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 struct Qdisc {
  40         int                     (*enqueue)(struct sk_buff *skb,
  41                                            struct Qdisc *sch,
  42                                            struct sk_buff **to_free);
  43         struct sk_buff *        (*dequeue)(struct Qdisc *sch);
  44         unsigned int            flags;
  45 #define TCQ_F_BUILTIN           1
  46 #define TCQ_F_INGRESS           2
  47 #define TCQ_F_CAN_BYPASS        4
  48 #define TCQ_F_MQROOT            8
  49 #define TCQ_F_ONETXQUEUE        0x10 /* dequeue_skb() can assume all skbs are for
  50                                       * q->dev_queue : It can test
  51                                       * netif_xmit_frozen_or_stopped() before
  52                                       * dequeueing next packet.
  53                                       * Its true for MQ/MQPRIO slaves, or non
  54                                       * multiqueue device.
  55                                       */
  56 #define TCQ_F_WARN_NONWC        (1 << 16)
  57 #define TCQ_F_CPUSTATS          0x20 /* run using percpu statistics */
  58 #define TCQ_F_NOPARENT          0x40 /* root of its hierarchy :
  59                                       * qdisc_tree_decrease_qlen() should stop.
  60                                       */
  61         u32                     limit;
  62         const struct Qdisc_ops  *ops;
  63         struct qdisc_size_table __rcu *stab;
  64         struct list_head        list;
  65         u32                     handle;
  66         u32                     parent;
  67         void                    *u32_node;
  68
  69         struct netdev_queue     *dev_queue;
  70
  71         struct gnet_stats_rate_est64    rate_est;
  72         struct gnet_stats_basic_cpu __percpu *cpu_bstats;
  73         struct gnet_stats_queue __percpu *cpu_qstats;
  74
  75         /*
  76          * For performance sake on SMP, we put highly modified fields at the end
  77          */
  78         struct sk_buff          *gso_skb ____cacheline_aligned_in_smp;
  79         struct sk_buff_head     q;
  80         struct gnet_stats_basic_packed bstats;
  81         seqcount_t              running;
  82         struct gnet_stats_queue qstats;
  83         unsigned long           state;
  84         struct Qdisc            *next_sched;
  85         struct sk_buff          *skb_bad_txq;
  86         struct rcu_head         rcu_head;
  87         int                     padded;
  88         atomic_t                refcnt;
  89
  90         spinlock_t              busylock ____cacheline_aligned_in_smp;
  91 };
  92
  93 static inline bool qdisc_is_running(const struct Qdisc *qdisc)
  94 {
  95         return (raw_read_seqcount(&qdisc->running) & 1) ? true : false;
  96 }
  97
  98 static inline bool qdisc_run_begin(struct Qdisc *qdisc)
  99 {
 100         if (qdisc_is_running(qdisc))
 101                 return false;
 102         /* Variant of write_seqcount_begin() telling lockdep a trylock
 103          * was attempted.
