Subject: Re: [EXT] Re: [v3,net-next 1/4] net: qos: introduce a gate control flow action

From: Vlad Buslov <[email-masked]>
Date: Thu, 23 Apr 2020 10:43:01 +0300

On Thu 23 Apr 2020 at 06:14, Po Liu <[email-masked]> wrote:
> Hi Vlad Buslov,
>
>> -----Original Message-----
>> From: Vlad Buslov <[email-masked]>
>> Sent: 2020年4月22日 21:23
>> To: Po Liu <[email-masked]>
>> Cc: [email-masked]; [email-masked];
>> [email-masked]; [email-masked]; Claudiu Manoil
>> <[email-masked]>; Vladimir Oltean <[email-masked]>;
>> Alexandru Marginean <[email-masked]>;
>> [email-masked]; [email-masked];
>> [email-masked]; [email-masked]; [email-masked];
>> [email-masked]; [email-masked];
>> [email-masked]; [email-masked]; [email-masked];
>> [email-masked]; [email-masked];
>> [email-masked]; [email-masked]; [email-masked];
>> [email-masked]; [email-masked]
>> Subject: [EXT] Re: [v3,net-next 1/4] net: qos: introduce a gate control flow
>> action
>> 
>> Caution: EXT Email
>> 
>> Hi Po,
>> 
>> On Wed 22 Apr 2020 at 05:48, Po Liu <[email-masked]> wrote:
>> > Introduce a ingress frame gate control flow action.
>> > Tc gate action does the work like this:
>> > Assume there is a gate allow specified ingress frames can be passed at
>> > specific time slot, and be dropped at specific time slot. Tc filter
>> > chooses the ingress frames, and tc gate action would specify what slot
>> > does these frames can be passed to device and what time slot would be
>> > dropped.
>> > Tc gate action would provide an entry list to tell how much time gate
>> > keep open and how much time gate keep state close. Gate action also
>> > assign a start time to tell when the entry list start. Then driver
>> > would repeat the gate entry list cyclically.
>> > For the software simulation, gate action requires the user assign a
>> > time clock type.
>> >
>> > Below is the setting example in user space. Tc filter a stream source
>> > ip address is 192.168.0.20 and gate action own two time slots. One is
>> > last 200ms gate open let frame pass another is last 100ms gate close
>> > let frames dropped. When the frames have passed total frames over
>> > 8000000 bytes, frames will be dropped in one 200000000ns time slot.
>> >
>> >> tc qdisc add dev eth0 ingress
>> >
>> >> tc filter add dev eth0 parent ffff: protocol ip \
>> >          flower src_ip 192.168.0.20 \
>> >          action gate index 2 clockid CLOCK_TAI \
>> >          sched-entry open 200000000 -1 8000000 \
>> >          sched-entry close 100000000 -1 -1
>> >
>> >> tc chain del dev eth0 ingress chain 0
>> >
>> > "sched-entry" follow the name taprio style. Gate state is
>> > "open"/"close". Follow with period nanosecond. Then next item is
>> > internal priority value means which ingress queue should put. "-1"
>> > means wildcard. The last value optional specifies the maximum number
>> > of MSDU octets that are permitted to pass the gate during the
>> > specified time interval.
>> > Base-time is not set will be 0 as default, as result start time would
>> > be ((N + 1) * cycletime) which is the minimal of future time.
>> >
>> > Below example shows filtering a stream with destination mac address is
>> > 10:00:80:00:00:00 and ip type is ICMP, follow the action gate. The
>> > gate action would run with one close time slot which means always keep
>> close.
>> > The time cycle is total 200000000ns. The base-time would calculate by:
>> >
>> >  1357000000000 + (N + 1) * cycletime
>> >
>> > When the total value is the future time, it will be the start time.
>> > The cycletime here would be 200000000ns for this case.
