linux/include/net/sch_generic.h
Guoju Fang 2e8728c955 net: sched: add barrier to fix packet stuck problem for lockless qdisc
In qdisc_run_end(), the spin_unlock() only has store-release semantic,
which guarantees all earlier memory access are visible before it. But
the subsequent test_bit() has no barrier semantics so may be reordered
ahead of the spin_unlock(). The store-load reordering may cause a packet
stuck problem.

The concurrent operations can be described as below,
         CPU 0                      |          CPU 1
   qdisc_run_end()                  |     qdisc_run_begin()
          .                         |           .
 ----> /* may be reorderd here */   |           .
|         .                         |           .
|     spin_unlock()                 |         set_bit()
|         .                         |         smp_mb__after_atomic()
 ---- test_bit()                    |         spin_trylock()
          .                         |          .

Consider the following sequence of events:
    CPU 0 reorder test_bit() ahead and see MISSED = 0
    CPU 1 calls set_bit()
    CPU 1 calls spin_trylock() and return fail
    CPU 0 executes spin_unlock()

At the end of the sequence, CPU 0 calls spin_unlock() and does nothing
because it see MISSED = 0. The skb on CPU 1 has beed enqueued but no one
take it, until the next cpu pushing to the qdisc (if ever ...) will
notice and dequeue it.

This patch fix this by adding one explicit barrier. As spin_unlock() and
test_bit() ordering is a store-load ordering, a full memory barrier
smp_mb() is needed here.

Fixes: a90c57f2ce ("net: sched: fix packet stuck problem for lockless qdisc")
Signed-off-by: Guoju Fang <gjfang@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220528101628.120193-1-gjfang@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-31 20:39:28 -07:00

1321 lines
33 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __NET_SCHED_GENERIC_H
#define __NET_SCHED_GENERIC_H
#include <linux/netdevice.h>
#include <linux/types.h>
#include <linux/rcupdate.h>
#include <linux/pkt_sched.h>
#include <linux/pkt_cls.h>
#include <linux/percpu.h>
#include <linux/dynamic_queue_limits.h>
#include <linux/list.h>
#include <linux/refcount.h>
#include <linux/workqueue.h>
#include <linux/mutex.h>
#include <linux/rwsem.h>
#include <linux/atomic.h>
#include <linux/hashtable.h>
#include <net/gen_stats.h>
#include <net/rtnetlink.h>
#include <net/flow_offload.h>
struct Qdisc_ops;
struct qdisc_walker;
struct tcf_walker;
struct module;
struct bpf_flow_keys;
struct qdisc_rate_table {
struct tc_ratespec rate;
u32 data[256];
struct qdisc_rate_table *next;
int refcnt;
};
enum qdisc_state_t {
__QDISC_STATE_SCHED,
__QDISC_STATE_DEACTIVATED,
__QDISC_STATE_MISSED,
__QDISC_STATE_DRAINING,
};
enum qdisc_state2_t {
/* Only for !TCQ_F_NOLOCK qdisc. Never access it directly.
* Use qdisc_run_begin/end() or qdisc_is_running() instead.
*/
__QDISC_STATE2_RUNNING,
};
#define QDISC_STATE_MISSED BIT(__QDISC_STATE_MISSED)
#define QDISC_STATE_DRAINING BIT(__QDISC_STATE_DRAINING)
#define QDISC_STATE_NON_EMPTY (QDISC_STATE_MISSED | \
QDISC_STATE_DRAINING)
struct qdisc_size_table {
struct rcu_head rcu;
struct list_head list;
struct tc_sizespec szopts;
int refcnt;
u16 data[];
};
/* similar to sk_buff_head, but skb->prev pointer is undefined. */
struct qdisc_skb_head {
struct sk_buff *head;
struct sk_buff *tail;
__u32 qlen;
spinlock_t lock;
};
struct Qdisc {
int (*enqueue)(struct sk_buff *skb,
struct Qdisc *sch,
struct sk_buff **to_free);
struct sk_buff * (*dequeue)(struct Qdisc *sch);
unsigned int flags;
#define TCQ_F_BUILTIN 1
#define TCQ_F_INGRESS 2
#define TCQ_F_CAN_BYPASS 4
#define TCQ_F_MQROOT 8
#define TCQ_F_ONETXQUEUE 0x10 /* dequeue_skb() can assume all skbs are for
* q->dev_queue : It can test
* netif_xmit_frozen_or_stopped() before
* dequeueing next packet.
* Its true for MQ/MQPRIO slaves, or non
* multiqueue device.
*/
#define TCQ_F_WARN_NONWC (1 << 16)
#define TCQ_F_CPUSTATS 0x20 /* run using percpu statistics */
#define TCQ_F_NOPARENT 0x40 /* root of its hierarchy :
* qdisc_tree_decrease_qlen() should stop.