 104          */
 105         raw_write_seqcount_begin(&qdisc->running);
 106         seqcount_acquire(&qdisc->running.dep_map, 0, 1, _RET_IP_);
 107         return true;
 108 }
 109
 110 static inline void qdisc_run_end(struct Qdisc *qdisc)
 111 {
 112         write_seqcount_end(&qdisc->running);
 113 }
 114
 115 static inline bool qdisc_may_bulk(const struct Qdisc *qdisc)
 116 {
 117         return qdisc->flags & TCQ_F_ONETXQUEUE;
 118 }
 119
 120 static inline int qdisc_avail_bulklimit(const struct netdev_queue *txq)
 121 {
 122 #ifdef CONFIG_BQL
 123         /* Non-BQL migrated drivers will return 0, too. */
 124         return dql_avail(&txq->dql);
 125 #else
 126         return 0;
 127 #endif
 128 }
 129
 130 struct Qdisc_class_ops {
 131         /* Child qdisc manipulation */
 132         struct netdev_queue *   (*select_queue)(struct Qdisc *, struct tcmsg *);
 133         int                     (*graft)(struct Qdisc *, unsigned long cl,
 134                                         struct Qdisc *, struct Qdisc **);
 135         struct Qdisc *          (*leaf)(struct Qdisc *, unsigned long cl);
 136         void                    (*qlen_notify)(struct Qdisc *, unsigned long);
 137
 138         /* Class manipulation routines */
 139         unsigned long           (*get)(struct Qdisc *, u32 classid);
 140         void                    (*put)(struct Qdisc *, unsigned long);
 141         int                     (*change)(struct Qdisc *, u32, u32,
 142                                         struct nlattr **, unsigned long *);
 143         int                     (*delete)(struct Qdisc *, unsigned long);
 144         void                    (*walk)(struct Qdisc *, struct qdisc_walker * arg);
 145
 146         /* Filter manipulation */
 147         struct tcf_proto __rcu ** (*tcf_chain)(struct Qdisc *, unsigned long);
 148         bool                    (*tcf_cl_offload)(u32 classid);
 149         unsigned long           (*bind_tcf)(struct Qdisc *, unsigned long,
 150                                         u32 classid);
 151         void                    (*unbind_tcf)(struct Qdisc *, unsigned long);
 152
 153         /* rtnetlink specific */
 154         int                     (*dump)(struct Qdisc *, unsigned long,
 155                                         struct sk_buff *skb, struct tcmsg*);
 156         int                     (*dump_stats)(struct Qdisc *, unsigned long,
 157                                         struct gnet_dump *);
 158 };
 159
 160 struct Qdisc_ops {
 161         struct Qdisc_ops        *next;
 162         const struct Qdisc_class_ops    *cl_ops;
 163         char                    id[IFNAMSIZ];
 164         int                     priv_size;
 165
 166         int                     (*enqueue)(struct sk_buff *skb,
 167                                            struct Qdisc *sch,
 168                                            struct sk_buff **to_free);
 169         struct sk_buff *        (*dequeue)(struct Qdisc *);
 170         struct sk_buff *        (*peek)(struct Qdisc *);
 171
 172         int                     (*init)(struct Qdisc *, struct nlattr *arg);
 173         void                    (*reset)(struct Qdisc *);
 174         void                    (*destroy)(struct Qdisc *);
 175         int                     (*change)(struct Qdisc *, struct nlattr *arg);
 176         void                    (*attach)(struct Qdisc *);
 177
 178         int                     (*dump)(struct Qdisc *, struct sk_buff *);
 179         int                     (*dump_stats)(struct Qdisc *, struct gnet_dump *);
 180
 181         struct module           *owner;
 182 };
 183
 184
 185 struct tcf_result {
 186         unsigned long   class;
 187         u32             classid;
 188 };
 189
 190 struct tcf_proto_ops {
 191         struct list_head        head;
 192         char                    kind[IFNAMSIZ];
 193
 194         int                     (*classify)(struct sk_buff *,
 195                                             const struct tcf_proto *,
 196                                             struct tcf_result *);
 197         int                     (*init)(struct tcf_proto*);
 198         bool                    (*destroy)(struct tcf_proto*, bool);
 199
 200         unsigned long           (*get)(struct tcf_proto*, u32 handle);
 201         int                     (*change)(struct net *net, struct sk_buff *,
 202                                         struct tcf_proto*, unsigned long,
 203                                         u32 handle, struct nlattr **,
 204                                         unsigned long *, bool);
