linux/include/net/sch_generic.h
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   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
  14struct Qdisc_ops;
  15struct qdisc_walker;
  16struct tcf_walker;
  17struct module;
  18
  19struct qdisc_rate_table {
  20        struct tc_ratespec rate;
  21        u32             data[256];
  22        struct qdisc_rate_table *next;
  23        int             refcnt;
  24};
  25
  26enum qdisc_state_t {
  27        __QDISC_STATE_SCHED,
  28        __QDISC_STATE_DEACTIVATED,
  29        __QDISC_STATE_THROTTLED,
  30};
  31
  32/*
  33 * following bits are only changed while qdisc lock is held
  34 */
  35enum qdisc___state_t {
  36        __QDISC___STATE_RUNNING = 1,
  37};
  38
  39struct qdisc_size_table {
  40        struct rcu_head         rcu;
  41        struct list_head        list;
  42        struct tc_sizespec      szopts;
  43        int                     refcnt;
  44        u16                     data[];
  45};
  46
  47struct Qdisc {
  48        int                     (*enqueue)(struct sk_buff *skb, struct Qdisc *dev);
  49        struct sk_buff *        (*dequeue)(struct Qdisc *dev);
  50        unsigned int            flags;
  51#define TCQ_F_BUILTIN           1
  52#define TCQ_F_INGRESS           2
  53#define TCQ_F_CAN_BYPASS        4
  54#define TCQ_F_MQROOT            8
  55#define TCQ_F_ONETXQUEUE        0x10 /* dequeue_skb() can assume all skbs are for
  56                                      * q->dev_queue : It can test
  57                                      * netif_xmit_frozen_or_stopped() before
  58                                      * dequeueing next packet.
  59                                      * Its true for MQ/MQPRIO slaves, or non
  60                                      * multiqueue device.
  61                                      */
  62#define TCQ_F_WARN_NONWC        (1 << 16)
  63#define TCQ_F_CPUSTATS          0x20 /* run using percpu statistics */
  64#define TCQ_F_NOPARENT          0x40 /* root of its hierarchy :
  65                                      * qdisc_tree_decrease_qlen() should stop.
  66                                      */
  67        u32                     limit;
  68        const struct Qdisc_ops  *ops;
  69        struct qdisc_size_table __rcu *stab;
  70        struct list_head        list;
  71        u32                     handle;
  72        u32                     parent;
  73        int                     (*reshape_fail)(struct sk_buff *skb,
  74                                        struct Qdisc *q);
  75
  76        void                    *u32_node;
  77
  78        /* This field is deprecated, but it is still used by CBQ
  79         * and it will live until better solution will be invented.
  80         */
  81        struct Qdisc            *__parent;
  82        struct netdev_queue     *dev_queue;
  83
  84        struct gnet_stats_rate_est64    rate_est;
  85        struct gnet_stats_basic_cpu __percpu *cpu_bstats;
  86        struct gnet_stats_queue __percpu *cpu_qstats;
  87
  88        struct Qdisc            *next_sched;
  89        struct sk_buff          *gso_skb;
  90        /*
  91         * For performance sake on SMP, we put highly modified fields at the end
  92         */
  93        unsigned long           state;
  94        struct sk_buff_head     q;
  95        struct gnet_stats_basic_packed bstats;
  96        unsigned int            __state;
  97        struct gnet_stats_queue qstats;
  98        struct rcu_head         rcu_head;
  99        int                     padded;
 100        atomic_t                refcnt;
 101
 102        spinlock_t              busylock ____cacheline_aligned_in_smp;
 103};
 104
 105static inline bool qdisc_is_running(const struct Qdisc *qdisc)
 106{
 107        return (qdisc->__state & __QDISC___STATE_RUNNING) ? true : false;
 108}
 109
 110static inline bool qdisc_run_begin(struct Qdisc *qdisc)
 111{
 112        if (qdisc_is_running(qdisc))
 113                return false;
 114        qdisc->__state |= __QDISC___STATE_RUNNING;
 115        return true;
 116}
 117
 118static inline void qdisc_run_end(struct Qdisc *qdisc)
 119{
 120        qdisc->__state &= ~__QDISC___STATE_RUNNING;
 121}
 122
 123static inline bool qdisc_may_bulk(const struct Qdisc *qdisc)
 124{
 125        return qdisc->flags & TCQ_F_ONETXQUEUE;
 126}
 127
