linux/include/net/sch_generic.h
Davide Caratti af0cb3fa3f net/sched: fix false lockdep warning on qdisc root lock
Xiumei and Christoph reported the following lockdep splat, complaining of
the qdisc root lock being taken twice:

 ============================================
 WARNING: possible recursive locking detected
 6.7.0-rc3+ #598 Not tainted
 --------------------------------------------
 swapper/2/0 is trying to acquire lock:
 ffff888177190110 (&sch->q.lock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1560/0x2e70

 but task is already holding lock:
 ffff88811995a110 (&sch->q.lock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1560/0x2e70

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&sch->q.lock);
   lock(&sch->q.lock);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 5 locks held by swapper/2/0:
  #0: ffff888135a09d98 ((&in_dev->mr_ifc_timer)){+.-.}-{0:0}, at: call_timer_fn+0x11a/0x510
  #1: ffffffffaaee5260 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x2c0/0x1ed0
  #2: ffffffffaaee5200 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x209/0x2e70
  #3: ffff88811995a110 (&sch->q.lock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1560/0x2e70
  #4: ffffffffaaee5200 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x209/0x2e70

 stack backtrace:
 CPU: 2 PID: 0 Comm: swapper/2 Not tainted 6.7.0-rc3+ #598
 Hardware name: Red Hat KVM, BIOS 1.13.0-2.module+el8.3.0+7353+9de0a3cc 04/01/2014
 Call Trace:
  <IRQ>
  dump_stack_lvl+0x4a/0x80
  __lock_acquire+0xfdd/0x3150
  lock_acquire+0x1ca/0x540
  _raw_spin_lock+0x34/0x80
  __dev_queue_xmit+0x1560/0x2e70
  tcf_mirred_act+0x82e/0x1260 [act_mirred]
  tcf_action_exec+0x161/0x480
  tcf_classify+0x689/0x1170
  prio_enqueue+0x316/0x660 [sch_prio]
  dev_qdisc_enqueue+0x46/0x220
  __dev_queue_xmit+0x1615/0x2e70
  ip_finish_output2+0x1218/0x1ed0
  __ip_finish_output+0x8b3/0x1350
  ip_output+0x163/0x4e0
  igmp_ifc_timer_expire+0x44b/0x930
  call_timer_fn+0x1a2/0x510
  run_timer_softirq+0x54d/0x11a0
  __do_softirq+0x1b3/0x88f
  irq_exit_rcu+0x18f/0x1e0
  sysvec_apic_timer_interrupt+0x6f/0x90
  </IRQ>

This happens when TC does a mirred egress redirect from the root qdisc of
device A to the root qdisc of device B. As long as these two locks aren't
protecting the same qdisc, they can be acquired in chain: add a per-qdisc
lockdep key to silence false warnings.
This dynamic key should safely replace the static key we have in sch_htb:
it was added to allow enqueueing to the device "direct qdisc" while still
holding the qdisc root lock.

v2: don't use static keys anymore in HTB direct qdiscs (thanks Eric Dumazet)

CC: Maxim Mikityanskiy <maxim@isovalent.com>
CC: Xiumei Mu <xmu@redhat.com>
Reported-by: Christoph Paasch <cpaasch@apple.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/451
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Link: https://lore.kernel.org/r/7dc06d6158f72053cf877a82e2a7a5bd23692faa.1713448007.git.dcaratti@redhat.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-04-26 10:46:41 +02:00

1362 lines
34 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>
#include <linux/xarray.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;
int owner;
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;
struct lock_class_key root_lock_key;
/* 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);
}
static inline bool qdisc_refcount_dec_if_one(struct Qdisc *qdisc)
{
if (qdisc->flags & TCQ_F_BUILTIN)
return true;
return refcount_dec_if_one(&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)
{
return netdev_queue_dql_avail(txq);
}
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;
};
};
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);
void (*tmplt_reoffload)(struct tcf_chain *chain,
bool add,
flow_setup_cb_t *cb,
void *cb_priv);
struct tcf_exts * (*get_exts)(const struct tcf_proto *tp,
u32 handle);
/* 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;
bool counted;
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 {
struct xarray ports; /* datapath accessible */
/* 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;
bool bypass_wanted;
atomic_t filtercnt; /* Number of filters */
atomic_t skipswcnt; /* Number of skip_sw filters */
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. */
};
struct tcf_block *tcf_block_lookup(struct net *net, u32 block_index);
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 rcu_dereference_rtnl(qdisc->dev_queue->qdisc_sleeping);
}
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 const u8 sch_default_prio2band[TC_PRIO_MAX + 1];
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;
unsigned int filter_cnt;
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 bool qdisc_class_in_use(const struct Qdisc_class_common *cl)
{
return cl->filter_cnt > 0;
}
static inline void qdisc_class_get(struct Qdisc_class_common *cl)
{
unsigned int res;
if (check_add_overflow(cl->filter_cnt, 1, &res))
WARN(1, "Qdisc class overflow");
cl->filter_cnt = res;
}
static inline void qdisc_class_put(struct Qdisc_class_common *cl)
{
unsigned int res;
if (check_sub_overflow(cl->filter_cnt, 1, &res))
WARN(1, "Qdisc class underflow");
cl->filter_cnt = res;
}
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_destroy(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
void qdisc_offload_query_caps(struct net_device *dev,
enum tc_setup_type type,
void *caps, size_t caps_len);
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_XGRESS
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) !=
rcu_access_pointer(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_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;
}
struct tc_skb_cb {
struct qdisc_skb_cb qdisc_cb;
u32 drop_reason;
u16 zone; /* Only valid if post_ct = true */
u16 mru;
u8 post_ct:1;
u8 post_ct_snat:1;
u8 post_ct_dnat:1;
};
static inline struct tc_skb_cb *tc_skb_cb(const struct sk_buff *skb)
{
struct tc_skb_cb *cb = (struct tc_skb_cb *)skb->cb;
BUILD_BUG_ON(sizeof(*cb) > sizeof_field(struct sk_buff, cb));
return cb;
}
static inline enum skb_drop_reason
tcf_get_drop_reason(const struct sk_buff *skb)
{
return tc_skb_cb(skb)->drop_reason;
}
static inline void tcf_set_drop_reason(const struct sk_buff *skb,
enum skb_drop_reason reason)
{
tc_skb_cb(skb)->drop_reason = reason;
}
/* 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);
}
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;
}
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));
/* Make sure qdisc is no longer in SCHED state. */
static inline void qdisc_synchronize(const struct Qdisc *q)
{
while (test_bit(__QDISC_STATE_SCHED, &q->state))
msleep(1);
}
#endif