xref: /openbmc/linux/include/net/sch_generic.h (revision 9cfc5c90)
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			tc_classid;
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 struct Qdisc_ops noqueue_qdisc_ops;
344 extern const struct Qdisc_ops *default_qdisc_ops;
345 
346 struct Qdisc_class_common {
347 	u32			classid;
348 	struct hlist_node	hnode;
349 };
350 
351 struct Qdisc_class_hash {
352 	struct hlist_head	*hash;
353 	unsigned int		hashsize;
354 	unsigned int		hashmask;
355 	unsigned int		hashelems;
356 };
357 
358 static inline unsigned int qdisc_class_hash(u32 id, u32 mask)
359 {
360 	id ^= id >> 8;
361 	id ^= id >> 4;
362 	return id & mask;
363 }
364 
365 static inline struct Qdisc_class_common *
366 qdisc_class_find(const struct Qdisc_class_hash *hash, u32 id)
367 {
368 	struct Qdisc_class_common *cl;
369 	unsigned int h;
370 
371 	h = qdisc_class_hash(id, hash->hashmask);
372 	hlist_for_each_entry(cl, &hash->hash[h], hnode) {
373 		if (cl->classid == id)
374 			return cl;
375 	}
376 	return NULL;
377 }
378 
379 int qdisc_class_hash_init(struct Qdisc_class_hash *);
380 void qdisc_class_hash_insert(struct Qdisc_class_hash *,
381 			     struct Qdisc_class_common *);
382 void qdisc_class_hash_remove(struct Qdisc_class_hash *,
383 			     struct Qdisc_class_common *);
384 void qdisc_class_hash_grow(struct Qdisc *, struct Qdisc_class_hash *);
385 void qdisc_class_hash_destroy(struct Qdisc_class_hash *);
386 
387 void dev_init_scheduler(struct net_device *dev);
388 void dev_shutdown(struct net_device *dev);
389 void dev_activate(struct net_device *dev);
390 void dev_deactivate(struct net_device *dev);
391 void dev_deactivate_many(struct list_head *head);
392 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
393 			      struct Qdisc *qdisc);
394 void qdisc_reset(struct Qdisc *qdisc);
395 void qdisc_destroy(struct Qdisc *qdisc);
396 void qdisc_tree_decrease_qlen(struct Qdisc *qdisc, unsigned int n);
397 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
398 			  const struct Qdisc_ops *ops);
399 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
400 				const struct Qdisc_ops *ops, u32 parentid);
401 void __qdisc_calculate_pkt_len(struct sk_buff *skb,
402 			       const struct qdisc_size_table *stab);
403 bool tcf_destroy(struct tcf_proto *tp, bool force);
404 void tcf_destroy_chain(struct tcf_proto __rcu **fl);
405 int skb_do_redirect(struct sk_buff *);
406 
407 /* Reset all TX qdiscs greater then index of a device.  */
408 static inline void qdisc_reset_all_tx_gt(struct net_device *dev, unsigned int i)
409 {
410 	struct Qdisc *qdisc;
411 
412 	for (; i < dev->num_tx_queues; i++) {
413 		qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc);
414 		if (qdisc) {
415 			spin_lock_bh(qdisc_lock(qdisc));
416 			qdisc_reset(qdisc);
417 			spin_unlock_bh(qdisc_lock(qdisc));
418 		}
419 	}
420 }
421 
422 static inline void qdisc_reset_all_tx(struct net_device *dev)
423 {
424 	qdisc_reset_all_tx_gt(dev, 0);
425 }
426 
427 /* Are all TX queues of the device empty?  */
428 static inline bool qdisc_all_tx_empty(const struct net_device *dev)
429 {
430 	unsigned int i;
431 
432 	rcu_read_lock();
433 	for (i = 0; i < dev->num_tx_queues; i++) {
