xref: /openbmc/linux/include/net/sch_generic.h (revision 4161b450)
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 Qdisc		*next_sched;
83 	struct sk_buff		*gso_skb;
84 	/*
85 	 * For performance sake on SMP, we put highly modified fields at the end
86 	 */
87 	unsigned long		state;
88 	struct sk_buff_head	q;
89 	union {
90 		struct gnet_stats_basic_packed bstats;
91 		struct gnet_stats_basic_cpu __percpu *cpu_bstats;
92 	} __packed;
93 	unsigned int		__state;
94 	union {
95 		struct gnet_stats_queue	qstats;
96 		struct gnet_stats_queue	__percpu *cpu_qstats;
97 	} __packed;
98 	struct rcu_head		rcu_head;
99 	int			padded;
100 	atomic_t		refcnt;
101 
102 	spinlock_t		busylock ____cacheline_aligned_in_smp;
103 };
104 
105 static inline bool qdisc_is_running(const struct Qdisc *qdisc)
106 {
107 	return (qdisc->__state & __QDISC___STATE_RUNNING) ? true : false;
108 }
109 
110 static inline bool qdisc_run_begin(struct Qdisc *qdisc)
111 {
112 	if (qdisc_is_running(qdisc))
113 		return false;
114 	qdisc->__state |= __QDISC___STATE_RUNNING;
115 	return true;
116 }
117 
118 static inline void qdisc_run_end(struct Qdisc *qdisc)
119 {
120 	qdisc->__state &= ~__QDISC___STATE_RUNNING;
121 }
122 
123 static inline bool qdisc_may_bulk(const struct Qdisc *qdisc)
124 {
125 	return qdisc->flags & TCQ_F_ONETXQUEUE;
126 }
127 
128 static inline int qdisc_avail_bulklimit(const struct netdev_queue *txq)
129 {
130 #ifdef CONFIG_BQL
131 	/* Non-BQL migrated drivers will return 0, too. */
132 	return dql_avail(&txq->dql);
133 #else
134 	return 0;
135 #endif
136 }
137 
138 static inline bool qdisc_is_throttled(const struct Qdisc *qdisc)
139 {
140 	return test_bit(__QDISC_STATE_THROTTLED, &qdisc->state) ? true : false;
141 }
142 
143 static inline void qdisc_throttled(struct Qdisc *qdisc)
144 {
145 	set_bit(__QDISC_STATE_THROTTLED, &qdisc->state);
146 }
147 
148 static inline void qdisc_unthrottled(struct Qdisc *qdisc)
149 {
150 	clear_bit(__QDISC_STATE_THROTTLED, &qdisc->state);
151 }
152 
153 struct Qdisc_class_ops {
154 	/* Child qdisc manipulation */
155 	struct netdev_queue *	(*select_queue)(struct Qdisc *, struct tcmsg *);
156 	int			(*graft)(struct Qdisc *, unsigned long cl,
157 					struct Qdisc *, struct Qdisc **);
158 	struct Qdisc *		(*leaf)(struct Qdisc *, unsigned long cl);
159 	void			(*qlen_notify)(struct Qdisc *, unsigned long);
160 
161 	/* Class manipulation routines */
162 	unsigned long		(*get)(struct Qdisc *, u32 classid);
163 	void			(*put)(struct Qdisc *, unsigned long);
164 	int			(*change)(struct Qdisc *, u32, u32,
165 					struct nlattr **, unsigned long *);
166 	int			(*delete)(struct Qdisc *, unsigned long);
167 	void			(*walk)(struct Qdisc *, struct qdisc_walker * arg);
168 
169 	/* Filter manipulation */
170 	struct tcf_proto __rcu ** (*tcf_chain)(struct Qdisc *, unsigned long);
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 
188 	int 			(*enqueue)(struct sk_buff *, struct Qdisc *);
189 	struct sk_buff *	(*dequeue)(struct Qdisc *);
190 	struct sk_buff *	(*peek)(struct Qdisc *);
191 	unsigned int		(*drop)(struct Qdisc *);
192 
193 	int			(*init)(struct Qdisc *, struct nlattr *arg);
194 	void			(*reset)(struct Qdisc *);
195 	void			(*destroy)(struct Qdisc *);
196 	int			(*change)(struct Qdisc *, struct nlattr *arg);
