xref: /openbmc/linux/include/net/sch_generic.h (revision 03cb0503)
1 #ifndef __NET_SCHED_GENERIC_H
2 #define __NET_SCHED_GENERIC_H
3 
4 #include <linux/netdevice.h>
5 #include <linux/types.h>
6 #include <linux/rcupdate.h>
7 #include <linux/pkt_sched.h>
8 #include <linux/pkt_cls.h>
9 #include <linux/percpu.h>
10 #include <linux/dynamic_queue_limits.h>
11 #include <net/gen_stats.h>
12 #include <net/rtnetlink.h>
13 
14 struct Qdisc_ops;
15 struct qdisc_walker;
16 struct tcf_walker;
17 struct module;
18 
19 struct qdisc_rate_table {
20 	struct tc_ratespec rate;
21 	u32		data[256];
22 	struct qdisc_rate_table *next;
23 	int		refcnt;
24 };
25 
26 enum qdisc_state_t {
27 	__QDISC_STATE_SCHED,
28 	__QDISC_STATE_DEACTIVATED,
29 	__QDISC_STATE_THROTTLED,
30 };
31 
32 /*
33  * following bits are only changed while qdisc lock is held
34  */
35 enum qdisc___state_t {
36 	__QDISC___STATE_RUNNING = 1,
37 };
38 
39 struct qdisc_size_table {
40 	struct rcu_head		rcu;
41 	struct list_head	list;
42 	struct tc_sizespec	szopts;
43 	int			refcnt;
44 	u16			data[];
45 };
46 
47 struct Qdisc {
48 	int 			(*enqueue)(struct sk_buff *skb, struct Qdisc *dev);
49 	struct sk_buff *	(*dequeue)(struct Qdisc *dev);
50 	unsigned int		flags;
51 #define TCQ_F_BUILTIN		1
52 #define TCQ_F_INGRESS		2
53 #define TCQ_F_CAN_BYPASS	4
54 #define TCQ_F_MQROOT		8
55 #define TCQ_F_ONETXQUEUE	0x10 /* dequeue_skb() can assume all skbs are for
56 				      * q->dev_queue : It can test
57 				      * netif_xmit_frozen_or_stopped() before
58 				      * dequeueing next packet.
59 				      * Its true for MQ/MQPRIO slaves, or non
60 				      * multiqueue device.
61 				      */
62 #define TCQ_F_WARN_NONWC	(1 << 16)
63 #define TCQ_F_CPUSTATS		0x20 /* run using percpu statistics */
64 	u32			limit;
65 	const struct Qdisc_ops	*ops;
66 	struct qdisc_size_table	__rcu *stab;
67 	struct list_head	list;
68 	u32			handle;
69 	u32			parent;
70 	int			(*reshape_fail)(struct sk_buff *skb,
71 					struct Qdisc *q);
72 
73 	void			*u32_node;
74 
75 	/* This field is deprecated, but it is still used by CBQ
76 	 * and it will live until better solution will be invented.
77 	 */
78 	struct Qdisc		*__parent;
79 	struct netdev_queue	*dev_queue;
80 
81 	struct gnet_stats_rate_est64	rate_est;
82 	struct gnet_stats_basic_cpu __percpu *cpu_bstats;
83 	struct gnet_stats_queue	__percpu *cpu_qstats;
84 
85 	struct Qdisc		*next_sched;
86 	struct sk_buff		*gso_skb;
87 	/*
88 	 * For performance sake on SMP, we put highly modified fields at the end
89 	 */
90 	unsigned long		state;
91 	struct sk_buff_head	q;
92 	struct gnet_stats_basic_packed bstats;
93 	unsigned int		__state;
94 	struct gnet_stats_queue	qstats;
95 	struct rcu_head		rcu_head;
96 	int			padded;
97 	atomic_t		refcnt;
98 
99 	spinlock_t		busylock ____cacheline_aligned_in_smp;
100 };
101 
102 static inline bool qdisc_is_running(const struct Qdisc *qdisc)
103 {
104 	return (qdisc->__state & __QDISC___STATE_RUNNING) ? true : false;