434 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
435 		const struct Qdisc *q = rcu_dereference(txq->qdisc);
436 
437 		if (q->q.qlen) {
438 			rcu_read_unlock();
439 			return false;
440 		}
441 	}
442 	rcu_read_unlock();
443 	return true;
444 }
445 
446 /* Are any of the TX qdiscs changing?  */
447 static inline bool qdisc_tx_changing(const struct net_device *dev)
448 {
449 	unsigned int i;
450 
451 	for (i = 0; i < dev->num_tx_queues; i++) {
452 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
453 		if (rcu_access_pointer(txq->qdisc) != txq->qdisc_sleeping)
454 			return true;
455 	}
456 	return false;
457 }
458 
459 /* Is the device using the noop qdisc on all queues?  */
460 static inline bool qdisc_tx_is_noop(const struct net_device *dev)
461 {
462 	unsigned int i;
463 
464 	for (i = 0; i < dev->num_tx_queues; i++) {
465 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
466 		if (rcu_access_pointer(txq->qdisc) != &noop_qdisc)
467 			return false;
468 	}
469 	return true;
470 }
471 
472 static inline unsigned int qdisc_pkt_len(const struct sk_buff *skb)
473 {
474 	return qdisc_skb_cb(skb)->pkt_len;
475 }
476 
477 /* additional qdisc xmit flags (NET_XMIT_MASK in linux/netdevice.h) */
478 enum net_xmit_qdisc_t {
479 	__NET_XMIT_STOLEN = 0x00010000,
480 	__NET_XMIT_BYPASS = 0x00020000,
481 };
482 
483 #ifdef CONFIG_NET_CLS_ACT
484 #define net_xmit_drop_count(e)	((e) & __NET_XMIT_STOLEN ? 0 : 1)
485 #else
486 #define net_xmit_drop_count(e)	(1)
487 #endif
488 
489 static inline void qdisc_calculate_pkt_len(struct sk_buff *skb,
490 					   const struct Qdisc *sch)
491 {
492 #ifdef CONFIG_NET_SCHED
493 	struct qdisc_size_table *stab = rcu_dereference_bh(sch->stab);
494 
495 	if (stab)
496 		__qdisc_calculate_pkt_len(skb, stab);
497 #endif
498 }
499 
500 static inline int qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
501 {
502 	qdisc_calculate_pkt_len(skb, sch);
503 	return sch->enqueue(skb, sch);
504 }
505 
506 static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
507 {
508 	return q->flags & TCQ_F_CPUSTATS;
509 }
510 
511 static inline void bstats_update(struct gnet_stats_basic_packed *bstats,
512 				 const struct sk_buff *skb)
513 {
514 	bstats->bytes += qdisc_pkt_len(skb);
515 	bstats->packets += skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 1;
516 }
517 
518 static inline void bstats_cpu_update(struct gnet_stats_basic_cpu *bstats,
519 				     const struct sk_buff *skb)
520 {
521 	u64_stats_update_begin(&bstats->syncp);
522 	bstats_update(&bstats->bstats, skb);
523 	u64_stats_update_end(&bstats->syncp);
524 }
525 
526 static inline void qdisc_bstats_cpu_update(struct Qdisc *sch,
527 					   const struct sk_buff *skb)
528 {
529 	bstats_cpu_update(this_cpu_ptr(sch->cpu_bstats), skb);
530 }
531 
532 static inline void qdisc_bstats_update(struct Qdisc *sch,
533 				       const struct sk_buff *skb)
534 {
535 	bstats_update(&sch->bstats, skb);
536 }
537 
538 static inline void qdisc_qstats_backlog_dec(struct Qdisc *sch,
539 					    const struct sk_buff *skb)
540 {
541 	sch->qstats.backlog -= qdisc_pkt_len(skb);
542 }
543 
544 static inline void qdisc_qstats_backlog_inc(struct Qdisc *sch,
545 					    const struct sk_buff *skb)
546 {
