xref: /openbmc/linux/include/net/sch_generic.h (revision 6774def6)
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 	void			(*put)(struct tcf_proto*, unsigned long);
223 	int			(*change)(struct net *net, struct sk_buff *,
224 					struct tcf_proto*, unsigned long,
225 					u32 handle, struct nlattr **,
226 					unsigned long *, bool);
227 	int			(*delete)(struct tcf_proto*, unsigned long);
228 	void			(*walk)(struct tcf_proto*, struct tcf_walker *arg);
229 
230 	/* rtnetlink specific */
231 	int			(*dump)(struct net*, struct tcf_proto*, unsigned long,
232 					struct sk_buff *skb, struct tcmsg*);
233 
234 	struct module		*owner;
235 };
236 
237 struct tcf_proto {
238 	/* Fast access part */
239 	struct tcf_proto __rcu	*next;
240 	void __rcu		*root;
241 	int			(*classify)(struct sk_buff *,
242 					    const struct tcf_proto *,
243 					    struct tcf_result *);
244 	__be16			protocol;
245 
246 	/* All the rest */
247 	u32			prio;
248 	u32			classid;
249 	struct Qdisc		*q;
250 	void			*data;
251 	const struct tcf_proto_ops	*ops;
252 	struct rcu_head		rcu;
253 };
254 
255 struct qdisc_skb_cb {
256 	unsigned int		pkt_len;
257 	u16			slave_dev_queue_mapping;
258 	u16			_pad;
259 #define QDISC_CB_PRIV_LEN 20
260 	unsigned char		data[QDISC_CB_PRIV_LEN];
261 };
262 
263 static inline void qdisc_cb_private_validate(const struct sk_buff *skb, int sz)
264 {
265 	struct qdisc_skb_cb *qcb;
266 
267 	BUILD_BUG_ON(sizeof(skb->cb) < offsetof(struct qdisc_skb_cb, data) + sz);
268 	BUILD_BUG_ON(sizeof(qcb->data) < sz);
269 }
270 
271 static inline int qdisc_qlen(const struct Qdisc *q)
272 {
273 	return q->q.qlen;
274 }
275 
276 static inline struct qdisc_skb_cb *qdisc_skb_cb(const struct sk_buff *skb)
277 {
278 	return (struct qdisc_skb_cb *)skb->cb;
279 }
280 
281 static inline spinlock_t *qdisc_lock(struct Qdisc *qdisc)
282 {
283 	return &qdisc->q.lock;
284 }
285 
286 static inline struct Qdisc *qdisc_root(const struct Qdisc *qdisc)
287 {
288 	struct Qdisc *q = rcu_dereference_rtnl(qdisc->dev_queue->qdisc);
289 
290 	return q;
291 }
292 
293 static inline struct Qdisc *qdisc_root_sleeping(const struct Qdisc *qdisc)
294 {
295 	return qdisc->dev_queue->qdisc_sleeping;
296 }
297 
298 /* The qdisc root lock is a mechanism by which to top level
299  * of a qdisc tree can be locked from any qdisc node in the
300  * forest.  This allows changing the configuration of some
301  * aspect of the qdisc tree while blocking out asynchronous
302  * qdisc access in the packet processing paths.
303  *
304  * It is only legal to do this when the root will not change
305  * on us.  Otherwise we'll potentially lock the wrong qdisc
306  * root.  This is enforced by holding the RTNL semaphore, which
307  * all users of this lock accessor must do.
