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net_sched: Add size table for qdiscs
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Add size table functions for qdiscs and calculate packet size in
qdisc_enqueue().

Based on patch by Patrick McHardy
 http://marc.info/?l=linux-netdev&m=115201979221729&w=2

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
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@jkivilin @davem330
jkivilin authored and davem330 committed Jul 20, 2008
1 parent 0abf77e commit 175f9c1
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Showing 7 changed files with 199 additions and 5 deletions.
20 changes: 20 additions & 0 deletions include/linux/pkt_sched.h
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Original file line number Diff line number Diff line change
Expand Up @@ -85,6 +85,26 @@ struct tc_ratespec

#define TC_RTAB_SIZE 1024

struct tc_sizespec {
unsigned char cell_log;
unsigned char size_log;
short cell_align;
int overhead;
unsigned int linklayer;
unsigned int mpu;
unsigned int mtu;
unsigned int tsize;
};

enum {
TCA_STAB_UNSPEC,
TCA_STAB_BASE,
TCA_STAB_DATA,
__TCA_STAB_MAX
};

#define TCA_STAB_MAX (__TCA_STAB_MAX - 1)

/* FIFO section */

struct tc_fifo_qopt
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1 change: 1 addition & 0 deletions include/linux/rtnetlink.h
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Original file line number Diff line number Diff line change
Expand Up @@ -482,6 +482,7 @@ enum
TCA_RATE,
TCA_FCNT,
TCA_STATS2,
TCA_STAB,
__TCA_MAX
};

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1 change: 1 addition & 0 deletions include/net/pkt_sched.h
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Original file line number Diff line number Diff line change
Expand Up @@ -83,6 +83,7 @@ extern struct Qdisc *qdisc_lookup_class(struct net_device *dev, u32 handle);
extern struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
struct nlattr *tab);
extern void qdisc_put_rtab(struct qdisc_rate_table *tab);
extern void qdisc_put_stab(struct qdisc_size_table *tab);

extern void __qdisc_run(struct Qdisc *q);

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25 changes: 24 additions & 1 deletion include/net/sch_generic.h
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,13 @@ enum qdisc_state_t
__QDISC_STATE_SCHED,
};

struct qdisc_size_table {
struct list_head list;
struct tc_sizespec szopts;
int refcnt;
u16 data[];
};

struct Qdisc
{
int (*enqueue)(struct sk_buff *skb, struct Qdisc *dev);
Expand All @@ -39,6 +46,7 @@ struct Qdisc
#define TCQ_F_INGRESS 4
int padded;
struct Qdisc_ops *ops;
struct qdisc_size_table *stab;
u32 handle;
u32 parent;
atomic_t refcnt;
Expand Down Expand Up @@ -165,6 +173,16 @@ struct tcf_proto
struct tcf_proto_ops *ops;
};

struct qdisc_skb_cb {
unsigned int pkt_len;
char data[];
};

static inline struct qdisc_skb_cb *qdisc_skb_cb(struct sk_buff *skb)
{
return (struct qdisc_skb_cb *)skb->cb;
}

static inline spinlock_t *qdisc_lock(struct Qdisc *qdisc)
{
return &qdisc->q.lock;
Expand Down Expand Up @@ -257,6 +275,8 @@ extern struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
extern struct Qdisc *qdisc_create_dflt(struct net_device *dev,
struct netdev_queue *dev_queue,
struct Qdisc_ops *ops, u32 parentid);
extern void qdisc_calculate_pkt_len(struct sk_buff *skb,
struct qdisc_size_table *stab);
extern void tcf_destroy(struct tcf_proto *tp);
extern void tcf_destroy_chain(struct tcf_proto **fl);

Expand Down Expand Up @@ -308,16 +328,19 @@ static inline bool qdisc_tx_is_noop(const struct net_device *dev)

static inline unsigned int qdisc_pkt_len(struct sk_buff *skb)
{
return skb->len;
return qdisc_skb_cb(skb)->pkt_len;
}

static inline int qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{
if (sch->stab)
qdisc_calculate_pkt_len(skb, sch->stab);
return sch->enqueue(skb, sch);
}

static inline int qdisc_enqueue_root(struct sk_buff *skb, struct Qdisc *sch)
{
qdisc_skb_cb(skb)->pkt_len = skb->len;
return qdisc_enqueue(skb, sch);
}

