holding the RTNL semaphore, which
357  * all users of this lock accessor must do.
358  */
359 static inline spinlock_t *qdisc_root_lock(const struct Qdisc *qdisc)
360 {
361 	struct Qdisc *root = qdisc_root(qdisc);
362 
363 	ASSERT_RTNL();
364 	return qdisc_lock(root);
365 }
366 
367 static inline spinlock_t *qdisc_root_sleeping_lock(const struct Qdisc *qdisc)
368 {
369 	struct Qdisc *root = qdisc_root_sleeping(qdisc);
370 
371 	ASSERT_RTNL();
372 	return qdisc_lock(root);
373 }
374 
375 static inline seqcount_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc)
376 {
377 	struct Qdisc *root = qdisc_root_sleeping(qdisc);
378 
379 	ASSERT_RTNL();
380 	return &root->running;
381 }
382 
383 static inline struct net_device *qdisc_dev(const struct Qdisc *qdisc)
384 {
385 	return qdisc->dev_queue->dev;
386 }
387 
388 static inline void sch_tree_lock(const struct Qdisc *q)
389 {
390 	spin_lock_bh(qdisc_root_sleeping_lock(q));
391 }
392 
393 static inline void sch_tree_unlock(const struct Qdisc *q)
394 {
395 	spin_unlock_bh(qdisc_root_sleeping_lock(q));
396 }
397 
398 extern struct Qdisc noop_qdisc;
399 extern struct Qdisc_ops noop_qdisc_ops;
400 extern struct Qdisc_ops pfifo_fast_ops;
401 extern struct Qdisc_ops mq_qdisc_ops;
402 extern struct Qdisc_ops noqueue_qdisc_ops;
403 extern const struct Qdisc_ops *default_qdisc_ops;
404 static inline const struct Qdisc_ops *
405 get_default_qdisc_ops(const struct net_device *dev, int ntx)
406 {
407 	return ntx < dev->real_num_tx_queues ?
408 			default_qdisc_ops : &pfifo_fast_ops;
409 }
410 
411 struct Qdisc_class_common {
412 	u32			classid;
413 	struct hlist_node	hnode;
414 };
415 
416 struct Qdisc_class_hash {
417 	struct hlist_head	*hash;
418 	unsigned int		hashsize;
419 	unsigned int		hashmask;
420 	unsigned int		hashelems;
421 };
422 
423 static inline unsigned int qdisc_class_hash(u32 id, u32 mask)
424 {
425 	id ^= id >> 8;
426 	id ^= id >> 4;
427 	return id & mask;
428 }
429 
430 static inline struct Qdisc_class_common *
431 qdisc_class_find(const struct Qdisc_class_hash *hash, u32 id)
432 {
433 	struct Qdisc_class_common *cl;
434 	unsigned int h;
435 
436 	if (!id)
437 		return NULL;
438 
439 	h = qdisc_class_hash(id, hash->hashmask);
440 	hlist_for_each_entry(cl, &hash->hash[h], hnode) {
441 		if (cl->classid == id)
442 			return cl;
443 	}
444 	return NULL;
445 }
446 
447 static inline int tc_classid_to_hwtc(struct net_device *dev, u32 classid)
448 {
449 	u32 hwtc = TC_H_MIN(classid) - TC_H_MIN_PRIORITY;
450 
451 	return (hwtc < netdev_get_num_tc(dev)) ? hwtc : -EINVAL;
452 }
453 
454 int qdisc_class_hash_init(struct Qdisc_class_hash *);
455 void qdisc_class_hash_insert(struct Qdisc_class_hash *,
456 			     struct Qdisc_class_common *);
457 void qdisc_class_hash_remove(struct Qdisc_class_hash *,
458 			     struct Qdisc_class_common *);
459 void qdisc_class_hash_grow(struct Qdisc *, struct Qdisc_class_hash *);
460 void qdisc_class_hash_destroy(struct Qdisc_class_hash *);
461 
462 void dev_init_scheduler(struct net_device *dev);
463 void dev_shutdown(struct net_device *dev);
464 void dev_activate(struct net_device *dev);