 205         int                     (*delete)(struct tcf_proto*, unsigned long);
 206         void                    (*walk)(struct tcf_proto*, struct tcf_walker *arg);
 207
 208         /* rtnetlink specific */
 209         int                     (*dump)(struct net*, struct tcf_proto*, unsigned long,
 210                                         struct sk_buff *skb, struct tcmsg*);
 211
 212         struct module           *owner;
 213 };
 214
 215 struct tcf_proto {
 216         /* Fast access part */
 217         struct tcf_proto __rcu  *next;
 218         void __rcu              *root;
 219         int                     (*classify)(struct sk_buff *,
 220                                             const struct tcf_proto *,
 221                                             struct tcf_result *);
 222         __be16                  protocol;
 223
 224         /* All the rest */
 225         u32                     prio;
 226         u32                     classid;
 227         struct Qdisc            *q;
 228         void                    *data;
 229         const struct tcf_proto_ops      *ops;
 230         struct rcu_head         rcu;
 231 };
 232
 233 struct qdisc_skb_cb {
 234         unsigned int            pkt_len;
 235         u16                     slave_dev_queue_mapping;
 236         u16                     tc_classid;
 237 #define QDISC_CB_PRIV_LEN 20
 238         unsigned char           data[QDISC_CB_PRIV_LEN];
 239 };
 240
 241 static inline void qdisc_cb_private_validate(const struct sk_buff *skb, int sz)
 242 {
 243         struct qdisc_skb_cb *qcb;
 244
 245         BUILD_BUG_ON(sizeof(skb->cb) < offsetof(struct qdisc_skb_cb, data) + sz);
 246         BUILD_BUG_ON(sizeof(qcb->data) < sz);
 247 }
 248
 249 static inline int qdisc_qlen(const struct Qdisc *q)
 250 {
 251         return q->q.qlen;
 252 }
 253
 254 static inline struct qdisc_skb_cb *qdisc_skb_cb(const struct sk_buff *skb)
 255 {
 256         return (struct qdisc_skb_cb *)skb->cb;
 257 }
 258
 259 static inline spinlock_t *qdisc_lock(struct Qdisc *qdisc)
 260 {
 261         return &qdisc->q.lock;
 262 }
 263
 264 static inline struct Qdisc *qdisc_root(const struct Qdisc *qdisc)
 265 {
 266         struct Qdisc *q = rcu_dereference_rtnl(qdisc->dev_queue->qdisc);
 267
 268         return q;
 269 }
 270
 271 static inline struct Qdisc *qdisc_root_sleeping(const struct Qdisc *qdisc)
 272 {
 273         return qdisc->dev_queue->qdisc_sleeping;
 274 }
 275
 276 /* The qdisc root lock is a mechanism by which to top level
 277  * of a qdisc tree can be locked from any qdisc node in the
 278  * forest.  This allows changing the configuration of some
 279  * aspect of the qdisc tree while blocking out asynchronous
 280  * qdisc access in the packet processing paths.
 281  *
 282  * It is only legal to do this when the root will not change
 283  * on us.  Otherwise we'll potentially lock the wrong qdisc
 284  * root.  This is enforced by holding the RTNL semaphore, which
 285  * all users of this lock accessor must do.
 286  */
 287 static inline spinlock_t *qdisc_root_lock(const struct Qdisc *qdisc)
 288 {
 289         struct Qdisc *root = qdisc_root(qdisc);
 290
 291         ASSERT_RTNL();
 292         return qdisc_lock(root);
 293 }
 294
 295 static inline spinlock_t *qdisc_root_sleeping_lock(const struct Qdisc *qdisc)
 296 {
 297         struct Qdisc *root = qdisc_root_sleeping(qdisc);
 298
 299         ASSERT_RTNL();
 300         return qdisc_lock(root);
 301 }
 302
 303 static inline seqcount_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc)
 304 {
 305         struct Qdisc *root = qdisc_root_sleeping(qdisc);
 306
 307         ASSERT_RTNL();
 308         return &root->running;
 309 }
 310
 311 static inline struct net_device *qdisc_dev(const struct Qdisc *qdisc)
 312 {
 313         return qdisc->dev_queue->dev;
 314 }
 315
 316 static inline void sch_tree_lock(const struct Qdisc *q)
 317 {
 318         spin_lock_bh(qdisc_root_sleeping_lock(q));
 319 }
 320
 321 static inline void sch_tree_unlock(const struct Qdisc *q)
 322 {
 323         spin_unlock_bh(qdisc_root_sleeping_lock(q));
 324 }
 325
 326 #define tcf_tree_lock(tp)       sch_tree_lock((tp)->q)
 327 #define tcf_tree_unlock(tp)     sch_tree_unlock((tp)->q)
 328
 329 extern struct Qdisc noop_qdisc;
 330 extern struct Qdisc_ops noop_qdisc_ops;
 331 extern struct Qdisc_ops pfifo_fast_ops;
 332 extern struct Qdisc_ops mq_qdisc_ops;
 333 extern struct Qdisc_ops noqueue_qdisc_ops;
 334 extern const struct Qdisc_ops *default_qdisc_ops;
 335 static inline const struct Qdisc_ops *
 336 get_default_qdisc_ops(const struct net_device *dev, int ntx)
 337 {
 338         return ntx < dev->real_num_tx_queues ?