 128static inline int qdisc_avail_bulklimit(const struct netdev_queue *txq)
 129{
 130#ifdef CONFIG_BQL
 131        /* Non-BQL migrated drivers will return 0, too. */
 132        return dql_avail(&txq->dql);
 133#else
 134        return 0;
 135#endif
 136}
 137
 138static inline bool qdisc_is_throttled(const struct Qdisc *qdisc)
 139{
 140        return test_bit(__QDISC_STATE_THROTTLED, &qdisc->state) ? true : false;
 141}
 142
 143static inline void qdisc_throttled(struct Qdisc *qdisc)
 144{
 145        set_bit(__QDISC_STATE_THROTTLED, &qdisc->state);
 146}
 147
 148static inline void qdisc_unthrottled(struct Qdisc *qdisc)
 149{
 150        clear_bit(__QDISC_STATE_THROTTLED, &qdisc->state);
 151}
 152
 153struct Qdisc_class_ops {
 154        /* Child qdisc manipulation */
 155        struct netdev_queue *   (*select_queue)(struct Qdisc *, struct tcmsg *);
 156        int                     (*graft)(struct Qdisc *, unsigned long cl,
 157                                        struct Qdisc *, struct Qdisc **);
 158        struct Qdisc *          (*leaf)(struct Qdisc *, unsigned long cl);
 159        void                    (*qlen_notify)(struct Qdisc *, unsigned long);
 160
 161        /* Class manipulation routines */
 162        unsigned long           (*get)(struct Qdisc *, u32 classid);
 163        void                    (*put)(struct Qdisc *, unsigned long);
 164        int                     (*change)(struct Qdisc *, u32, u32,
 165                                        struct nlattr **, unsigned long *);
 166        int                     (*delete)(struct Qdisc *, unsigned long);
 167        void                    (*walk)(struct Qdisc *, struct qdisc_walker * arg);
 168
 169        /* Filter manipulation */
 170        struct tcf_proto __rcu ** (*tcf_chain)(struct Qdisc *, unsigned long);
 171        unsigned long           (*bind_tcf)(struct Qdisc *, unsigned long,
 172                                        u32 classid);
 173        void                    (*unbind_tcf)(struct Qdisc *, unsigned long);
 174
 175        /* rtnetlink specific */
 176        int                     (*dump)(struct Qdisc *, unsigned long,
 177                                        struct sk_buff *skb, struct tcmsg*);
 178        int                     (*dump_stats)(struct Qdisc *, unsigned long,
 179                                        struct gnet_dump *);
 180};
 181
 182struct Qdisc_ops {
 183        struct Qdisc_ops        *next;
 184        const struct Qdisc_class_ops    *cl_ops;
 185        char                    id[IFNAMSIZ];
 186        int                     priv_size;
 187
 188        int                     (*enqueue)(struct sk_buff *, struct Qdisc *);
 189        struct sk_buff *        (*dequeue)(struct Qdisc *);
 190        struct sk_buff *        (*peek)(struct Qdisc *);
 191        unsigned int            (*drop)(struct Qdisc *);
 192
 193        int                     (*init)(struct Qdisc *, struct nlattr *arg);
 194        void                    (*reset)(struct Qdisc *);
 195        void                    (*destroy)(struct Qdisc *);
 196        int                     (*change)(struct Qdisc *, struct nlattr *arg);
 197        void                    (*attach)(struct Qdisc *);
 198
 199        int                     (*dump)(struct Qdisc *, struct sk_buff *);
 200        int                     (*dump_stats)(struct Qdisc *, struct gnet_dump *);
 201
 202        struct module           *owner;
 203};
 204
 205
 206struct tcf_result {
 207        unsigned long   class;
 208        u32             classid;
 209};
 210
 211struct tcf_proto_ops {
 212        struct list_head        head;
 213        char                    kind[IFNAMSIZ];
 214
 215        int                     (*classify)(struct sk_buff *,
 216                                            const struct tcf_proto *,
 217                                            struct tcf_result *);
 218        int                     (*init)(struct tcf_proto*);
 219        bool                    (*destroy)(struct tcf_proto*, bool);
 220
 221        unsigned long           (*get)(struct tcf_proto*, u32 handle);
 222        int                     (*change)(struct net *net, struct sk_buff *,
 223                                        struct tcf_proto*, unsigned long,
 224                                        u32 handle, struct nlattr **,
 225                                        unsigned long *, bool);