*/
#define TCQ_F_INVISIBLE 0x80 /* invisible by default in dump */
#define TCQ_F_NOLOCK 0x100 /* qdisc does not require locking */
#define TCQ_F_OFFLOADED 0x200 /* qdisc is offloaded to HW */
u32 limit;
const struct Qdisc_ops *ops;
struct qdisc_size_table __rcu *stab;
struct hlist_node hash;
u32 handle;
u32 parent;
struct netdev_queue *dev_queue;
struct net_rate_estimator __rcu *rate_est;
struct gnet_stats_basic_sync __percpu *cpu_bstats;
struct gnet_stats_queue __percpu *cpu_qstats;
int pad;
refcount_t refcnt;
/*
* For performance sake on SMP, we put highly modified fields at the end
*/
struct sk_buff_head gso_skb ____cacheline_aligned_in_smp;
struct qdisc_skb_head q;
struct gnet_stats_basic_sync bstats;
struct gnet_stats_queue qstats;
unsigned long state;
unsigned long state2; /* must be written under qdisc spinlock */
struct Qdisc *next_sched;
struct sk_buff_head skb_bad_txq;
spinlock_t busylock ____cacheline_aligned_in_smp;
spinlock_t seqlock;
struct rcu_head rcu;
netdevice_tracker dev_tracker;
/* private data */
long privdata[] ____cacheline_aligned;
};
static inline void qdisc_refcount_inc(struct Qdisc *qdisc)
{
if (qdisc->flags & TCQ_F_BUILTIN)
return;
refcount_inc(&qdisc->refcnt);
}
/* Intended to be used by unlocked users, when concurrent qdisc release is
* possible.
*/
static inline struct Qdisc *qdisc_refcount_inc_nz(struct Qdisc *qdisc)
{
if (qdisc->flags & TCQ_F_BUILTIN)
return qdisc;
if (refcount_inc_not_zero(&qdisc->refcnt))
return qdisc;
return NULL;
}
/* For !TCQ_F_NOLOCK qdisc: callers must either call this within a qdisc
* root_lock section, or provide their own memory barriers -- ordering
* against qdisc_run_begin/end() atomic bit operations.
*/
static inline bool qdisc_is_running(struct Qdisc *qdisc)
{
if (qdisc->flags & TCQ_F_NOLOCK)
return spin_is_locked(&qdisc->seqlock);
return test_bit(__QDISC_STATE2_RUNNING, &qdisc->state2);
}
static inline bool nolock_qdisc_is_empty(const struct Qdisc *qdisc)
{
return !(READ_ONCE(qdisc->state) & QDISC_STATE_NON_EMPTY);
}
static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
{
return q->flags & TCQ_F_CPUSTATS;
}
static inline bool qdisc_is_empty(const struct Qdisc *qdisc)
{
if (qdisc_is_percpu_stats(qdisc))
return nolock_qdisc_is_empty(qdisc);
return !READ_ONCE(qdisc->q.qlen);
}
/* For !TCQ_F_NOLOCK qdisc, qdisc_run_begin/end() must be invoked with
* the qdisc root lock acquired.
*/
static inline bool qdisc_run_begin(struct Qdisc *qdisc)
{
if (qdisc->flags & TCQ_F_NOLOCK) {
if (spin_trylock(&qdisc->seqlock))
return true;
/* No need to insist if the MISSED flag was already set.
* Note that test_and_set_bit() also gives us memory ordering
* guarantees wrt potential earlier enqueue() and below
* spin_trylock(), both of which are necessary to prevent races
*/
if (test_and_set_bit(__QDISC_STATE_MISSED, &qdisc->state))
return false;
/* Try to take the lock again to make sure that we will either
* grab it or the CPU that still has it will see MISSED set
* when testing it in qdisc_run_end()
*/
return spin_trylock(&qdisc->seqlock);
}
return !__test_and_set_bit(__QDISC_STATE2_RUNNING, &qdisc->state2);
}
static inline void qdisc_run_end(struct Qdisc *qdisc)
{
if (qdisc->flags & TCQ_F_NOLOCK) {
spin_unlock(&qdisc->seqlock);
/* spin_unlock() only has store-release semantic. The unlock
* and test_bit() ordering is a store-load ordering, so a full
* memory barrier is needed here.
*/
smp_mb();
if (unlikely(test_bit(__QDISC_STATE_MISSED,
&qdisc->state)))
__netif_schedule(qdisc);
} else {
__clear_bit(__QDISC_STATE2_RUNNING, &qdisc->state2);
}
}
static inline bool qdisc_may_bulk(const struct Qdisc *qdisc)
{
return qdisc->flags & TCQ_F_ONETXQUEUE;
}
static inline int qdisc_avail_bulklimit(const struct netdev_queue *txq)
{
#ifdef CONFIG_BQL
/* Non-BQL migrated drivers will return 0, too. */
return dql_avail(&txq->dql);
#else
return 0;
#endif
}
struct Qdisc_class_ops {
unsigned int flags;
/* Child qdisc manipulation */
struct netdev_queue * (*select_queue)(struct Qdisc *, struct tcmsg *);
int (*graft)(struct Qdisc *, unsigned long cl,
struct Qdisc *, struct Qdisc **,
struct netlink_ext_ack *extack);
struct Qdisc * (*leaf)(struct Qdisc *, unsigned long cl);
void (*qlen_notify)(struct Qdisc *, unsigned long);
/* Class manipulation routines */
unsigned long (*find)(struct Qdisc *, u32 classid);
int (*change)(struct Qdisc *, u32, u32,