465 void dev_deactivate(struct net_device *dev);
466 void dev_deactivate_many(struct list_head *head);
467 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
468 			      struct Qdisc *qdisc);
469 void qdisc_reset(struct Qdisc *qdisc);
470 void qdisc_destroy(struct Qdisc *qdisc);
471 void qdisc_tree_reduce_backlog(struct Qdisc *qdisc, unsigned int n,
472 			       unsigned int len);
473 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
474 			  const struct Qdisc_ops *ops,
475 			  struct netlink_ext_ack *extack);
476 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
477 				const struct Qdisc_ops *ops, u32 parentid,
478 				struct netlink_ext_ack *extack);
479 void __qdisc_calculate_pkt_len(struct sk_buff *skb,
480 			       const struct qdisc_size_table *stab);
481 int skb_do_redirect(struct sk_buff *);
482 
483 static inline void skb_reset_tc(struct sk_buff *skb)
484 {
485 #ifdef CONFIG_NET_CLS_ACT
486 	skb->tc_redirected = 0;
487 #endif
488 }
489 
490 static inline bool skb_at_tc_ingress(const struct sk_buff *skb)
491 {
492 #ifdef CONFIG_NET_CLS_ACT
493 	return skb->tc_at_ingress;
494 #else
495 	return false;
496 #endif
497 }
498 
499 static inline bool skb_skip_tc_classify(struct sk_buff *skb)
500 {
501 #ifdef CONFIG_NET_CLS_ACT
502 	if (skb->tc_skip_classify) {
503 		skb->tc_skip_classify = 0;
504 		return true;
505 	}
506 #endif
507 	return false;
508 }
509 
510 /* Reset all TX qdiscs greater then index of a device.  */
511 static inline void qdisc_reset_all_tx_gt(struct net_device *dev, unsigned int i)
512 {
513 	struct Qdisc *qdisc;
514 
515 	for (; i < dev->num_tx_queues; i++) {
516 		qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc);
517 		if (qdisc) {
518 			spin_lock_bh(qdisc_lock(qdisc));
519 			qdisc_reset(qdisc);
520 			spin_unlock_bh(qdisc_lock(qdisc));
521 		}
522 	}
523 }
524 
525 static inline void qdisc_reset_all_tx(struct net_device *dev)
526 {
527 	qdisc_reset_all_tx_gt(dev, 0);
528 }
529 
530 /* Are all TX queues of the device empty?  */
531 static inline bool qdisc_all_tx_empty(const struct net_device *dev)
532 {
533 	unsigned int i;
534 
535 	rcu_read_lock();
536 	for (i = 0; i < dev->num_tx_queues; i++) {
537 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
538 		const struct Qdisc *q = rcu_dereference(txq->qdisc);
539 
540 		if (q->q.qlen) {
541 			rcu_read_unlock();
542 			return false;
543 		}
544 	}
545 	rcu_read_unlock();
546 	return true;
547 }
548 
549 /* Are any of the TX qdiscs changing?  */
550 static inline bool qdisc_tx_changing(const struct net_device *dev)
551 {
552 	unsigned int i;
553 
554 	for (i = 0; i < dev->num_tx_queues; i++) {
555 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
556 		if (rcu_access_pointer(txq->qdisc) != txq->qdisc_sleeping)
557 			return true;
558 	}
559 	return false;
560 }
561 
562 /* Is the device using the noop qdisc on all queues?  */
563 static inline bool qdisc_tx_is_noop(const struct net_device *dev)
564 {
565 	unsigned int i;
566 
567 	for (i = 0; i < dev->num_tx_queues; i++) {
568 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
569 		if (rcu_access_pointer(txq->qdisc) != &noop_qdisc)
570 			return false;