547 	sch->qstats.backlog += qdisc_pkt_len(skb);
548 }
549 
550 static inline void __qdisc_qstats_drop(struct Qdisc *sch, int count)
551 {
552 	sch->qstats.drops += count;
553 }
554 
555 static inline void qstats_drop_inc(struct gnet_stats_queue *qstats)
556 {
557 	qstats->drops++;
558 }
559 
560 static inline void qstats_overlimit_inc(struct gnet_stats_queue *qstats)
561 {
562 	qstats->overlimits++;
563 }
564 
565 static inline void qdisc_qstats_drop(struct Qdisc *sch)
566 {
567 	qstats_drop_inc(&sch->qstats);
568 }
569 
570 static inline void qdisc_qstats_cpu_drop(struct Qdisc *sch)
571 {
572 	qstats_drop_inc(this_cpu_ptr(sch->cpu_qstats));
573 }
574 
575 static inline void qdisc_qstats_overlimit(struct Qdisc *sch)
576 {
577 	sch->qstats.overlimits++;
578 }
579 
580 static inline int __qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch,
581 				       struct sk_buff_head *list)
582 {
583 	__skb_queue_tail(list, skb);
584 	qdisc_qstats_backlog_inc(sch, skb);
585 
586 	return NET_XMIT_SUCCESS;
587 }
588 
589 static inline int qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch)
590 {
591 	return __qdisc_enqueue_tail(skb, sch, &sch->q);
592 }
593 
594 static inline struct sk_buff *__qdisc_dequeue_head(struct Qdisc *sch,
595 						   struct sk_buff_head *list)
596 {
597 	struct sk_buff *skb = __skb_dequeue(list);
598 
599 	if (likely(skb != NULL)) {
600 		qdisc_qstats_backlog_dec(sch, skb);
601 		qdisc_bstats_update(sch, skb);
602 	}
603 
604 	return skb;
605 }
606 
607 static inline struct sk_buff *qdisc_dequeue_head(struct Qdisc *sch)
608 {
609 	return __qdisc_dequeue_head(sch, &sch->q);
610 }
611 
612 static inline unsigned int __qdisc_queue_drop_head(struct Qdisc *sch,
613 					      struct sk_buff_head *list)
614 {
615 	struct sk_buff *skb = __skb_dequeue(list);
616 
617 	if (likely(skb != NULL)) {
618 		unsigned int len = qdisc_pkt_len(skb);
619 		qdisc_qstats_backlog_dec(sch, skb);
620 		kfree_skb(skb);
621 		return len;
622 	}
623 
624 	return 0;
625 }
626 
627 static inline unsigned int qdisc_queue_drop_head(struct Qdisc *sch)
628 {
629 	return __qdisc_queue_drop_head(sch, &sch->q);
630 }
631 
632 static inline struct sk_buff *__qdisc_dequeue_tail(struct Qdisc *sch,
633 						   struct sk_buff_head *list)
634 {
635 	struct sk_buff *skb = __skb_dequeue_tail(list);
636 
637 	if (likely(skb != NULL))
638 		qdisc_qstats_backlog_dec(sch, skb);
639 
640 	return skb;
641 }
642 
643 static inline struct sk_buff *qdisc_dequeue_tail(struct Qdisc *sch)
644 {
645 	return __qdisc_dequeue_tail(sch, &sch->q);
646 }
647 
648 static inline struct sk_buff *qdisc_peek_head(struct Qdisc *sch)
649 {
650 	return skb_peek(&sch->q);
651 }
652 
653 /* generic pseudo peek method for non-work-conserving qdisc */
654 static inline struct sk_buff *qdisc_peek_dequeued(struct Qdisc *sch)
655 {
656 	/* we can reuse ->gso_skb because peek isn't called for root qdiscs */
657 	if (!sch->gso_skb) {
658 		sch->gso_skb = sch->dequeue(sch);
659 		if (sch->gso_skb)
660 			/* it's still part of the queue */
661 			sch->q.qlen++;
662 	}
663 
664 	return sch->gso_skb;
665 }
666 
667 /* use instead of qdisc->dequeue() for all qdiscs queried with ->peek() */
668 static inline struct sk_buff *qdisc_dequeue_peeked(struct Qdisc *sch)