struct nlattr **, unsigned long *,
struct netlink_ext_ack *);
int (*delete)(struct Qdisc *, unsigned long,
struct netlink_ext_ack *);
void (*walk)(struct Qdisc *, struct qdisc_walker * arg);
/* Filter manipulation */
struct tcf_block * (*tcf_block)(struct Qdisc *sch,
unsigned long arg,
struct netlink_ext_ack *extack);
unsigned long (*bind_tcf)(struct Qdisc *, unsigned long,
u32 classid);
void (*unbind_tcf)(struct Qdisc *, unsigned long);
/* rtnetlink specific */
int (*dump)(struct Qdisc *, unsigned long,
struct sk_buff *skb, struct tcmsg*);
int (*dump_stats)(struct Qdisc *, unsigned long,
struct gnet_dump *);
};
/* Qdisc_class_ops flag values */
/* Implements API that doesn't require rtnl lock */
enum qdisc_class_ops_flags {
QDISC_CLASS_OPS_DOIT_UNLOCKED = 1,
};
struct Qdisc_ops {
struct Qdisc_ops *next;
const struct Qdisc_class_ops *cl_ops;
char id[IFNAMSIZ];
int priv_size;
unsigned int static_flags;
int (*enqueue)(struct sk_buff *skb,
struct Qdisc *sch,
struct sk_buff **to_free);
struct sk_buff * (*dequeue)(struct Qdisc *);
struct sk_buff * (*peek)(struct Qdisc *);
int (*init)(struct Qdisc *sch, struct nlattr *arg,
struct netlink_ext_ack *extack);
void (*reset)(struct Qdisc *);
void (*destroy)(struct Qdisc *);
int (*change)(struct Qdisc *sch,
struct nlattr *arg,
struct netlink_ext_ack *extack);
void (*attach)(struct Qdisc *sch);
int (*change_tx_queue_len)(struct Qdisc *, unsigned int);
void (*change_real_num_tx)(struct Qdisc *sch,
unsigned int new_real_tx);
int (*dump)(struct Qdisc *, struct sk_buff *);
int (*dump_stats)(struct Qdisc *, struct gnet_dump *);
void (*ingress_block_set)(struct Qdisc *sch,
u32 block_index);
void (*egress_block_set)(struct Qdisc *sch,
u32 block_index);
u32 (*ingress_block_get)(struct Qdisc *sch);
u32 (*egress_block_get)(struct Qdisc *sch);
struct module *owner;
};
struct tcf_result {
union {
struct {
unsigned long class;
u32 classid;
};
const struct tcf_proto *goto_tp;
/* used in the skb_tc_reinsert function */
struct {
bool ingress;
struct gnet_stats_queue *qstats;
};
};
};
struct tcf_chain;
struct tcf_proto_ops {
struct list_head head;
char kind[IFNAMSIZ];
int (*classify)(struct sk_buff *,
const struct tcf_proto *,
struct tcf_result *);
int (*init)(struct tcf_proto*);
void (*destroy)(struct tcf_proto *tp, bool rtnl_held,
struct netlink_ext_ack *extack);
void* (*get)(struct tcf_proto*, u32 handle);
void (*put)(struct tcf_proto *tp, void *f);
int (*change)(struct net *net, struct sk_buff *,
struct tcf_proto*, unsigned long,
u32 handle, struct nlattr **,
void **, u32,
struct netlink_ext_ack *);
int (*delete)(struct tcf_proto *tp, void *arg,
bool *last, bool rtnl_held,
struct netlink_ext_ack *);
bool (*delete_empty)(struct tcf_proto *tp);
void (*walk)(struct tcf_proto *tp,
struct tcf_walker *arg, bool rtnl_held);
int (*reoffload)(struct tcf_proto *tp, bool add,
flow_setup_cb_t *cb, void *cb_priv,
struct netlink_ext_ack *extack);
void (*hw_add)(struct tcf_proto *tp,
void *type_data);
void (*hw_del)(struct tcf_proto *tp,
void *type_data);
void (*bind_class)(void *, u32, unsigned long,
void *, unsigned long);
void * (*tmplt_create)(struct net *net,
struct tcf_chain *chain,
struct nlattr **tca,
struct netlink_ext_ack *extack);
void (*tmplt_destroy)(void *tmplt_priv);
/* rtnetlink specific */
int (*dump)(struct net*, struct tcf_proto*, void *,
struct sk_buff *skb, struct tcmsg*,
bool);
int (*terse_dump)(struct net *net,
struct tcf_proto *tp, void *fh,
struct sk_buff *skb,
struct tcmsg *t, bool rtnl_held);
int (*tmplt_dump)(struct sk_buff *skb,
struct net *net,
void *tmplt_priv);
struct module *owner;
int flags;
};
/* Classifiers setting TCF_PROTO_OPS_DOIT_UNLOCKED in tcf_proto_ops->flags
* are expected to implement tcf_proto_ops->delete_empty(), otherwise race
* conditions can occur when filters are inserted/deleted simultaneously.
*/
enum tcf_proto_ops_flags {
TCF_PROTO_OPS_DOIT_UNLOCKED = 1,
};
struct tcf_proto {
/* Fast access part */
struct tcf_proto __rcu *next;
void __rcu *root;
/* called under RCU BH lock*/
int (*classify)(struct sk_buff *,
const struct tcf_proto *,
struct tcf_result *);
__be16 protocol;
/* All the rest */
u32 prio;
void *data;
const struct tcf_proto_ops *ops;
struct tcf_chain *chain;
/* Lock protects tcf_proto shared state and can be used by unlocked
* classifiers to protect their private data.