571 	}
572 	return true;
573 }
574 
575 static inline unsigned int qdisc_pkt_len(const struct sk_buff *skb)
576 {
577 	return qdisc_skb_cb(skb)->pkt_len;
578 }
579 
580 /* additional qdisc xmit flags (NET_XMIT_MASK in linux/netdevice.h) */
581 enum net_xmit_qdisc_t {
582 	__NET_XMIT_STOLEN = 0x00010000,
583 	__NET_XMIT_BYPASS = 0x00020000,
584 };
585 
586 #ifdef CONFIG_NET_CLS_ACT
587 #define net_xmit_drop_count(e)	((e) & __NET_XMIT_STOLEN ? 0 : 1)
588 #else
589 #define net_xmit_drop_count(e)	(1)
590 #endif
591 
592 static inline void qdisc_calculate_pkt_len(struct sk_buff *skb,
593 					   const struct Qdisc *sch)
594 {
595 #ifdef CONFIG_NET_SCHED
596 	struct qdisc_size_table *stab = rcu_dereference_bh(sch->stab);
597 
598 	if (stab)
599 		__qdisc_calculate_pkt_len(skb, stab);
600 #endif
601 }
602 
603 static inline int qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch,
604 				struct sk_buff **to_free)
605 {
606 	qdisc_calculate_pkt_len(skb, sch);
607 	return sch->enqueue(skb, sch, to_free);
608 }
609 
610 static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
611 {
612 	return q->flags & TCQ_F_CPUSTATS;
613 }
614 
615 static inline void _bstats_update(struct gnet_stats_basic_packed *bstats,
616 				  __u64 bytes, __u32 packets)
617 {
618 	bstats->bytes += bytes;
619 	bstats->packets += packets;
620 }
621 
622 static inline void bstats_update(struct gnet_stats_basic_packed *bstats,
623 				 const struct sk_buff *skb)
624 {
625 	_bstats_update(bstats,
626 		       qdisc_pkt_len(skb),
627 		       skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 1);
628 }
629 
630 static inline void _bstats_cpu_update(struct gnet_stats_basic_cpu *bstats,
631 				      __u64 bytes, __u32 packets)
632 {
633 	u64_stats_update_begin(&bstats->syncp);
634 	_bstats_update(&bstats->bstats, bytes, packets);
635 	u64_stats_update_end(&bstats->syncp);
636 }
637 
638 static inline void bstats_cpu_update(struct gnet_stats_basic_cpu *bstats,
639 				     const struct sk_buff *skb)
640 {
641 	u64_stats_update_begin(&bstats->syncp);
642 	bstats_update(&bstats->bstats, skb);
643 	u64_stats_update_end(&bstats->syncp);
644 }
645 
646 static inline void qdisc_bstats_cpu_update(struct Qdisc *sch,
647 					   const struct sk_buff *skb)
648 {
649 	bstats_cpu_update(this_cpu_ptr(sch->cpu_bstats), skb);
650 }
651 
652 static inline void qdisc_bstats_update(struct Qdisc *sch,
653 				       const struct sk_buff *skb)
654 {
655 	bstats_update(&sch->bstats, skb);
656 }
657 
658 static inline void qdisc_qstats_backlog_dec(struct Qdisc *sch,
659 					    const struct sk_buff *skb)
660 {
661 	sch->qstats.backlog -= qdisc_pkt_len(skb);
662 }
663 
664 static inline void qdisc_qstats_cpu_backlog_dec(struct Qdisc *sch,
665 						const struct sk_buff *skb)
666 {
667 	this_cpu_sub(sch->cpu_qstats->backlog, qdisc_pkt_len(skb));
668 }
669 
670 static inline void qdisc_qstats_backlog_inc(struct Qdisc *sch,
671 					    const struct sk_buff *skb)
672 {
673 	sch->qstats.backlog += qdisc_pkt_len(skb);
674 }
675 
676 static inline void qdisc_qstats_cpu_backlog_inc(struct Qdisc *sch,
677 						const struct sk_buff *skb)