 339                         default_qdisc_ops : &pfifo_fast_ops;
 340 }
 341
 342 struct Qdisc_class_common {
 343         u32                     classid;
 344         struct hlist_node       hnode;
 345 };
 346
 347 struct Qdisc_class_hash {
 348         struct hlist_head       *hash;
 349         unsigned int            hashsize;
 350         unsigned int            hashmask;
 351         unsigned int            hashelems;
 352 };
 353
 354 static inline unsigned int qdisc_class_hash(u32 id, u32 mask)
 355 {
 356         id ^= id >> 8;
 357         id ^= id >> 4;
 358         return id & mask;
 359 }
 360
 361 static inline struct Qdisc_class_common *
 362 qdisc_class_find(const struct Qdisc_class_hash *hash, u32 id)
 363 {
 364         struct Qdisc_class_common *cl;
 365         unsigned int h;
 366
 367         h = qdisc_class_hash(id, hash->hashmask);
 368         hlist_for_each_entry(cl, &hash->hash[h], hnode) {
 369                 if (cl->classid == id)
 370                         return cl;
 371         }
 372         return NULL;
 373 }
 374
 375 int qdisc_class_hash_init(struct Qdisc_class_hash *);
 376 void qdisc_class_hash_insert(struct Qdisc_class_hash *,
 377                              struct Qdisc_class_common *);
 378 void qdisc_class_hash_remove(struct Qdisc_class_hash *,
 379                              struct Qdisc_class_common *);
 380 void qdisc_class_hash_grow(struct Qdisc *, struct Qdisc_class_hash *);
 381 void qdisc_class_hash_destroy(struct Qdisc_class_hash *);
 382
 383 void dev_init_scheduler(struct net_device *dev);
 384 void dev_shutdown(struct net_device *dev);
 385 void dev_activate(struct net_device *dev);
 386 void dev_deactivate(struct net_device *dev);
 387 void dev_deactivate_many(struct list_head *head);
 388 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
 389                               struct Qdisc *qdisc);
 390 void qdisc_reset(struct Qdisc *qdisc);
 391 void qdisc_destroy(struct Qdisc *qdisc);
 392 void qdisc_tree_reduce_backlog(struct Qdisc *qdisc, unsigned int n,
 393                                unsigned int len);
 394 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 395                           const struct Qdisc_ops *ops);
 396 struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
 397                                 const struct Qdisc_ops *ops, u32 parentid);
 398 void __qdisc_calculate_pkt_len(struct sk_buff *skb,
 399                                const struct qdisc_size_table *stab);
 400 bool tcf_destroy(struct tcf_proto *tp, bool force);
 401 void tcf_destroy_chain(struct tcf_proto __rcu **fl);
 402 int skb_do_redirect(struct sk_buff *);
 403
 404 static inline bool skb_at_tc_ingress(const struct sk_buff *skb)
 405 {
 406 #ifdef CONFIG_NET_CLS_ACT
 407         return G_TC_AT(skb->tc_verd) & AT_INGRESS;
 408 #else
 409         return false;
 410 #endif
 411 }
 412
 413 /* Reset all TX qdiscs greater then index of a device.  */
 414 static inline void qdisc_reset_all_tx_gt(struct net_device *dev, unsigned int i)
 415 {
 416         struct Qdisc *qdisc;
 417
 418         for (; i < dev->num_tx_queues; i++) {
 419                 qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc);
 420                 if (qdisc) {
 421                         spin_lock_bh(qdisc_lock(qdisc));
 422                         qdisc_reset(qdisc);
 423                         spin_unlock_bh(qdisc_lock(qdisc));
 424                 }
 425         }
 426 }
 427
 428 static inline void qdisc_reset_all_tx(struct net_device *dev)
 429 {
 430         qdisc_reset_all_tx_gt(dev, 0);
 431 }
 432
 433 /* Are all TX queues of the device empty?  */
 434 static inline bool qdisc_all_tx_empty(const struct net_device *dev)
 435 {