308  */
309 static inline spinlock_t *qdisc_root_lock(const struct Qdisc *qdisc)
310 {
311 	struct Qdisc *root = qdisc_root(qdisc);
312 
313 	ASSERT_RTNL();
314 	return qdisc_lock(root);
315 }
316 
317 static inline spinlock_t *qdisc_root_sleeping_lock(const struct Qdisc *qdisc)
318 {
319 	struct Qdisc *root = qdisc_root_sleeping(qdisc);
320 
321 	ASSERT_RTNL();
322 	return qdisc_lock(root);
323 }
324 
325 static inline struct net_device *qdisc_dev(const struct Qdisc *qdisc)
326 {
327 	return qdisc->dev_queue->dev;
328 }
329 
330 static inline void sch_tree_lock(const struct Qdisc *q)
331 {
332 	spin_lock_bh(qdisc_root_sleeping_lock(q));
333 }
334 
335 static inline void sch_tree_unlock(const struct Qdisc *q)
336 {
337 	spin_unlock_bh(qdisc_root_sleeping_lock(q));
338 }
339 
340 #define tcf_tree_lock(tp)	sch_tree_lock((tp)->q)
341 #define tcf_tree_unlock(tp)	sch_tree_unlock((tp)->q)
342 
343 extern struct Qdisc noop_qdisc;
344 extern struct Qdisc_ops noop_qdisc_ops;
345 extern struct Qdisc_ops pfifo_fast_ops;
346 extern struct Qdisc_ops mq_qdisc_ops;
347 extern const struct Qdisc_ops *default_qdisc_ops;
348 
349 struct Qdisc_class_common {
350 	u32			classid;
351 	struct hlist_node	hnode;
352 };
353 
354 struct Qdisc_class_hash {
355 	struct hlist_head	*hash;
356 	unsigned int		hashsize;
357 	unsigned int		hashmask;
358 	unsigned int		hashelems;
359 };
360 
361 static inline unsigned int qdisc_class_hash(u32 id, u32 mask)
362 {
363 	id ^= id >> 8;
364 	id ^= id >> 4;
365 	return id & mask;
366 }
367 
368 static inline struct Qdisc_class_common *
369 qdisc_class_find(const struct Qdisc_class_hash *hash, u32 id)
370 {
371 	struct Qdisc_class_common *cl;
372 	unsigned int h;
373 
374 	h = qdisc_class_hash(id, hash->hashmask);
375 	hlist_for_each_entry(cl, &hash->hash[h], hnode) {
376 		if (cl->classid == id)
377 			return cl;
378 	}
379 	return NULL;
380 }
381 
382 int qdisc_class_hash_init(struct Qdisc_class_hash *);
383 void qdisc_class_hash_insert(struct Qdisc_class_hash *,
384 			     struct Qdisc_class_common *);
385 void qdisc_class_hash_remove(struct Qdisc_class_hash *,
386 			     struct Qdisc_class_common *);
387 void qdisc_class_hash_grow(struct Qdisc *, struct Qdisc_class_hash *);
388 void qdisc_class_hash_destroy(struct Qdisc_class_hash *);
389 
390 void dev_init_scheduler(struct net_device *dev);
391 void dev_shutdown(struct net_device *dev);
392 void dev_activate(struct net_device *dev);
393 void dev_deactivate(struct net_device *dev);
394 void dev_deactivate_many(struct list_head *head);
395 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
396 			      struct Qdisc *qdisc);
397 void qdisc_reset(struct Qdisc *qdisc);
398 void qdisc_destroy(struct Qdisc *qdisc);
399 void qdisc_tree_decrease_qlen(struct Qdisc *qdisc, unsigned int n);
400 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
401 			  const struct Qdisc_ops *ops);
402 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
403 				const struct Qdisc_ops *ops, u32 parentid);
404 void __qdisc_calculate_pkt_len(struct sk_buff *skb,
405 			       const struct qdisc_size_table *stab);
406 void tcf_destroy(struct tcf_proto *tp);
407 void tcf_destroy_chain(struct tcf_proto __rcu **fl);
408 
409 /* Reset all TX qdiscs greater then index of a device.  */
410 static inline void qdisc_reset_all_tx_gt(struct net_device *dev, unsigned int i)
411 {
412 	struct Qdisc *qdisc;
413 
414 	for (; i < dev->num_tx_queues; i++) {
415 		qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc);
