xref: /linux/include/net/sch_generic.h (revision 40e79150c1686263e6a031d7702aec63aff31332)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __NET_SCHED_GENERIC_H
3 #define __NET_SCHED_GENERIC_H
4 
5 #include <linux/netdevice.h>
6 #include <linux/types.h>
7 #include <linux/rcupdate.h>
8 #include <linux/pkt_sched.h>
9 #include <linux/pkt_cls.h>
10 #include <linux/percpu.h>
11 #include <linux/dynamic_queue_limits.h>
12 #include <linux/list.h>
13 #include <linux/refcount.h>
14 #include <linux/workqueue.h>
15 #include <linux/mutex.h>
16 #include <linux/rwsem.h>
17 #include <linux/atomic.h>
18 #include <linux/hashtable.h>
19 #include <net/gen_stats.h>
20 #include <net/rtnetlink.h>
21 #include <net/flow_offload.h>
22 
23 struct Qdisc_ops;
24 struct qdisc_walker;
25 struct tcf_walker;
26 struct module;
27 struct bpf_flow_keys;
28 
29 struct qdisc_rate_table {
30 	struct tc_ratespec rate;
31 	u32		data[256];
32 	struct qdisc_rate_table *next;
33 	int		refcnt;
34 };
35 
36 enum qdisc_state_t {
37 	__QDISC_STATE_SCHED,
38 	__QDISC_STATE_DEACTIVATED,
39 };
40 
41 struct qdisc_size_table {
42 	struct rcu_head		rcu;
43 	struct list_head	list;
44 	struct tc_sizespec	szopts;
45 	int			refcnt;
46 	u16			data[];
47 };
48 
49 /* similar to sk_buff_head, but skb->prev pointer is undefined. */
50 struct qdisc_skb_head {
51 	struct sk_buff	*head;
52 	struct sk_buff	*tail;
53 	__u32		qlen;
54 	spinlock_t	lock;
55 };
56 
57 struct Qdisc {
58 	int 			(*enqueue)(struct sk_buff *skb,
59 					   struct Qdisc *sch,
60 					   struct sk_buff **to_free);
61 	struct sk_buff *	(*dequeue)(struct Qdisc *sch);
62 	unsigned int		flags;
63 #define TCQ_F_BUILTIN		1
64 #define TCQ_F_INGRESS		2
65 #define TCQ_F_CAN_BYPASS	4
66 #define TCQ_F_MQROOT		8
67 #define TCQ_F_ONETXQUEUE	0x10 /* dequeue_skb() can assume all skbs are for
68 				      * q->dev_queue : It can test
69 				      * netif_xmit_frozen_or_stopped() before
70 				      * dequeueing next packet.
71 				      * Its true for MQ/MQPRIO slaves, or non
72 				      * multiqueue device.
73 				      */
74 #define TCQ_F_WARN_NONWC	(1 << 16)
75 #define TCQ_F_CPUSTATS		0x20 /* run using percpu statistics */
76 #define TCQ_F_NOPARENT		0x40 /* root of its hierarchy :
77 				      * qdisc_tree_decrease_qlen() should stop.
78 				      */
79 #define TCQ_F_INVISIBLE		0x80 /* invisible by default in dump */
80 #define TCQ_F_NOLOCK		0x100 /* qdisc does not require locking */
81 #define TCQ_F_OFFLOADED		0x200 /* qdisc is offloaded to HW */
82 	u32			limit;
83 	const struct Qdisc_ops	*ops;
84 	struct qdisc_size_table	__rcu *stab;
85 	struct hlist_node       hash;
86 	u32			handle;
87 	u32			parent;
88 
89 	struct netdev_queue	*dev_queue;
90 
91 	struct net_rate_estimator __rcu *rate_est;
92 	struct gnet_stats_basic_cpu __percpu *cpu_bstats;
93 	struct gnet_stats_queue	__percpu *cpu_qstats;
94 	int			padded;
95 	refcount_t		refcnt;
96 
97 	/*
98 	 * For performance sake on SMP, we put highly modified fields at the end
99 	 */
100 	struct sk_buff_head	gso_skb ____cacheline_aligned_in_smp;
101 	struct qdisc_skb_head	q;
102 	struct gnet_stats_basic_packed bstats;
103 	seqcount_t		running;
104 	struct gnet_stats_queue	qstats;
105 	unsigned long		state;
106 	struct Qdisc            *next_sched;
107 	struct sk_buff_head	skb_bad_txq;
108 
109 	spinlock_t		busylock ____cacheline_aligned_in_smp;
110 	spinlock_t		seqlock;
111 
112 	/* for NOLOCK qdisc, true if there are no enqueued skbs */
113 	bool			empty;
114 	struct rcu_head		rcu;
115 };
116 
117 static inline void qdisc_refcount_inc(struct Qdisc *qdisc)
118 {
119 	if (qdisc->flags & TCQ_F_BUILTIN)
120 		return;
121 	refcount_inc(&qdisc->refcnt);
122 }
123 
124 /* Intended to be used by unlocked users, when concurrent qdisc release is
125  * possible.
126  */
127 
128 static inline struct Qdisc *qdisc_refcount_inc_nz(struct Qdisc *qdisc)
129 {
130 	if (qdisc->flags & TCQ_F_BUILTIN)
131 		return qdisc;
132 	if (refcount_inc_not_zero(&qdisc->refcnt))
133 		return qdisc;
134 	return NULL;
135 }
136 
137 static inline bool qdisc_is_running(struct Qdisc *qdisc)
138 {
139 	if (qdisc->flags & TCQ_F_NOLOCK)
140 		return spin_is_locked(&qdisc->seqlock);
141 	return (raw_read_seqcount(&qdisc->running) & 1) ? true : false;
142 }
143 
144 static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
145 {
146 	return q->flags & TCQ_F_CPUSTATS;
147 }
148 
149 static inline bool qdisc_is_empty(const struct Qdisc *qdisc)
150 {
151 	if (qdisc_is_percpu_stats(qdisc))
152 		return READ_ONCE(qdisc->empty);
153 	return !READ_ONCE(qdisc->q.qlen);
154 }
155 
156 static inline bool qdisc_run_begin(struct Qdisc *qdisc)
157 {
158 	if (qdisc->flags & TCQ_F_NOLOCK) {
159 		if (!spin_trylock(&qdisc->seqlock))
160 			return false;
161 		WRITE_ONCE(qdisc->empty, false);
162 	} else if (qdisc_is_running(qdisc)) {
163 		return false;
164 	}
165 	/* Variant of write_seqcount_begin() telling lockdep a trylock
166 	 * was attempted.
