include/net/sch_generic.h

   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 };
  30
  31 struct qdisc_size_table {
  32         struct rcu_head         rcu;
  33         struct list_head        list;
  34         struct tc_sizespec      szopts;
  35         int                     refcnt;
  36         u16                     data[];
  37 };
  38
  39 /* similar to sk_buff_head, but skb->prev pointer is undefined. */
  40 struct qdisc_skb_head {
  41         struct sk_buff  *head;
  42         struct sk_buff  *tail;
  43         __u32           qlen;
  44         spinlock_t      lock;
  45 };
  46
  47 struct Qdisc {
  48         int                     (*enqueue)(struct sk_buff *skb,
  49                                            struct Qdisc *sch,
  50                                            struct sk_buff **to_free);
  51         struct sk_buff *        (*dequeue)(struct Qdisc *sch);
  52         unsigned int            flags;
  53 #define TCQ_F_BUILTIN           1
  54 #define TCQ_F_INGRESS           2
  55 #define TCQ_F_CAN_BYPASS        4
  56 #define TCQ_F_MQROOT            8
  57 #define TCQ_F_ONETXQUEUE        0x10 /* dequeue_skb() can assume all skbs are for
  58                                       * q->dev_queue : It can test
  59                                       * netif_xmit_frozen_or_stopped() before
  60                                       * dequeueing next packet.
  61                                       * Its true for MQ/MQPRIO slaves, or non
  62                                       * multiqueue device.
  63                                       */
  64 #define TCQ_F_WARN_NONWC        (1 << 16)
  65 #define TCQ_F_CPUSTATS          0x20 /* run using percpu statistics */
  66 #define TCQ_F_NOPARENT          0x40 /* root of its hierarchy :
  67                                       * qdisc_tree_decrease_qlen() should stop.
  68                                       */
  69 #define TCQ_F_INVISIBLE         0x80 /* invisible by default in dump */
  70         u32                     limit;
  71         const struct Qdisc_ops  *ops;
  72         struct qdisc_size_table __rcu *stab;
  73         struct hlist_node       hash;
  74         u32                     handle;
  75         u32                     parent;
  76         void                    *u32_node;
  77
  78         struct netdev_queue     *dev_queue;
  79
  80         struct net_rate_estimator __rcu *rate_est;
  81         struct gnet_stats_basic_cpu __percpu *cpu_bstats;
  82         struct gnet_stats_queue __percpu *cpu_qstats;
  83
  84         /*
  85          * For performance sake on SMP, we put highly modified fields at the end
  86          */
  87         struct sk_buff          *gso_skb ____cacheline_aligned_in_smp;
  88         struct qdisc_skb_head   q;
  89         struct gnet_stats_basic_packed bstats;
  90         seqcount_t              running;
  91         struct gnet_stats_queue qstats;
  92         unsigned long           state;
  93         struct Qdisc            *next_sched;
  94         struct sk_buff          *skb_bad_txq;
  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 (raw_read_seqcount(&qdisc->running) & 1) ? 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         /* Variant of write_seqcount_begin() telling lockdep a trylock
 112          * was attempted.