>> >
>> >> tc filter add dev eth0 parent ffff:  protocol ip \
>> >          flower skip_hw ip_proto icmp dst_mac 10:00:80:00:00:00 \
>> >          action gate index 12 base-time 1357000000000 \
>> >          sched-entry close 200000000 -1 -1 \
>> >          clockid CLOCK_TAI
>> >
>> > Signed-off-by: Po Liu <[email-masked]>
>> > ---
>> >  include/net/tc_act/tc_gate.h        |  54 +++
>> >  include/uapi/linux/pkt_cls.h        |   1 +
>> >  include/uapi/linux/tc_act/tc_gate.h |  47 ++
>> >  net/sched/Kconfig                   |  13 +
>> >  net/sched/Makefile                  |   1 +
>> >  net/sched/act_gate.c                | 647 ++++++++++++++++++++++++++++
>> >  6 files changed, 763 insertions(+)
>> >  create mode 100644 include/net/tc_act/tc_gate.h  create mode 100644
>> > include/uapi/linux/tc_act/tc_gate.h
>> >  create mode 100644 net/sched/act_gate.c
>> >
>> > diff --git a/include/net/tc_act/tc_gate.h
>> > b/include/net/tc_act/tc_gate.h new file mode 100644 index
>> > 000000000000..b0ace55b2aaa
>> > --- /dev/null
>> > +++ b/include/net/tc_act/tc_gate.h
>> > @@ -0,0 +1,54 @@
>> > +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> > +/* Copyright 2020 NXP */
>> > +
>> > +#ifndef __NET_TC_GATE_H
>> > +#define __NET_TC_GATE_H
>> > +
>> > +#include <net/act_api.h>
>> > +#include <linux/tc_act/tc_gate.h>
>> > +
>> > +struct tcfg_gate_entry {
>> > +     int                     index;
>> > +     u8                      gate_state;
>> > +     u32                     interval;
>> > +     s32                     ipv;
>> > +     s32                     maxoctets;
>> > +     struct list_head        list;
>> > +};
>> > +
>> > +struct tcf_gate_params {
>> > +     s32                     tcfg_priority;
>> > +     u64                     tcfg_basetime;
>> > +     u64                     tcfg_cycletime;
>> > +     u64                     tcfg_cycletime_ext;
>> > +     u32                     tcfg_flags;
>> > +     s32                     tcfg_clockid;
>> > +     size_t                  num_entries;
>> > +     struct list_head        entries;
>> > +};
>> > +
>> > +#define GATE_ACT_GATE_OPEN   BIT(0)
>> > +#define GATE_ACT_PENDING     BIT(1)
>> > +struct gate_action {
>> > +     struct tcf_gate_params param;
>> > +     spinlock_t entry_lock;
>> > +     u8 current_gate_status;
>> > +     ktime_t current_close_time;
>> > +     u32 current_entry_octets;
>> > +     s32 current_max_octets;
>> > +     struct tcfg_gate_entry __rcu *next_entry;
>> > +     struct hrtimer hitimer;
>> > +     enum tk_offsets tk_offset;
>> > +     struct rcu_head rcu;
>> > +};
>> > +
>> > +struct tcf_gate {
>> > +     struct tc_action                common;
>> > +     struct gate_action __rcu        *actg;
>> > +};
>> > +#define to_gate(a) ((struct tcf_gate *)a)
>> > +
>> > +#define get_gate_param(act) ((struct tcf_gate_params *)act) #define