416 		if (qdisc) {
417 			spin_lock_bh(qdisc_lock(qdisc));
418 			qdisc_reset(qdisc);
419 			spin_unlock_bh(qdisc_lock(qdisc));
420 		}
421 	}
422 }
423 
424 static inline void qdisc_reset_all_tx(struct net_device *dev)
425 {
426 	qdisc_reset_all_tx_gt(dev, 0);
427 }
428 
429 /* Are all TX queues of the device empty?  */
430 static inline bool qdisc_all_tx_empty(const struct net_device *dev)
431 {
432 	unsigned int i;
433 
434 	rcu_read_lock();
435 	for (i = 0; i < dev->num_tx_queues; i++) {
436 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
437 		const struct Qdisc *q = rcu_dereference(txq->qdisc);
438 
439 		if (q->q.qlen) {
440 			rcu_read_unlock();
441 			return false;
442 		}
443 	}
444 	rcu_read_unlock();
445 	return true;
446 }
447 
448 /* Are any of the TX qdiscs changing?  */
449 static inline bool qdisc_tx_changing(const struct net_device *dev)
450 {
451 	unsigned int i;
452 
453 	for (i = 0; i < dev->num_tx_queues; i++) {
454 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
455 		if (rcu_access_pointer(txq->qdisc) != txq->qdisc_sleeping)
456 			return true;
457 	}
458 	return false;
459 }
460 
461 /* Is the device using the noop qdisc on all queues?  */
462 static inline bool qdisc_tx_is_noop(const struct net_device *dev)
463 {
464 	unsigned int i;
465 
466 	for (i = 0; i < dev->num_tx_queues; i++) {
467 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
468 		if (rcu_access_pointer(txq->qdisc) != &noop_qdisc)
469 			return false;
470 	}
471 	return true;
472 }
473 
474 static inline unsigned int qdisc_pkt_len(const struct sk_buff *skb)
475 {
476 	return qdisc_skb_cb(skb)->pkt_len;
477 }
478 
479 /* additional qdisc xmit flags (NET_XMIT_MASK in linux/netdevice.h) */
480 enum net_xmit_qdisc_t {
481 	__NET_XMIT_STOLEN = 0x00010000,
482 	__NET_XMIT_BYPASS = 0x00020000,
483 };
484 
485 #ifdef CONFIG_NET_CLS_ACT
486 #define net_xmit_drop_count(e)	((e) & __NET_XMIT_STOLEN ? 0 : 1)
487 #else
488 #define net_xmit_drop_count(e)	(1)
489 #endif
490 
491 static inline void qdisc_calculate_pkt_len(struct sk_buff *skb,
492 					   const struct Qdisc *sch)
493 {
494 #ifdef CONFIG_NET_SCHED
495 	struct qdisc_size_table *stab = rcu_dereference_bh(sch->stab);
496 
497 	if (stab)
498 		__qdisc_calculate_pkt_len(skb, stab);
499 #endif
500 }
501 
502 static inline int qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
503 {
504 	qdisc_calculate_pkt_len(skb, sch);
505 	return sch->enqueue(skb, sch);
506 }
507 
508 static inline int qdisc_enqueue_root(struct sk_buff *skb, struct Qdisc *sch)
509 {
510 	qdisc_skb_cb(skb)->pkt_len = skb->len;
511 	return qdisc_enqueue(skb, sch) & NET_XMIT_MASK;
512 }
513 
514 static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
515 {
516 	return q->flags & TCQ_F_CPUSTATS;
517 }
518 
519 static inline void bstats_update(struct gnet_stats_basic_packed *bstats,
520 				 const struct sk_buff *skb)
521 {
522 	bstats->bytes += qdisc_pkt_len(skb);
523 	bstats->packets += skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 1;
524 }
525 
526 static inline void qdisc_bstats_update_cpu(struct Qdisc *sch,
527 					   const struct sk_buff *skb)
528 {
529 	struct gnet_stats_basic_cpu *bstats =
530 				this_cpu_ptr(sch->cpu_bstats);
531 
532 	u64_stats_update_begin(&bstats->syncp);
533 	bstats_update(&bstats->bstats, skb);
534 	u64_stats_update_end(&bstats->syncp);
535 }
536 
537 static inline void qdisc_bstats_update(struct Qdisc *sch,
538 				       const struct sk_buff *skb)
539 {