 226        int                     (*delete)(struct tcf_proto*, unsigned long);
 227        void                    (*walk)(struct tcf_proto*, struct tcf_walker *arg);
 228
 229        /* rtnetlink specific */
 230        int                     (*dump)(struct net*, struct tcf_proto*, unsigned long,
 231                                        struct sk_buff *skb, struct tcmsg*);
 232
 233        struct module           *owner;
 234};
 235
 236struct tcf_proto {
 237        /* Fast access part */
 238        struct tcf_proto __rcu  *next;
 239        void __rcu              *root;
 240        int                     (*classify)(struct sk_buff *,
 241                                            const struct tcf_proto *,
 242                                            struct tcf_result *);
 243        __be16                  protocol;
 244
 245        /* All the rest */
 246        u32                     prio;
 247        u32                     classid;
 248        struct Qdisc            *q;
 249        void                    *data;
 250        const struct tcf_proto_ops      *ops;
 251        struct rcu_head         rcu;
 252};
 253
 254struct qdisc_skb_cb {
 255        unsigned int            pkt_len;
 256        u16                     slave_dev_queue_mapping;
 257        u16                     tc_classid;
 258#define QDISC_CB_PRIV_LEN 20
 259        unsigned char           data[QDISC_CB_PRIV_LEN];
 260};
 261
 262static inline void qdisc_cb_private_validate(const struct sk_buff *skb, int sz)
 263{
 264        struct qdisc_skb_cb *qcb;
 265
 266        BUILD_BUG_ON(sizeof(skb->cb) < offsetof(struct qdisc_skb_cb, data) + sz);
 267        BUILD_BUG_ON(sizeof(qcb->data) < sz);
 268}
 269
 270static inline int qdisc_qlen(const struct Qdisc *q)
 271{
 272        return q->q.qlen;
 273}
 274
 275static inline struct qdisc_skb_cb *qdisc_skb_cb(const struct sk_buff *skb)
 276{
 277        return (struct qdisc_skb_cb *)skb->cb;
 278}
 279
 280static inline spinlock_t *qdisc_lock(struct Qdisc *qdisc)
 281{
 282        return &qdisc->q.lock;
 283}
 284
 285static inline struct Qdisc *qdisc_root(const struct Qdisc *qdisc)
 286{
 287        struct Qdisc *q = rcu_dereference_rtnl(qdisc->dev_queue->qdisc);
 288
 289        return q;
 290}
 291
 292static inline struct Qdisc *qdisc_root_sleeping(const struct Qdisc *qdisc)
 293{
 294        return qdisc->dev_queue->qdisc_sleeping;
 295}
 296
 297/* The qdisc root lock is a mechanism by which to top level
 298 * of a qdisc tree can be locked from any qdisc node in the
 299 * forest.  This allows changing the configuration of some
 300 * aspect of the qdisc tree while blocking out asynchronous
 301 * qdisc access in the packet processing paths.
 302 *
 303 * It is only legal to do this when the root will not change
 304 * on us.  Otherwise we'll potentially lock the wrong qdisc
 305 * root.  This is enforced by holding the RTNL semaphore, which
 306 * all users of this lock accessor must do.
 307 */
 308static inline spinlock_t *qdisc_root_lock(const struct Qdisc *qdisc)
 309{
 310        struct Qdisc *root = qdisc_root(qdisc);
 311
 312        ASSERT_RTNL();
 313        return qdisc_lock(root);
 314}
 315
 316static inline spinlock_t *qdisc_root_sleeping_lock(const struct Qdisc *qdisc)
 317{
 318        struct Qdisc *root = qdisc_root_sleeping(qdisc);
 319
 320        ASSERT_RTNL();
 321        return qdisc_lock(root);
 322}
 323
 324static inline struct net_device *qdisc_dev(const struct Qdisc *qdisc)
 325{
 326        return qdisc->dev_queue->dev;
 327}
 328
 329static inline void sch_tree_lock(const struct Qdisc *q)
 330{
 331        spin_lock_bh(qdisc_root_sleeping_lock(q));
 332}
 333
 334static inline void sch_tree_unlock(const struct Qdisc *q)
 335{
 336        spin_unlock_bh(qdisc_root_sleeping_lock(q));
 337}
 338
 339#define tcf_tree_lock(tp)       sch_tree_lock((tp)->q)
 340#define tcf_tree_unlock(tp)     sch_tree_unlock((tp)->q)
 341
 342extern struct Qdisc noop_qdisc;
 343extern struct Qdisc_ops noop_qdisc_ops;
 344extern struct Qdisc_ops pfifo_fast_ops;
 345extern struct Qdisc_ops mq_qdisc_ops;
 346extern struct Qdisc_ops noqueue_qdisc_ops;
 347extern const struct Qdisc_ops *default_qdisc_ops;
 348static inline const struct Qdisc_ops *
 349get_default_qdisc_ops(const struct net_device *dev, int ntx)
 350{
 351        return ntx < dev->real_num_tx_queues ?