 113          */
 114         raw_write_seqcount_begin(&qdisc->running);
 115         seqcount_acquire(&qdisc->running.dep_map, 0, 1, _RET_IP_);
 116         return true;
 117 }
 118
 119 static inline void qdisc_run_end(struct Qdisc *qdisc)
 120 {
 121         write_seqcount_end(&qdisc->running);
 122 }
 123
 124 static inline bool qdisc_may_bulk(const struct Qdisc *qdisc)
 125 {
 126         return qdisc->flags & TCQ_F_ONETXQUEUE;
 127 }
 128
 129 static inline int qdisc_avail_bulklimit(const struct netdev_queue *txq)
 130 {
 131 #ifdef CONFIG_BQL
 132         /* Non-BQL migrated drivers will return 0, too. */
 133         return dql_avail(&txq->dql);
 134 #else
 135         return 0;
 136 #endif
 137 }
 138
 139 struct Qdisc_class_ops {
 140         /* Child qdisc manipulation */
 141         struct netdev_queue *   (*select_queue)(struct Qdisc *, struct tcmsg *);
 142         int                     (*graft)(struct Qdisc *, unsigned long cl,
 143                                         struct Qdisc *, struct Qdisc **);
 144         struct Qdisc *          (*leaf)(struct Qdisc *, unsigned long cl);
 145         void                    (*qlen_notify)(struct Qdisc *, unsigned long);
 146
 147         /* Class manipulation routines */
 148         unsigned long           (*get)(struct Qdisc *, u32 classid);
 149         void                    (*put)(struct Qdisc *, unsigned long);
 150         int                     (*change)(struct Qdisc *, u32, u32,
 151                                         struct nlattr **, unsigned long *);
 152         int                     (*delete)(struct Qdisc *, unsigned long);
 153         void                    (*walk)(struct Qdisc *, struct qdisc_walker * arg);
 154
 155         /* Filter manipulation */
 156         struct tcf_proto __rcu ** (*tcf_chain)(struct Qdisc *, unsigned long);
 157         bool                    (*tcf_cl_offload)(u32 classid);
 158         unsigned long           (*bind_tcf)(struct Qdisc *, unsigned long,
 159                                         u32 classid);
 160         void                    (*unbind_tcf)(struct Qdisc *, unsigned long);
 161
 162         /* rtnetlink specific */
 163         int                     (*dump)(struct Qdisc *, unsigned long,
 164                                         struct sk_buff *skb, struct tcmsg*);
 165         int                     (*dump_stats)(struct Qdisc *, unsigned long,
 166                                         struct gnet_dump *);
 167 };
 168
 169 struct Qdisc_ops {
 170         struct Qdisc_ops        *next;
 171         const struct Qdisc_class_ops    *cl_ops;
 172         char                    id[IFNAMSIZ];
 173         int                     priv_size;
 174
 175         int                     (*enqueue)(struct sk_buff *skb,
 176                                            struct Qdisc *sch,
 177                                            struct sk_buff **to_free);
 178         struct sk_buff *        (*dequeue)(struct Qdisc *);
 179         struct sk_buff *        (*peek)(struct Qdisc *);
 180
 181         int                     (*init)(struct Qdisc *, struct nlattr *arg);
 182         void                    (*reset)(struct Qdisc *);
 183         void                    (*destroy)(struct Qdisc *);
 184         int                     (*change)(struct Qdisc *, struct nlattr *arg);
 185         void                    (*attach)(struct Qdisc *);
 186
 187         int                     (*dump)(struct Qdisc *, struct sk_buff *);
 188         int                     (*dump_stats)(struct Qdisc *, struct gnet_dump *);
 189
 190         struct module           *owner;
 191 };
 192
 193
 194 struct tcf_result {
 195         unsigned long   class;
 196         u32             classid;
 197 };
 198
 199 struct tcf_proto_ops {
 200         struct list_head        head;
 201         char                    kind[IFNAMSIZ];
 202
 203         int                     (*classify)(struct sk_buff *,
 204                                             const struct tcf_proto *,
 205                                             struct tcf_result *);
 206         int                     (*init)(struct tcf_proto*);
 207         void                    (*destroy)(struct tcf_proto*);
 208
 209         unsigned long           (*get)(struct tcf_proto*, u32 handle);
 210         int                     (*change)(struct net *net, struct sk_buff *,
 211                                         struct tcf_proto*, unsigned long,
 212                                         u32 handle, struct nlattr **,
 213                                         unsigned long *, bool);
