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};
  30
  31struct 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
  39struct 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
  93static inline bool qdisc_is_running(const struct Qdisc *qdisc)
  94{
  95        return (raw_read_seqcount(&qdisc->running) & 1) ? true : false;
  96}
  97
  98static 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
 110static inline void qdisc_run_end(struct Qdisc *qdisc)
 111{
 112        write_seqcount_end(&qdisc->running);
 113}
 114
 115static inline bool qdisc_may_bulk(const struct Qdisc *qdisc)
 116{
 117        return qdisc->flags & TCQ_F_ONETXQUEUE;
 118}
 119
 120static 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
 130struct 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
 160struct 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
 185struct tcf_result {
 186        unsigned long   class;
 187        u32             classid;
 188};
 189
 190struct 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
 215struct 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
 233struct 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
 241static 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
 249static inline int qdisc_qlen(const struct Qdisc *q)
 250{
 251        return q->q.qlen;
 252}
 253
 254static inline struct qdisc_skb_cb *qdisc_skb_cb(const struct sk_buff *skb)
 255{
 256        return (struct qdisc_skb_cb *)skb->cb;
 257}
 258
 259static inline spinlock_t *qdisc_lock(struct Qdisc *qdisc)
 260{
 261        return &qdisc->q.lock;
 262}
 263
 264static 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
 271static 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 */
 287static 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
 295static 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
 303static 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
 311static inline struct net_device *qdisc_dev(const struct Qdisc *qdisc)
 312{
 313        return qdisc->dev_queue->dev;
 314}
 315
 316static inline void sch_tree_lock(const struct Qdisc *q)
 317{
 318        spin_lock_bh(qdisc_root_sleeping_lock(q));
 319}
 320
 321static 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
 329extern struct Qdisc noop_qdisc;
 330extern struct Qdisc_ops noop_qdisc_ops;
 331extern struct Qdisc_ops pfifo_fast_ops;
 332extern struct Qdisc_ops mq_qdisc_ops;
 333extern struct Qdisc_ops noqueue_qdisc_ops;
 334extern const struct Qdisc_ops *default_qdisc_ops;
 335static inline const struct Qdisc_ops *
 336get_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
 342struct Qdisc_class_common {
 343        u32                     classid;
 344        struct hlist_node       hnode;
 345};
 346
 347struct Qdisc_class_hash {
 348        struct hlist_head       *hash;
 349        unsigned int            hashsize;
 350        unsigned int            hashmask;
 351        unsigned int            hashelems;
 352};
 353
 354static 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
 361static inline struct Qdisc_class_common *
 362qdisc_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
 375int qdisc_class_hash_init(struct Qdisc_class_hash *);
 376void qdisc_class_hash_insert(struct Qdisc_class_hash *,
 377                             struct Qdisc_class_common *);
 378void qdisc_class_hash_remove(struct Qdisc_class_hash *,
 379                             struct Qdisc_class_common *);
 380void qdisc_class_hash_grow(struct Qdisc *, struct Qdisc_class_hash *);
 381void qdisc_class_hash_destroy(struct Qdisc_class_hash *);
 382
 383void dev_init_scheduler(struct net_device *dev);
 384void dev_shutdown(struct net_device *dev);
 385void dev_activate(struct net_device *dev);
 386void dev_deactivate(struct net_device *dev);
 387void dev_deactivate_many(struct list_head *head);
 388struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
 389                              struct Qdisc *qdisc);
 390void qdisc_reset(struct Qdisc *qdisc);
 391void qdisc_destroy(struct Qdisc *qdisc);
 392void qdisc_tree_reduce_backlog(struct Qdisc *qdisc, unsigned int n,
 393                               unsigned int len);
 394struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 395                          const struct Qdisc_ops *ops);
 396struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
 397                                const struct Qdisc_ops *ops, u32 parentid);
 398void __qdisc_calculate_pkt_len(struct sk_buff *skb,
 399                               const struct qdisc_size_table *stab);
 400bool tcf_destroy(struct tcf_proto *tp, bool force);
 401void tcf_destroy_chain(struct tcf_proto __rcu **fl);
 402int skb_do_redirect(struct sk_buff *);
 403
 404static 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.  */
 414static 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
 428static 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?  */
 434static 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?  */
 453static 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?  */
 466static 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
 478static 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) */
 484enum 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
 495static 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
 506static 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
 513static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
 514{
 515        return q->flags & TCQ_F_CPUSTATS;
 516}
 517
 518static 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
 525static 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
 533static 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
 541static 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
 549static 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
 555static inline void qdisc_bstats_update(struct Qdisc *sch,
 556                                       const struct sk_buff *skb)
 557{
 558        bstats_update(&sch->bstats, skb);
 559}
 560
 561static 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
 567static 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
 573static inline void __qdisc_qstats_drop(struct Qdisc *sch, int count)
 574{
 575        sch->qstats.drops += count;
 576}
 577
 578static inline void qstats_drop_inc(struct gnet_stats_queue *qstats)
 579{
 580        qstats->drops++;
 581}
 582
 583static inline void qstats_overlimit_inc(struct gnet_stats_queue *qstats)
 584{
 585        qstats->overlimits++;
 586}
 587
 588static inline void qdisc_qstats_drop(struct Qdisc *sch)
 589{
 590        qstats_drop_inc(&sch->qstats);
 591}
 592
 593static inline void qdisc_qstats_cpu_drop(struct Qdisc *sch)
 594{
 595        qstats_drop_inc(this_cpu_ptr(sch->cpu_qstats));
 596}
 597
 598static inline void qdisc_qstats_overlimit(struct Qdisc *sch)
 599{
 600        sch->qstats.overlimits++;
 601}
 602
 603static 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
 612static inline int qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch)
 613{
 614        return __qdisc_enqueue_tail(skb, sch, &sch->q);
 615}
 616
 617static 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
 630static 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 */
 638static 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
 644static 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
 661static 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
 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                        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() */
 689static 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
 704static 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
 716static inline void qdisc_reset_queue(struct Qdisc *sch)
 717{
 718        __qdisc_reset_queue(&sch->q);
 719        sch->qstats.backlog = 0;
 720}
 721
 722static 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
 739static 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
 746static 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 */
 758static 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
 769struct psched_ratecfg {
 770        u64     rate_bytes_ps; /* bytes per second */
 771        u32     mult;
 772        u16     overhead;
 773        u8      linklayer;
 774        u8      shift;
 775};
 776
 777static 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
 788void psched_ratecfg_precompute(struct psched_ratecfg *r,
 789                               const struct tc_ratespec *conf,
 790                               u64 rate64);
 791
 792static inline void psched_ratecfg_getrate(struct tc_ratespec *res,
 793                                          const struct psched_ratecfg *r)
 794{
 795        memset(res, 0, sizeof(*res));
 796
 797        /* legacy struct tc_ratespec has a 32bit @rate field
 798         * Qdisc using 64bit rate should add new attributes
 799         * in order to maintain compatibility.
 800         */
 801        res->rate = min_t(u64, r->rate_bytes_ps, ~0U);
 802
 803        res->overhead = r->overhead;
 804        res->linklayer = (r->linklayer & TC_LINKLAYER_MASK);
 805}
 806
 807#endif
 808