 352                        default_qdisc_ops : &pfifo_fast_ops;
 353}
 354
 355struct Qdisc_class_common {
 356        u32                     classid;
 357        struct hlist_node       hnode;
 358};
 359
 360struct Qdisc_class_hash {
 361        struct hlist_head       *hash;
 362        unsigned int            hashsize;
 363        unsigned int            hashmask;
 364        unsigned int            hashelems;
 365};
 366
 367static inline unsigned int qdisc_class_hash(u32 id, u32 mask)
 368{
 369        id ^= id >> 8;
 370        id ^= id >> 4;
 371        return id & mask;
 372}
 373
 374static inline struct Qdisc_class_common *
 375qdisc_class_find(const struct Qdisc_class_hash *hash, u32 id)
 376{
 377        struct Qdisc_class_common *cl;
 378        unsigned int h;
 379
 380        h = qdisc_class_hash(id, hash->hashmask);
 381        hlist_for_each_entry(cl, &hash->hash[h], hnode) {
 382                if (cl->classid == id)
 383                        return cl;
 384        }
 385        return NULL;
 386}
 387
 388int qdisc_class_hash_init(struct Qdisc_class_hash *);
 389void qdisc_class_hash_insert(struct Qdisc_class_hash *,
 390                             struct Qdisc_class_common *);
 391void qdisc_class_hash_remove(struct Qdisc_class_hash *,
 392                             struct Qdisc_class_common *);
 393void qdisc_class_hash_grow(struct Qdisc *, struct Qdisc_class_hash *);
 394void qdisc_class_hash_destroy(struct Qdisc_class_hash *);
 395
 396void dev_init_scheduler(struct net_device *dev);
 397void dev_shutdown(struct net_device *dev);
 398void dev_activate(struct net_device *dev);
 399void dev_deactivate(struct net_device *dev);
 400void dev_deactivate_many(struct list_head *head);
 401struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
 402                              struct Qdisc *qdisc);
 403void qdisc_reset(struct Qdisc *qdisc);
 404void qdisc_destroy(struct Qdisc *qdisc);
 405void qdisc_tree_reduce_backlog(struct Qdisc *qdisc, unsigned int n,
 406                               unsigned int len);
 407struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 408                          const struct Qdisc_ops *ops);
 409struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
 410                                const struct Qdisc_ops *ops, u32 parentid);
 411void __qdisc_calculate_pkt_len(struct sk_buff *skb,
 412                               const struct qdisc_size_table *stab);
 413bool tcf_destroy(struct tcf_proto *tp, bool force);
 414void tcf_destroy_chain(struct tcf_proto __rcu **fl);
 415int skb_do_redirect(struct sk_buff *);
 416
 417static inline bool skb_at_tc_ingress(const struct sk_buff *skb)
 418{
 419#ifdef CONFIG_NET_CLS_ACT
 420        return G_TC_AT(skb->tc_verd) & AT_INGRESS;
 421#else
 422        return false;
 423#endif
 424}
 425
 426/* Reset all TX qdiscs greater then index of a device.  */
 427static inline void qdisc_reset_all_tx_gt(struct net_device *dev, unsigned int i)
 428{
 429        struct Qdisc *qdisc;
 430
 431        for (; i < dev->num_tx_queues; i++) {
 432                qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc);
 433                if (qdisc) {
 434                        spin_lock_bh(qdisc_lock(qdisc));
 435                        qdisc_reset(qdisc);
 436                        spin_unlock_bh(qdisc_lock(qdisc));
 437                }
 438        }
 439}
 440
 441static inline void qdisc_reset_all_tx(struct net_device *dev)
 442{
 443        qdisc_reset_all_tx_gt(dev, 0);
 444}
 445
 446/* Are all TX queues of the device empty?  */
 447static inline bool qdisc_all_tx_empty(const struct net_device *dev)
 448{
 449        unsigned int i;
 450
 451        rcu_read_lock();
 452        for (i = 0; i < dev->num_tx_queues; i++) {