 214         int                     (*delete)(struct tcf_proto*, unsigned long, bool*);
 215         void                    (*walk)(struct tcf_proto*, struct tcf_walker *arg);
 216
 217         /* rtnetlink specific */
 218         int                     (*dump)(struct net*, struct tcf_proto*, unsigned long,
 219                                         struct sk_buff *skb, struct tcmsg*);
 220
 221         struct module           *owner;
 222 };
 223
 224 struct tcf_proto {
 225         /* Fast access part */
 226         struct tcf_proto __rcu  *next;
 227         void __rcu              *root;
 228         int                     (*classify)(struct sk_buff *,
 229                                             const struct tcf_proto *,
 230                                             struct tcf_result *);
 231         __be16                  protocol;
 232
 233         /* All the rest */
 234         u32                     prio;
 235         u32                     classid;
 236         struct Qdisc            *q;
 237         void                    *data;
 238         const struct tcf_proto_ops      *ops;
 239         struct rcu_head         rcu;
 240 };
 241
 242 struct qdisc_skb_cb {
 243         unsigned int            pkt_len;
 244         u16                     slave_dev_queue_mapping;
 245         u16                     tc_classid;
 246 #define QDISC_CB_PRIV_LEN 20
 247         unsigned char           data[QDISC_CB_PRIV_LEN];
 248 };
 249
 250 static inline void qdisc_cb_private_validate(const struct sk_buff *skb, int sz)
 251 {
 252         struct qdisc_skb_cb *qcb;
 253
 254         BUILD_BUG_ON(sizeof(skb->cb) < offsetof(struct qdisc_skb_cb, data) + sz);
 255         BUILD_BUG_ON(sizeof(qcb->data) < sz);
 256 }
 257
 258 static inline int qdisc_qlen(const struct Qdisc *q)
 259 {
 260         return q->q.qlen;
 261 }
 262
 263 static inline struct qdisc_skb_cb *qdisc_skb_cb(const struct sk_buff *skb)
 264 {
 265         return (struct qdisc_skb_cb *)skb->cb;
 266 }
 267
 268 static inline spinlock_t *qdisc_lock(struct Qdisc *qdisc)
 269 {
 270         return &qdisc->q.lock;
 271 }
 272
 273 static inline struct Qdisc *qdisc_root(const struct Qdisc *qdisc)
 274 {
 275         struct Qdisc *q = rcu_dereference_rtnl(qdisc->dev_queue->qdisc);
 276
 277         return q;
 278 }
 279
 280 static inline struct Qdisc *qdisc_root_sleeping(const struct Qdisc *qdisc)
 281 {
 282         return qdisc->dev_queue->qdisc_sleeping;
 283 }
 284
 285 /* The qdisc root lock is a mechanism by which to top level
 286  * of a qdisc tree can be locked from any qdisc node in the
 287  * forest.  This allows changing the configuration of some
 288  * aspect of the qdisc tree while blocking out asynchronous
 289  * qdisc access in the packet processing paths.
 290  *
 291  * It is only legal to do this when the root will not change
 292  * on us.  Otherwise we'll potentially lock the wrong qdisc
 293  * root.  This is enforced by holding the RTNL semaphore, which
 294  * all users of this lock accessor must do.
 295  */
 296 static inline spinlock_t *qdisc_root_lock(const struct Qdisc *qdisc)
 297 {
 298         struct Qdisc *root = qdisc_root(qdisc);
 299
 300         ASSERT_RTNL();
 301         return qdisc_lock(root);
 302 }
 303
 304 static inline spinlock_t *qdisc_root_sleeping_lock(const struct Qdisc *qdisc)
 305 {
 306         struct Qdisc *root = qdisc_root_sleeping(qdisc);
 307
 308         ASSERT_RTNL();
 309         return qdisc_lock(root);
 310 }
 311
 312 static inline seqcount_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc)
 313 {
 314         struct Qdisc *root = qdisc_root_sleeping(qdisc);
 315
 316         ASSERT_RTNL();
 317         return &root->running;
 318 }
 319
 320 static inline struct net_device *qdisc_dev(const struct Qdisc *qdisc)
 321 {
 322         return qdisc->dev_queue->dev;
 323 }
 324
 325 static inline void sch_tree_lock(const struct Qdisc *q)
 326 {
 327         spin_lock_bh(qdisc_root_sleeping_lock(q));
 328 }
 329
 330 static inline void sch_tree_unlock(const struct Qdisc *q)
 331 {
 332         spin_unlock_bh(qdisc_root_sleeping_lock(q));
 333 }
 334
 335 #define tcf_tree_lock(tp)       sch_tree_lock((tp)->q)
 336 #define tcf_tree_unlock(tp)     sch_tree_unlock((tp)->q)
 337
 338 extern struct Qdisc noop_qdisc;
 339 extern struct Qdisc_ops noop_qdisc_ops;
 340 extern struct Qdisc_ops pfifo_fast_ops;
 341 extern struct Qdisc_ops mq_qdisc_ops;
 342 extern struct Qdisc_ops noqueue_qdisc_ops;
 343 extern const struct Qdisc_ops *default_qdisc_ops;
 344 static inline const struct Qdisc_ops *
 345 get_default_qdisc_ops(const struct net_device *dev, int ntx)
 346 {
 347         return ntx < dev->real_num_tx_queues ?