Expand Down
151 changes: 149 additions & 2 deletions net/sched/sch_api.c
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Original file line number Diff line number Diff line change
Expand Up @@ -286,6 +286,129 @@ void qdisc_put_rtab(struct qdisc_rate_table *tab)
}
EXPORT_SYMBOL(qdisc_put_rtab);

static LIST_HEAD(qdisc_stab_list);
static DEFINE_SPINLOCK(qdisc_stab_lock);

static const struct nla_policy stab_policy[TCA_STAB_MAX + 1] = {
[TCA_STAB_BASE] = { .len = sizeof(struct tc_sizespec) },
[TCA_STAB_DATA] = { .type = NLA_BINARY },
};

static struct qdisc_size_table *qdisc_get_stab(struct nlattr *opt)
{
struct nlattr *tb[TCA_STAB_MAX + 1];
struct qdisc_size_table *stab;
struct tc_sizespec *s;
unsigned int tsize = 0;
u16 *tab = NULL;
int err;

err = nla_parse_nested(tb, TCA_STAB_MAX, opt, stab_policy);
if (err < 0)
return ERR_PTR(err);
if (!tb[TCA_STAB_BASE])
return ERR_PTR(-EINVAL);

s = nla_data(tb[TCA_STAB_BASE]);

if (s->tsize > 0) {
if (!tb[TCA_STAB_DATA])
return ERR_PTR(-EINVAL);
tab = nla_data(tb[TCA_STAB_DATA]);
tsize = nla_len(tb[TCA_STAB_DATA]) / sizeof(u16);
}

if (!s || tsize != s->tsize || (!tab && tsize > 0))
return ERR_PTR(-EINVAL);

spin_lock(&qdisc_stab_lock);

list_for_each_entry(stab, &qdisc_stab_list, list) {
if (memcmp(&stab->szopts, s, sizeof(*s)))
continue;
if (tsize > 0 && memcmp(stab->data, tab, tsize * sizeof(u16)))
continue;
stab->refcnt++;
spin_unlock(&qdisc_stab_lock);
return stab;
}

spin_unlock(&qdisc_stab_lock);

stab = kmalloc(sizeof(*stab) + tsize * sizeof(u16), GFP_KERNEL);
if (!stab)
return ERR_PTR(-ENOMEM);

stab->refcnt = 1;
stab->szopts = *s;
if (tsize > 0)
memcpy(stab->data, tab, tsize * sizeof(u16));

spin_lock(&qdisc_stab_lock);
list_add_tail(&stab->list, &qdisc_stab_list);
spin_unlock(&qdisc_stab_lock);

return stab;
}

void qdisc_put_stab(struct qdisc_size_table *tab)
{
if (!tab)
return;

spin_lock(&qdisc_stab_lock);

if (--tab->refcnt == 0) {
list_del(&tab->list);
kfree(tab);
}

spin_unlock(&qdisc_stab_lock);
}
EXPORT_SYMBOL(qdisc_put_stab);

static int qdisc_dump_stab(struct sk_buff *skb, struct qdisc_size_table *stab)
{
struct nlattr *nest;

nest = nla_nest_start(skb, TCA_STAB);
NLA_PUT(skb, TCA_STAB_BASE, sizeof(stab->szopts), &stab->szopts);
nla_nest_end(skb, nest);

return skb->len;

nla_put_failure:
return -1;
}

void qdisc_calculate_pkt_len(struct sk_buff *skb, struct qdisc_size_table *stab)
{
int pkt_len, slot;

pkt_len = skb->len + stab->szopts.overhead;
if (unlikely(!stab->szopts.tsize))
goto out;

slot = pkt_len + stab->szopts.cell_align;
if (unlikely(slot < 0))
slot = 0;

slot >>= stab->szopts.cell_log;
if (likely(slot < stab->szopts.tsize))
pkt_len = stab->data[slot];
else
pkt_len = stab->data[stab->szopts.tsize - 1] *
(slot / stab->szopts.tsize) +
stab->data[slot % stab->szopts.tsize];