 453                struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
 454                const struct Qdisc *q = rcu_dereference(txq->qdisc);
 455
 456                if (q->q.qlen) {
 457                        rcu_read_unlock();
 458                        return false;
 459                }
 460        }
 461        rcu_read_unlock();
 462        return true;
 463}
 464
 465/* Are any of the TX qdiscs changing?  */
 466static inline bool qdisc_tx_changing(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) != txq->qdisc_sleeping)
 473                        return true;
 474        }
 475        return false;
 476}
 477
 478/* Is the device using the noop qdisc on all queues?  */
 479static inline bool qdisc_tx_is_noop(const struct net_device *dev)
 480{
 481        unsigned int i;
 482
 483        for (i = 0; i < dev->num_tx_queues; i++) {
 484                struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
 485                if (rcu_access_pointer(txq->qdisc) != &noop_qdisc)
 486                        return false;
 487        }
 488        return true;
 489}
 490
 491static inline unsigned int qdisc_pkt_len(const struct sk_buff *skb)
 492{
 493        return qdisc_skb_cb(skb)->pkt_len;
 494}
 495
 496/* additional qdisc xmit flags (NET_XMIT_MASK in linux/netdevice.h) */
 497enum net_xmit_qdisc_t {
 498        __NET_XMIT_STOLEN = 0x00010000,
 499        __NET_XMIT_BYPASS = 0x00020000,
 500};
 501
 502#ifdef CONFIG_NET_CLS_ACT
 503#define net_xmit_drop_count(e)  ((e) & __NET_XMIT_STOLEN ? 0 : 1)
 504#else
 505#define net_xmit_drop_count(e)  (1)
 506#endif
 507
 508static inline void qdisc_calculate_pkt_len(struct sk_buff *skb,
 509                                           const struct Qdisc *sch)
 510{
 511#ifdef CONFIG_NET_SCHED
 512        struct qdisc_size_table *stab = rcu_dereference_bh(sch->stab);
 513
 514        if (stab)
 515                __qdisc_calculate_pkt_len(skb, stab);
 516#endif
 517}
 518
 519static inline int qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 520{
 521        qdisc_calculate_pkt_len(skb, sch);
 522        return sch->enqueue(skb, sch);
 523}
 524
 525static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
 526{
 527        return q->flags & TCQ_F_CPUSTATS;
 528}
 529
 530static inline void bstats_update(struct gnet_stats_basic_packed *bstats,
 531                                 const struct sk_buff *skb)
 532{
 533        bstats->bytes += qdisc_pkt_len(skb);
 534        bstats->packets += skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 1;
 535}
 536
 537static inline void bstats_cpu_update(struct gnet_stats_basic_cpu *bstats,
 538                                     const struct sk_buff *skb)
 539{
 540        u64_stats_update_begin(&bstats->syncp);
 541        bstats_update(&bstats->bstats, skb);
 542        u64_stats_update_end(&bstats->syncp);
 543}
 544
 545static inline void qdisc_bstats_cpu_update(struct Qdisc *sch,
 546                                           const struct sk_buff *skb)
 547{
 548        bstats_cpu_update(this_cpu_ptr(sch->cpu_bstats), skb);
 549}
 550
 551static inline void qdisc_bstats_update(struct Qdisc *sch,
 552                                       const struct sk_buff *skb)
 553{
 554        bstats_update(&sch->bstats, skb);
 555}
 556
 557static inline void qdisc_qstats_backlog_dec(struct Qdisc *sch,
 558                                            const struct sk_buff *skb)
 559{
 560        sch->qstats.backlog -= qdisc_pkt_len(skb);
 561}
 562
 563static inline void qdisc_qstats_backlog_inc(struct Qdisc *sch,
 564                                            const struct sk_buff *skb)
 565{
 566        sch->qstats.backlog += qdisc_pkt_len(skb);
 567}
 568
 569static inline void __qdisc_qstats_drop(struct Qdisc *sch, int count)
 570{