 348                         default_qdisc_ops : &pfifo_fast_ops;
 349 }
 350
 351 struct Qdisc_class_common {
 352         u32                     classid;
 353         struct hlist_node       hnode;
 354 };
 355
 356 struct Qdisc_class_hash {
 357         struct hlist_head       *hash;
 358         unsigned int            hashsize;
 359         unsigned int            hashmask;
 360         unsigned int            hashelems;
 361 };
 362
 363 static inline unsigned int qdisc_class_hash(u32 id, u32 mask)
 364 {
 365         id ^= id >> 8;
 366         id ^= id >> 4;
 367         return id & mask;
 368 }
 369
 370 static inline struct Qdisc_class_common *
 371 qdisc_class_find(const struct Qdisc_class_hash *hash, u32 id)
 372 {
 373         struct Qdisc_class_common *cl;
 374         unsigned int h;
 375
 376         h = qdisc_class_hash(id, hash->hashmask);
 377         hlist_for_each_entry(cl, &hash->hash[h], hnode) {
 378                 if (cl->classid == id)
 379                         return cl;
 380         }
 381         return NULL;
 382 }
 383
 384 int qdisc_class_hash_init(struct Qdisc_class_hash *);
 385 void qdisc_class_hash_insert(struct Qdisc_class_hash *,
 386                              struct Qdisc_class_common *);
 387 void qdisc_class_hash_remove(struct Qdisc_class_hash *,
 388                              struct Qdisc_class_common *);
 389 void qdisc_class_hash_grow(struct Qdisc *, struct Qdisc_class_hash *);
 390 void qdisc_class_hash_destroy(struct Qdisc_class_hash *);
 391
 392 void dev_init_scheduler(struct net_device *dev);
 393 void dev_shutdown(struct net_device *dev);
 394 void dev_activate(struct net_device *dev);
 395 void dev_deactivate(struct net_device *dev);
 396 void dev_deactivate_many(struct list_head *head);
 397 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
 398                               struct Qdisc *qdisc);
 399 void qdisc_reset(struct Qdisc *qdisc);
 400 void qdisc_destroy(struct Qdisc *qdisc);
 401 void qdisc_tree_reduce_backlog(struct Qdisc *qdisc, unsigned int n,
 402                                unsigned int len);
 403 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 404                           const struct Qdisc_ops *ops);
 405 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
 406                                 const struct Qdisc_ops *ops, u32 parentid);
 407 void __qdisc_calculate_pkt_len(struct sk_buff *skb,
 408                                const struct qdisc_size_table *stab);
 409 int skb_do_redirect(struct sk_buff *);
 410
 411 static inline void skb_reset_tc(struct sk_buff *skb)
 412 {
 413 #ifdef CONFIG_NET_CLS_ACT
 414         skb->tc_redirected = 0;
 415 #endif
 416 }
 417
 418 static inline bool skb_at_tc_ingress(const struct sk_buff *skb)
 419 {
 420 #ifdef CONFIG_NET_CLS_ACT
 421         return skb->tc_at_ingress;
 422 #else
 423         return false;
 424 #endif
 425 }
 426
 427 static inline bool skb_skip_tc_classify(struct sk_buff *skb)
 428 {
 429 #ifdef CONFIG_NET_CLS_ACT
 430         if (skb->tc_skip_classify) {
 431                 skb->tc_skip_classify = 0;
 432                 return true;
 433         }
 434 #endif
 435         return false;
 436 }
 437
 438 /* Reset all TX qdiscs greater then index of a device.  */
 439 static inline void qdisc_reset_all_tx_gt(struct net_device *dev, unsigned int i)
 440 {
 441         struct Qdisc *qdisc;
 442
 443         for (; i < dev->num_tx_queues; i++) {