 436         unsigned int i;
 437
 438         rcu_read_lock();
 439         for (i = 0; i < dev->num_tx_queues; i++) {
 440                 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
 441                 const struct Qdisc *q = rcu_dereference(txq->qdisc);
 442
 443                 if (q->q.qlen) {
 444                         rcu_read_unlock();
 445                         return false;
 446                 }
 447         }
 448         rcu_read_unlock();
 449         return true;
 450 }
 451
 452 /* Are any of the TX qdiscs changing?  */
 453 static inline bool qdisc_tx_changing(const struct net_device *dev)
 454 {
 455         unsigned int i;
 456
 457         for (i = 0; i < dev->num_tx_queues; i++) {
 458                 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
 459                 if (rcu_access_pointer(txq->qdisc) != txq->qdisc_sleeping)
 460                         return true;
 461         }
 462         return false;
 463 }
 464
 465 /* Is the device using the noop qdisc on all queues?  */
 466 static inline bool qdisc_tx_is_noop(const struct net_device *dev)
 467 {
 468         unsigned int i;
 469
 470         for (i = 0; i < dev->num_tx_queues; i++) {
 471                 struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
 472                 if (rcu_access_pointer(txq->qdisc) != &noop_qdisc)
 473                         return false;
 474         }
 475         return true;
 476 }
 477
 478 static inline unsigned int qdisc_pkt_len(const struct sk_buff *skb)
 479 {
 480         return qdisc_skb_cb(skb)->pkt_len;
 481 }
 482
 483 /* additional qdisc xmit flags (NET_XMIT_MASK in linux/netdevice.h) */
 484 enum net_xmit_qdisc_t {
 485         __NET_XMIT_STOLEN = 0x00010000,
 486         __NET_XMIT_BYPASS = 0x00020000,
 487 };
 488
 489 #ifdef CONFIG_NET_CLS_ACT
 490 #define net_xmit_drop_count(e)  ((e) & __NET_XMIT_STOLEN ? 0 : 1)
 491 #else
 492 #define net_xmit_drop_count(e)  (1)
 493 #endif
 494
 495 static inline void qdisc_calculate_pkt_len(struct sk_buff *skb,
 496                                            const struct Qdisc *sch)
 497 {
 498 #ifdef CONFIG_NET_SCHED
 499         struct qdisc_size_table *stab = rcu_dereference_bh(sch->stab);
 500
 501         if (stab)
 502                 __qdisc_calculate_pkt_len(skb, stab);
 503 #endif
 504 }
 505
 506 static inline int qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 507                                 struct sk_buff **to_free)
 508 {
 509         qdisc_calculate_pkt_len(skb, sch);
 510         return sch->enqueue(skb, sch, to_free);
 511 }
 512
 513 static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
 514 {
 515         return q->flags & TCQ_F_CPUSTATS;
 516 }
 517
 518 static inline void _bstats_update(struct gnet_stats_basic_packed *bstats,
 519                                   __u64 bytes, __u32 packets)
 520 {
 521         bstats->bytes += bytes;
 522         bstats->packets += packets;
 523 }
 524
 525 static inline void bstats_update(struct gnet_stats_basic_packed *bstats,
 526                                  const struct sk_buff *skb)
 527 {
 528         _bstats_update(bstats,
 529                        qdisc_pkt_len(skb),
 530                        skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 1);
 531 }
 532
 533 static inline void _bstats_cpu_update(struct gnet_stats_basic_cpu *bstats,
 534                                       __u64 bytes, __u32 packets)
 535 {
 536         u64_stats_update_begin(&bstats->syncp);
 537         _bstats_update(&bstats->bstats, bytes, packets);
 538         u64_stats_update_end(&bstats->syncp);
 539 }
 540
 541 static inline void bstats_cpu_update(struct gnet_stats_basic_cpu *bstats,