>> > +get_gate_action(p) ((struct gate_action *)p)
>> > +
>> > +#endif
>> > diff --git a/include/uapi/linux/pkt_cls.h
>> > b/include/uapi/linux/pkt_cls.h index 9f06d29cab70..fc672b232437
>> 100644
>> > --- a/include/uapi/linux/pkt_cls.h
>> > +++ b/include/uapi/linux/pkt_cls.h
>> > @@ -134,6 +134,7 @@ enum tca_id {
>> >       TCA_ID_CTINFO,
>> >       TCA_ID_MPLS,
>> >       TCA_ID_CT,
>> > +     TCA_ID_GATE,
>> >       /* other actions go here */
>> >       __TCA_ID_MAX = 255
>> >  };
>> > diff --git a/include/uapi/linux/tc_act/tc_gate.h
>> > b/include/uapi/linux/tc_act/tc_gate.h
>> > new file mode 100644
>> > index 000000000000..f214b3a6d44f
>> > --- /dev/null
>> > +++ b/include/uapi/linux/tc_act/tc_gate.h
>> > @@ -0,0 +1,47 @@
>> > +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
>> > +/* Copyright 2020 NXP */
>> > +
>> > +#ifndef __LINUX_TC_GATE_H
>> > +#define __LINUX_TC_GATE_H
>> > +
>> > +#include <linux/pkt_cls.h>
>> > +
>> > +struct tc_gate {
>> > +     tc_gen;
>> > +};
>> > +
>> > +enum {
>> > +     TCA_GATE_ENTRY_UNSPEC,
>> > +     TCA_GATE_ENTRY_INDEX,
>> > +     TCA_GATE_ENTRY_GATE,
>> > +     TCA_GATE_ENTRY_INTERVAL,
>> > +     TCA_GATE_ENTRY_IPV,
>> > +     TCA_GATE_ENTRY_MAX_OCTETS,
>> > +     __TCA_GATE_ENTRY_MAX,
>> > +};
>> > +#define TCA_GATE_ENTRY_MAX (__TCA_GATE_ENTRY_MAX - 1)
>> > +
>> > +enum {
>> > +     TCA_GATE_ONE_ENTRY_UNSPEC,
>> > +     TCA_GATE_ONE_ENTRY,
>> > +     __TCA_GATE_ONE_ENTRY_MAX,
>> > +};
>> > +#define TCA_GATE_ONE_ENTRY_MAX (__TCA_GATE_ONE_ENTRY_MAX
>> - 1)
>> > +
>> > +enum {
>> > +     TCA_GATE_UNSPEC,
>> > +     TCA_GATE_TM,
>> > +     TCA_GATE_PARMS,
>> > +     TCA_GATE_PAD,
>> > +     TCA_GATE_PRIORITY,
>> > +     TCA_GATE_ENTRY_LIST,
>> > +     TCA_GATE_BASE_TIME,
>> > +     TCA_GATE_CYCLE_TIME,
>> > +     TCA_GATE_CYCLE_TIME_EXT,
>> > +     TCA_GATE_FLAGS,
>> > +     TCA_GATE_CLOCKID,
>> > +     __TCA_GATE_MAX,
>> > +};
>> > +#define TCA_GATE_MAX (__TCA_GATE_MAX - 1)
>> > +
>> > +#endif
>> > diff --git a/net/sched/Kconfig b/net/sched/Kconfig index
>> > bfbefb7bff9d..1314549c7567 100644
>> > --- a/net/sched/Kconfig
>> > +++ b/net/sched/Kconfig
>> > @@ -981,6 +981,19 @@ config NET_ACT_CT
>> >         To compile this code as a module, choose M here: the
>> >         module will be called act_ct.
>> >
>> > +config NET_ACT_GATE
>> > +     tristate "Frame gate entry list control tc action"
>> > +     depends on NET_CLS_ACT
>> > +     help
>> > +       Say Y here to allow to control the ingress flow to be passed at
>> > +       specific time slot and be dropped at other specific time slot by
>> > +       the gate entry list. The manipulation will simulate the IEEE
>> > +       802.1Qci stream gate control behavior.
>> > +
>> > +       If unsure, say N.
>> > +       To compile this code as a module, choose M here: the
>> > +       module will be called act_gate.