197 	void			(*attach)(struct Qdisc *);
198 
199 	int			(*dump)(struct Qdisc *, struct sk_buff *);
200 	int			(*dump_stats)(struct Qdisc *, struct gnet_dump *);
201 
202 	struct module		*owner;
203 };
204 
205 
206 struct tcf_result {
207 	unsigned long	class;
208 	u32		classid;
209 };
210 
211 struct tcf_proto_ops {
212 	struct list_head	head;
213 	char			kind[IFNAMSIZ];
214 
215 	int			(*classify)(struct sk_buff *,
216 					    const struct tcf_proto *,
217 					    struct tcf_result *);
218 	int			(*init)(struct tcf_proto*);
219 	void			(*destroy)(struct tcf_proto*);
220 
221 	unsigned long		(*get)(struct tcf_proto*, u32 handle);
222 	int			(*change)(struct net *net, struct sk_buff *,
223 					struct tcf_proto*, unsigned long,
224 					u32 handle, struct nlattr **,
225 					unsigned long *, bool);
226 	int			(*delete)(struct tcf_proto*, unsigned long);
227 	void			(*walk)(struct tcf_proto*, struct tcf_walker *arg);
228 
229 	/* rtnetlink specific */
230 	int			(*dump)(struct net*, struct tcf_proto*, unsigned long,
231 					struct sk_buff *skb, struct tcmsg*);
232 
233 	struct module		*owner;
234 };
235 
236 struct tcf_proto {
237 	/* Fast access part */
238 	struct tcf_proto __rcu	*next;
239 	void __rcu		*root;
240 	int			(*classify)(struct sk_buff *,
241 					    const struct tcf_proto *,
242 					    struct tcf_result *);
243 	__be16			protocol;
244 
245 	/* All the rest */
246 	u32			prio;
247 	u32			classid;
248 	struct Qdisc		*q;
249 	void			*data;
250 	const struct tcf_proto_ops	*ops;
251 	struct rcu_head		rcu;
252 };
253 
254 struct qdisc_skb_cb {
255 	unsigned int		pkt_len;
256 	u16			slave_dev_queue_mapping;
257 	u16			_pad;
258 #define QDISC_CB_PRIV_LEN 20
259 	unsigned char		data[QDISC_CB_PRIV_LEN];
260 };
261 
262 static inline void qdisc_cb_private_validate(const struct sk_buff *skb, int sz)
263 {
264 	struct qdisc_skb_cb *qcb;
265 
266 	BUILD_BUG_ON(sizeof(skb->cb) < offsetof(struct qdisc_skb_cb, data) + sz);
267 	BUILD_BUG_ON(sizeof(qcb->data) < sz);
268 }
269 
270 static inline int qdisc_qlen(const struct Qdisc *q)
271 {
272 	return q->q.qlen;
273 }
274 
275 static inline struct qdisc_skb_cb *qdisc_skb_cb(const struct sk_buff *skb)
276 {
277 	return (struct qdisc_skb_cb *)skb->cb;
278 }
279 
280 static inline spinlock_t *qdisc_lock(struct Qdisc *qdisc)
281 {
282 	return &qdisc->q.lock;
283 }
284 
285 static inline struct Qdisc *qdisc_root(const struct Qdisc *qdisc)
286 {
287 	struct Qdisc *q = rcu_dereference_rtnl(qdisc->dev_queue->qdisc);
288 
289 	return q;
290 }
291 
292 static inline struct Qdisc *qdisc_root_sleeping(const struct Qdisc *qdisc)
293 {
294 	return qdisc->dev_queue->qdisc_sleeping;
295 }
296 
297 /* The qdisc root lock is a mechanism by which to top level
298  * of a qdisc tree can be locked from any qdisc node in the
299  * forest.  This allows changing the configuration of some
300  * aspect of the qdisc tree while blocking out asynchronous
301  * qdisc access in the packet processing paths.
302  *
303  * It is only legal to do this when the root will not change
304  * on us.  Otherwise we'll potentially lock the wrong qdisc
305  * root.  This is enforced by holding the RTNL semaphore, which
306  * all users of this lock accessor must do.