167 	 */
168 	raw_write_seqcount_begin(&qdisc->running);
169 	seqcount_acquire(&qdisc->running.dep_map, 0, 1, _RET_IP_);
170 	return true;
171 }
172 
173 static inline void qdisc_run_end(struct Qdisc *qdisc)
174 {
175 	write_seqcount_end(&qdisc->running);
176 	if (qdisc->flags & TCQ_F_NOLOCK)
177 		spin_unlock(&qdisc->seqlock);
178 }
179 
180 static inline bool qdisc_may_bulk(const struct Qdisc *qdisc)
181 {
182 	return qdisc->flags & TCQ_F_ONETXQUEUE;
183 }
184 
185 static inline int qdisc_avail_bulklimit(const struct netdev_queue *txq)
186 {
187 #ifdef CONFIG_BQL
188 	/* Non-BQL migrated drivers will return 0, too. */
189 	return dql_avail(&txq->dql);
190 #else
191 	return 0;
192 #endif
193 }
194 
195 struct Qdisc_class_ops {
196 	unsigned int		flags;
197 	/* Child qdisc manipulation */
198 	struct netdev_queue *	(*select_queue)(struct Qdisc *, struct tcmsg *);
199 	int			(*graft)(struct Qdisc *, unsigned long cl,
200 					struct Qdisc *, struct Qdisc **,
201 					struct netlink_ext_ack *extack);
202 	struct Qdisc *		(*leaf)(struct Qdisc *, unsigned long cl);
203 	void			(*qlen_notify)(struct Qdisc *, unsigned long);
204 
205 	/* Class manipulation routines */
206 	unsigned long		(*find)(struct Qdisc *, u32 classid);
207 	int			(*change)(struct Qdisc *, u32, u32,
208 					struct nlattr **, unsigned long *,
209 					struct netlink_ext_ack *);
210 	int			(*delete)(struct Qdisc *, unsigned long);
211 	void			(*walk)(struct Qdisc *, struct qdisc_walker * arg);
212 
213 	/* Filter manipulation */
214 	struct tcf_block *	(*tcf_block)(struct Qdisc *sch,
215 					     unsigned long arg,
216 					     struct netlink_ext_ack *extack);
217 	unsigned long		(*bind_tcf)(struct Qdisc *, unsigned long,
218 					u32 classid);
219 	void			(*unbind_tcf)(struct Qdisc *, unsigned long);
220 
221 	/* rtnetlink specific */
222 	int			(*dump)(struct Qdisc *, unsigned long,
223 					struct sk_buff *skb, struct tcmsg*);
224 	int			(*dump_stats)(struct Qdisc *, unsigned long,
225 					struct gnet_dump *);
226 };
227 
228 /* Qdisc_class_ops flag values */
229 
230 /* Implements API that doesn't require rtnl lock */
231 enum qdisc_class_ops_flags {
232 	QDISC_CLASS_OPS_DOIT_UNLOCKED = 1,
233 };
234 
235 struct Qdisc_ops {
236 	struct Qdisc_ops	*next;
237 	const struct Qdisc_class_ops	*cl_ops;
238 	char			id[IFNAMSIZ];
239 	int			priv_size;
240 	unsigned int		static_flags;
241 
242 	int 			(*enqueue)(struct sk_buff *skb,
243 					   struct Qdisc *sch,
244 					   struct sk_buff **to_free);
245 	struct sk_buff *	(*dequeue)(struct Qdisc *);
246 	struct sk_buff *	(*peek)(struct Qdisc *);
247 
248 	int			(*init)(struct Qdisc *sch, struct nlattr *arg,
249 					struct netlink_ext_ack *extack);
250 	void			(*reset)(struct Qdisc *);
251 	void			(*destroy)(struct Qdisc *);
252 	int			(*change)(struct Qdisc *sch,
253 					  struct nlattr *arg,
254 					  struct netlink_ext_ack *extack);
255 	void			(*attach)(struct Qdisc *sch);
256 	int			(*change_tx_queue_len)(struct Qdisc *, unsigned int);
257 
258 	int			(*dump)(struct Qdisc *, struct sk_buff *);
259 	int			(*dump_stats)(struct Qdisc *, struct gnet_dump *);
260 
261 	void			(*ingress_block_set)(struct Qdisc *sch,
262 						     u32 block_index);
263 	void			(*egress_block_set)(struct Qdisc *sch,
264 						    u32 block_index);
265 	u32			(*ingress_block_get)(struct Qdisc *sch);
266 	u32			(*egress_block_get)(struct Qdisc *sch);
267 
268 	struct module		*owner;
269 };
270 
271 
272 struct tcf_result {
273 	union {
274 		struct {
275 			unsigned long	class;
276 			u32		classid;
277 		};
278 		const struct tcf_proto *goto_tp;
279 
280 		/* used in the skb_tc_reinsert function */
281 		struct {
282 			bool		ingress;
283 			struct gnet_stats_queue *qstats;
284 		};
285 	};
286 };
287 
288 struct tcf_chain;
289 
290 struct tcf_proto_ops {
291 	struct list_head	head;
292 	char			kind[IFNAMSIZ];
293 
294 	int			(*classify)(struct sk_buff *,
295 					    const struct tcf_proto *,
296 					    struct tcf_result *);
297 	int			(*init)(struct tcf_proto*);
298 	void			(*destroy)(struct tcf_proto *tp, bool rtnl_held,
299 					   struct netlink_ext_ack *extack);
300 
301 	void*			(*get)(struct tcf_proto*, u32 handle);
302 	void			(*put)(struct tcf_proto *tp, void *f);
303 	int			(*change)(struct net *net, struct sk_buff *,
304 					struct tcf_proto*, unsigned long,
305 					u32 handle, struct nlattr **,
306 					void **, bool, bool,
307 					struct netlink_ext_ack *);
308 	int			(*delete)(struct tcf_proto *tp, void *arg,
309 					  bool *last, bool rtnl_held,
310 					  struct netlink_ext_ack *);
311 	bool			(*delete_empty)(struct tcf_proto *tp);
312 	void			(*walk)(struct tcf_proto *tp,
313 					struct tcf_walker *arg, bool rtnl_held);
314 	int			(*reoffload)(struct tcf_proto *tp, bool add,
315 					     flow_setup_cb_t *cb, void *cb_priv,
316 					     struct netlink_ext_ack *extack);
317 	void			(*hw_add)(struct tcf_proto *tp,
318 					  void *type_data);
319 	void			(*hw_del)(struct tcf_proto *tp,
320 					  void *type_data);
321 	void			(*bind_class)(void *, u32, unsigned long,
322 					      void *, unsigned long);
323 	void *			(*tmplt_create)(struct net *net,
324 						struct tcf_chain *chain,
325 						struct nlattr **tca,
326 						struct netlink_ext_ack *extack);
327 	void			(*tmplt_destroy)(void *tmplt_priv);
328 
329 	/* rtnetlink specific */
330 	int			(*dump)(struct net*, struct tcf_proto*, void *,
331 					struct sk_buff *skb, struct tcmsg*,
332 					bool);
333 	int			(*tmplt_dump)(struct sk_buff *skb,
334 					      struct net *net,
335 					      void *tmplt_priv);
336 
337 	struct module		*owner;
338 	int			flags;
339 };
340 
341 /* Classifiers setting TCF_PROTO_OPS_DOIT_UNLOCKED in tcf_proto_ops->flags
342  * are expected to implement tcf_proto_ops->delete_empty(), otherwise race
343  * conditions can occur when filters are inserted/deleted simultaneously.