*/
spinlock_t lock;
bool deleting;
refcount_t refcnt;
struct rcu_head rcu;
struct hlist_node destroy_ht_node;
};
struct qdisc_skb_cb {
struct {
unsigned int pkt_len;
u16 slave_dev_queue_mapping;
u16 tc_classid;
};
#define QDISC_CB_PRIV_LEN 20
unsigned char data[QDISC_CB_PRIV_LEN];
};
typedef void tcf_chain_head_change_t(struct tcf_proto *tp_head, void *priv);
struct tcf_chain {
/* Protects filter_chain. */
struct mutex filter_chain_lock;
struct tcf_proto __rcu *filter_chain;
struct list_head list;
struct tcf_block *block;
u32 index; /* chain index */
unsigned int refcnt;
unsigned int action_refcnt;
bool explicitly_created;
bool flushing;
const struct tcf_proto_ops *tmplt_ops;
void *tmplt_priv;
struct rcu_head rcu;
};
struct tcf_block {
/* Lock protects tcf_block and lifetime-management data of chains
* attached to the block (refcnt, action_refcnt, explicitly_created).
*/
struct mutex lock;
struct list_head chain_list;
u32 index; /* block index for shared blocks */
u32 classid; /* which class this block belongs to */
refcount_t refcnt;
struct net *net;
struct Qdisc *q;
struct rw_semaphore cb_lock; /* protects cb_list and offload counters */
struct flow_block flow_block;
struct list_head owner_list;
bool keep_dst;
atomic_t offloadcnt; /* Number of oddloaded filters */
unsigned int nooffloaddevcnt; /* Number of devs unable to do offload */
unsigned int lockeddevcnt; /* Number of devs that require rtnl lock. */
struct {
struct tcf_chain *chain;
struct list_head filter_chain_list;
} chain0;
struct rcu_head rcu;
DECLARE_HASHTABLE(proto_destroy_ht, 7);
struct mutex proto_destroy_lock; /* Lock for proto_destroy hashtable. */
};
static inline bool lockdep_tcf_chain_is_locked(struct tcf_chain *chain)
{
return lockdep_is_held(&chain->filter_chain_lock);
}
static inline bool lockdep_tcf_proto_is_locked(struct tcf_proto *tp)
{
return lockdep_is_held(&tp->lock);
}
#define tcf_chain_dereference(p, chain) \
rcu_dereference_protected(p, lockdep_tcf_chain_is_locked(chain))
#define tcf_proto_dereference(p, tp) \
rcu_dereference_protected(p, lockdep_tcf_proto_is_locked(tp))
static inline void qdisc_cb_private_validate(const struct sk_buff *skb, int sz)
{
struct qdisc_skb_cb *qcb;
BUILD_BUG_ON(sizeof(skb->cb) < sizeof(*qcb));
BUILD_BUG_ON(sizeof(qcb->data) < sz);
}
static inline int qdisc_qlen(const struct Qdisc *q)
{
return q->q.qlen;
}
static inline int qdisc_qlen_sum(const struct Qdisc *q)
{
__u32 qlen = q->qstats.qlen;
int i;
if (qdisc_is_percpu_stats(q)) {
for_each_possible_cpu(i)
qlen += per_cpu_ptr(q->cpu_qstats, i)->qlen;
} else {
qlen += q->q.qlen;
}
return qlen;
}
static inline struct qdisc_skb_cb *qdisc_skb_cb(const struct sk_buff *skb)
{
return (struct qdisc_skb_cb *)skb->cb;
}
static inline spinlock_t *qdisc_lock(struct Qdisc *qdisc)
{
return &qdisc->q.lock;
}
static inline struct Qdisc *qdisc_root(const struct Qdisc *qdisc)
{
struct Qdisc *q = rcu_dereference_rtnl(qdisc->dev_queue->qdisc);
return q;
}
static inline struct Qdisc *qdisc_root_bh(const struct Qdisc *qdisc)
{
return rcu_dereference_bh(qdisc->dev_queue->qdisc);
}
static inline struct Qdisc *qdisc_root_sleeping(const struct Qdisc *qdisc)
{
return qdisc->dev_queue->qdisc_sleeping;
}
/* The qdisc root lock is a mechanism by which to top level
* of a qdisc tree can be locked from any qdisc node in the
* forest. This allows changing the configuration of some
* aspect of the qdisc tree while blocking out asynchronous
* qdisc access in the packet processing paths.
*
* It is only legal to do this when the root will not change
* on us. Otherwise we'll potentially lock the wrong qdisc
* root. This is enforced by holding the RTNL semaphore, which
* all users of this lock accessor must do.
*/
static inline spinlock_t *qdisc_root_lock(const struct Qdisc *qdisc)
{
struct Qdisc *root = qdisc_root(qdisc);
ASSERT_RTNL();
return qdisc_lock(root);
}
static inline spinlock_t *qdisc_root_sleeping_lock(const struct Qdisc *qdisc)
{
struct Qdisc *root = qdisc_root_sleeping(qdisc);
ASSERT_RTNL();
return qdisc_lock(root);
}
static inline struct net_device *qdisc_dev(const struct Qdisc *qdisc)
{
return qdisc->dev_queue->dev;
}
static inline void sch_tree_lock(struct Qdisc *q)
{
if (q->flags & TCQ_F_MQROOT)
spin_lock_bh(qdisc_lock(q));
else
spin_lock_bh(qdisc_root_sleeping_lock(q));
}
static inline void sch_tree_unlock(struct Qdisc *q)
{
if (q->flags & TCQ_F_MQROOT)
spin_unlock_bh(qdisc_lock(q));
else
spin_unlock_bh(qdisc_root_sleeping_lock(q));
}
extern struct Qdisc noop_qdisc;
extern struct Qdisc_ops noop_qdisc_ops;
extern struct Qdisc_ops pfifo_fast_ops;
extern struct Qdisc_ops mq_qdisc_ops;
extern struct Qdisc_ops noqueue_qdisc_ops;
extern const struct Qdisc_ops *default_qdisc_ops;
static inline const struct Qdisc_ops *
get_default_qdisc_ops(const struct net_device *dev, int ntx)
{
return ntx < dev->real_num_tx_queues ?