307  */
308 static inline spinlock_t *qdisc_root_lock(const struct Qdisc *qdisc)
309 {
310 	struct Qdisc *root = qdisc_root(qdisc);
311 
312 	ASSERT_RTNL();
313 	return qdisc_lock(root);
314 }
315 
316 static inline spinlock_t *qdisc_root_sleeping_lock(const struct Qdisc *qdisc)
317 {
318 	struct Qdisc *root = qdisc_root_sleeping(qdisc);
319 
320 	ASSERT_RTNL();
321 	return qdisc_lock(root);
322 }
323 
324 static inline struct net_device *qdisc_dev(const struct Qdisc *qdisc)
325 {
326 	return qdisc->dev_queue->dev;
327 }
328 
329 static inline void sch_tree_lock(const struct Qdisc *q)
330 {
331 	spin_lock_bh(qdisc_root_sleeping_lock(q));
332 }
333 
334 static inline void sch_tree_unlock(const struct Qdisc *q)
335 {
336 	spin_unlock_bh(qdisc_root_sleeping_lock(q));
337 }
338 
339 #define tcf_tree_lock(tp)	sch_tree_lock((tp)->q)
340 #define tcf_tree_unlock(tp)	sch_tree_unlock((tp)->q)
341 
342 extern struct Qdisc noop_qdisc;
343 extern struct Qdisc_ops noop_qdisc_ops;
344 extern struct Qdisc_ops pfifo_fast_ops;
345 extern struct Qdisc_ops mq_qdisc_ops;
346 extern const struct Qdisc_ops *default_qdisc_ops;
347 
348 struct Qdisc_class_common {
349 	u32			classid;
350 	struct hlist_node	hnode;
351 };
352 
353 struct Qdisc_class_hash {
354 	struct hlist_head	*hash;
355 	unsigned int		hashsize;
356 	unsigned int		hashmask;
357 	unsigned int		hashelems;
358 };
359 
360 static inline unsigned int qdisc_class_hash(u32 id, u32 mask)
361 {
362 	id ^= id >> 8;
363 	id ^= id >> 4;
364 	return id & mask;
365 }
366 
367 static inline struct Qdisc_class_common *
368 qdisc_class_find(const struct Qdisc_class_hash *hash, u32 id)
369 {
370 	struct Qdisc_class_common *cl;
371 	unsigned int h;
372 
373 	h = qdisc_class_hash(id, hash->hashmask);
374 	hlist_for_each_entry(cl, &hash->hash[h], hnode) {
375 		if (cl->classid == id)
376 			return cl;
377 	}
378 	return NULL;
379 }
380 
381 int qdisc_class_hash_init(struct Qdisc_class_hash *);
382 void qdisc_class_hash_insert(struct Qdisc_class_hash *,
383 			     struct Qdisc_class_common *);
384 void qdisc_class_hash_remove(struct Qdisc_class_hash *,
385 			     struct Qdisc_class_common *);
386 void qdisc_class_hash_grow(struct Qdisc *, struct Qdisc_class_hash *);
387 void qdisc_class_hash_destroy(struct Qdisc_class_hash *);
388 
389 void dev_init_scheduler(struct net_device *dev);
390 void dev_shutdown(struct net_device *dev);
391 void dev_activate(struct net_device *dev);
392 void dev_deactivate(struct net_device *dev);
393 void dev_deactivate_many(struct list_head *head);
394 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
395 			      struct Qdisc *qdisc);
396 void qdisc_reset(struct Qdisc *qdisc);
397 void qdisc_destroy(struct Qdisc *qdisc);
398 void qdisc_tree_decrease_qlen(struct Qdisc *qdisc, unsigned int n);
399 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
400 			  const struct Qdisc_ops *ops);
401 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
402 				const struct Qdisc_ops *ops, u32 parentid);
403 void __qdisc_calculate_pkt_len(struct sk_buff *skb,
404 			       const struct qdisc_size_table *stab);
405 void tcf_destroy(struct tcf_proto *tp);
406 void tcf_destroy_chain(struct tcf_proto __rcu **fl);
407 
408 /* Reset all TX qdiscs greater then index of a device.  */
409 static inline void qdisc_reset_all_tx_gt(struct net_device *dev, unsigned int i)
410 {
411 	struct Qdisc *qdisc;
412 
413 	for (; i < dev->num_tx_queues; i++) {
414 		qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc);