105 }
106 
107 static inline bool qdisc_run_begin(struct Qdisc *qdisc)
108 {
109 	if (qdisc_is_running(qdisc))
110 		return false;
111 	qdisc->__state |= __QDISC___STATE_RUNNING;
112 	return true;
113 }
114 
115 static inline void qdisc_run_end(struct Qdisc *qdisc)
116 {
117 	qdisc->__state &= ~__QDISC___STATE_RUNNING;
118 }
119 
120 static inline bool qdisc_may_bulk(const struct Qdisc *qdisc)
121 {
122 	return qdisc->flags & TCQ_F_ONETXQUEUE;
123 }
124 
125 static inline int qdisc_avail_bulklimit(const struct netdev_queue *txq)
126 {
127 #ifdef CONFIG_BQL
128 	/* Non-BQL migrated drivers will return 0, too. */
129 	return dql_avail(&txq->dql);
130 #else
131 	return 0;
132 #endif
133 }
134 
135 static inline bool qdisc_is_throttled(const struct Qdisc *qdisc)
136 {
137 	return test_bit(__QDISC_STATE_THROTTLED, &qdisc->state) ? true : false;
138 }
139 
140 static inline void qdisc_throttled(struct Qdisc *qdisc)
141 {
142 	set_bit(__QDISC_STATE_THROTTLED, &qdisc->state);
143 }
144 
145 static inline void qdisc_unthrottled(struct Qdisc *qdisc)
146 {
147 	clear_bit(__QDISC_STATE_THROTTLED, &qdisc->state);
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 Qdisc *		(*leaf)(struct Qdisc *, unsigned long cl);
156 	void			(*qlen_notify)(struct Qdisc *, unsigned long);
157 
158 	/* Class manipulation routines */
159 	unsigned long		(*get)(struct Qdisc *, u32 classid);
160 	void			(*put)(struct Qdisc *, unsigned long);
161 	int			(*change)(struct Qdisc *, u32, u32,
162 					struct nlattr **, unsigned long *);
163 	int			(*delete)(struct Qdisc *, unsigned long);
164 	void			(*walk)(struct Qdisc *, struct qdisc_walker * arg);
165 
166 	/* Filter manipulation */
167 	struct tcf_proto __rcu ** (*tcf_chain)(struct Qdisc *, unsigned long);
168 	unsigned long		(*bind_tcf)(struct Qdisc *, unsigned long,
169 					u32 classid);
170 	void			(*unbind_tcf)(struct Qdisc *, unsigned long);
171 
172 	/* rtnetlink specific */
173 	int			(*dump)(struct Qdisc *, unsigned long,
174 					struct sk_buff *skb, struct tcmsg*);
175 	int			(*dump_stats)(struct Qdisc *, unsigned long,
176 					struct gnet_dump *);
177 };
178 
179 struct Qdisc_ops {
180 	struct Qdisc_ops	*next;
181 	const struct Qdisc_class_ops	*cl_ops;
182 	char			id[IFNAMSIZ];
183 	int			priv_size;
184 
185 	int 			(*enqueue)(struct sk_buff *, struct Qdisc *);
186 	struct sk_buff *	(*dequeue)(struct Qdisc *);
187 	struct sk_buff *	(*peek)(struct Qdisc *);
188 	unsigned int		(*drop)(struct Qdisc *);
189 
190 	int			(*init)(struct Qdisc *, struct nlattr *arg);
191 	void			(*reset)(struct Qdisc *);
192 	void			(*destroy)(struct Qdisc *);
193 	int			(*change)(struct Qdisc *, struct nlattr *arg);
194 	void			(*attach)(struct Qdisc *);
195 
196 	int			(*dump)(struct Qdisc *, struct sk_buff *);
197 	int			(*dump_stats)(struct Qdisc *, struct gnet_dump *);
198 
199 	struct module		*owner;
200 };
201 
202 
203 struct tcf_result {
204 	unsigned long	class;
205 	u32		classid;