540 	bstats_update(&sch->bstats, skb);
541 }
542 
543 static inline void qdisc_qstats_backlog_dec(struct Qdisc *sch,
544 					    const struct sk_buff *skb)
545 {
546 	sch->qstats.backlog -= qdisc_pkt_len(skb);
547 }
548 
549 static inline void qdisc_qstats_backlog_inc(struct Qdisc *sch,
550 					    const struct sk_buff *skb)
551 {
552 	sch->qstats.backlog += qdisc_pkt_len(skb);
553 }
554 
555 static inline void __qdisc_qstats_drop(struct Qdisc *sch, int count)
556 {
557 	sch->qstats.drops += count;
558 }
559 
560 static inline void qdisc_qstats_drop(struct Qdisc *sch)
561 {
562 	sch->qstats.drops++;
563 }
564 
565 static inline void qdisc_qstats_drop_cpu(struct Qdisc *sch)
566 {
567 	struct gnet_stats_queue *qstats = this_cpu_ptr(sch->cpu_qstats);
568 
569 	qstats->drops++;
570 }
571 
572 static inline void qdisc_qstats_overlimit(struct Qdisc *sch)
573 {
574 	sch->qstats.overlimits++;
575 }
576 
577 static inline int __qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch,
578 				       struct sk_buff_head *list)
579 {
580 	__skb_queue_tail(list, skb);
581 	qdisc_qstats_backlog_inc(sch, skb);
582 
583 	return NET_XMIT_SUCCESS;
584 }
585 
586 static inline int qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch)
587 {
588 	return __qdisc_enqueue_tail(skb, sch, &sch->q);
589 }
590 
591 static inline struct sk_buff *__qdisc_dequeue_head(struct Qdisc *sch,
592 						   struct sk_buff_head *list)
593 {
594 	struct sk_buff *skb = __skb_dequeue(list);
595 
596 	if (likely(skb != NULL)) {
597 		qdisc_qstats_backlog_dec(sch, skb);
598 		qdisc_bstats_update(sch, skb);
599 	}
600 
601 	return skb;
602 }
603 
604 static inline struct sk_buff *qdisc_dequeue_head(struct Qdisc *sch)
605 {
606 	return __qdisc_dequeue_head(sch, &sch->q);
607 }
608 
609 static inline unsigned int __qdisc_queue_drop_head(struct Qdisc *sch,
610 					      struct sk_buff_head *list)
611 {
612 	struct sk_buff *skb = __skb_dequeue(list);
613 
614 	if (likely(skb != NULL)) {
615 		unsigned int len = qdisc_pkt_len(skb);
616 		qdisc_qstats_backlog_dec(sch, skb);
617 		kfree_skb(skb);
618 		return len;
619 	}
620 
621 	return 0;
622 }
623 
624 static inline unsigned int qdisc_queue_drop_head(struct Qdisc *sch)
625 {
626 	return __qdisc_queue_drop_head(sch, &sch->q);
627 }
628 
629 static inline struct sk_buff *__qdisc_dequeue_tail(struct Qdisc *sch,
630 						   struct sk_buff_head *list)
631 {
632 	struct sk_buff *skb = __skb_dequeue_tail(list);
633 
634 	if (likely(skb != NULL))
635 		qdisc_qstats_backlog_dec(sch, skb);
636 
637 	return skb;
638 }
639 
640 static inline struct sk_buff *qdisc_dequeue_tail(struct Qdisc *sch)
641 {
642 	return __qdisc_dequeue_tail(sch, &sch->q);
643 }
644 
645 static inline struct sk_buff *qdisc_peek_head(struct Qdisc *sch)
646 {
647 	return skb_peek(&sch->q);
648 }
649 
650 /* generic pseudo peek method for non-work-conserving qdisc */
651 static inline struct sk_buff *qdisc_peek_dequeued(struct Qdisc *sch)
652 {
653 	/* we can reuse ->gso_skb because peek isn't called for root qdiscs */
654 	if (!sch->gso_skb) {
655 		sch->gso_skb = sch->dequeue(sch);
656 		if (sch->gso_skb)
657 			/* it's still part of the queue */
658 			sch->q.qlen++;
659 	}
660 
661 	return sch->gso_skb;
662 }
663 
664 /* use instead of qdisc->dequeue() for all qdiscs queried with ->peek() */
665 static inline struct sk_buff *qdisc_dequeue_peeked(struct Qdisc *sch)
666 {
667 	struct sk_buff *skb = sch->gso_skb;
668 
669 	if (skb) {
670 		sch->gso_skb = NULL;
671 		sch->q.qlen--;