344  */
345 enum tcf_proto_ops_flags {
346 	TCF_PROTO_OPS_DOIT_UNLOCKED = 1,
347 };
348 
349 struct tcf_proto {
350 	/* Fast access part */
351 	struct tcf_proto __rcu	*next;
352 	void __rcu		*root;
353 
354 	/* called under RCU BH lock*/
355 	int			(*classify)(struct sk_buff *,
356 					    const struct tcf_proto *,
357 					    struct tcf_result *);
358 	__be16			protocol;
359 
360 	/* All the rest */
361 	u32			prio;
362 	void			*data;
363 	const struct tcf_proto_ops	*ops;
364 	struct tcf_chain	*chain;
365 	/* Lock protects tcf_proto shared state and can be used by unlocked
366 	 * classifiers to protect their private data.
367 	 */
368 	spinlock_t		lock;
369 	bool			deleting;
370 	refcount_t		refcnt;
371 	struct rcu_head		rcu;
372 	struct hlist_node	destroy_ht_node;
373 };
374 
375 struct qdisc_skb_cb {
376 	struct {
377 		unsigned int		pkt_len;
378 		u16			slave_dev_queue_mapping;
379 		u16			tc_classid;
380 	};
381 #define QDISC_CB_PRIV_LEN 20
382 	unsigned char		data[QDISC_CB_PRIV_LEN];
383 };
384 
385 typedef void tcf_chain_head_change_t(struct tcf_proto *tp_head, void *priv);
386 
387 struct tcf_chain {
388 	/* Protects filter_chain. */
389 	struct mutex filter_chain_lock;
390 	struct tcf_proto __rcu *filter_chain;
391 	struct list_head list;
392 	struct tcf_block *block;
393 	u32 index; /* chain index */
394 	unsigned int refcnt;
395 	unsigned int action_refcnt;
396 	bool explicitly_created;
397 	bool flushing;
398 	const struct tcf_proto_ops *tmplt_ops;
399 	void *tmplt_priv;
400 	struct rcu_head rcu;
401 };
402 
403 struct tcf_block {
404 	/* Lock protects tcf_block and lifetime-management data of chains
405 	 * attached to the block (refcnt, action_refcnt, explicitly_created).
406 	 */
407 	struct mutex lock;
408 	struct list_head chain_list;
409 	u32 index; /* block index for shared blocks */
410 	refcount_t refcnt;
411 	struct net *net;
412 	struct Qdisc *q;
413 	struct rw_semaphore cb_lock; /* protects cb_list and offload counters */
414 	struct flow_block flow_block;
415 	struct list_head owner_list;
416 	bool keep_dst;
417 	atomic_t offloadcnt; /* Number of oddloaded filters */
418 	unsigned int nooffloaddevcnt; /* Number of devs unable to do offload */
419 	unsigned int lockeddevcnt; /* Number of devs that require rtnl lock. */
420 	struct {
421 		struct tcf_chain *chain;
422 		struct list_head filter_chain_list;
423 	} chain0;
424 	struct rcu_head rcu;
425 	DECLARE_HASHTABLE(proto_destroy_ht, 7);
426 	struct mutex proto_destroy_lock; /* Lock for proto_destroy hashtable. */
427 };
428 
429 #ifdef CONFIG_PROVE_LOCKING
430 static inline bool lockdep_tcf_chain_is_locked(struct tcf_chain *chain)
431 {
432 	return lockdep_is_held(&chain->filter_chain_lock);
433 }
434 
435 static inline bool lockdep_tcf_proto_is_locked(struct tcf_proto *tp)
436 {
437 	return lockdep_is_held(&tp->lock);
438 }
439 #else
440 static inline bool lockdep_tcf_chain_is_locked(struct tcf_block *chain)
441 {
442 	return true;
443 }
444 
445 static inline bool lockdep_tcf_proto_is_locked(struct tcf_proto *tp)
446 {
447 	return true;
448 }
449 #endif /* #ifdef CONFIG_PROVE_LOCKING */
450 
451 #define tcf_chain_dereference(p, chain)					\
452 	rcu_dereference_protected(p, lockdep_tcf_chain_is_locked(chain))
453 
454 #define tcf_proto_dereference(p, tp)					\
455 	rcu_dereference_protected(p, lockdep_tcf_proto_is_locked(tp))
456 
457 static inline void qdisc_cb_private_validate(const struct sk_buff *skb, int sz)