pkt_len <<= stab->szopts.size_log;
out:
if (unlikely(pkt_len < 1))
pkt_len = 1;
qdisc_skb_cb(skb)->pkt_len = pkt_len;
}
EXPORT_SYMBOL(qdisc_calculate_pkt_len);

static enum hrtimer_restart qdisc_watchdog(struct hrtimer *timer)
{
struct qdisc_watchdog *wd = container_of(timer, struct qdisc_watchdog,
Expand Down Expand Up @@ -613,6 +736,7 @@ qdisc_create(struct net_device *dev, struct netdev_queue *dev_queue,
struct nlattr *kind = tca[TCA_KIND];
struct Qdisc *sch;
struct Qdisc_ops *ops;
struct qdisc_size_table *stab;

ops = qdisc_lookup_ops(kind);
#ifdef CONFIG_KMOD
Expand Down Expand Up @@ -670,6 +794,14 @@ qdisc_create(struct net_device *dev, struct netdev_queue *dev_queue,
sch->handle = handle;

if (!ops->init || (err = ops->init(sch, tca[TCA_OPTIONS])) == 0) {
if (tca[TCA_STAB]) {
stab = qdisc_get_stab(tca[TCA_STAB]);
if (IS_ERR(stab)) {
err = PTR_ERR(stab);
goto err_out3;
}
sch->stab = stab;
}
if (tca[TCA_RATE]) {
err = gen_new_estimator(&sch->bstats, &sch->rate_est,
qdisc_root_lock(sch),
Expand All @@ -691,6 +823,7 @@ qdisc_create(struct net_device *dev, struct netdev_queue *dev_queue,
return sch;
}
err_out3:
qdisc_put_stab(sch->stab);
dev_put(dev);
kfree((char *) sch - sch->padded);
err_out2:
Expand All @@ -702,15 +835,26 @@ qdisc_create(struct net_device *dev, struct netdev_queue *dev_queue,

static int qdisc_change(struct Qdisc *sch, struct nlattr **tca)
{
if (tca[TCA_OPTIONS]) {
int err;
struct qdisc_size_table *stab = NULL;
int err = 0;

if (tca[TCA_OPTIONS]) {
if (sch->ops->change == NULL)
return -EINVAL;
err = sch->ops->change(sch, tca[TCA_OPTIONS]);
if (err)
return err;
}

if (tca[TCA_STAB]) {
stab = qdisc_get_stab(tca[TCA_STAB]);
if (IS_ERR(stab))
return PTR_ERR(stab);
}

qdisc_put_stab(sch->stab);
sch->stab = stab;

if (tca[TCA_RATE])
gen_replace_estimator(&sch->bstats, &sch->rate_est,
qdisc_root_lock(sch), tca[TCA_RATE]);
Expand Down Expand Up @@ -994,6 +1138,9 @@ static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
goto nla_put_failure;
q->qstats.qlen = q->q.qlen;

if (q->stab && qdisc_dump_stab(skb, q->stab) < 0)
goto nla_put_failure;

if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS,
TCA_XSTATS, qdisc_root_lock(q), &d) < 0)
goto nla_put_failure;
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1 change: 1 addition & 0 deletions net/sched/sch_generic.c
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Original file line number Diff line number Diff line change
Expand Up @@ -469,6 +469,7 @@ static void __qdisc_destroy(struct rcu_head *head)
struct Qdisc *qdisc = container_of(head, struct Qdisc, q_rcu);
const struct Qdisc_ops *ops = qdisc->ops;

qdisc_put_stab(qdisc->stab);
gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);
if (ops->reset)
ops->reset(qdisc);
Expand Down
5 changes: 3 additions & 2 deletions net/sched/sch_netem.c
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Original file line number Diff line number Diff line change
Expand Up @@ -84,8 +84,9 @@ struct netem_skb_cb {

static inline struct netem_skb_cb *netem_skb_cb(struct sk_buff *skb)
{
BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct netem_skb_cb));
return (struct netem_skb_cb *)skb->cb;
BUILD_BUG_ON(sizeof(skb->cb) <
sizeof(struct qdisc_skb_cb) + sizeof(struct netem_skb_cb));
return (struct netem_skb_cb *)qdisc_skb_cb(skb)->data;
}

/* init_crandom - initialize correlated random number generator
Expand Down

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