415 		if (qdisc) {
416 			spin_lock_bh(qdisc_lock(qdisc));
417 			qdisc_reset(qdisc);
418 			spin_unlock_bh(qdisc_lock(qdisc));
419 		}
420 	}
421 }
422 
423 static inline void qdisc_reset_all_tx(struct net_device *dev)
424 {
425 	qdisc_reset_all_tx_gt(dev, 0);
426 }
427 
428 /* Are all TX queues of the device empty?  */
429 static inline bool qdisc_all_tx_empty(const struct net_device *dev)
430 {
431 	unsigned int i;
432 
433 	rcu_read_lock();
434 	for (i = 0; i < dev->num_tx_queues; i++) {
435 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
436 		const struct Qdisc *q = rcu_dereference(txq->qdisc);
437 
438 		if (q->q.qlen) {
439 			rcu_read_unlock();
440 			return false;
441 		}
442 	}
443 	rcu_read_unlock();
444 	return true;
445 }
446 
447 /* Are any of the TX qdiscs changing?  */
448 static inline bool qdisc_tx_changing(const struct net_device *dev)
449 {
450 	unsigned int i;
451 
452 	for (i = 0; i < dev->num_tx_queues; i++) {
453 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
454 		if (rcu_access_pointer(txq->qdisc) != txq->qdisc_sleeping)
455 			return true;
456 	}
457 	return false;
458 }
459 
460 /* Is the device using the noop qdisc on all queues?  */
461 static inline bool qdisc_tx_is_noop(const struct net_device *dev)
462 {
463 	unsigned int i;
464 
465 	for (i = 0; i < dev->num_tx_queues; i++) {
466 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
467 		if (rcu_access_pointer(txq->qdisc) != &noop_qdisc)
468 			return false;
469 	}
470 	return true;
471 }
472 
473 static inline unsigned int qdisc_pkt_len(const struct sk_buff *skb)
474 {
475 	return qdisc_skb_cb(skb)->pkt_len;
476 }
477 
478 /* additional qdisc xmit flags (NET_XMIT_MASK in linux/netdevice.h) */
479 enum net_xmit_qdisc_t {
480 	__NET_XMIT_STOLEN = 0x00010000,
481 	__NET_XMIT_BYPASS = 0x00020000,
482 };
483 
484 #ifdef CONFIG_NET_CLS_ACT
485 #define net_xmit_drop_count(e)	((e) & __NET_XMIT_STOLEN ? 0 : 1)
486 #else
487 #define net_xmit_drop_count(e)	(1)
488 #endif
489 
490 static inline void qdisc_calculate_pkt_len(struct sk_buff *skb,
491 					   const struct Qdisc *sch)
492 {
493 #ifdef CONFIG_NET_SCHED
494 	struct qdisc_size_table *stab = rcu_dereference_bh(sch->stab);
495 
496 	if (stab)
497 		__qdisc_calculate_pkt_len(skb, stab);
498 #endif
499 }
500 
501 static inline int qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
502 {
503 	qdisc_calculate_pkt_len(skb, sch);
504 	return sch->enqueue(skb, sch);
505 }
506 
507 static inline int qdisc_enqueue_root(struct sk_buff *skb, struct Qdisc *sch)
508 {
509 	qdisc_skb_cb(skb)->pkt_len = skb->len;
510 	return qdisc_enqueue(skb, sch) & NET_XMIT_MASK;
511 }
512 
513 static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
514 {
515 	return q->flags & TCQ_F_CPUSTATS;
516 }
517 
518 static inline void bstats_update(struct gnet_stats_basic_packed *bstats,
519 				 const struct sk_buff *skb)
520 {
521 	bstats->bytes += qdisc_pkt_len(skb);
522 	bstats->packets += skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 1;
523 }
524 
525 static inline void qdisc_bstats_update_cpu(struct Qdisc *sch,
526 					   const struct sk_buff *skb)
527 {
528 	struct gnet_stats_basic_cpu *bstats =
529 				this_cpu_ptr(sch->cpu_bstats);
530 
531 	u64_stats_update_begin(&bstats->syncp);
532 	bstats_update(&bstats->bstats, skb);
533 	u64_stats_update_end(&bstats->syncp);
534 }
535 
536 static inline void qdisc_bstats_update(struct Qdisc *sch,
537 				       const struct sk_buff *skb)
538 {