458 {
459 	struct qdisc_skb_cb *qcb;
460 
461 	BUILD_BUG_ON(sizeof(skb->cb) < offsetof(struct qdisc_skb_cb, data) + sz);
462 	BUILD_BUG_ON(sizeof(qcb->data) < sz);
463 }
464 
465 static inline int qdisc_qlen_cpu(const struct Qdisc *q)
466 {
467 	return this_cpu_ptr(q->cpu_qstats)->qlen;
468 }
469 
470 static inline int qdisc_qlen(const struct Qdisc *q)
471 {
472 	return q->q.qlen;
473 }
474 
475 static inline int qdisc_qlen_sum(const struct Qdisc *q)
476 {
477 	__u32 qlen = q->qstats.qlen;
478 	int i;
479 
480 	if (qdisc_is_percpu_stats(q)) {
481 		for_each_possible_cpu(i)
482 			qlen += per_cpu_ptr(q->cpu_qstats, i)->qlen;
483 	} else {
484 		qlen += q->q.qlen;
485 	}
486 
487 	return qlen;
488 }
489 
490 static inline struct qdisc_skb_cb *qdisc_skb_cb(const struct sk_buff *skb)
491 {
492 	return (struct qdisc_skb_cb *)skb->cb;
493 }
494 
495 static inline spinlock_t *qdisc_lock(struct Qdisc *qdisc)
496 {
497 	return &qdisc->q.lock;
498 }
499 
500 static inline struct Qdisc *qdisc_root(const struct Qdisc *qdisc)
501 {
502 	struct Qdisc *q = rcu_dereference_rtnl(qdisc->dev_queue->qdisc);
503 
504 	return q;
505 }
506 
507 static inline struct Qdisc *qdisc_root_bh(const struct Qdisc *qdisc)
508 {
509 	return rcu_dereference_bh(qdisc->dev_queue->qdisc);
510 }
511 
512 static inline struct Qdisc *qdisc_root_sleeping(const struct Qdisc *qdisc)
513 {
514 	return qdisc->dev_queue->qdisc_sleeping;
515 }
516 
517 /* The qdisc root lock is a mechanism by which to top level
518  * of a qdisc tree can be locked from any qdisc node in the
519  * forest.  This allows changing the configuration of some
520  * aspect of the qdisc tree while blocking out asynchronous
521  * qdisc access in the packet processing paths.
522  *
523  * It is only legal to do this when the root will not change
524  * on us.  Otherwise we'll potentially lock the wrong qdisc
525  * root.  This is enforced by holding the RTNL semaphore, which
526  * all users of this lock accessor must do.
527  */
528 static inline spinlock_t *qdisc_root_lock(const struct Qdisc *qdisc)
529 {
530 	struct Qdisc *root = qdisc_root(qdisc);
531 
532 	ASSERT_RTNL();
533 	return qdisc_lock(root);
534 }
535 
536 static inline spinlock_t *qdisc_root_sleeping_lock(const struct Qdisc *qdisc)
537 {
538 	struct Qdisc *root = qdisc_root_sleeping(qdisc);
539 
540 	ASSERT_RTNL();
541 	return qdisc_lock(root);
542 }
543 
544 static inline seqcount_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc)
545 {
546 	struct Qdisc *root = qdisc_root_sleeping(qdisc);
547 
548 	ASSERT_RTNL();
549 	return &root->running;
550 }
551 
552 static inline struct net_device *qdisc_dev(const struct Qdisc *qdisc)
553 {
554 	return qdisc->dev_queue->dev;
555 }
556 
557 static inline void sch_tree_lock(const struct Qdisc *q)
558 {
559 	spin_lock_bh(qdisc_root_sleeping_lock(q));
560 }
561 
562 static inline void sch_tree_unlock(const struct Qdisc *q)
563 {
564 	spin_unlock_bh(qdisc_root_sleeping_lock(q));
565 }
566 
567 extern struct Qdisc noop_qdisc;
568 extern struct Qdisc_ops noop_qdisc_ops;
569 extern struct Qdisc_ops pfifo_fast_ops;
570 extern struct Qdisc_ops mq_qdisc_ops;
571 extern struct Qdisc_ops noqueue_qdisc_ops;
572 extern const struct Qdisc_ops *default_qdisc_ops;
573 static inline const struct Qdisc_ops *
574 get_default_qdisc_ops(const struct net_device *dev, int ntx)
575 {
576 	return ntx < dev->real_num_tx_queues ?