>> > +
>> >  config NET_IFE_SKBMARK
>> >       tristate "Support to encoding decoding skb mark on IFE action"
>> >       depends on NET_ACT_IFE
>> > diff --git a/net/sched/Makefile b/net/sched/Makefile index
>> > 31c367a6cd09..66bbf9a98f9e 100644
>> > --- a/net/sched/Makefile
>> > +++ b/net/sched/Makefile
>> > @@ -30,6 +30,7 @@ obj-$(CONFIG_NET_IFE_SKBPRIO)       +=
>> act_meta_skbprio.o
>> >  obj-$(CONFIG_NET_IFE_SKBTCINDEX)     += act_meta_skbtcindex.o
>> >  obj-$(CONFIG_NET_ACT_TUNNEL_KEY)+= act_tunnel_key.o
>> >  obj-$(CONFIG_NET_ACT_CT)     += act_ct.o
>> > +obj-$(CONFIG_NET_ACT_GATE)   += act_gate.o
>> >  obj-$(CONFIG_NET_SCH_FIFO)   += sch_fifo.o
>> >  obj-$(CONFIG_NET_SCH_CBQ)    += sch_cbq.o
>> >  obj-$(CONFIG_NET_SCH_HTB)    += sch_htb.o
>> > diff --git a/net/sched/act_gate.c b/net/sched/act_gate.c new file mode
>> > 100644 index 000000000000..e932f402b4f1
>> > --- /dev/null
>> > +++ b/net/sched/act_gate.c
>> > @@ -0,0 +1,647 @@
>> > +// SPDX-License-Identifier: GPL-2.0-or-later
>> > +/* Copyright 2020 NXP */
>> > +
>> > +#include <linux/module.h>
>> > +#include <linux/types.h>
>> > +#include <linux/kernel.h>
>> > +#include <linux/string.h>
>> > +#include <linux/errno.h>
>> > +#include <linux/skbuff.h>
>> > +#include <linux/rtnetlink.h>
>> > +#include <linux/init.h>
>> > +#include <linux/slab.h>
>> > +#include <net/act_api.h>
>> > +#include <net/netlink.h>
>> > +#include <net/pkt_cls.h>
>> > +#include <net/tc_act/tc_gate.h>
>> > +
>> > +static unsigned int gate_net_id;
>> > +static struct tc_action_ops act_gate_ops;
>> > +
>> > +static ktime_t gate_get_time(struct gate_action *gact) {
>> > +     ktime_t mono = ktime_get();
>> > +
>> > +     switch (gact->tk_offset) {
>> > +     case TK_OFFS_MAX:
>> > +             return mono;
>> > +     default:
>> > +             return ktime_mono_to_any(mono, gact->tk_offset);
>> > +     }
>> > +
>> > +     return KTIME_MAX;
>> > +}
>> > +
>> > +static int gate_get_start_time(struct gate_action *gact, ktime_t
>> > +*start) {
>> > +     struct tcf_gate_params *param = get_gate_param(gact);
>> > +     ktime_t now, base, cycle;
>> > +     u64 n;
>> > +
>> > +     base = ns_to_ktime(param->tcfg_basetime);
>> > +     now = gate_get_time(gact);
>> > +
>> > +     if (ktime_after(base, now)) {
>> > +             *start = base;
>> > +             return 0;
>> > +     }
>> > +
>> > +     cycle = param->tcfg_cycletime;
>> > +
>> > +     /* cycle time should not be zero */
>> > +     if (WARN_ON(!cycle))
>> > +             return -EFAULT;
>> 
>> Looking at the init code it seems that this value can be set to 0 directly
>> from netlink packet without further validation, which would allow user to
>> trigger warning here.
>
> Yes,  will avoid at ahead point.
>
>> 
>> > +
>> > +     n = div64_u64(ktime_sub_ns(now, base), cycle);
>> > +     *start = ktime_add_ns(base, (n + 1) * cycle);
>> > +     return 0;
>> > +}
>> > +
>> > +static void gate_start_timer(struct gate_action *gact, ktime_t start)
>> > +{
>> > +     ktime_t expires;
>> > +
>> > +     expires = hrtimer_get_expires(&gact->hitimer);
>> > +     if (expires == 0)
>> > +             expires = KTIME_MAX;
>> > +
>> > +     start = min_t(ktime_t, start, expires);
>> > +
>> > +     hrtimer_start(&gact->hitimer, start, HRTIMER_MODE_ABS); }
>> > +
>> > +static enum hrtimer_restart gate_timer_func(struct hrtimer *timer) {
>> > +     struct gate_action *gact = container_of(timer, struct gate_action,
>> > +                                             hitimer);
>> > +     struct tcf_gate_params *p = get_gate_param(gact);
>> > +     struct tcfg_gate_entry *next;
>> > +     ktime_t close_time, now;
>> > +
>> > +     spin_lock(&gact->entry_lock);
>> > +
>> > +     next = rcu_dereference_protected(gact->next_entry,
>> > +
>> > + lockdep_is_held(&gact->entry_lock));
>> > +
>> > +     /* cycle start, clear pending bit, clear total octets */
>> > +     gact->current_gate_status = next->gate_state ?