672 	} else {
673 		skb = sch->dequeue(sch);
674 	}
675 
676 	return skb;
677 }
678 
679 static inline void __qdisc_reset_queue(struct Qdisc *sch,
680 				       struct sk_buff_head *list)
681 {
682 	/*
683 	 * We do not know the backlog in bytes of this list, it
684 	 * is up to the caller to correct it
685 	 */
686 	__skb_queue_purge(list);
687 }
688 
689 static inline void qdisc_reset_queue(struct Qdisc *sch)
690 {
691 	__qdisc_reset_queue(sch, &sch->q);
692 	sch->qstats.backlog = 0;
693 }
694 
695 static inline unsigned int __qdisc_queue_drop(struct Qdisc *sch,
696 					      struct sk_buff_head *list)
697 {
698 	struct sk_buff *skb = __qdisc_dequeue_tail(sch, list);
699 
700 	if (likely(skb != NULL)) {
701 		unsigned int len = qdisc_pkt_len(skb);
702 		kfree_skb(skb);
703 		return len;
704 	}
705 
706 	return 0;
707 }
708 
709 static inline unsigned int qdisc_queue_drop(struct Qdisc *sch)
710 {
711 	return __qdisc_queue_drop(sch, &sch->q);
712 }
713 
714 static inline int qdisc_drop(struct sk_buff *skb, struct Qdisc *sch)
715 {
716 	kfree_skb(skb);
717 	qdisc_qstats_drop(sch);
718 
719 	return NET_XMIT_DROP;
720 }
721 
722 static inline int qdisc_reshape_fail(struct sk_buff *skb, struct Qdisc *sch)
723 {
724 	qdisc_qstats_drop(sch);
725 
726 #ifdef CONFIG_NET_CLS_ACT
727 	if (sch->reshape_fail == NULL || sch->reshape_fail(skb, sch))
728 		goto drop;
729 
730 	return NET_XMIT_SUCCESS;
731 
732 drop:
733 #endif
734 	kfree_skb(skb);
735 	return NET_XMIT_DROP;
736 }
737 
738 /* Length to Time (L2T) lookup in a qdisc_rate_table, to determine how
739    long it will take to send a packet given its size.
740  */
741 static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen)
742 {
743 	int slot = pktlen + rtab->rate.cell_align + rtab->rate.overhead;
744 	if (slot < 0)
745 		slot = 0;
746 	slot >>= rtab->rate.cell_log;
747 	if (slot > 255)
748 		return rtab->data[255]*(slot >> 8) + rtab->data[slot & 0xFF];
749 	return rtab->data[slot];
750 }
751 
752 #ifdef CONFIG_NET_CLS_ACT
753 static inline struct sk_buff *skb_act_clone(struct sk_buff *skb, gfp_t gfp_mask,
754 					    int action)
755 {
756 	struct sk_buff *n;
757 
758 	n = skb_clone(skb, gfp_mask);
759 
760 	if (n) {
761 		n->tc_verd = SET_TC_VERD(n->tc_verd, 0);
762 		n->tc_verd = CLR_TC_OK2MUNGE(n->tc_verd);
763 		n->tc_verd = CLR_TC_MUNGED(n->tc_verd);
764 	}
765 	return n;
766 }
767 #endif
768 
769 struct psched_ratecfg {
770 	u64	rate_bytes_ps; /* bytes per second */
771 	u32	mult;
772 	u16	overhead;
773 	u8	linklayer;
774 	u8	shift;
775 };
776 
777 static inline u64 psched_l2t_ns(const struct psched_ratecfg *r,
778 				unsigned int len)
779 {
780 	len += r->overhead;
781 
782 	if (unlikely(r->linklayer == TC_LINKLAYER_ATM))
783 		return ((u64)(DIV_ROUND_UP(len,48)*53) * r->mult) >> r->shift;
784 
785 	return ((u64)len * r->mult) >> r->shift;
786 }
787 
788 void psched_ratecfg_precompute(struct psched_ratecfg *r,
789 			       const struct tc_ratespec *conf,
790 			       u64 rate64);
791 
792 static inline void psched_ratecfg_getrate(struct tc_ratespec *res,
793 					  const struct psched_ratecfg *r)
794 {
795 	memset(res, 0, sizeof(*res));
796 
797 	/* legacy struct tc_ratespec has a 32bit @rate field
798 	 * Qdisc using 64bit rate should add new attributes
799 	 * in order to maintain compatibility.
800 	 */
801 	res->rate = min_t(u64, r->rate_bytes_ps, ~0U);
802 
803 	res->overhead = r->overhead;
804 	res->linklayer = (r->linklayer & TC_LINKLAYER_MASK);
805 }
806 
807 #endif
808