206 };
207 
208 struct tcf_proto_ops {
209 	struct list_head	head;
210 	char			kind[IFNAMSIZ];
211 
212 	int			(*classify)(struct sk_buff *,
213 					    const struct tcf_proto *,
214 					    struct tcf_result *);
215 	int			(*init)(struct tcf_proto*);
216 	bool			(*destroy)(struct tcf_proto*, bool);
217 
218 	unsigned long		(*get)(struct tcf_proto*, u32 handle);
219 	int			(*change)(struct net *net, struct sk_buff *,
220 					struct tcf_proto*, unsigned long,
221 					u32 handle, struct nlattr **,
222 					unsigned long *, bool);
223 	int			(*delete)(struct tcf_proto*, unsigned long);
224 	void			(*walk)(struct tcf_proto*, struct tcf_walker *arg);
225 
226 	/* rtnetlink specific */
227 	int			(*dump)(struct net*, struct tcf_proto*, unsigned long,
228 					struct sk_buff *skb, struct tcmsg*);
229 
230 	struct module		*owner;
231 };
232 
233 struct tcf_proto {
234 	/* Fast access part */
235 	struct tcf_proto __rcu	*next;
236 	void __rcu		*root;
237 	int			(*classify)(struct sk_buff *,
238 					    const struct tcf_proto *,
239 					    struct tcf_result *);
240 	__be16			protocol;
241 
242 	/* All the rest */
243 	u32			prio;
244 	u32			classid;
245 	struct Qdisc		*q;
246 	void			*data;
247 	const struct tcf_proto_ops	*ops;
248 	struct rcu_head		rcu;
249 };
250 
251 struct qdisc_skb_cb {
252 	unsigned int		pkt_len;
253 	u16			slave_dev_queue_mapping;
254 	u16			_pad;
255 #define QDISC_CB_PRIV_LEN 20
256 	unsigned char		data[QDISC_CB_PRIV_LEN];
257 };
258 
259 static inline void qdisc_cb_private_validate(const struct sk_buff *skb, int sz)
260 {
261 	struct qdisc_skb_cb *qcb;
262 
263 	BUILD_BUG_ON(sizeof(skb->cb) < offsetof(struct qdisc_skb_cb, data) + sz);
264 	BUILD_BUG_ON(sizeof(qcb->data) < sz);
265 }
266 
267 static inline int qdisc_qlen(const struct Qdisc *q)
268 {
269 	return q->q.qlen;
270 }
271 
272 static inline struct qdisc_skb_cb *qdisc_skb_cb(const struct sk_buff *skb)
273 {
274 	return (struct qdisc_skb_cb *)skb->cb;
275 }
276 
277 static inline spinlock_t *qdisc_lock(struct Qdisc *qdisc)
278 {
279 	return &qdisc->q.lock;
280 }
281 
282 static inline struct Qdisc *qdisc_root(const struct Qdisc *qdisc)
283 {
284 	struct Qdisc *q = rcu_dereference_rtnl(qdisc->dev_queue->qdisc);
285 
286 	return q;
287 }
288 
289 static inline struct Qdisc *qdisc_root_sleeping(const struct Qdisc *qdisc)
290 {
291 	return qdisc->dev_queue->qdisc_sleeping;
292 }
293 
294 /* The qdisc root lock is a mechanism by which to top level
295  * of a qdisc tree can be locked from any qdisc node in the
296  * forest.  This allows changing the configuration of some
297  * aspect of the qdisc tree while blocking out asynchronous
298  * qdisc access in the packet processing paths.
299  *
300  * It is only legal to do this when the root will not change
301  * on us.  Otherwise we'll potentially lock the wrong qdisc
302  * root.  This is enforced by holding the RTNL semaphore, which
303  * all users of this lock accessor must do.