 444                 qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc);
 445                 if (qdisc) {
 446                         spin_lock_bh(qdisc_lock(qdisc));
 447                         qdisc_reset(qdisc);
 448                         spin_unlock_bh(qdisc_lock(qdisc));
 449                 }
 450         }
 451 }
 452
 453 static inline void qdisc_reset_all_tx(struct net_device *dev)
 454 {
 455         qdisc_reset_all_tx_gt(dev, 0);
 456 }
 457
 458 /* Are all TX queues of the device empty?  */
 459 static inline bool qdisc_all_tx_empty(const struct net_device *dev)
 460 {
 461         unsigned int i;
 462
 463         rcu_read_lock();
 464         for (i = 0; i < dev->num_tx_queues; i++) {
 465                 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
 466                 const struct Qdisc *q = rcu_dereference(txq->qdisc);
 467
 468                 if (q->q.qlen) {
 469                         rcu_read_unlock();
 470                         return false;
 471                 }
 472         }
 473         rcu_read_unlock();
 474         return true;
 475 }
 476
 477 /* Are any of the TX qdiscs changing?  */
 478 static inline bool qdisc_tx_changing(const struct net_device *dev)
 479 {
 480         unsigned int i;
 481
 482         for (i = 0; i < dev->num_tx_queues; i++) {
 483                 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
 484                 if (rcu_access_pointer(txq->qdisc) != txq->qdisc_sleeping)
 485                         return true;
 486         }
 487         return false;
 488 }
 489
 490 /* Is the device using the noop qdisc on all queues?  */
 491 static inline bool qdisc_tx_is_noop(const struct net_device *dev)
 492 {
 493         unsigned int i;
 494
 495         for (i = 0; i < dev->num_tx_queues; i++) {
 496                 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
 497                 if (rcu_access_pointer(txq->qdisc) != &noop_qdisc)
 498                         return false;
 499         }
 500         return true;
 501 }
 502
 503 static inline unsigned int qdisc_pkt_len(const struct sk_buff *skb)
 504 {
 505         return qdisc_skb_cb(skb)->pkt_len;
 506 }
 507
 508 /* additional qdisc xmit flags (NET_XMIT_MASK in linux/netdevice.h) */
 509 enum net_xmit_qdisc_t {
 510         __NET_XMIT_STOLEN = 0x00010000,
 511         __NET_XMIT_BYPASS = 0x00020000,
 512 };
 513
 514 #ifdef CONFIG_NET_CLS_ACT
 515 #define net_xmit_drop_count(e)  ((e) & __NET_XMIT_STOLEN ? 0 : 1)
 516 #else
 517 #define net_xmit_drop_count(e)  (1)
 518 #endif
 519
 520 static inline void qdisc_calculate_pkt_len(struct sk_buff *skb,
 521                                            const struct Qdisc *sch)
 522 {
 523 #ifdef CONFIG_NET_SCHED
 524         struct qdisc_size_table *stab = rcu_dereference_bh(sch->stab);
 525
 526         if (stab)
 527                 __qdisc_calculate_pkt_len(skb, stab);
 528 #endif
 529 }
 530
 531 static inline int qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 532                                 struct sk_buff **to_free)
 533 {
 534         qdisc_calculate_pkt_len(skb, sch);
 535         return sch->enqueue(skb, sch, to_free);
 536 }
 537
 538 static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
 539 {
 540         return q->flags & TCQ_F_CPUSTATS;
 541 }
 542
 543 static inline void _bstats_update(struct gnet_stats_basic_packed *bstats,
 544                                   __u64 bytes, __u32 packets)
 545 {
 546         bstats->bytes += bytes;