default_qdisc_ops : &pfifo_fast_ops;
}
struct Qdisc_class_common {
u32 classid;
struct hlist_node hnode;
};
struct Qdisc_class_hash {
struct hlist_head *hash;
unsigned int hashsize;
unsigned int hashmask;
unsigned int hashelems;
};
static inline unsigned int qdisc_class_hash(u32 id, u32 mask)
{
id ^= id >> 8;
id ^= id >> 4;
return id & mask;
}
static inline struct Qdisc_class_common *
qdisc_class_find(const struct Qdisc_class_hash *hash, u32 id)
{
struct Qdisc_class_common *cl;
unsigned int h;
if (!id)
return NULL;
h = qdisc_class_hash(id, hash->hashmask);
hlist_for_each_entry(cl, &hash->hash[h], hnode) {
if (cl->classid == id)
return cl;
}
return NULL;
}
static inline int tc_classid_to_hwtc(struct net_device *dev, u32 classid)
{
u32 hwtc = TC_H_MIN(classid) - TC_H_MIN_PRIORITY;
return (hwtc < netdev_get_num_tc(dev)) ? hwtc : -EINVAL;
}
int qdisc_class_hash_init(struct Qdisc_class_hash *);
void qdisc_class_hash_insert(struct Qdisc_class_hash *,
struct Qdisc_class_common *);
void qdisc_class_hash_remove(struct Qdisc_class_hash *,
struct Qdisc_class_common *);
void qdisc_class_hash_grow(struct Qdisc *, struct Qdisc_class_hash *);
void qdisc_class_hash_destroy(struct Qdisc_class_hash *);
int dev_qdisc_change_tx_queue_len(struct net_device *dev);
void dev_qdisc_change_real_num_tx(struct net_device *dev,
unsigned int new_real_tx);
void dev_init_scheduler(struct net_device *dev);
void dev_shutdown(struct net_device *dev);
void dev_activate(struct net_device *dev);
void dev_deactivate(struct net_device *dev);
void dev_deactivate_many(struct list_head *head);
struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
struct Qdisc *qdisc);
void qdisc_reset(struct Qdisc *qdisc);
void qdisc_put(struct Qdisc *qdisc);
void qdisc_put_unlocked(struct Qdisc *qdisc);
void qdisc_tree_reduce_backlog(struct Qdisc *qdisc, int n, int len);
#ifdef CONFIG_NET_SCHED
int qdisc_offload_dump_helper(struct Qdisc *q, enum tc_setup_type type,
void *type_data);
void qdisc_offload_graft_helper(struct net_device *dev, struct Qdisc *sch,
struct Qdisc *new, struct Qdisc *old,
enum tc_setup_type type, void *type_data,
struct netlink_ext_ack *extack);
#else
static inline int
qdisc_offload_dump_helper(struct Qdisc *q, enum tc_setup_type type,
void *type_data)
{
q->flags &= ~TCQ_F_OFFLOADED;
return 0;
}
static inline void
qdisc_offload_graft_helper(struct net_device *dev, struct Qdisc *sch,
struct Qdisc *new, struct Qdisc *old,
enum tc_setup_type type, void *type_data,
struct netlink_ext_ack *extack)
{
}
#endif
struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
const struct Qdisc_ops *ops,
struct netlink_ext_ack *extack);
void qdisc_free(struct Qdisc *qdisc);
struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
const struct Qdisc_ops *ops, u32 parentid,
struct netlink_ext_ack *extack);
void __qdisc_calculate_pkt_len(struct sk_buff *skb,
const struct qdisc_size_table *stab);
int skb_do_redirect(struct sk_buff *);
static inline bool skb_at_tc_ingress(const struct sk_buff *skb)
{
#ifdef CONFIG_NET_CLS_ACT
return skb->tc_at_ingress;
#else
return false;
#endif
}
static inline bool skb_skip_tc_classify(struct sk_buff *skb)
{
#ifdef CONFIG_NET_CLS_ACT
if (skb->tc_skip_classify) {
skb->tc_skip_classify = 0;
return true;
}
#endif
return false;
}
/* Reset all TX qdiscs greater than index of a device. */
static inline void qdisc_reset_all_tx_gt(struct net_device *dev, unsigned int i)
{
struct Qdisc *qdisc;
for (; i < dev->num_tx_queues; i++) {
qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc);
if (qdisc) {
spin_lock_bh(qdisc_lock(qdisc));
qdisc_reset(qdisc);
spin_unlock_bh(qdisc_lock(qdisc));
}
}
}
/* Are all TX queues of the device empty? */
static inline bool qdisc_all_tx_empty(const struct net_device *dev)
{
unsigned int i;
rcu_read_lock();
for (i = 0; i < dev->num_tx_queues; i++) {
struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
const struct Qdisc *q = rcu_dereference(txq->qdisc);
if (!qdisc_is_empty(q)) {
rcu_read_unlock();
return false;
}
}
rcu_read_unlock();
return true;
}
/* Are any of the TX qdiscs changing? */