577 			default_qdisc_ops : &pfifo_fast_ops;
578 }
579 
580 struct Qdisc_class_common {
581 	u32			classid;
582 	struct hlist_node	hnode;
583 };
584 
585 struct Qdisc_class_hash {
586 	struct hlist_head	*hash;
587 	unsigned int		hashsize;
588 	unsigned int		hashmask;
589 	unsigned int		hashelems;
590 };
591 
592 static inline unsigned int qdisc_class_hash(u32 id, u32 mask)
593 {
594 	id ^= id >> 8;
595 	id ^= id >> 4;
596 	return id & mask;
597 }
598 
599 static inline struct Qdisc_class_common *
600 qdisc_class_find(const struct Qdisc_class_hash *hash, u32 id)
601 {
602 	struct Qdisc_class_common *cl;
603 	unsigned int h;
604 
605 	if (!id)
606 		return NULL;
607 
608 	h = qdisc_class_hash(id, hash->hashmask);
609 	hlist_for_each_entry(cl, &hash->hash[h], hnode) {
610 		if (cl->classid == id)
611 			return cl;
612 	}
613 	return NULL;
614 }
615 
616 static inline int tc_classid_to_hwtc(struct net_device *dev, u32 classid)
617 {
618 	u32 hwtc = TC_H_MIN(classid) - TC_H_MIN_PRIORITY;
619 
620 	return (hwtc < netdev_get_num_tc(dev)) ? hwtc : -EINVAL;
621 }
622 
623 int qdisc_class_hash_init(struct Qdisc_class_hash *);
624 void qdisc_class_hash_insert(struct Qdisc_class_hash *,
625 			     struct Qdisc_class_common *);
626 void qdisc_class_hash_remove(struct Qdisc_class_hash *,
627 			     struct Qdisc_class_common *);
628 void qdisc_class_hash_grow(struct Qdisc *, struct Qdisc_class_hash *);
629 void qdisc_class_hash_destroy(struct Qdisc_class_hash *);
630 
631 int dev_qdisc_change_tx_queue_len(struct net_device *dev);
632 void dev_init_scheduler(struct net_device *dev);
633 void dev_shutdown(struct net_device *dev);
634 void dev_activate(struct net_device *dev);
635 void dev_deactivate(struct net_device *dev);
636 void dev_deactivate_many(struct list_head *head);
637 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
638 			      struct Qdisc *qdisc);
639 void qdisc_reset(struct Qdisc *qdisc);
640 void qdisc_put(struct Qdisc *qdisc);
641 void qdisc_put_unlocked(struct Qdisc *qdisc);
642 void qdisc_tree_reduce_backlog(struct Qdisc *qdisc, int n, int len);
643 #ifdef CONFIG_NET_SCHED
644 int qdisc_offload_dump_helper(struct Qdisc *q, enum tc_setup_type type,
645 			      void *type_data);
646 void qdisc_offload_graft_helper(struct net_device *dev, struct Qdisc *sch,
647 				struct Qdisc *new, struct Qdisc *old,
648 				enum tc_setup_type type, void *type_data,
649 				struct netlink_ext_ack *extack);
650 #else
651 static inline int
652 qdisc_offload_dump_helper(struct Qdisc *q, enum tc_setup_type type,
653 			  void *type_data)
654 {
655 	q->flags &= ~TCQ_F_OFFLOADED;
656 	return 0;
657 }
658 
659 static inline void
660 qdisc_offload_graft_helper(struct net_device *dev, struct Qdisc *sch,
661 			   struct Qdisc *new, struct Qdisc *old,
662 			   enum tc_setup_type type, void *type_data,
663 			   struct netlink_ext_ack *extack)
664 {
665 }
666 #endif
667 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
668 			  const struct Qdisc_ops *ops,
669 			  struct netlink_ext_ack *extack);
670 void qdisc_free(struct Qdisc *qdisc);
671 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
672 				const struct Qdisc_ops *ops, u32 parentid,
673 				struct netlink_ext_ack *extack);
674 void __qdisc_calculate_pkt_len(struct sk_buff *skb,
675 			       const struct qdisc_size_table *stab);
676 int skb_do_redirect(struct sk_buff *);
677 
678 static inline bool skb_at_tc_ingress(const struct sk_buff *skb)
679 {
680 #ifdef CONFIG_NET_CLS_ACT
681 	return skb->tc_at_ingress;
682 #else
683 	return false;
684 #endif
685 }
686 
687 static inline bool skb_skip_tc_classify(struct sk_buff *skb)
688 {
689 #ifdef CONFIG_NET_CLS_ACT
690 	if (skb->tc_skip_classify) {
691 		skb->tc_skip_classify = 0;
692 		return true;
693 	}
694 #endif
695 	return false;
696 }
697 
698 /* Reset all TX qdiscs greater than index of a device.  */
699 static inline void qdisc_reset_all_tx_gt(struct net_device *dev, unsigned int i)
700 {
701 	struct Qdisc *qdisc;
702 
703 	for (; i < dev->num_tx_queues; i++) {
704 		qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc);
705 		if (qdisc) {
706 			spin_lock_bh(qdisc_lock(qdisc));
707 			qdisc_reset(qdisc);
708 			spin_unlock_bh(qdisc_lock(qdisc));
709 		}
710 	}
711 }
712 
713 /* Are all TX queues of the device empty?  */
714 static inline bool qdisc_all_tx_empty(const struct net_device *dev)
715 {
716 	unsigned int i;
717 
718 	rcu_read_lock();
719 	for (i = 0; i < dev->num_tx_queues; i++) {
720 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
721 		const struct Qdisc *q = rcu_dereference(txq->qdisc);
722 
723 		if (!qdisc_is_empty(q)) {
724 			rcu_read_unlock();
725 			return false;
726 		}
727 	}
728 	rcu_read_unlock();
729 	return true;
730 }
731 
732 /* Are any of the TX qdiscs changing?  */
733 static inline bool qdisc_tx_changing(const struct net_device *dev)
734 {
735 	unsigned int i;
736 
737 	for (i = 0; i < dev->num_tx_queues; i++) {
738 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
739 		if (rcu_access_pointer(txq->qdisc) != txq->qdisc_sleeping)