669 {
670 	struct sk_buff *skb = sch->gso_skb;
671 
672 	if (skb) {
673 		sch->gso_skb = NULL;
674 		sch->q.qlen--;
675 	} else {
676 		skb = sch->dequeue(sch);
677 	}
678 
679 	return skb;
680 }
681 
682 static inline void __qdisc_reset_queue(struct Qdisc *sch,
683 				       struct sk_buff_head *list)
684 {
685 	/*
686 	 * We do not know the backlog in bytes of this list, it
687 	 * is up to the caller to correct it
688 	 */
689 	__skb_queue_purge(list);
690 }
691 
692 static inline void qdisc_reset_queue(struct Qdisc *sch)
693 {
694 	__qdisc_reset_queue(sch, &sch->q);
695 	sch->qstats.backlog = 0;
696 }
697 
698 static inline unsigned int __qdisc_queue_drop(struct Qdisc *sch,
699 					      struct sk_buff_head *list)
700 {
701 	struct sk_buff *skb = __qdisc_dequeue_tail(sch, list);
702 
703 	if (likely(skb != NULL)) {
704 		unsigned int len = qdisc_pkt_len(skb);
705 		kfree_skb(skb);
706 		return len;
707 	}
708 
709 	return 0;
710 }
711 
712 static inline unsigned int qdisc_queue_drop(struct Qdisc *sch)
713 {
714 	return __qdisc_queue_drop(sch, &sch->q);
715 }
716 
717 static inline int qdisc_drop(struct sk_buff *skb, struct Qdisc *sch)
718 {
719 	kfree_skb(skb);
720 	qdisc_qstats_drop(sch);
721 
722 	return NET_XMIT_DROP;
723 }
724 
725 static inline int qdisc_reshape_fail(struct sk_buff *skb, struct Qdisc *sch)
726 {
727 	qdisc_qstats_drop(sch);
728 
729 #ifdef CONFIG_NET_CLS_ACT
730 	if (sch->reshape_fail == NULL || sch->reshape_fail(skb, sch))
731 		goto drop;
732 
733 	return NET_XMIT_SUCCESS;
734 
735 drop:
736 #endif
737 	kfree_skb(skb);
738 	return NET_XMIT_DROP;
739 }
740 
741 /* Length to Time (L2T) lookup in a qdisc_rate_table, to determine how
742    long it will take to send a packet given its size.
743  */
744 static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen)
745 {
746 	int slot = pktlen + rtab->rate.cell_align + rtab->rate.overhead;
747 	if (slot < 0)
748 		slot = 0;
749 	slot >>= rtab->rate.cell_log;
750 	if (slot > 255)
751 		return rtab->data[255]*(slot >> 8) + rtab->data[slot & 0xFF];
752 	return rtab->data[slot];
753 }
754 
755 struct psched_ratecfg {
756 	u64	rate_bytes_ps; /* bytes per second */
757 	u32	mult;
758 	u16	overhead;
759 	u8	linklayer;
760 	u8	shift;
761 };
762 
763 static inline u64 psched_l2t_ns(const struct psched_ratecfg *r,
764 				unsigned int len)
765 {
766 	len += r->overhead;
767 
768 	if (unlikely(r->linklayer == TC_LINKLAYER_ATM))
769 		return ((u64)(DIV_ROUND_UP(len,48)*53) * r->mult) >> r->shift;
770 
771 	return ((u64)len * r->mult) >> r->shift;
772 }
773 
774 void psched_ratecfg_precompute(struct psched_ratecfg *r,
775 			       const struct tc_ratespec *conf,
776 			       u64 rate64);
777 
778 static inline void psched_ratecfg_getrate(struct tc_ratespec *res,
779 					  const struct psched_ratecfg *r)
780 {
781 	memset(res, 0, sizeof(*res));
782 
783 	/* legacy struct tc_ratespec has a 32bit @rate field
784 	 * Qdisc using 64bit rate should add new attributes
785 	 * in order to maintain compatibility.
786 	 */
787 	res->rate = min_t(u64, r->rate_bytes_ps, ~0U);
788 
789 	res->overhead = r->overhead;
790 	res->linklayer = (r->linklayer & TC_LINKLAYER_MASK);
791 }
792 
793 #endif
794