static inline bool qdisc_tx_changing(const struct net_device *dev)
{
unsigned int i;
for (i = 0; i < dev->num_tx_queues; i++) {
struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
if (rcu_access_pointer(txq->qdisc) != txq->qdisc_sleeping)
return true;
}
return false;
}
/* Is the device using the noop qdisc on all queues? */
static inline bool qdisc_tx_is_noop(const struct net_device *dev)
{
unsigned int i;
for (i = 0; i < dev->num_tx_queues; i++) {
struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
if (rcu_access_pointer(txq->qdisc) != &noop_qdisc)
return false;
}
return true;
}
static inline unsigned int qdisc_pkt_len(const struct sk_buff *skb)
{
return qdisc_skb_cb(skb)->pkt_len;
}
/* additional qdisc xmit flags (NET_XMIT_MASK in linux/netdevice.h) */
enum net_xmit_qdisc_t {
__NET_XMIT_STOLEN = 0x00010000,
__NET_XMIT_BYPASS = 0x00020000,
};
#ifdef CONFIG_NET_CLS_ACT
#define net_xmit_drop_count(e) ((e) & __NET_XMIT_STOLEN ? 0 : 1)
#else
#define net_xmit_drop_count(e) (1)
#endif
static inline void qdisc_calculate_pkt_len(struct sk_buff *skb,
const struct Qdisc *sch)
{
#ifdef CONFIG_NET_SCHED
struct qdisc_size_table *stab = rcu_dereference_bh(sch->stab);
if (stab)
__qdisc_calculate_pkt_len(skb, stab);
#endif
}
static inline int qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch,
struct sk_buff **to_free)
{
qdisc_calculate_pkt_len(skb, sch);
return sch->enqueue(skb, sch, to_free);
}
static inline void _bstats_update(struct gnet_stats_basic_sync *bstats,
__u64 bytes, __u32 packets)
{
u64_stats_update_begin(&bstats->syncp);
u64_stats_add(&bstats->bytes, bytes);
u64_stats_add(&bstats->packets, packets);
u64_stats_update_end(&bstats->syncp);
}
static inline void bstats_update(struct gnet_stats_basic_sync *bstats,
const struct sk_buff *skb)
{
_bstats_update(bstats,
qdisc_pkt_len(skb),
skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 1);
}
static inline void qdisc_bstats_cpu_update(struct Qdisc *sch,
const struct sk_buff *skb)
{
bstats_update(this_cpu_ptr(sch->cpu_bstats), skb);
}
static inline void qdisc_bstats_update(struct Qdisc *sch,
const struct sk_buff *skb)
{
bstats_update(&sch->bstats, skb);
}
static inline void qdisc_qstats_backlog_dec(struct Qdisc *sch,
const struct sk_buff *skb)
{
sch->qstats.backlog -= qdisc_pkt_len(skb);
}
static inline void qdisc_qstats_cpu_backlog_dec(struct Qdisc *sch,
const struct sk_buff *skb)
{
this_cpu_sub(sch->cpu_qstats->backlog, qdisc_pkt_len(skb));
}
static inline void qdisc_qstats_backlog_inc(struct Qdisc *sch,
const struct sk_buff *skb)
{
sch->qstats.backlog += qdisc_pkt_len(skb);
}
static inline void qdisc_qstats_cpu_backlog_inc(struct Qdisc *sch,
const struct sk_buff *skb)
{
this_cpu_add(sch->cpu_qstats->backlog, qdisc_pkt_len(skb));
}
static inline void qdisc_qstats_cpu_qlen_inc(struct Qdisc *sch)
{
this_cpu_inc(sch->cpu_qstats->qlen);
}
static inline void qdisc_qstats_cpu_qlen_dec(struct Qdisc *sch)
{
this_cpu_dec(sch->cpu_qstats->qlen);
}
static inline void qdisc_qstats_cpu_requeues_inc(struct Qdisc *sch)
{
this_cpu_inc(sch->cpu_qstats->requeues);
}
static inline void __qdisc_qstats_drop(struct Qdisc *sch, int count)
{
sch->qstats.drops += count;
}
static inline void qstats_drop_inc(struct gnet_stats_queue *qstats)
{
qstats->drops++;
}
static inline void qstats_overlimit_inc(struct gnet_stats_queue *qstats)
{
qstats->overlimits++;
}
static inline void qdisc_qstats_drop(struct Qdisc *sch)
{
qstats_drop_inc(&sch->qstats);
}
static inline void qdisc_qstats_cpu_drop(struct Qdisc *sch)
{
this_cpu_inc(sch->cpu_qstats->drops);
}
static inline void qdisc_qstats_overlimit(struct Qdisc *sch)
{
sch->qstats.overlimits++;
}
static inline int qdisc_qstats_copy(struct gnet_dump *d, struct Qdisc *sch)
{
__u32 qlen = qdisc_qlen_sum(sch);
return gnet_stats_copy_queue(d, sch->cpu_qstats, &sch->qstats, qlen);
}
static inline void qdisc_qstats_qlen_backlog(struct Qdisc *sch, __u32 *qlen,
__u32 *backlog)
{
struct gnet_stats_queue qstats = { 0 };
gnet_stats_add_queue(&qstats, sch->cpu_qstats, &sch->qstats);
*qlen = qstats.qlen + qdisc_qlen(sch);