539 	bstats_update(&sch->bstats, skb);
540 }
541 
542 static inline void qdisc_qstats_backlog_dec(struct Qdisc *sch,
543 					    const struct sk_buff *skb)
544 {
545 	sch->qstats.backlog -= qdisc_pkt_len(skb);
546 }
547 
548 static inline void qdisc_qstats_backlog_inc(struct Qdisc *sch,
549 					    const struct sk_buff *skb)
550 {
551 	sch->qstats.backlog += qdisc_pkt_len(skb);
552 }
553 
554 static inline void __qdisc_qstats_drop(struct Qdisc *sch, int count)
555 {
556 	sch->qstats.drops += count;
557 }
558 
559 static inline void qdisc_qstats_drop(struct Qdisc *sch)
560 {
561 	sch->qstats.drops++;
562 }
563 
564 static inline void qdisc_qstats_drop_cpu(struct Qdisc *sch)
565 {
566 	struct gnet_stats_queue *qstats = this_cpu_ptr(sch->cpu_qstats);
567 
568 	qstats->drops++;
569 }
570 
571 static inline void qdisc_qstats_overlimit(struct Qdisc *sch)
572 {
573 	sch->qstats.overlimits++;
574 }
575 
576 static inline int __qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch,
577 				       struct sk_buff_head *list)
578 {
579 	__skb_queue_tail(list, skb);
580 	qdisc_qstats_backlog_inc(sch, skb);
581 
582 	return NET_XMIT_SUCCESS;
583 }
584 
585 static inline int qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch)
586 {
587 	return __qdisc_enqueue_tail(skb, sch, &sch->q);
588 }
589 
590 static inline struct sk_buff *__qdisc_dequeue_head(struct Qdisc *sch,
591 						   struct sk_buff_head *list)
592 {
593 	struct sk_buff *skb = __skb_dequeue(list);
594 
595 	if (likely(skb != NULL)) {
596 		qdisc_qstats_backlog_dec(sch, skb);
597 		qdisc_bstats_update(sch, skb);
598 	}
599 
600 	return skb;
601 }
602 
603 static inline struct sk_buff *qdisc_dequeue_head(struct Qdisc *sch)
604 {
605 	return __qdisc_dequeue_head(sch, &sch->q);
606 }
607 
608 static inline unsigned int __qdisc_queue_drop_head(struct Qdisc *sch,
609 					      struct sk_buff_head *list)
610 {
611 	struct sk_buff *skb = __skb_dequeue(list);
612 
613 	if (likely(skb != NULL)) {
614 		unsigned int len = qdisc_pkt_len(skb);
615 		qdisc_qstats_backlog_dec(sch, skb);
616 		kfree_skb(skb);
617 		return len;
618 	}
619 
620 	return 0;
621 }
622 
623 static inline unsigned int qdisc_queue_drop_head(struct Qdisc *sch)
624 {
625 	return __qdisc_queue_drop_head(sch, &sch->q);
626 }
627 
628 static inline struct sk_buff *__qdisc_dequeue_tail(struct Qdisc *sch,
629 						   struct sk_buff_head *list)
630 {
631 	struct sk_buff *skb = __skb_dequeue_tail(list);
632 
633 	if (likely(skb != NULL))
634 		qdisc_qstats_backlog_dec(sch, skb);
635 
636 	return skb;
637 }
638 
639 static inline struct sk_buff *qdisc_dequeue_tail(struct Qdisc *sch)
640 {
641 	return __qdisc_dequeue_tail(sch, &sch->q);
642 }
643 
644 static inline struct sk_buff *qdisc_peek_head(struct Qdisc *sch)
645 {
646 	return skb_peek(&sch->q);
647 }
648 
649 /* generic pseudo peek method for non-work-conserving qdisc */
650 static inline struct sk_buff *qdisc_peek_dequeued(struct Qdisc *sch)
651 {
652 	/* we can reuse ->gso_skb because peek isn't called for root qdiscs */
653 	if (!sch->gso_skb) {
654 		sch->gso_skb = sch->dequeue(sch);
655 		if (sch->gso_skb)
656 			/* it's still part of the queue */
657 			sch->q.qlen++;
658 	}
659 
660 	return sch->gso_skb;
661 }
662 
663 /* use instead of qdisc->dequeue() for all qdiscs queried with ->peek() */
664 static inline struct sk_buff *qdisc_dequeue_peeked(struct Qdisc *sch)
665 {
666 	struct sk_buff *skb = sch->gso_skb;
667 
668 	if (skb) {
669 		sch->gso_skb = NULL;
670 		sch->q.qlen--;