 547         bstats->packets += packets;
 548 }
 549
 550 static inline void bstats_update(struct gnet_stats_basic_packed *bstats,
 551                                  const struct sk_buff *skb)
 552 {
 553         _bstats_update(bstats,
 554                        qdisc_pkt_len(skb),
 555                        skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 1);
 556 }
 557
 558 static inline void _bstats_cpu_update(struct gnet_stats_basic_cpu *bstats,
 559                                       __u64 bytes, __u32 packets)
 560 {
 561         u64_stats_update_begin(&bstats->syncp);
 562         _bstats_update(&bstats->bstats, bytes, packets);
 563         u64_stats_update_end(&bstats->syncp);
 564 }
 565
 566 static inline void bstats_cpu_update(struct gnet_stats_basic_cpu *bstats,
 567                                      const struct sk_buff *skb)
 568 {
 569         u64_stats_update_begin(&bstats->syncp);
 570         bstats_update(&bstats->bstats, skb);
 571         u64_stats_update_end(&bstats->syncp);
 572 }
 573
 574 static inline void qdisc_bstats_cpu_update(struct Qdisc *sch,
 575                                            const struct sk_buff *skb)
 576 {
 577         bstats_cpu_update(this_cpu_ptr(sch->cpu_bstats), skb);
 578 }
 579
 580 static inline void qdisc_bstats_update(struct Qdisc *sch,
 581                                        const struct sk_buff *skb)
 582 {
 583         bstats_update(&sch->bstats, skb);
 584 }
 585
 586 static inline void qdisc_qstats_backlog_dec(struct Qdisc *sch,
 587                                             const struct sk_buff *skb)
 588 {
 589         sch->qstats.backlog -= qdisc_pkt_len(skb);
 590 }
 591
 592 static inline void qdisc_qstats_backlog_inc(struct Qdisc *sch,
 593                                             const struct sk_buff *skb)
 594 {
 595         sch->qstats.backlog += qdisc_pkt_len(skb);
 596 }
 597
 598 static inline void __qdisc_qstats_drop(struct Qdisc *sch, int count)
 599 {
 600         sch->qstats.drops += count;
 601 }
 602
 603 static inline void qstats_drop_inc(struct gnet_stats_queue *qstats)
 604 {
 605         qstats->drops++;
 606 }
 607
 608 static inline void qstats_overlimit_inc(struct gnet_stats_queue *qstats)
 609 {
 610         qstats->overlimits++;
 611 }
 612
 613 static inline void qdisc_qstats_drop(struct Qdisc *sch)
 614 {
 615         qstats_drop_inc(&sch->qstats);
 616 }
 617
 618 static inline void qdisc_qstats_cpu_drop(struct Qdisc *sch)
 619 {
 620         this_cpu_inc(sch->cpu_qstats->drops);
 621 }
 622
 623 static inline void qdisc_qstats_overlimit(struct Qdisc *sch)
 624 {
 625         sch->qstats.overlimits++;
 626 }
 627
 628 static inline void qdisc_skb_head_init(struct qdisc_skb_head *qh)
 629 {
 630         qh->head = NULL;
 631         qh->tail = NULL;
 632         qh->qlen = 0;
 633 }
 634
 635 static inline int __qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch,
 636                                        struct qdisc_skb_head *qh)
 637 {
 638         struct sk_buff *last = qh->tail;
 639
 640         if (last) {
 641                 skb->next = NULL;
 642                 last->next = skb;
 643                 qh->tail = skb;
 644         } else {
 645                 qh->tail = skb;
 646                 qh->head = skb;
 647         }
 648         qh->qlen++;
 649         qdisc_qstats_backlog_inc(sch, skb);
 650
 651         return NET_XMIT_SUCCESS;
 652 }
 653
 654 static inline int qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch)