>> GATE_ACT_GATE_OPEN : 0;
>> > +     gact->current_entry_octets = 0;
>> > +     gact->current_max_octets = next->maxoctets;
>> > +
>> > +     gact->current_close_time = ktime_add_ns(gact->current_close_time,
>> > +                                             next->interval);
>> > +
>> > +     close_time = gact->current_close_time;
>> > +
>> > +     if (list_is_last(&next->list, &p->entries))
>> > +             next = list_first_entry(&p->entries,
>> > +                                     struct tcfg_gate_entry, list);
>> > +     else
>> > +             next = list_next_entry(next, list);
>> > +
>> > +     now = gate_get_time(gact);
>> > +
>> > +     if (ktime_after(now, close_time)) {
>> > +             ktime_t cycle, base;
>> > +             u64 n;
>> > +
>> > +             cycle = p->tcfg_cycletime;
>> > +             base = ns_to_ktime(p->tcfg_basetime);
>> > +             n = div64_u64(ktime_sub_ns(now, base), cycle);
>> > +             close_time = ktime_add_ns(base, (n + 1) * cycle);
>> > +     }
>> > +
>> > +     rcu_assign_pointer(gact->next_entry, next);
>> > +     spin_unlock(&gact->entry_lock);
>> 
>> I have couple of question about synchronization here:
>> 
>> - Why do you need next_entry to be rcu pointer? It is only assigned here
>> with entry_lock protection and in init code before action is visible to
>> concurrent users. I don't see any unlocked rcu-protected readers here that
>> could benefit from it.
>> 
>> - Why create dedicated entry_lock instead of using already existing per-
>> action tcf_lock?
>
> Will try to use the tcf_lock for verification.
> The thoughts came from that the timer period arrived then check through the list and then update next time would take much more time.  Action function would be busy when traffic. So use a separate lock here for  
>
>> 
>> > +
>> > +     hrtimer_set_expires(&gact->hitimer, close_time);
>> > +
>> > +     return HRTIMER_RESTART;
>> > +}
>> > +
>> > +static int tcf_gate_act(struct sk_buff *skb, const struct tc_action *a,
>> > +                     struct tcf_result *res) {
>> > +     struct tcf_gate *g = to_gate(a);
>> > +     struct gate_action *gact;
>> > +     int action;
>> > +
>> > +     tcf_lastuse_update(&g->tcf_tm);
>> > +     bstats_cpu_update(this_cpu_ptr(g->common.cpu_bstats), skb);
>> > +
>> > +     action = READ_ONCE(g->tcf_action);
>> > +     rcu_read_lock();
>> 
>> Action fastpath is already rcu read lock protected, you don't need to
>> manually obtain it.
>
> Will be removed.
>
>> 
>> > +     gact = rcu_dereference_bh(g->actg);
>> > +     if (unlikely(gact->current_gate_status & GATE_ACT_PENDING)) {
>> 
>> Can't current_gate_status be concurrently modified by timer callback?
>> This function doesn't use entry_lock to synchronize with timer.
>
> Will try tcf_lock either.
>
>> 
>> > +             rcu_read_unlock();
>> > +             return action;
>> > +     }
>> > +
>> > +     if (!(gact->current_gate_status & GATE_ACT_GATE_OPEN))
>> 
>> ...and here
>> 
>> > +             goto drop;
>> > +
>> > +     if (gact->current_max_octets >= 0) {
>> > +             gact->current_entry_octets += qdisc_pkt_len(skb);
>> > +             if (gact->current_entry_octets >
>> > + gact->current_max_octets) {
>> 
>> here also.