 571        sch->qstats.drops += count;
 572}
 573
 574static inline void qstats_drop_inc(struct gnet_stats_queue *qstats)
 575{
 576        qstats->drops++;
 577}
 578
 579static inline void qstats_overlimit_inc(struct gnet_stats_queue *qstats)
 580{
 581        qstats->overlimits++;
 582}
 583
 584static inline void qdisc_qstats_drop(struct Qdisc *sch)
 585{
 586        qstats_drop_inc(&sch->qstats);
 587}
 588
 589static inline void qdisc_qstats_cpu_drop(struct Qdisc *sch)
 590{
 591        qstats_drop_inc(this_cpu_ptr(sch->cpu_qstats));
 592}
 593
 594static inline void qdisc_qstats_overlimit(struct Qdisc *sch)
 595{
 596        sch->qstats.overlimits++;
 597}
 598
 599static inline int __qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch,
 600                                       struct sk_buff_head *list)
 601{
 602        __skb_queue_tail(list, skb);
 603        qdisc_qstats_backlog_inc(sch, skb);
 604
 605        return NET_XMIT_SUCCESS;
 606}
 607
 608static inline int qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch)
 609{
 610        return __qdisc_enqueue_tail(skb, sch, &sch->q);
 611}
 612
 613static inline struct sk_buff *__qdisc_dequeue_head(struct Qdisc *sch,
 614                                                   struct sk_buff_head *list)
 615{
 616        struct sk_buff *skb = __skb_dequeue(list);
 617
 618        if (likely(skb != NULL)) {
 619                qdisc_qstats_backlog_dec(sch, skb);
 620                qdisc_bstats_update(sch, skb);
 621        }
 622
 623        return skb;
 624}
 625
 626static inline struct sk_buff *qdisc_dequeue_head(struct Qdisc *sch)
 627{
 628        return __qdisc_dequeue_head(sch, &sch->q);
 629}
 630
 631static inline unsigned int __qdisc_queue_drop_head(struct Qdisc *sch,
 632                                              struct sk_buff_head *list)
 633{
 634        struct sk_buff *skb = __skb_dequeue(list);
 635
 636        if (likely(skb != NULL)) {
 637                unsigned int len = qdisc_pkt_len(skb);
 638                qdisc_qstats_backlog_dec(sch, skb);
 639                kfree_skb(skb);
 640                return len;
 641        }
 642
 643        return 0;
 644}
 645
 646static inline unsigned int qdisc_queue_drop_head(struct Qdisc *sch)
 647{
 648        return __qdisc_queue_drop_head(sch, &sch->q);
 649}
 650
 651static inline struct sk_buff *__qdisc_dequeue_tail(struct Qdisc *sch,
 652                                                   struct sk_buff_head *list)
 653{
 654        struct sk_buff *skb = __skb_dequeue_tail(list);
 655
 656        if (likely(skb != NULL))
 657                qdisc_qstats_backlog_dec(sch, skb);
 658
 659        return skb;
 660}
 661
 662static inline struct sk_buff *qdisc_dequeue_tail(struct Qdisc *sch)
 663{
 664        return __qdisc_dequeue_tail(sch, &sch->q);
 665}
 666
 667static 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 */
 673static 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                        sch->q.qlen++;
 681        }
 682
 683        return sch->gso_skb;
 684}
 685
 686/* use instead of qdisc->dequeue() for all qdiscs queried with ->peek() */
 687static inline struct sk_buff *qdisc_dequeue_peeked(struct Qdisc *sch)
 688{
 689        struct sk_buff *skb = sch->gso_skb;
 690
 691        if (skb) {
 692                sch->gso_skb = NULL;
 693                sch->q.qlen--;
 694        } else {
 695                skb = sch->dequeue(sch);
 696        }
 697
 698        return skb;
 699}
 700
 701static inline void __qdisc_reset_queue(struct Qdisc *sch,
 702                                       struct sk_buff_head *list)
 703{
 704        /*
 705         * We do not know the backlog in bytes of this list, it
 706         * is up to the caller to correct it
 707         */