304  */
305 static inline spinlock_t *qdisc_root_lock(const struct Qdisc *qdisc)
306 {
307 	struct Qdisc *root = qdisc_root(qdisc);
308 
309 	ASSERT_RTNL();
310 	return qdisc_lock(root);
311 }
312 
313 static inline spinlock_t *qdisc_root_sleeping_lock(const struct Qdisc *qdisc)
314 {
315 	struct Qdisc *root = qdisc_root_sleeping(qdisc);
316 
317 	ASSERT_RTNL();
318 	return qdisc_lock(root);
319 }
320 
321 static inline struct net_device *qdisc_dev(const struct Qdisc *qdisc)
322 {
323 	return qdisc->dev_queue->dev;
324 }
325 
326 static inline void sch_tree_lock(const struct Qdisc *q)
327 {
328 	spin_lock_bh(qdisc_root_sleeping_lock(q));
329 }
330 
331 static inline void sch_tree_unlock(const struct Qdisc *q)
332 {
333 	spin_unlock_bh(qdisc_root_sleeping_lock(q));
334 }
335 
336 #define tcf_tree_lock(tp)	sch_tree_lock((tp)->q)
337 #define tcf_tree_unlock(tp)	sch_tree_unlock((tp)->q)
338 
339 extern struct Qdisc noop_qdisc;
340 extern struct Qdisc_ops noop_qdisc_ops;
341 extern struct Qdisc_ops pfifo_fast_ops;
342 extern struct Qdisc_ops mq_qdisc_ops;
343 extern const struct Qdisc_ops *default_qdisc_ops;
344 
345 struct Qdisc_class_common {
346 	u32			classid;
347 	struct hlist_node	hnode;
348 };
349 
350 struct Qdisc_class_hash {
351 	struct hlist_head	*hash;
352 	unsigned int		hashsize;
353 	unsigned int		hashmask;
354 	unsigned int		hashelems;
355 };
356 
357 static inline unsigned int qdisc_class_hash(u32 id, u32 mask)
358 {
359 	id ^= id >> 8;
360 	id ^= id >> 4;
361 	return id & mask;
362 }
363 
364 static inline struct Qdisc_class_common *
365 qdisc_class_find(const struct Qdisc_class_hash *hash, u32 id)
366 {
367 	struct Qdisc_class_common *cl;
368 	unsigned int h;
369 
370 	h = qdisc_class_hash(id, hash->hashmask);
371 	hlist_for_each_entry(cl, &hash->hash[h], hnode) {
372 		if (cl->classid == id)
373 			return cl;
374 	}
375 	return NULL;
376 }
377 
378 int qdisc_class_hash_init(struct Qdisc_class_hash *);
379 void qdisc_class_hash_insert(struct Qdisc_class_hash *,
380 			     struct Qdisc_class_common *);
381 void qdisc_class_hash_remove(struct Qdisc_class_hash *,
382 			     struct Qdisc_class_common *);
383 void qdisc_class_hash_grow(struct Qdisc *, struct Qdisc_class_hash *);
384 void qdisc_class_hash_destroy(struct Qdisc_class_hash *);
385 
386 void dev_init_scheduler(struct net_device *dev);
387 void dev_shutdown(struct net_device *dev);
388 void dev_activate(struct net_device *dev);
389 void dev_deactivate(struct net_device *dev);
390 void dev_deactivate_many(struct list_head *head);
391 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
392 			      struct Qdisc *qdisc);
393 void qdisc_reset(struct Qdisc *qdisc);
394 void qdisc_destroy(struct Qdisc *qdisc);
395 void qdisc_tree_decrease_qlen(struct Qdisc *qdisc, unsigned int n);
396 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
397 			  const struct Qdisc_ops *ops);
398 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
399 				const struct Qdisc_ops *ops, u32 parentid);
400 void __qdisc_calculate_pkt_len(struct sk_buff *skb,
401 			       const struct qdisc_size_table *stab);
402 bool tcf_destroy(struct tcf_proto *tp, bool force);
403 void tcf_destroy_chain(struct tcf_proto __rcu **fl);
404 
405 /* Reset all TX qdiscs greater then index of a device.  */
406 static inline void qdisc_reset_all_tx_gt(struct net_device *dev, unsigned int i)
407 {
408 	struct Qdisc *qdisc;
409 
410 	for (; i < dev->num_tx_queues; i++) {
411 		qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc);