>> 
>> > +
>> > + qstats_overlimit_inc(this_cpu_ptr(g->common.cpu_qstats));
>> 
>> Please use tcf_action_inc_overlimit_qstats() and other wrappers for stats.
>> Otherwise it will crash if user passes TCA_ACT_FLAGS_NO_PERCPU_STATS
>> flag.
>
> The tcf_action_inc_overlimit_qstats() can't show limit counts in tc show command. Is there anything need to do? 

What do you mean? Internally tcf_action_inc_overlimit_qstats() just
calls qstats_overlimit_inc, if cpu_qstats percpu counter is not NULL:

	if (likely(a->cpu_qstats)) {
		qstats_overlimit_inc(this_cpu_ptr(a->cpu_qstats));
		return;
	}

Is there a subtle bug somewhere in this function?

>
>> 
>> > +                     goto drop;
>> > +             }
>> > +     }
>> > +     rcu_read_unlock();
>> > +
>> > +     return action;
>> > +drop:
>> > +     rcu_read_unlock();
>> > +     qstats_drop_inc(this_cpu_ptr(g->common.cpu_qstats));
>> > +     return TC_ACT_SHOT;
>> > +}
>> > +
>> > +static const struct nla_policy entry_policy[TCA_GATE_ENTRY_MAX + 1]
>> = {
>> > +     [TCA_GATE_ENTRY_INDEX]          = { .type = NLA_U32 },
>> > +     [TCA_GATE_ENTRY_GATE]           = { .type = NLA_FLAG },
>> > +     [TCA_GATE_ENTRY_INTERVAL]       = { .type = NLA_U32 },
>> > +     [TCA_GATE_ENTRY_IPV]            = { .type = NLA_S32 },
>> > +     [TCA_GATE_ENTRY_MAX_OCTETS]     = { .type = NLA_S32 },
>> > +};
>> > +
>> > +static const struct nla_policy gate_policy[TCA_GATE_MAX + 1] = {
>> > +     [TCA_GATE_PARMS]                = { .len = sizeof(struct tc_gate),
>> > +                                         .type = NLA_EXACT_LEN },
>> > +     [TCA_GATE_PRIORITY]             = { .type = NLA_S32 },
>> > +     [TCA_GATE_ENTRY_LIST]           = { .type = NLA_NESTED },
>> > +     [TCA_GATE_BASE_TIME]            = { .type = NLA_U64 },
>> > +     [TCA_GATE_CYCLE_TIME]           = { .type = NLA_U64 },
>> > +     [TCA_GATE_CYCLE_TIME_EXT]       = { .type = NLA_U64 },
>> > +     [TCA_GATE_FLAGS]                = { .type = NLA_U32 },
>> > +     [TCA_GATE_CLOCKID]              = { .type = NLA_S32 },
>> > +};
>> > +
>> > +static int fill_gate_entry(struct nlattr **tb, struct tcfg_gate_entry *entry,
>> > +                        struct netlink_ext_ack *extack) {
>> > +     u32 interval = 0;
>> > +
>> > +     entry->gate_state = nla_get_flag(tb[TCA_GATE_ENTRY_GATE]);
>> > +
>> > +     if (tb[TCA_GATE_ENTRY_INTERVAL])
>> > +             interval = nla_get_u32(tb[TCA_GATE_ENTRY_INTERVAL]);
>> > +
>> > +     if (interval == 0) {
>> > +             NL_SET_ERR_MSG(extack, "Invalid interval for schedule entry");
>> > +             return -EINVAL;
>> > +     }
>> > +
>> > +     entry->interval = interval;
>> > +
>> > +     if (tb[TCA_GATE_ENTRY_IPV])
>> > +             entry->ipv = nla_get_s32(tb[TCA_GATE_ENTRY_IPV]);
>> > +     else
>> > +             entry->ipv = -1;
>> > +
>> > +     if (tb[TCA_GATE_ENTRY_MAX_OCTETS])
>> > +             entry->maxoctets =
>> nla_get_s32(tb[TCA_GATE_ENTRY_MAX_OCTETS]);
>> > +     else
>> > +             entry->maxoctets = -1;
>> > +
>> > +     return 0;
>> > +}
>> > +
>> > +static int parse_gate_entry(struct nlattr *n, struct  tcfg_gate_entry
>> *entry,
>> > +                         int index, struct netlink_ext_ack *extack) {