 655 {
 656         return __qdisc_enqueue_tail(skb, sch, &sch->q);
 657 }
 658
 659 static inline struct sk_buff *__qdisc_dequeue_head(struct qdisc_skb_head *qh)
 660 {
 661         struct sk_buff *skb = qh->head;
 662
 663         if (likely(skb != NULL)) {
 664                 qh->head = skb->next;
 665                 qh->qlen--;
 666                 if (qh->head == NULL)
 667                         qh->tail = NULL;
 668                 skb->next = NULL;
 669         }
 670
 671         return skb;
 672 }
 673
 674 static inline struct sk_buff *qdisc_dequeue_head(struct Qdisc *sch)
 675 {
 676         struct sk_buff *skb = __qdisc_dequeue_head(&sch->q);
 677
 678         if (likely(skb != NULL)) {
 679                 qdisc_qstats_backlog_dec(sch, skb);
 680                 qdisc_bstats_update(sch, skb);
 681         }
 682
 683         return skb;
 684 }
 685
 686 /* Instead of calling kfree_skb() while root qdisc lock is held,
 687  * queue the skb for future freeing at end of __dev_xmit_skb()
 688  */
 689 static inline void __qdisc_drop(struct sk_buff *skb, struct sk_buff **to_free)
 690 {
 691         skb->next = *to_free;
 692         *to_free = skb;
 693 }
 694
 695 static inline unsigned int __qdisc_queue_drop_head(struct Qdisc *sch,
 696                                                    struct qdisc_skb_head *qh,
 697                                                    struct sk_buff **to_free)
 698 {
 699         struct sk_buff *skb = __qdisc_dequeue_head(qh);
 700
 701         if (likely(skb != NULL)) {
 702                 unsigned int len = qdisc_pkt_len(skb);
 703
 704                 qdisc_qstats_backlog_dec(sch, skb);
 705                 __qdisc_drop(skb, to_free);
 706                 return len;
 707         }
 708
 709         return 0;
 710 }
 711
 712 static inline unsigned int qdisc_queue_drop_head(struct Qdisc *sch,
 713                                                  struct sk_buff **to_free)
 714 {
 715         return __qdisc_queue_drop_head(sch, &sch->q, to_free);
 716 }
 717
 718 static inline struct sk_buff *qdisc_peek_head(struct Qdisc *sch)
 719 {
 720         const struct qdisc_skb_head *qh = &sch->q;
 721
 722         return qh->head;
 723 }
 724
 725 /* generic pseudo peek method for non-work-conserving qdisc */
 726 static inline struct sk_buff *qdisc_peek_dequeued(struct Qdisc *sch)
 727 {
 728         /* we can reuse ->gso_skb because peek isn't called for root qdiscs */
 729         if (!sch->gso_skb) {
 730                 sch->gso_skb = sch->dequeue(sch);
 731                 if (sch->gso_skb) {
 732                         /* it's still part of the queue */
 733                         qdisc_qstats_backlog_inc(sch, sch->gso_skb);
 734                         sch->q.qlen++;
 735                 }
 736         }
 737
 738         return sch->gso_skb;
 739 }
 740
 741 /* use instead of qdisc->dequeue() for all qdiscs queried with ->peek() */
 742 static inline struct sk_buff *qdisc_dequeue_peeked(struct Qdisc *sch)
 743 {
 744         struct sk_buff *skb = sch->gso_skb;
 745
 746         if (skb) {
 747                 sch->gso_skb = NULL;
 748                 qdisc_qstats_backlog_dec(sch, skb);
 749                 sch->q.qlen--;
 750         } else {
 751                 skb = sch->dequeue(sch);
 752         }
 753
 754         return skb;
 755 }
 756
 757 static inline void __qdisc_reset_queue(struct qdisc_skb_head *qh)
 758 {
 759         /*