412 		if (qdisc) {
413 			spin_lock_bh(qdisc_lock(qdisc));
414 			qdisc_reset(qdisc);
415 			spin_unlock_bh(qdisc_lock(qdisc));
416 		}
417 	}
418 }
419 
420 static inline void qdisc_reset_all_tx(struct net_device *dev)
421 {
422 	qdisc_reset_all_tx_gt(dev, 0);
423 }
424 
425 /* Are all TX queues of the device empty?  */
426 static inline bool qdisc_all_tx_empty(const struct net_device *dev)
427 {
428 	unsigned int i;
429 
430 	rcu_read_lock();
431 	for (i = 0; i < dev->num_tx_queues; i++) {
432 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
433 		const struct Qdisc *q = rcu_dereference(txq->qdisc);
434 
435 		if (q->q.qlen) {
436 			rcu_read_unlock();
437 			return false;
438 		}
439 	}
440 	rcu_read_unlock();
441 	return true;
442 }
443 
444 /* Are any of the TX qdiscs changing?  */
445 static inline bool qdisc_tx_changing(const struct net_device *dev)
446 {
447 	unsigned int i;
448 
449 	for (i = 0; i < dev->num_tx_queues; i++) {
450 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
451 		if (rcu_access_pointer(txq->qdisc) != txq->qdisc_sleeping)
452 			return true;
453 	}
454 	return false;
455 }
456 
457 /* Is the device using the noop qdisc on all queues?  */
458 static inline bool qdisc_tx_is_noop(const struct net_device *dev)
459 {
460 	unsigned int i;
461 
462 	for (i = 0; i < dev->num_tx_queues; i++) {
463 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
464 		if (rcu_access_pointer(txq->qdisc) != &noop_qdisc)
465 			return false;
466 	}
467 	return true;
468 }
469 
470 static inline unsigned int qdisc_pkt_len(const struct sk_buff *skb)
471 {
472 	return qdisc_skb_cb(skb)->pkt_len;
473 }
474 
475 /* additional qdisc xmit flags (NET_XMIT_MASK in linux/netdevice.h) */
476 enum net_xmit_qdisc_t {
477 	__NET_XMIT_STOLEN = 0x00010000,
478 	__NET_XMIT_BYPASS = 0x00020000,
479 };
480 
481 #ifdef CONFIG_NET_CLS_ACT
482 #define net_xmit_drop_count(e)	((e) & __NET_XMIT_STOLEN ? 0 : 1)
483 #else
484 #define net_xmit_drop_count(e)	(1)
485 #endif
486 
487 static inline void qdisc_calculate_pkt_len(struct sk_buff *skb,
488 					   const struct Qdisc *sch)
489 {
490 #ifdef CONFIG_NET_SCHED
491 	struct qdisc_size_table *stab = rcu_dereference_bh(sch->stab);
492 
493 	if (stab)
494 		__qdisc_calculate_pkt_len(skb, stab);
495 #endif
496 }
497 
498 static inline int qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
499 {
500 	qdisc_calculate_pkt_len(skb, sch);
501 	return sch->enqueue(skb, sch);
502 }
503 
504 static inline int qdisc_enqueue_root(struct sk_buff *skb, struct Qdisc *sch)
505 {
506 	qdisc_skb_cb(skb)->pkt_len = skb->len;
507 	return qdisc_enqueue(skb, sch) & NET_XMIT_MASK;
508 }
509 
510 static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
511 {
512 	return q->flags & TCQ_F_CPUSTATS;
513 }
514 
515 static inline void bstats_update(struct gnet_stats_basic_packed *bstats,
516 				 const struct sk_buff *skb)
517 {
518 	bstats->bytes += qdisc_pkt_len(skb);
519 	bstats->packets += skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 1;
520 }
521 
522 static inline void qdisc_bstats_update_cpu(struct Qdisc *sch,
523 					   const struct sk_buff *skb)
524 {
525 	struct gnet_stats_basic_cpu *bstats =
526 				this_cpu_ptr(sch->cpu_bstats);
527 
528 	u64_stats_update_begin(&bstats->syncp);
529 	bstats_update(&bstats->bstats, skb);
530 	u64_stats_update_end(&bstats->syncp);
531 }
532 
533 static inline void qdisc_bstats_update(struct Qdisc *sch,
534 				       const struct sk_buff *skb)
535 {