>> > +     struct nlattr *tb[TCA_GATE_ENTRY_MAX + 1] = { };
>> > +     int err;
>> 
>> > +     err = nla_parse_nested(tb, TCA_GATE_ENTRY_MAX, n, entry_policy,
>> extack);
>> > +     if (err < 0) {
>> > +             NL_SET_ERR_MSG(extack, "Could not parse nested entry");
>> > +             return -EINVAL;
>> > +     }
>> > +
>> > +     entry->index = index;
>> > +
>> > +     return fill_gate_entry(tb, entry, extack); }
>> > +
>> > +static int parse_gate_list(struct nlattr *list_attr,
>> > +                        struct tcf_gate_params *sched,
>> > +                        struct netlink_ext_ack *extack) {
>> > +     struct tcfg_gate_entry *entry, *e;
>> > +     struct nlattr *n;
>> > +     int err, rem;
>> > +     int i = 0;
>> > +
>> > +     if (!list_attr)
>> > +             return -EINVAL;
>> > +
>> > +     nla_for_each_nested(n, list_attr, rem) {
>> > +             if (nla_type(n) != TCA_GATE_ONE_ENTRY) {
>> > +                     NL_SET_ERR_MSG(extack, "Attribute isn't type 'entry'");
>> > +                     continue;
>> > +             }
>> > +
>> > +             entry = kzalloc(sizeof(*entry), GFP_KERNEL);
>> > +             if (!entry) {
>> > +                     NL_SET_ERR_MSG(extack, "Not enough memory for entry");
>> > +                     err = -ENOMEM;
>> > +                     goto release_list;
>> > +             }
>> > +
>> > +             err = parse_gate_entry(n, entry, i, extack);
>> > +             if (err < 0) {
>> > +                     kfree(entry);
>> > +                     goto release_list;
>> > +             }
>> > +
>> > +             list_add_tail(&entry->list, &sched->entries);
>> > +             i++;
>> > +     }
>> > +
>> > +     sched->num_entries = i;
>> > +
>> > +     return i;
>> > +
>> > +release_list:
>> > +     list_for_each_entry_safe(entry, e, &sched->entries, list) {
>> > +             list_del(&entry->list);
>> > +             kfree(entry);
>> > +     }
>> > +
>> > +     return err;
>> > +}
>> > +
>> > +static int tcf_gate_init(struct net *net, struct nlattr *nla,
>> > +                      struct nlattr *est, struct tc_action **a,
>> > +                      int ovr, int bind, bool rtnl_held,
>> > +                      struct tcf_proto *tp, u32 flags,
>> > +                      struct netlink_ext_ack *extack) {
>> > +     struct tc_action_net *tn = net_generic(net, gate_net_id);
>> > +     enum tk_offsets tk_offset = TK_OFFS_TAI;
>> > +     struct nlattr *tb[TCA_GATE_MAX + 1];
>> > +     struct tcf_chain *goto_ch = NULL;
>> > +     struct tcfg_gate_entry *next;
>> > +     struct tcf_gate_params *p;
>> > +     struct gate_action *gact;
>> > +     s32 clockid = CLOCK_TAI;
>> > +     struct tc_gate *parm;
>> > +     struct tcf_gate *g;
>> > +     int ret = 0, err;
>> > +     u64 basetime = 0;
>> > +     u32 gflags = 0;
>> > +     s32 prio = -1;
>> > +     ktime_t start;
>> > +     u32 index;
>> > +
>> > +     if (!nla)
>> > +             return -EINVAL;
>> > +
>> > +     err = nla_parse_nested(tb, TCA_GATE_MAX, nla, gate_policy, extack);
>> > +     if (err < 0)
>> > +             return err;
>> > +
>> > +     if (!tb[TCA_GATE_PARMS])
>> > +             return -EINVAL;
>> > +     parm = nla_data(tb[TCA_GATE_PARMS]);