 760          * We do not know the backlog in bytes of this list, it
 761          * is up to the caller to correct it
 762          */
 763         ASSERT_RTNL();
 764         if (qh->qlen) {
 765                 rtnl_kfree_skbs(qh->head, qh->tail);
 766
 767                 qh->head = NULL;
 768                 qh->tail = NULL;
 769                 qh->qlen = 0;
 770         }
 771 }
 772
 773 static inline void qdisc_reset_queue(struct Qdisc *sch)
 774 {
 775         __qdisc_reset_queue(&sch->q);
 776         sch->qstats.backlog = 0;
 777 }
 778
 779 static inline struct Qdisc *qdisc_replace(struct Qdisc *sch, struct Qdisc *new,
 780                                           struct Qdisc **pold)
 781 {
 782         struct Qdisc *old;
 783
 784         sch_tree_lock(sch);
 785         old = *pold;
 786         *pold = new;
 787         if (old != NULL) {
 788                 qdisc_tree_reduce_backlog(old, old->q.qlen, old->qstats.backlog);
 789                 qdisc_reset(old);
 790         }
 791         sch_tree_unlock(sch);
 792
 793         return old;
 794 }
 795
 796 static inline void rtnl_qdisc_drop(struct sk_buff *skb, struct Qdisc *sch)
 797 {
 798         rtnl_kfree_skbs(skb, skb);
 799         qdisc_qstats_drop(sch);
 800 }
 801
 802
 803 static inline int qdisc_drop(struct sk_buff *skb, struct Qdisc *sch,
 804                              struct sk_buff **to_free)
 805 {
 806         __qdisc_drop(skb, to_free);
 807         qdisc_qstats_drop(sch);
 808
 809         return NET_XMIT_DROP;
 810 }
 811
 812 /* Length to Time (L2T) lookup in a qdisc_rate_table, to determine how
 813    long it will take to send a packet given its size.
 814  */
 815 static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen)
 816 {
 817         int slot = pktlen + rtab->rate.cell_align + rtab->rate.overhead;
 818         if (slot < 0)
 819                 slot = 0;
 820         slot >>= rtab->rate.cell_log;
 821         if (slot > 255)
 822                 return rtab->data[255]*(slot >> 8) + rtab->data[slot & 0xFF];
 823         return rtab->data[slot];
 824 }
 825
 826 struct psched_ratecfg {
 827         u64     rate_bytes_ps; /* bytes per second */
 828         u32     mult;
 829         u16     overhead;
 830         u8      linklayer;
 831         u8      shift;
 832 };
 833
 834 static inline u64 psched_l2t_ns(const struct psched_ratecfg *r,
 835                                 unsigned int len)
 836 {
 837         len += r->overhead;
 838
 839         if (unlikely(r->linklayer == TC_LINKLAYER_ATM))
 840                 return ((u64)(DIV_ROUND_UP(len,48)*53) * r->mult) >> r->shift;
 841
 842         return ((u64)len * r->mult) >> r->shift;
 843 }
 844
 845 void psched_ratecfg_precompute(struct psched_ratecfg *r,
 846                                const struct tc_ratespec *conf,
 847                                u64 rate64);
 848
 849 static inline void psched_ratecfg_getrate(struct tc_ratespec *res,
 850                                           const struct psched_ratecfg *r)
 851 {
 852         memset(res, 0, sizeof(*res));
 853
 854         /* legacy struct tc_ratespec has a 32bit @rate field
 855          * Qdisc using 64bit rate should add new attributes
 856          * in order to maintain compatibility.
 857          */
 858         res->rate = min_t(u64, r->rate_bytes_ps, ~0U);
 859
 860         res->overhead = r->overhead;
 861         res->linklayer = (r->linklayer & TC_LINKLAYER_MASK);
 862 }
 863
 864 #endif