*backlog = qstats.backlog;
}
static inline void qdisc_tree_flush_backlog(struct Qdisc *sch)
{
__u32 qlen, backlog;
qdisc_qstats_qlen_backlog(sch, &qlen, &backlog);
qdisc_tree_reduce_backlog(sch, qlen, backlog);
}
static inline void qdisc_purge_queue(struct Qdisc *sch)
{
__u32 qlen, backlog;
qdisc_qstats_qlen_backlog(sch, &qlen, &backlog);
qdisc_reset(sch);
qdisc_tree_reduce_backlog(sch, qlen, backlog);
}
static inline void qdisc_skb_head_init(struct qdisc_skb_head *qh)
{
qh->head = NULL;
qh->tail = NULL;
qh->qlen = 0;
}
static inline void __qdisc_enqueue_tail(struct sk_buff *skb,
struct qdisc_skb_head *qh)
{
struct sk_buff *last = qh->tail;
if (last) {
skb->next = NULL;
last->next = skb;
qh->tail = skb;
} else {
qh->tail = skb;
qh->head = skb;
}
qh->qlen++;
}
static inline int qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch)
{
__qdisc_enqueue_tail(skb, &sch->q);
qdisc_qstats_backlog_inc(sch, skb);
return NET_XMIT_SUCCESS;
}
static inline void __qdisc_enqueue_head(struct sk_buff *skb,
struct qdisc_skb_head *qh)
{
skb->next = qh->head;
if (!qh->head)
qh->tail = skb;
qh->head = skb;
qh->qlen++;
}
static inline struct sk_buff *__qdisc_dequeue_head(struct qdisc_skb_head *qh)
{
struct sk_buff *skb = qh->head;
if (likely(skb != NULL)) {
qh->head = skb->next;
qh->qlen--;
if (qh->head == NULL)
qh->tail = NULL;
skb->next = NULL;
}
return skb;
}
static inline struct sk_buff *qdisc_dequeue_head(struct Qdisc *sch)
{
struct sk_buff *skb = __qdisc_dequeue_head(&sch->q);
if (likely(skb != NULL)) {
qdisc_qstats_backlog_dec(sch, skb);
qdisc_bstats_update(sch, skb);
}
return skb;
}
/* Instead of calling kfree_skb() while root qdisc lock is held,
* queue the skb for future freeing at end of __dev_xmit_skb()
*/
static inline void __qdisc_drop(struct sk_buff *skb, struct sk_buff **to_free)
{
skb->next = *to_free;
*to_free = skb;
}
static inline void __qdisc_drop_all(struct sk_buff *skb,
struct sk_buff **to_free)
{
if (skb->prev)
skb->prev->next = *to_free;
else
skb->next = *to_free;
*to_free = skb;
}
static inline unsigned int __qdisc_queue_drop_head(struct Qdisc *sch,
struct qdisc_skb_head *qh,
struct sk_buff **to_free)
{
struct sk_buff *skb = __qdisc_dequeue_head(qh);
if (likely(skb != NULL)) {
unsigned int len = qdisc_pkt_len(skb);
qdisc_qstats_backlog_dec(sch, skb);
__qdisc_drop(skb, to_free);
return len;
}
return 0;
}
static inline struct sk_buff *qdisc_peek_head(struct Qdisc *sch)
{
const struct qdisc_skb_head *qh = &sch->q;
return qh->head;
}
/* generic pseudo peek method for non-work-conserving qdisc */
static inline struct sk_buff *qdisc_peek_dequeued(struct Qdisc *sch)
{
struct sk_buff *skb = skb_peek(&sch->gso_skb);
/* we can reuse ->gso_skb because peek isn't called for root qdiscs */
if (!skb) {
skb = sch->dequeue(sch);
if (skb) {
__skb_queue_head(&sch->gso_skb, skb);
/* it's still part of the queue */
qdisc_qstats_backlog_inc(sch, skb);
sch->q.qlen++;
}
}
return skb;
}
static inline void qdisc_update_stats_at_dequeue(struct Qdisc *sch,
struct sk_buff *skb)
{
if (qdisc_is_percpu_stats(sch)) {
qdisc_qstats_cpu_backlog_dec(sch, skb);
qdisc_bstats_cpu_update(sch, skb);
qdisc_qstats_cpu_qlen_dec(sch);
} else {
qdisc_qstats_backlog_dec(sch, skb);
qdisc_bstats_update(sch, skb);
sch->q.qlen--;
}
}
static inline void qdisc_update_stats_at_enqueue(struct Qdisc *sch,
unsigned int pkt_len)
{
if (qdisc_is_percpu_stats(sch)) {
qdisc_qstats_cpu_qlen_inc(sch);
this_cpu_add(sch->cpu_qstats->backlog, pkt_len);
} else {
sch->qstats.backlog += pkt_len;
sch->q.qlen++;
}
}
/* use instead of qdisc->dequeue() for all qdiscs queried with ->peek() */
static inline struct sk_buff *qdisc_dequeue_peeked(struct Qdisc *sch)
{
struct sk_buff *skb = skb_peek(&sch->gso_skb);
if (skb) {
skb = __skb_dequeue(&sch->gso_skb);
if (qdisc_is_percpu_stats(sch)) {
qdisc_qstats_cpu_backlog_dec(sch, skb);
qdisc_qstats_cpu_qlen_dec(sch);
} else {
qdisc_qstats_backlog_dec(sch, skb);
sch->q.qlen--;
}
} else {
skb = sch->dequeue(sch);
}
return skb;
}
static inline void __qdisc_reset_queue(struct qdisc_skb_head *qh)
{
/*