536 	bstats_update(&sch->bstats, skb);
537 }
538 
539 static inline void qdisc_qstats_backlog_dec(struct Qdisc *sch,
540 					    const struct sk_buff *skb)
541 {
542 	sch->qstats.backlog -= qdisc_pkt_len(skb);
543 }
544 
545 static inline void qdisc_qstats_backlog_inc(struct Qdisc *sch,
546 					    const struct sk_buff *skb)
547 {
548 	sch->qstats.backlog += qdisc_pkt_len(skb);
549 }
550 
551 static inline void __qdisc_qstats_drop(struct Qdisc *sch, int count)
552 {
553 	sch->qstats.drops += count;
554 }
555 
556 static inline void qdisc_qstats_drop(struct Qdisc *sch)
557 {
558 	sch->qstats.drops++;
559 }
560 
561 static inline void qdisc_qstats_drop_cpu(struct Qdisc *sch)
562 {
563 	struct gnet_stats_queue *qstats = this_cpu_ptr(sch->cpu_qstats);
564 
565 	qstats->drops++;
566 }
567 
568 static inline void qdisc_qstats_overlimit(struct Qdisc *sch)
569 {
570 	sch->qstats.overlimits++;
571 }
572 
573 static inline int __qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch,
574 				       struct sk_buff_head *list)
575 {
576 	__skb_queue_tail(list, skb);
577 	qdisc_qstats_backlog_inc(sch, skb);
578 
579 	return NET_XMIT_SUCCESS;
580 }
581 
582 static inline int qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch)
583 {
584 	return __qdisc_enqueue_tail(skb, sch, &sch->q);
585 }
586 
587 static inline struct sk_buff *__qdisc_dequeue_head(struct Qdisc *sch,
588 						   struct sk_buff_head *list)
589 {
590 	struct sk_buff *skb = __skb_dequeue(list);
591 
592 	if (likely(skb != NULL)) {
593 		qdisc_qstats_backlog_dec(sch, skb);
594 		qdisc_bstats_update(sch, skb);
595 	}
596 
597 	return skb;
598 }
599 
600 static inline struct sk_buff *qdisc_dequeue_head(struct Qdisc *sch)
601 {
602 	return __qdisc_dequeue_head(sch, &sch->q);
603 }
604 
605 static inline unsigned int __qdisc_queue_drop_head(struct Qdisc *sch,
606 					      struct sk_buff_head *list)
607 {
608 	struct sk_buff *skb = __skb_dequeue(list);
609 
610 	if (likely(skb != NULL)) {
611 		unsigned int len = qdisc_pkt_len(skb);
612 		qdisc_qstats_backlog_dec(sch, skb);
613 		kfree_skb(skb);
614 		return len;
615 	}
616 
617 	return 0;
618 }
619 
620 static inline unsigned int qdisc_queue_drop_head(struct Qdisc *sch)
621 {
622 	return __qdisc_queue_drop_head(sch, &sch->q);
623 }
624 
625 static inline struct sk_buff *__qdisc_dequeue_tail(struct Qdisc *sch,
626 						   struct sk_buff_head *list)
627 {
628 	struct sk_buff *skb = __skb_dequeue_tail(list);
629 
630 	if (likely(skb != NULL))
631 		qdisc_qstats_backlog_dec(sch, skb);
632 
633 	return skb;
634 }
635 
636 static inline struct sk_buff *qdisc_dequeue_tail(struct Qdisc *sch)
637 {
638 	return __qdisc_dequeue_tail(sch, &sch->q);
639 }
640 
641 static inline struct sk_buff *qdisc_peek_head(struct Qdisc *sch)
642 {
643 	return skb_peek(&sch->q);
644 }
645 
646 /* generic pseudo peek method for non-work-conserving qdisc */
647 static inline struct sk_buff *qdisc_peek_dequeued(struct Qdisc *sch)
648 {
649 	/* we can reuse ->gso_skb because peek isn't called for root qdiscs */
650 	if (!sch->gso_skb) {
651 		sch->gso_skb = sch->dequeue(sch);
652 		if (sch->gso_skb)
653 			/* it's still part of the queue */
654 			sch->q.qlen++;
655 	}
656 
657 	return sch->gso_skb;
658 }
659 
660 /* use instead of qdisc->dequeue() for all qdiscs queried with ->peek() */
661 static inline struct sk_buff *qdisc_dequeue_peeked(struct Qdisc *sch)
662 {
663 	struct sk_buff *skb = sch->gso_skb;
664 
665 	if (skb) {
666 		sch->gso_skb = NULL;
667 		sch->q.qlen--;