678 {
679 	this_cpu_add(sch->cpu_qstats->backlog, qdisc_pkt_len(skb));
680 }
681 
682 static inline void qdisc_qstats_cpu_qlen_inc(struct Qdisc *sch)
683 {
684 	this_cpu_inc(sch->cpu_qstats->qlen);
685 }
686 
687 static inline void qdisc_qstats_cpu_qlen_dec(struct Qdisc *sch)
688 {
689 	this_cpu_dec(sch->cpu_qstats->qlen);
690 }
691 
692 static inline void qdisc_qstats_cpu_requeues_inc(struct Qdisc *sch)
693 {
694 	this_cpu_inc(sch->cpu_qstats->requeues);
695 }
696 
697 static inline void __qdisc_qstats_drop(struct Qdisc *sch, int count)
698 {
699 	sch->qstats.drops += count;
700 }
701 
702 static inline void qstats_drop_inc(struct gnet_stats_queue *qstats)
703 {
704 	qstats->drops++;
705 }
706 
707 static inline void qstats_overlimit_inc(struct gnet_stats_queue *qstats)
708 {
709 	qstats->overlimits++;
710 }
711 
712 static inline void qdisc_qstats_drop(struct Qdisc *sch)
713 {
714 	qstats_drop_inc(&sch->qstats);
715 }
716 
717 static inline void qdisc_qstats_cpu_drop(struct Qdisc *sch)
718 {
719 	this_cpu_inc(sch->cpu_qstats->drops);
720 }
721 
722 static inline void qdisc_qstats_overlimit(struct Qdisc *sch)
723 {
724 	sch->qstats.overlimits++;
725 }
726 
727 static inline void qdisc_skb_head_init(struct qdisc_skb_head *qh)
728 {
729 	qh->head = NULL;
730 	qh->tail = NULL;
731 	qh->qlen = 0;
732 }
733 
734 static inline int __qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch,
735 				       struct qdisc_skb_head *qh)
736 {
737 	struct sk_buff *last = qh->tail;
738 
739 	if (last) {
740 		skb->next = NULL;
741 		last->next = skb;
742 		qh->tail = skb;
743 	} else {
744 		qh->tail = skb;
745 		qh->head = skb;
746 	}
747 	qh->qlen++;
748 	qdisc_qstats_backlog_inc(sch, skb);
749 
750 	return NET_XMIT_SUCCESS;
751 }
752 
753 static inline int qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch)
754 {
755 	return __qdisc_enqueue_tail(skb, sch, &sch->q);
756 }
757 
758 static inline struct sk_buff *__qdisc_dequeue_head(struct qdisc_skb_head *qh)
759 {
760 	struct sk_buff *skb = qh->head;
761 
762 	if (likely(skb != NULL)) {
763 		qh->head = skb->next;
764 		qh->qlen--;
765 		if (qh->head == NULL)
766 			qh->tail = NULL;
767 		skb->next = NULL;
768 	}
769 
770 	return skb;
771 }
772 
773 static inline struct sk_buff *qdisc_dequeue_head(struct Qdisc *sch)
774 {
775 	struct sk_buff *skb = __qdisc_dequeue_head(&sch->q);
776 
777 	if (likely(skb != NULL)) {
778 		qdisc_qstats_backlog_dec(sch, skb);
779 		qdisc_bstats_update(sch, skb);
780 	}
781 
782 	return skb;
783 }
784 
785 /* Instead of calling kfree_skb() while root qdisc lock is held,
786  * queue the skb for future freeing at end of __dev_xmit_skb()
787  */
788 static inline void __qdisc_drop(struct sk_buff *skb, struct sk_buff **to_free)
789 {
790 	skb->next = *to_free;
791 	*to_free = skb;
792 }
793 
794 static inline unsigned int __qdisc_queue_drop_head(struct Qdisc *sch,
795 						   struct qdisc_skb_head *qh,
796 						   struct sk_buff **to_free)
797 {
798 	struct sk_buff *skb = __qdisc_dequeue_head(qh);
799 
800 	if (likely(skb != NULL)) {
801 		unsigned int len = qdisc_pkt_len(skb);
802 
803 		qdisc_qstats_backlog_dec(sch, skb);