* We do not know the backlog in bytes of this list, it
* is up to the caller to correct it
*/
ASSERT_RTNL();
if (qh->qlen) {
rtnl_kfree_skbs(qh->head, qh->tail);
qh->head = NULL;
qh->tail = NULL;
qh->qlen = 0;
}
}
static inline void qdisc_reset_queue(struct Qdisc *sch)
{
__qdisc_reset_queue(&sch->q);
sch->qstats.backlog = 0;
}
static inline struct Qdisc *qdisc_replace(struct Qdisc *sch, struct Qdisc *new,
struct Qdisc **pold)
{
struct Qdisc *old;
sch_tree_lock(sch);
old = *pold;
*pold = new;
if (old != NULL)
qdisc_purge_queue(old);
sch_tree_unlock(sch);
return old;
}
static inline void rtnl_qdisc_drop(struct sk_buff *skb, struct Qdisc *sch)
{
rtnl_kfree_skbs(skb, skb);
qdisc_qstats_drop(sch);
}
static inline int qdisc_drop_cpu(struct sk_buff *skb, struct Qdisc *sch,
struct sk_buff **to_free)
{
__qdisc_drop(skb, to_free);
qdisc_qstats_cpu_drop(sch);
return NET_XMIT_DROP;
}
static inline int qdisc_drop(struct sk_buff *skb, struct Qdisc *sch,
struct sk_buff **to_free)
{
__qdisc_drop(skb, to_free);
qdisc_qstats_drop(sch);
return NET_XMIT_DROP;
}
static inline int qdisc_drop_all(struct sk_buff *skb, struct Qdisc *sch,
struct sk_buff **to_free)
{
__qdisc_drop_all(skb, to_free);
qdisc_qstats_drop(sch);
return NET_XMIT_DROP;
}
/* Length to Time (L2T) lookup in a qdisc_rate_table, to determine how
long it will take to send a packet given its size.
*/
static inline u32 qdisc_l2t(struct qdisc_rate_table* rtab, unsigned int pktlen)
{
int slot = pktlen + rtab->rate.cell_align + rtab->rate.overhead;
if (slot < 0)
slot = 0;
slot >>= rtab->rate.cell_log;
if (slot > 255)
return rtab->data[255]*(slot >> 8) + rtab->data[slot & 0xFF];
return rtab->data[slot];
}
struct psched_ratecfg {
u64 rate_bytes_ps; /* bytes per second */
u32 mult;
u16 overhead;
u16 mpu;
u8 linklayer;
u8 shift;
};
static inline u64 psched_l2t_ns(const struct psched_ratecfg *r,
unsigned int len)
{
len += r->overhead;
if (len < r->mpu)
len = r->mpu;
if (unlikely(r->linklayer == TC_LINKLAYER_ATM))
return ((u64)(DIV_ROUND_UP(len,48)*53) * r->mult) >> r->shift;
return ((u64)len * r->mult) >> r->shift;
}
void psched_ratecfg_precompute(struct psched_ratecfg *r,
const struct tc_ratespec *conf,
u64 rate64);
static inline void psched_ratecfg_getrate(struct tc_ratespec *res,
const struct psched_ratecfg *r)
{
memset(res, 0, sizeof(*res));
/* legacy struct tc_ratespec has a 32bit @rate field
* Qdisc using 64bit rate should add new attributes
* in order to maintain compatibility.
*/
res->rate = min_t(u64, r->rate_bytes_ps, ~0U);
res->overhead = r->overhead;
res->mpu = r->mpu;
res->linklayer = (r->linklayer & TC_LINKLAYER_MASK);
}
struct psched_pktrate {
u64 rate_pkts_ps; /* packets per second */
u32 mult;
u8 shift;
};
static inline u64 psched_pkt2t_ns(const struct psched_pktrate *r,
unsigned int pkt_num)
{
return ((u64)pkt_num * r->mult) >> r->shift;
}
void psched_ppscfg_precompute(struct psched_pktrate *r, u64 pktrate64);
/* Mini Qdisc serves for specific needs of ingress/clsact Qdisc.
* The fast path only needs to access filter list and to update stats
*/
struct mini_Qdisc {
struct tcf_proto *filter_list;
struct tcf_block *block;
struct gnet_stats_basic_sync __percpu *cpu_bstats;
struct gnet_stats_queue __percpu *cpu_qstats;
unsigned long rcu_state;
};
static inline void mini_qdisc_bstats_cpu_update(struct mini_Qdisc *miniq,
const struct sk_buff *skb)
{
bstats_update(this_cpu_ptr(miniq->cpu_bstats), skb);
}
static inline void mini_qdisc_qstats_cpu_drop(struct mini_Qdisc *miniq)
{
this_cpu_inc(miniq->cpu_qstats->drops);
}
struct mini_Qdisc_pair {
struct mini_Qdisc miniq1;
struct mini_Qdisc miniq2;
struct mini_Qdisc __rcu **p_miniq;
};
void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp,
struct tcf_proto *tp_head);
void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc,
struct mini_Qdisc __rcu **p_miniq);
void mini_qdisc_pair_block_init(struct mini_Qdisc_pair *miniqp,
struct tcf_block *block);
void mq_change_real_num_tx(struct Qdisc *sch, unsigned int new_real_tx);
int sch_frag_xmit_hook(struct sk_buff *skb, int (*xmit)(struct sk_buff *skb));
#endif