740 			return true;
741 	}
742 	return false;
743 }
744 
745 /* Is the device using the noop qdisc on all queues?  */
746 static inline bool qdisc_tx_is_noop(const struct net_device *dev)
747 {
748 	unsigned int i;
749 
750 	for (i = 0; i < dev->num_tx_queues; i++) {
751 		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
752 		if (rcu_access_pointer(txq->qdisc) != &noop_qdisc)
753 			return false;
754 	}
755 	return true;
756 }
757 
758 static inline unsigned int qdisc_pkt_len(const struct sk_buff *skb)
759 {
760 	return qdisc_skb_cb(skb)->pkt_len;
761 }
762 
763 /* additional qdisc xmit flags (NET_XMIT_MASK in linux/netdevice.h) */
764 enum net_xmit_qdisc_t {
765 	__NET_XMIT_STOLEN = 0x00010000,
766 	__NET_XMIT_BYPASS = 0x00020000,
767 };
768 
769 #ifdef CONFIG_NET_CLS_ACT
770 #define net_xmit_drop_count(e)	((e) & __NET_XMIT_STOLEN ? 0 : 1)
771 #else
772 #define net_xmit_drop_count(e)	(1)
773 #endif
774 
775 static inline void qdisc_calculate_pkt_len(struct sk_buff *skb,
776 					   const struct Qdisc *sch)
777 {
778 #ifdef CONFIG_NET_SCHED
779 	struct qdisc_size_table *stab = rcu_dereference_bh(sch->stab);
780 
781 	if (stab)
782 		__qdisc_calculate_pkt_len(skb, stab);
783 #endif
784 }
785 
786 static inline int qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch,
787 				struct sk_buff **to_free)
788 {
789 	qdisc_calculate_pkt_len(skb, sch);
790 	return sch->enqueue(skb, sch, to_free);
791 }
792 
793 static inline void _bstats_update(struct gnet_stats_basic_packed *bstats,
794 				  __u64 bytes, __u32 packets)
795 {
796 	bstats->bytes += bytes;
797 	bstats->packets += packets;
798 }
799 
800 static inline void bstats_update(struct gnet_stats_basic_packed *bstats,
801 				 const struct sk_buff *skb)
802 {
803 	_bstats_update(bstats,
804 		       qdisc_pkt_len(skb),
805 		       skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 1);
806 }
807 
808 static inline void _bstats_cpu_update(struct gnet_stats_basic_cpu *bstats,
809 				      __u64 bytes, __u32 packets)
810 {
811 	u64_stats_update_begin(&bstats->syncp);
812 	_bstats_update(&bstats->bstats, bytes, packets);
813 	u64_stats_update_end(&bstats->syncp);
814 }
815 
816 static inline void bstats_cpu_update(struct gnet_stats_basic_cpu *bstats,
817 				     const struct sk_buff *skb)
818 {
819 	u64_stats_update_begin(&bstats->syncp);
820 	bstats_update(&bstats->bstats, skb);
821 	u64_stats_update_end(&bstats->syncp);
822 }
823 
824 static inline void qdisc_bstats_cpu_update(struct Qdisc *sch,
825 					   const struct sk_buff *skb)
826 {
827 	bstats_cpu_update(this_cpu_ptr(sch->cpu_bstats), skb);
828 }
829 
830 static inline void qdisc_bstats_update(struct Qdisc *sch,
831 				       const struct sk_buff *skb)
832 {
833 	bstats_update(&sch->bstats, skb);
834 }
835 
836 static inline void qdisc_qstats_backlog_dec(struct Qdisc *sch,
837 					    const struct sk_buff *skb)
838 {
839 	sch->qstats.backlog -= qdisc_pkt_len(skb);
840 }
841 
842 static inline void qdisc_qstats_cpu_backlog_dec(struct Qdisc *sch,
843 						const struct sk_buff *skb)
844 {
845 	this_cpu_sub(sch->cpu_qstats->backlog, qdisc_pkt_len(skb));
846 }
847 
848 static inline void qdisc_qstats_backlog_inc(struct Qdisc *sch,
849 					    const struct sk_buff *skb)
850 {
851 	sch->qstats.backlog += qdisc_pkt_len(skb);
852 }
853 
854 static inline void qdisc_qstats_cpu_backlog_inc(struct Qdisc *sch,
855 						const struct sk_buff *skb)
856 {
857 	this_cpu_add(sch->cpu_qstats->backlog, qdisc_pkt_len(skb));
858 }
859 
860 static inline void qdisc_qstats_cpu_qlen_inc(struct Qdisc *sch)
861 {
862 	this_cpu_inc(sch->cpu_qstats->qlen);
863 }
864 
865 static inline void qdisc_qstats_cpu_qlen_dec(struct Qdisc *sch)
866 {
867 	this_cpu_dec(sch->cpu_qstats->qlen);
868 }
869 
870 static inline void qdisc_qstats_cpu_requeues_inc(struct Qdisc *sch)
871 {
872 	this_cpu_inc(sch->cpu_qstats->requeues);
873 }
874 
875 static inline void __qdisc_qstats_drop(struct Qdisc *sch, int count)
876 {
877 	sch->qstats.drops += count;
878 }
879 
880 static inline void qstats_drop_inc(struct gnet_stats_queue *qstats)
881 {
882 	qstats->drops++;
883 }
884 
885 static inline void qstats_overlimit_inc(struct gnet_stats_queue *qstats)
886 {
887 	qstats->overlimits++;
888 }
889 
890 static inline void qdisc_qstats_drop(struct Qdisc *sch)
891 {
892 	qstats_drop_inc(&sch->qstats);
893 }
894 
895 static inline void qdisc_qstats_cpu_drop(struct Qdisc *sch)
896 {
897 	this_cpu_inc(sch->cpu_qstats->drops);
898 }
899 
900 static inline void qdisc_qstats_overlimit(struct Qdisc *sch)
901 {
902 	sch->qstats.overlimits++;
903 }
904 
905 static inline int qdisc_qstats_copy(struct gnet_dump *d, struct Qdisc *sch)
906 {
907 	__u32 qlen = qdisc_qlen_sum(sch);
908 
909 	return gnet_stats_copy_queue(d, sch->cpu_qstats, &sch->qstats, qlen);
910 }
911 
912 static inline void qdisc_qstats_qlen_backlog(struct Qdisc *sch,  __u32 *qlen,
913 					     __u32 *backlog)
914 {
915 	struct gnet_stats_queue qstats = { 0 };
916 	__u32 len = qdisc_qlen_sum(sch);
917 
918 	__gnet_stats_copy_queue(&qstats, sch->cpu_qstats, &sch->qstats, len);