 542                                      const struct sk_buff *skb)
 543 {
 544         u64_stats_update_begin(&bstats->syncp);
 545         bstats_update(&bstats->bstats, skb);
 546         u64_stats_update_end(&bstats->syncp);
 547 }
 548
 549 static inline void qdisc_bstats_cpu_update(struct Qdisc *sch,
 550                                            const struct sk_buff *skb)
 551 {
 552         bstats_cpu_update(this_cpu_ptr(sch->cpu_bstats), skb);
 553 }
 554
 555 static inline void qdisc_bstats_update(struct Qdisc *sch,
 556                                        const struct sk_buff *skb)
 557 {
 558         bstats_update(&sch->bstats, skb);
 559 }
 560
 561 static inline void qdisc_qstats_backlog_dec(struct Qdisc *sch,
 562                                             const struct sk_buff *skb)
 563 {
 564         sch->qstats.backlog -= qdisc_pkt_len(skb);
 565 }
 566
 567 static inline void qdisc_qstats_backlog_inc(struct Qdisc *sch,
 568                                             const struct sk_buff *skb)
 569 {
 570         sch->qstats.backlog += qdisc_pkt_len(skb);
 571 }
 572
 573 static inline void __qdisc_qstats_drop(struct Qdisc *sch, int count)
 574 {
 575         sch->qstats.drops += count;
 576 }
 577
 578 static inline void qstats_drop_inc(struct gnet_stats_queue *qstats)
 579 {
 580         qstats->drops++;
 581 }
 582
 583 static inline void qstats_overlimit_inc(struct gnet_stats_queue *qstats)
 584 {
 585         qstats->overlimits++;
 586 }
 587
 588 static inline void qdisc_qstats_drop(struct Qdisc *sch)
 589 {
 590         qstats_drop_inc(&sch->qstats);
 591 }
 592
 593 static inline void qdisc_qstats_cpu_drop(struct Qdisc *sch)
 594 {
 595         qstats_drop_inc(this_cpu_ptr(sch->cpu_qstats));
 596 }
 597
 598 static inline void qdisc_qstats_overlimit(struct Qdisc *sch)
 599 {
 600         sch->qstats.overlimits++;
 601 }
 602
 603 static inline int __qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch,
 604                                        struct sk_buff_head *list)
 605 {
 606         __skb_queue_tail(list, skb);
 607         qdisc_qstats_backlog_inc(sch, skb);
 608
 609         return NET_XMIT_SUCCESS;
 610 }
 611
 612 static inline int qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch)
 613 {
 614         return __qdisc_enqueue_tail(skb, sch, &sch->q);
 615 }
 616
 617 static inline struct sk_buff *__qdisc_dequeue_head(struct Qdisc *sch,
 618                                                    struct sk_buff_head *list)
 619 {
 620         struct sk_buff *skb = __skb_dequeue(list);
 621
 622         if (likely(skb != NULL)) {
 623                 qdisc_qstats_backlog_dec(sch, skb);
 624                 qdisc_bstats_update(sch, skb);
 625         }
 626
 627         return skb;
 628 }
 629
 630 static inline struct sk_buff *qdisc_dequeue_head(struct Qdisc *sch)
 631 {
 632         return __qdisc_dequeue_head(sch, &sch->q);
 633 }
 634
 635 /* Instead of calling kfree_skb() while root qdisc lock is held,
 636  * queue the skb for future freeing at end of __dev_xmit_skb()
 637  */
 638 static inline void __qdisc_drop(struct sk_buff *skb, struct sk_buff **to_free)
 639 {
 640         skb->next = *to_free;
 641         *to_free = skb;
 642 }
 643
 644 static inline unsigned int __qdisc_queue_drop_head(struct Qdisc *sch,
 645                                                    struct sk_buff_head *list,
 646                                                    struct sk_buff **to_free)
 647 {
 648         struct sk_buff *skb = __skb_dequeue(list);
 649
 650         if (likely(skb != NULL)) {
 651                 unsigned int len = qdisc_pkt_len(skb);
 652
 653                 qdisc_qstats_backlog_dec(sch, skb);
 654                 __qdisc_drop(skb, to_free);