804 		__qdisc_drop(skb, to_free);
805 		return len;
806 	}
807 
808 	return 0;
809 }
810 
811 static inline unsigned int qdisc_queue_drop_head(struct Qdisc *sch,
812 						 struct sk_buff **to_free)
813 {
814 	return __qdisc_queue_drop_head(sch, &sch->q, to_free);
815 }
816 
817 static inline struct sk_buff *qdisc_peek_head(struct Qdisc *sch)
818 {
819 	const struct qdisc_skb_head *qh = &sch->q;
820 
821 	return qh->head;
822 }
823 
824 /* generic pseudo peek method for non-work-conserving qdisc */
825 static inline struct sk_buff *qdisc_peek_dequeued(struct Qdisc *sch)
826 {
827 	struct sk_buff *skb = skb_peek(&sch->gso_skb);
828 
829 	/* we can reuse ->gso_skb because peek isn't called for root qdiscs */
830 	if (!skb) {
831 		skb = sch->dequeue(sch);
832 
833 		if (skb) {
834 			__skb_queue_head(&sch->gso_skb, skb);
835 			/* it's still part of the queue */
836 			qdisc_qstats_backlog_inc(sch, skb);
837 			sch->q.qlen++;
838 		}
839 	}
840 
841 	return skb;
842 }
843 
844 /* use instead of qdisc->dequeue() for all qdiscs queried with ->peek() */
845 static inline struct sk_buff *qdisc_dequeue_peeked(struct Qdisc *sch)
846 {
847 	struct sk_buff *skb = skb_peek(&sch->gso_skb);
848 
849 	if (skb) {
850 		skb = __skb_dequeue(&sch->gso_skb);
851 		qdisc_qstats_backlog_dec(sch, skb);
852 		sch->q.qlen--;
853 	} else {
854 		skb = sch->dequeue(sch);
855 	}
856 
857 	return skb;
858 }
859 
860 static inline void __qdisc_reset_queue(struct qdisc_skb_head *qh)
861 {
862 	/*
863 	 * We do not know the backlog in bytes of this list, it
864 	 * is up to the caller to correct it
865 	 */
866 	ASSERT_RTNL();
867 	if (qh->qlen) {
868 		rtnl_kfree_skbs(qh->head, qh->tail);
869 
870 		qh->head = NULL;
871 		qh->tail = NULL;
872 		qh->qlen = 0;
873 	}
874 }
875 
876 static inline void qdisc_reset_queue(struct Qdisc *sch)
877 {
878 	__qdisc_reset_queue(&sch->q);
879 	sch->qstats.backlog = 0;
880 }
881 
882 static inline struct Qdisc *qdisc_replace(struct Qdisc *sch, struct Qdisc *new,
883 					  struct Qdisc **pold)
884 {
885 	struct Qdisc *old;
886 
887 	sch_tree_lock(sch);
888 	old = *pold;
889 	*pold = new;
890 	if (old != NULL) {
891 		unsigned int qlen = old->q.qlen;
892 		unsigned int backlog = old->qstats.backlog;
893 
894 		qdisc_reset(old);
895 		qdisc_tree_reduce_backlog(old, qlen, backlog);
896 	}
897 	sch_tree_unlock(sch);
898 
899 	return old;
900 }
901 
902 static inline void rtnl_qdisc_drop(struct sk_buff *skb, struct Qdisc *sch)
903 {
904 	rtnl_kfree_skbs(skb, skb);
905 	qdisc_qstats_drop(sch);
906 }
907 
908 static inline int qdisc_drop_cpu(struct sk_buff *skb, struct Qdisc *sch,
909 				 struct sk_buff **to_free)
910 {
911 	__qdisc_drop(skb, to_free);
912 	qdisc_qstats_cpu_drop(sch);
913 
914 	return NET_XMIT_DROP;
915 }
916 
917 static inline int qdisc_drop(struct sk_buff *skb, struct Qdisc *sch,
918 			     struct sk_buff **to_free)
919 {
920 	__qdisc_drop(skb, to_free);
921 	qdisc_qstats_drop(sch);
922 
923 	return NET_XMIT_DROP;
924 }
925 
926 /* Length to Time (L2T) lookup in a qdisc_rate_table, to determine how
927    long it will take to send a packet given its size.