671 	} else {
672 		skb = sch->dequeue(sch);
673 	}
674 
675 	return skb;
676 }
677 
678 static inline void __qdisc_reset_queue(struct Qdisc *sch,
679 				       struct sk_buff_head *list)
680 {
681 	/*
682 	 * We do not know the backlog in bytes of this list, it
683 	 * is up to the caller to correct it
684 	 */
685 	__skb_queue_purge(list);
686 }
687 
688 static inline void qdisc_reset_queue(struct Qdisc *sch)
689 {
690 	__qdisc_reset_queue(sch, &sch->q);
691 	sch->qstats.backlog = 0;
692 }
693 
694 static inline unsigned int __qdisc_queue_drop(struct Qdisc *sch,
695 					      struct sk_buff_head *list)
696 {
697 	struct sk_buff *skb = __qdisc_dequeue_tail(sch, list);
698 
699 	if (likely(skb != NULL)) {
700 		unsigned int len = qdisc_pkt_len(skb);
701 		kfree_skb(skb);
702 		return len;
703 	}
704 
705 	return 0;
706 }
707 
708 static inline unsigned int qdisc_queue_drop(struct Qdisc *sch)
709 {
710 	return __qdisc_queue_drop(sch, &sch->q);
711 }
712 
713 static inline int qdisc_drop(struct sk_buff *skb, struct Qdisc *sch)
714 {
715 	kfree_skb(skb);
716 	qdisc_qstats_drop(sch);
717 
718 	return NET_XMIT_DROP;
719 }
720 
721 static inline int qdisc_reshape_fail(struct sk_buff *skb, struct Qdisc *sch)
722 {
723 	qdisc_qstats_drop(sch);
724 
725 #ifdef CONFIG_NET_CLS_ACT
726 	if (sch->reshape_fail == NULL || sch->reshape_fail(skb, sch))
727 		goto drop;
728 
729 	return NET_XMIT_SUCCESS;
730 
731 drop:
732 #endif
733 	kfree_skb(skb);
734 	return NET_XMIT_DROP;
735 }
736 
737 /* Length to Time (L2T) lookup in a qdisc_rate_table, to determine how
738    long it will take to send a packet given its size.
739  */
740 static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen)
741 {
742 	int slot = pktlen + rtab->rate.cell_align + rtab->rate.overhead;
743 	if (slot < 0)
744 		slot = 0;
745 	slot >>= rtab->rate.cell_log;
746 	if (slot > 255)
747 		return rtab->data[255]*(slot >> 8) + rtab->data[slot & 0xFF];
748 	return rtab->data[slot];
749 }
750 
751 #ifdef CONFIG_NET_CLS_ACT
752 static inline struct sk_buff *skb_act_clone(struct sk_buff *skb, gfp_t gfp_mask,
753 					    int action)
754 {
755 	struct sk_buff *n;
756 
757 	n = skb_clone(skb, gfp_mask);
758 
759 	if (n) {
760 		n->tc_verd = SET_TC_VERD(n->tc_verd, 0);
761 		n->tc_verd = CLR_TC_OK2MUNGE(n->tc_verd);
762 		n->tc_verd = CLR_TC_MUNGED(n->tc_verd);
763 	}
764 	return n;
765 }
766 #endif
767 
768 struct psched_ratecfg {
769 	u64	rate_bytes_ps; /* bytes per second */
770 	u32	mult;
771 	u16	overhead;
772 	u8	linklayer;
773 	u8	shift;
774 };
775 
776 static inline u64 psched_l2t_ns(const struct psched_ratecfg *r,
777 				unsigned int len)
778 {
779 	len += r->overhead;
780 
781 	if (unlikely(r->linklayer == TC_LINKLAYER_ATM))
782 		return ((u64)(DIV_ROUND_UP(len,48)*53) * r->mult) >> r->shift;
783 
784 	return ((u64)len * r->mult) >> r->shift;
785 }
786 
787 void psched_ratecfg_precompute(struct psched_ratecfg *r,
788 			       const struct tc_ratespec *conf,
789 			       u64 rate64);
790 
791 static inline void psched_ratecfg_getrate(struct tc_ratespec *res,
792 					  const struct psched_ratecfg *r)
793 {
794 	memset(res, 0, sizeof(*res));
795 
796 	/* legacy struct tc_ratespec has a 32bit @rate field
797 	 * Qdisc using 64bit rate should add new attributes
798 	 * in order to maintain compatibility.
799 	 */
800 	res->rate = min_t(u64, r->rate_bytes_ps, ~0U);
801 
802 	res->overhead = r->overhead;
803 	res->linklayer = (r->linklayer & TC_LINKLAYER_MASK);
804 }
805 
806 #endif
807