 655                 return len;
 656         }
 657
 658         return 0;
 659 }
 660
 661 static inline unsigned int qdisc_queue_drop_head(struct Qdisc *sch,
 662                                                  struct sk_buff **to_free)
 663 {
 664         return __qdisc_queue_drop_head(sch, &sch->q, to_free);
 665 }
 666
 667 static inline struct sk_buff *qdisc_peek_head(struct Qdisc *sch)
 668 {
 669         return skb_peek(&sch->q);
 670 }
 671
 672 /* generic pseudo peek method for non-work-conserving qdisc */
 673 static inline struct sk_buff *qdisc_peek_dequeued(struct Qdisc *sch)
 674 {
 675         /* we can reuse ->gso_skb because peek isn't called for root qdiscs */
 676         if (!sch->gso_skb) {
 677                 sch->gso_skb = sch->dequeue(sch);
 678                 if (sch->gso_skb) {
 679                         /* it's still part of the queue */
 680                         qdisc_qstats_backlog_inc(sch, sch->gso_skb);
 681                         sch->q.qlen++;
 682                 }
 683         }
 684
 685         return sch->gso_skb;
 686 }
 687
 688 /* use instead of qdisc->dequeue() for all qdiscs queried with ->peek() */
 689 static inline struct sk_buff *qdisc_dequeue_peeked(struct Qdisc *sch)
 690 {
 691         struct sk_buff *skb = sch->gso_skb;
 692
 693         if (skb) {
 694                 sch->gso_skb = NULL;
 695                 qdisc_qstats_backlog_dec(sch, skb);
 696                 sch->q.qlen--;
 697         } else {
 698                 skb = sch->dequeue(sch);
 699         }
 700
 701         return skb;
 702 }
 703
 704 static inline void __qdisc_reset_queue(struct sk_buff_head *list)
 705 {
 706         /*
 707          * We do not know the backlog in bytes of this list, it
 708          * is up to the caller to correct it
 709          */
 710         if (!skb_queue_empty(list)) {
 711                 rtnl_kfree_skbs(list->next, list->prev);
 712                 __skb_queue_head_init(list);
 713         }
 714 }
 715
 716 static inline void qdisc_reset_queue(struct Qdisc *sch)
 717 {
 718         __qdisc_reset_queue(&sch->q);
 719         sch->qstats.backlog = 0;
 720 }
 721
 722 static inline struct Qdisc *qdisc_replace(struct Qdisc *sch, struct Qdisc *new,
 723                                           struct Qdisc **pold)
 724 {
 725         struct Qdisc *old;
 726
 727         sch_tree_lock(sch);
 728         old = *pold;
 729         *pold = new;
 730         if (old != NULL) {
 731                 qdisc_tree_reduce_backlog(old, old->q.qlen, old->qstats.backlog);
 732                 qdisc_reset(old);
 733         }
 734         sch_tree_unlock(sch);
 735
 736         return old;
 737 }
 738
 739 static inline void rtnl_qdisc_drop(struct sk_buff *skb, struct Qdisc *sch)
 740 {
 741         rtnl_kfree_skbs(skb, skb);
 742         qdisc_qstats_drop(sch);
 743 }
 744
 745
 746 static inline int qdisc_drop(struct sk_buff *skb, struct Qdisc *sch,
 747                              struct sk_buff **to_free)
 748 {
 749         __qdisc_drop(skb, to_free);
 750         qdisc_qstats_drop(sch);
 751
 752         return NET_XMIT_DROP;
 753 }
 754
 755 /* Length to Time (L2T) lookup in a qdisc_rate_table, to determine how
 756    long it will take to send a packet given its size.
 757  */
 758 static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen)
 759 {
 760         int slot = pktlen + rtab->rate.cell_align + rtab->rate.overhead;
 761         if (slot < 0)
 762                 slot = 0;
 763         slot >>= rtab->rate.cell_log;
 764         if (slot > 255)
 765                 return rtab->data[255]*(slot >> 8) + rtab->data[slot & 0xFF];
 766         return rtab->data[slot];
 767 }
 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