928  */
929 static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen)
930 {
931 	int slot = pktlen + rtab->rate.cell_align + rtab->rate.overhead;
932 	if (slot < 0)
933 		slot = 0;
934 	slot >>= rtab->rate.cell_log;
935 	if (slot > 255)
936 		return rtab->data[255]*(slot >> 8) + rtab->data[slot & 0xFF];
937 	return rtab->data[slot];
938 }
939 
940 struct psched_ratecfg {
941 	u64	rate_bytes_ps; /* bytes per second */
942 	u32	mult;
943 	u16	overhead;
944 	u8	linklayer;
945 	u8	shift;
946 };
947 
948 static inline u64 psched_l2t_ns(const struct psched_ratecfg *r,
949 				unsigned int len)
950 {
951 	len += r->overhead;
952 
953 	if (unlikely(r->linklayer == TC_LINKLAYER_ATM))
954 		return ((u64)(DIV_ROUND_UP(len,48)*53) * r->mult) >> r->shift;
955 
956 	return ((u64)len * r->mult) >> r->shift;
957 }
958 
959 void psched_ratecfg_precompute(struct psched_ratecfg *r,
960 			       const struct tc_ratespec *conf,
961 			       u64 rate64);
962 
963 static inline void psched_ratecfg_getrate(struct tc_ratespec *res,
964 					  const struct psched_ratecfg *r)
965 {
966 	memset(res, 0, sizeof(*res));
967 
968 	/* legacy struct tc_ratespec has a 32bit @rate field
969 	 * Qdisc using 64bit rate should add new attributes
970 	 * in order to maintain compatibility.
971 	 */
972 	res->rate = min_t(u64, r->rate_bytes_ps, ~0U);
973 
974 	res->overhead = r->overhead;
975 	res->linklayer = (r->linklayer & TC_LINKLAYER_MASK);
976 }
977 
978 /* Mini Qdisc serves for specific needs of ingress/clsact Qdisc.
979  * The fast path only needs to access filter list and to update stats
980  */
981 struct mini_Qdisc {
982 	struct tcf_proto *filter_list;
983 	struct gnet_stats_basic_cpu __percpu *cpu_bstats;
984 	struct gnet_stats_queue	__percpu *cpu_qstats;
985 	struct rcu_head rcu;
986 };
987 
988 static inline void mini_qdisc_bstats_cpu_update(struct mini_Qdisc *miniq,
989 						const struct sk_buff *skb)
990 {
991 	bstats_cpu_update(this_cpu_ptr(miniq->cpu_bstats), skb);
992 }
993 
994 static inline void mini_qdisc_qstats_cpu_drop(struct mini_Qdisc *miniq)
995 {
996 	this_cpu_inc(miniq->cpu_qstats->drops);
997 }
998 
999 struct mini_Qdisc_pair {
1000 	struct mini_Qdisc miniq1;
1001 	struct mini_Qdisc miniq2;
1002 	struct mini_Qdisc __rcu **p_miniq;
1003 };
1004 
1005 void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp,
1006 			  struct tcf_proto *tp_head);
1007 void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,
1008 			  struct mini_Qdisc __rcu **p_miniq);
1009 
1010 #endif
1011