919 	*qlen = qstats.qlen;
920 	*backlog = qstats.backlog;
921 }
922 
923 static inline void qdisc_tree_flush_backlog(struct Qdisc *sch)
924 {
925 	__u32 qlen, backlog;
926 
927 	qdisc_qstats_qlen_backlog(sch, &qlen, &backlog);
928 	qdisc_tree_reduce_backlog(sch, qlen, backlog);
929 }
930 
931 static inline void qdisc_purge_queue(struct Qdisc *sch)
932 {
933 	__u32 qlen, backlog;
934 
935 	qdisc_qstats_qlen_backlog(sch, &qlen, &backlog);
936 	qdisc_reset(sch);
937 	qdisc_tree_reduce_backlog(sch, qlen, backlog);
938 }
939 
940 static inline void qdisc_skb_head_init(struct qdisc_skb_head *qh)
941 {
942 	qh->head = NULL;
943 	qh->tail = NULL;
944 	qh->qlen = 0;
945 }
946 
947 static inline void __qdisc_enqueue_tail(struct sk_buff *skb,
948 					struct qdisc_skb_head *qh)
949 {
950 	struct sk_buff *last = qh->tail;
951 
952 	if (last) {
953 		skb->next = NULL;
954 		last->next = skb;
955 		qh->tail = skb;
956 	} else {
957 		qh->tail = skb;
958 		qh->head = skb;
959 	}
960 	qh->qlen++;
961 }
962 
963 static inline int qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch)
964 {
965 	__qdisc_enqueue_tail(skb, &sch->q);
966 	qdisc_qstats_backlog_inc(sch, skb);
967 	return NET_XMIT_SUCCESS;
968 }
969 
970 static inline void __qdisc_enqueue_head(struct sk_buff *skb,
971 					struct qdisc_skb_head *qh)
972 {
973 	skb->next = qh->head;
974 
975 	if (!qh->head)
976 		qh->tail = skb;
977 	qh->head = skb;
978 	qh->qlen++;
979 }
980 
981 static inline struct sk_buff *__qdisc_dequeue_head(struct qdisc_skb_head *qh)
982 {
983 	struct sk_buff *skb = qh->head;
984 
985 	if (likely(skb != NULL)) {
986 		qh->head = skb->next;
987 		qh->qlen--;
988 		if (qh->head == NULL)
989 			qh->tail = NULL;
990 		skb->next = NULL;
991 	}
992 
993 	return skb;
994 }
995 
996 static inline struct sk_buff *qdisc_dequeue_head(struct Qdisc *sch)
997 {
998 	struct sk_buff *skb = __qdisc_dequeue_head(&sch->q);
999 
1000 	if (likely(skb != NULL)) {
1001 		qdisc_qstats_backlog_dec(sch, skb);
1002 		qdisc_bstats_update(sch, skb);
1003 	}
1004 
1005 	return skb;
1006 }
1007 
1008 /* Instead of calling kfree_skb() while root qdisc lock is held,
1009  * queue the skb for future freeing at end of __dev_xmit_skb()
1010  */
1011 static inline void __qdisc_drop(struct sk_buff *skb, struct sk_buff **to_free)
1012 {
1013 	skb->next = *to_free;
1014 	*to_free = skb;
1015 }
1016 
1017 static inline void __qdisc_drop_all(struct sk_buff *skb,
1018 				    struct sk_buff **to_free)
1019 {
1020 	if (skb->prev)
1021 		skb->prev->next = *to_free;
1022 	else
1023 		skb->next = *to_free;
1024 	*to_free = skb;
1025 }
1026 
1027 static inline unsigned int __qdisc_queue_drop_head(struct Qdisc *sch,
1028 						   struct qdisc_skb_head *qh,
1029 						   struct sk_buff **to_free)
1030 {
1031 	struct sk_buff *skb = __qdisc_dequeue_head(qh);
1032 
1033 	if (likely(skb != NULL)) {
1034 		unsigned int len = qdisc_pkt_len(skb);
1035 
1036 		qdisc_qstats_backlog_dec(sch, skb);
1037 		__qdisc_drop(skb, to_free);
1038 		return len;
1039 	}
1040 
1041 	return 0;
1042 }
1043 
1044 static inline unsigned int qdisc_queue_drop_head(struct Qdisc *sch,
1045 						 struct sk_buff **to_free)
1046 {
1047 	return __qdisc_queue_drop_head(sch, &sch->q, to_free);
1048 }
1049 
1050 static inline struct sk_buff *qdisc_peek_head(struct Qdisc *sch)
1051 {
1052 	const struct qdisc_skb_head *qh = &sch->q;
1053 
1054 	return qh->head;
1055 }
1056 
1057 /* generic pseudo peek method for non-work-conserving qdisc */
1058 static inline struct sk_buff *qdisc_peek_dequeued(struct Qdisc *sch)
1059 {
1060 	struct sk_buff *skb = skb_peek(&sch->gso_skb);
1061 
1062 	/* we can reuse ->gso_skb because peek isn't called for root qdiscs */
1063 	if (!skb) {
1064 		skb = sch->dequeue(sch);
1065 
1066 		if (skb) {
1067 			__skb_queue_head(&sch->gso_skb, skb);
1068 			/* it's still part of the queue */
1069 			qdisc_qstats_backlog_inc(sch, skb);
1070 			sch->q.qlen++;
1071 		}
1072 	}
1073 
1074 	return skb;
1075 }
1076 
1077 static inline void qdisc_update_stats_at_dequeue(struct Qdisc *sch,
1078 						 struct sk_buff *skb)
1079 {
1080 	if (qdisc_is_percpu_stats(sch)) {
1081 		qdisc_qstats_cpu_backlog_dec(sch, skb);
1082 		qdisc_bstats_cpu_update(sch, skb);
1083 		qdisc_qstats_cpu_qlen_dec(sch);
1084 	} else {
1085 		qdisc_qstats_backlog_dec(sch, skb);
1086 		qdisc_bstats_update(sch, skb);
1087 		sch->q.qlen--;
1088 	}
1089 }
1090 
1091 static inline void qdisc_update_stats_at_enqueue(struct Qdisc *sch,
1092 						 unsigned int pkt_len)
1093 {
1094 	if (qdisc_is_percpu_stats(sch)) {
1095 		qdisc_qstats_cpu_qlen_inc(sch);
1096 		this_cpu_add(sch->cpu_qstats->backlog, pkt_len);
1097 	} else {
1098 		sch->qstats.backlog += pkt_len;
1099 		sch->q.qlen++;
1100 	}
1101 }
1102 
1103 /* use instead of qdisc->dequeue() for all qdiscs queried with ->peek() */
1104 static inline struct sk_buff *qdisc_dequeue_peeked(struct Qdisc *sch)
1105 {
1106 	struct sk_buff *skb = skb_peek(&sch->gso_skb);
1107 
1108 	if (skb) {
1109 		skb = __skb_dequeue(&sch->gso_skb);
1110 		if (qdisc_is_percpu_stats(sch)) {