 708        __skb_queue_purge(list);
 709}
 710
 711static inline void qdisc_reset_queue(struct Qdisc *sch)
 712{
 713        __qdisc_reset_queue(sch, &sch->q);
 714        sch->qstats.backlog = 0;
 715}
 716
 717static inline struct Qdisc *qdisc_replace(struct Qdisc *sch, struct Qdisc *new,
 718                                          struct Qdisc **pold)
 719{
 720        struct Qdisc *old;
 721
 722        sch_tree_lock(sch);
 723        old = *pold;
 724        *pold = new;
 725        if (old != NULL) {
 726                qdisc_tree_reduce_backlog(old, old->q.qlen, old->qstats.backlog);
 727                qdisc_reset(old);
 728        }
 729        sch_tree_unlock(sch);
 730
 731        return old;
 732}
 733
 734static inline unsigned int __qdisc_queue_drop(struct Qdisc *sch,
 735                                              struct sk_buff_head *list)
 736{
 737        struct sk_buff *skb = __qdisc_dequeue_tail(sch, list);
 738
 739        if (likely(skb != NULL)) {
 740                unsigned int len = qdisc_pkt_len(skb);
 741                kfree_skb(skb);
 742                return len;
 743        }
 744
 745        return 0;
 746}
 747
 748static inline unsigned int qdisc_queue_drop(struct Qdisc *sch)
 749{
 750        return __qdisc_queue_drop(sch, &sch->q);
 751}
 752
 753static inline int qdisc_drop(struct sk_buff *skb, struct Qdisc *sch)
 754{
 755        kfree_skb(skb);
 756        qdisc_qstats_drop(sch);
 757
 758        return NET_XMIT_DROP;
 759}
 760
 761static inline int qdisc_reshape_fail(struct sk_buff *skb, struct Qdisc *sch)
 762{
 763        qdisc_qstats_drop(sch);
 764
 765#ifdef CONFIG_NET_CLS_ACT
 766        if (sch->reshape_fail == NULL || sch->reshape_fail(skb, sch))
 767                goto drop;
 768
 769        return NET_XMIT_SUCCESS;
 770
 771drop:
 772#endif
 773        kfree_skb(skb);
 774        return NET_XMIT_DROP;
 775}
 776
 777/* Length to Time (L2T) lookup in a qdisc_rate_table, to determine how
 778   long it will take to send a packet given its size.
 779 */
 780static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen)
 781{
 782        int slot = pktlen + rtab->rate.cell_align + rtab->rate.overhead;
 783        if (slot < 0)
 784                slot = 0;
 785        slot >>= rtab->rate.cell_log;
 786        if (slot > 255)
 787                return rtab->data[255]*(slot >> 8) + rtab->data[slot & 0xFF];
 788        return rtab->data[slot];
 789}
 790
 791struct psched_ratecfg {
 792        u64     rate_bytes_ps; /* bytes per second */
 793        u32     mult;
 794        u16     overhead;
 795        u8      linklayer;
 796        u8      shift;
 797};
 798
 799static inline u64 psched_l2t_ns(const struct psched_ratecfg *r,
 800                                unsigned int len)
 801{
 802        len += r->overhead;
 803
 804        if (unlikely(r->linklayer == TC_LINKLAYER_ATM))
 805                return ((u64)(DIV_ROUND_UP(len,48)*53) * r->mult) >> r->shift;
 806
 807        return ((u64)len * r->mult) >> r->shift;
 808}
 809
 810void psched_ratecfg_precompute(struct psched_ratecfg *r,
 811                               const struct tc_ratespec *conf,
 812                               u64 rate64);
 813
 814static inline void psched_ratecfg_getrate(struct tc_ratespec *res,
 815                                          const struct psched_ratecfg *r)
 816{
 817        memset(res, 0, sizeof(*res));
 818
 819        /* legacy struct tc_ratespec has a 32bit @rate field
 820         * Qdisc using 64bit rate should add new attributes
 821         * in order to maintain compatibility.
 822         */
 823        res->rate = min_t(u64, r->rate_bytes_ps, ~0U);
 824
 825        res->overhead = r->overhead;
 826        res->linklayer = (r->linklayer & TC_LINKLAYER_MASK);
 827}
 828
 829#endif
 830