668 	} else {
669 		skb = sch->dequeue(sch);
670 	}
671 
672 	return skb;
673 }
674 
675 static inline void __qdisc_reset_queue(struct Qdisc *sch,
676 				       struct sk_buff_head *list)
677 {
678 	/*
679 	 * We do not know the backlog in bytes of this list, it
680 	 * is up to the caller to correct it
681 	 */
682 	__skb_queue_purge(list);
683 }
684 
685 static inline void qdisc_reset_queue(struct Qdisc *sch)
686 {
687 	__qdisc_reset_queue(sch, &sch->q);
688 	sch->qstats.backlog = 0;
689 }
690 
691 static inline unsigned int __qdisc_queue_drop(struct Qdisc *sch,
692 					      struct sk_buff_head *list)
693 {
694 	struct sk_buff *skb = __qdisc_dequeue_tail(sch, list);
695 
696 	if (likely(skb != NULL)) {
697 		unsigned int len = qdisc_pkt_len(skb);
698 		kfree_skb(skb);
699 		return len;
700 	}
701 
702 	return 0;
703 }
704 
705 static inline unsigned int qdisc_queue_drop(struct Qdisc *sch)
706 {
707 	return __qdisc_queue_drop(sch, &sch->q);
708 }
709 
710 static inline int qdisc_drop(struct sk_buff *skb, struct Qdisc *sch)
711 {
712 	kfree_skb(skb);
713 	qdisc_qstats_drop(sch);
714 
715 	return NET_XMIT_DROP;
716 }
717 
718 static inline int qdisc_reshape_fail(struct sk_buff *skb, struct Qdisc *sch)
719 {
720 	qdisc_qstats_drop(sch);
721 
722 #ifdef CONFIG_NET_CLS_ACT
723 	if (sch->reshape_fail == NULL || sch->reshape_fail(skb, sch))
724 		goto drop;
725 
726 	return NET_XMIT_SUCCESS;
727 
728 drop:
729 #endif
730 	kfree_skb(skb);
731 	return NET_XMIT_DROP;
732 }
733 
734 /* Length to Time (L2T) lookup in a qdisc_rate_table, to determine how
735    long it will take to send a packet given its size.
736  */
737 static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen)
738 {
739 	int slot = pktlen + rtab->rate.cell_align + rtab->rate.overhead;
740 	if (slot < 0)
741 		slot = 0;
742 	slot >>= rtab->rate.cell_log;
743 	if (slot > 255)
744 		return rtab->data[255]*(slot >> 8) + rtab->data[slot & 0xFF];
745 	return rtab->data[slot];
746 }
747 
748 #ifdef CONFIG_NET_CLS_ACT
749 static inline struct sk_buff *skb_act_clone(struct sk_buff *skb, gfp_t gfp_mask,
750 					    int action)
751 {
752 	struct sk_buff *n;
753 
754 	n = skb_clone(skb, gfp_mask);
755 
756 	if (n) {
757 		n->tc_verd = SET_TC_VERD(n->tc_verd, 0);
758 		n->tc_verd = CLR_TC_OK2MUNGE(n->tc_verd);
759 		n->tc_verd = CLR_TC_MUNGED(n->tc_verd);
760 	}
761 	return n;
762 }
763 #endif
764 
765 struct psched_ratecfg {
766 	u64	rate_bytes_ps; /* bytes per second */
767 	u32	mult;
768 	u16	overhead;
769 	u8	linklayer;
770 	u8	shift;
771 };
772 
773 static inline u64 psched_l2t_ns(const struct psched_ratecfg *r,
774 				unsigned int len)
775 {
776 	len += r->overhead;
777 
778 	if (unlikely(r->linklayer == TC_LINKLAYER_ATM))
779 		return ((u64)(DIV_ROUND_UP(len,48)*53) * r->mult) >> r->shift;
780 
781 	return ((u64)len * r->mult) >> r->shift;
782 }
783 
784 void psched_ratecfg_precompute(struct psched_ratecfg *r,
785 			       const struct tc_ratespec *conf,
786 			       u64 rate64);
787 
788 static inline void psched_ratecfg_getrate(struct tc_ratespec *res,
789 					  const struct psched_ratecfg *r)
790 {
791 	memset(res, 0, sizeof(*res));
792 
793 	/* legacy struct tc_ratespec has a 32bit @rate field
794 	 * Qdisc using 64bit rate should add new attributes
795 	 * in order to maintain compatibility.
796 	 */
797 	res->rate = min_t(u64, r->rate_bytes_ps, ~0U);
798 
799 	res->overhead = r->overhead;
800 	res->linklayer = (r->linklayer & TC_LINKLAYER_MASK);
801 }
802 
803 #endif
804