1111 			qdisc_qstats_cpu_backlog_dec(sch, skb);
1112 			qdisc_qstats_cpu_qlen_dec(sch);
1113 		} else {
1114 			qdisc_qstats_backlog_dec(sch, skb);
1115 			sch->q.qlen--;
1116 		}
1117 	} else {
1118 		skb = sch->dequeue(sch);
1119 	}
1120 
1121 	return skb;
1122 }
1123 
1124 static inline void __qdisc_reset_queue(struct qdisc_skb_head *qh)
1125 {
1126 	/*
1127 	 * We do not know the backlog in bytes of this list, it
1128 	 * is up to the caller to correct it
1129 	 */
1130 	ASSERT_RTNL();
1131 	if (qh->qlen) {
1132 		rtnl_kfree_skbs(qh->head, qh->tail);
1133 
1134 		qh->head = NULL;
1135 		qh->tail = NULL;
1136 		qh->qlen = 0;
1137 	}
1138 }
1139 
1140 static inline void qdisc_reset_queue(struct Qdisc *sch)
1141 {
1142 	__qdisc_reset_queue(&sch->q);
1143 	sch->qstats.backlog = 0;
1144 }
1145 
1146 static inline struct Qdisc *qdisc_replace(struct Qdisc *sch, struct Qdisc *new,
1147 					  struct Qdisc **pold)
1148 {
1149 	struct Qdisc *old;
1150 
1151 	sch_tree_lock(sch);
1152 	old = *pold;
1153 	*pold = new;
1154 	if (old != NULL)
1155 		qdisc_tree_flush_backlog(old);
1156 	sch_tree_unlock(sch);
1157 
1158 	return old;
1159 }
1160 
1161 static inline void rtnl_qdisc_drop(struct sk_buff *skb, struct Qdisc *sch)
1162 {
1163 	rtnl_kfree_skbs(skb, skb);
1164 	qdisc_qstats_drop(sch);
1165 }
1166 
1167 static inline int qdisc_drop_cpu(struct sk_buff *skb, struct Qdisc *sch,
1168 				 struct sk_buff **to_free)
1169 {
1170 	__qdisc_drop(skb, to_free);
1171 	qdisc_qstats_cpu_drop(sch);
1172 
1173 	return NET_XMIT_DROP;
1174 }
1175 
1176 static inline int qdisc_drop(struct sk_buff *skb, struct Qdisc *sch,
1177 			     struct sk_buff **to_free)
1178 {
1179 	__qdisc_drop(skb, to_free);
1180 	qdisc_qstats_drop(sch);
1181 
1182 	return NET_XMIT_DROP;
1183 }
1184 
1185 static inline int qdisc_drop_all(struct sk_buff *skb, struct Qdisc *sch,
1186 				 struct sk_buff **to_free)
1187 {
1188 	__qdisc_drop_all(skb, to_free);
1189 	qdisc_qstats_drop(sch);
1190 
1191 	return NET_XMIT_DROP;
1192 }
1193 
1194 /* Length to Time (L2T) lookup in a qdisc_rate_table, to determine how
1195    long it will take to send a packet given its size.
1196  */
1197 static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen)
1198 {
1199 	int slot = pktlen + rtab->rate.cell_align + rtab->rate.overhead;
1200 	if (slot < 0)
1201 		slot = 0;
1202 	slot >>= rtab->rate.cell_log;
1203 	if (slot > 255)
1204 		return rtab->data[255]*(slot >> 8) + rtab->data[slot & 0xFF];
1205 	return rtab->data[slot];
1206 }
1207 
1208 struct psched_ratecfg {
1209 	u64	rate_bytes_ps; /* bytes per second */
1210 	u32	mult;
1211 	u16	overhead;
1212 	u8	linklayer;
1213 	u8	shift;
1214 };
1215 
1216 static inline u64 psched_l2t_ns(const struct psched_ratecfg *r,
1217 				unsigned int len)
1218 {
1219 	len += r->overhead;
1220 
1221 	if (unlikely(r->linklayer == TC_LINKLAYER_ATM))
1222 		return ((u64)(DIV_ROUND_UP(len,48)*53) * r->mult) >> r->shift;
1223 
1224 	return ((u64)len * r->mult) >> r->shift;
1225 }
1226 
1227 void psched_ratecfg_precompute(struct psched_ratecfg *r,
1228 			       const struct tc_ratespec *conf,
1229 			       u64 rate64);
1230 
1231 static inline void psched_ratecfg_getrate(struct tc_ratespec *res,
1232 					  const struct psched_ratecfg *r)
1233 {
1234 	memset(res, 0, sizeof(*res));
1235 
1236 	/* legacy struct tc_ratespec has a 32bit @rate field
1237 	 * Qdisc using 64bit rate should add new attributes
1238 	 * in order to maintain compatibility.
1239 	 */
1240 	res->rate = min_t(u64, r->rate_bytes_ps, ~0U);
1241 
1242 	res->overhead = r->overhead;
1243 	res->linklayer = (r->linklayer & TC_LINKLAYER_MASK);
1244 }
1245 
1246 /* Mini Qdisc serves for specific needs of ingress/clsact Qdisc.
1247  * The fast path only needs to access filter list and to update stats
1248  */
1249 struct mini_Qdisc {
1250 	struct tcf_proto *filter_list;
1251 	struct tcf_block *block;
1252 	struct gnet_stats_basic_cpu __percpu *cpu_bstats;
1253 	struct gnet_stats_queue	__percpu *cpu_qstats;
1254 	struct rcu_head rcu;
1255 };
1256 
1257 static inline void mini_qdisc_bstats_cpu_update(struct mini_Qdisc *miniq,
1258 						const struct sk_buff *skb)
1259 {
1260 	bstats_cpu_update(this_cpu_ptr(miniq->cpu_bstats), skb);
1261 }
1262 
1263 static inline void mini_qdisc_qstats_cpu_drop(struct mini_Qdisc *miniq)
1264 {
1265 	this_cpu_inc(miniq->cpu_qstats->drops);
1266 }
1267 
1268 struct mini_Qdisc_pair {
1269 	struct mini_Qdisc miniq1;
1270 	struct mini_Qdisc miniq2;
1271 	struct mini_Qdisc __rcu **p_miniq;
1272 };
1273 
1274 void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp,
1275 			  struct tcf_proto *tp_head);
1276 void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,
1277 			  struct mini_Qdisc __rcu **p_miniq);
1278 void mini_qdisc_pair_block_init(struct mini_Qdisc_pair *miniqp,
1279 				struct tcf_block *block);
1280 
1281 static inline int skb_tc_reinsert(struct sk_buff *skb, struct tcf_result *res)
1282 {
1283 	return res->ingress ? netif_receive_skb(skb) : dev_queue_xmit(skb);
1284 }
1285 
1286 #endif
1287