>> > +     index = parm->index;
>> > +     err = tcf_idr_check_alloc(tn, &index, a, bind);
>> > +     if (err < 0)
>> > +             return err;
>> > +
>> > +     if (err && bind)
>> > +             return 0;
>> > +
>> > +     if (!err) {
>> > +             ret = tcf_idr_create_from_flags(tn, index, est, a,
>> > +                                             &act_gate_ops, bind, flags);
>> > +             if (ret) {
>> > +                     tcf_idr_cleanup(tn, index);
>> > +                     return ret;
>> > +             }
>> > +
>> > +             ret = ACT_P_CREATED;
>> > +     } else if (!ovr) {
>> > +             tcf_idr_release(*a, bind);
>> > +             return -EEXIST;
>> > +     }
>> > +
>> > +     if (tb[TCA_GATE_PRIORITY])
>> > +             prio = nla_get_s32(tb[TCA_GATE_PRIORITY]);
>> > +
>> > +     if (tb[TCA_GATE_BASE_TIME])
>> > +             basetime = nla_get_u64(tb[TCA_GATE_BASE_TIME]);
>> > +
>> > +     if (tb[TCA_GATE_FLAGS])
>> > +             gflags = nla_get_u32(tb[TCA_GATE_FLAGS]);
>> > +
>> > +     if (tb[TCA_GATE_CLOCKID]) {
>> > +             clockid = nla_get_s32(tb[TCA_GATE_CLOCKID]);
>> > +             switch (clockid) {
>> > +             case CLOCK_REALTIME:
>> > +                     tk_offset = TK_OFFS_REAL;
>> > +                     break;
>> > +             case CLOCK_MONOTONIC:
>> > +                     tk_offset = TK_OFFS_MAX;
>> > +                     break;
>> > +             case CLOCK_BOOTTIME:
>> > +                     tk_offset = TK_OFFS_BOOT;
>> > +                     break;
>> > +             case CLOCK_TAI:
>> > +                     tk_offset = TK_OFFS_TAI;
>> > +                     break;
>> > +             default:
>> > +                     NL_SET_ERR_MSG(extack, "Invalid 'clockid'");
>> > +                     goto release_idr;
>> > +             }
>> > +     }
>> > +
>> > +     err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
>> > +     if (err < 0)
>> > +             goto release_idr;
>> > +
>> > +     g = to_gate(*a);
>> > +
>> > +     gact = kzalloc(sizeof(*gact), GFP_KERNEL);
>> > +     if (!gact) {
>> > +             err = -ENOMEM;
>> > +             goto put_chain;
>> > +     }
>> > +
>> > +     p = get_gate_param(gact);
>> > +
>> > +     INIT_LIST_HEAD(&p->entries);
>> > +     if (tb[TCA_GATE_ENTRY_LIST]) {
>> > +             err = parse_gate_list(tb[TCA_GATE_ENTRY_LIST], p, extack);
>> > +             if (err < 0)
>> > +                     goto release_mem;
>> > +     }
>> > +
>> > +     if (tb[TCA_GATE_CYCLE_TIME]) {
>> > +             p->tcfg_cycletime = nla_get_u64(tb[TCA_GATE_CYCLE_TIME]);
>> > +     } else {
>> > +             struct tcfg_gate_entry *entry;
>> > +             ktime_t cycle = 0;
>> > +
>> > +             list_for_each_entry(entry, &p->entries, list)
>> > +                     cycle = ktime_add_ns(cycle, entry->interval);
>> > +             p->tcfg_cycletime = cycle;
>> > +     }
>> > +
>> > +     if (tb[TCA_GATE_CYCLE_TIME_EXT])
>> > +             p->tcfg_cycletime_ext =
>> > +                     nla_get_u64(tb[TCA_GATE_CYCLE_TIME_EXT]);
>> > +
>> > +     p->tcfg_priority = prio;
>> > +     p->tcfg_basetime = basetime;
>> > +     p->tcfg_clockid = clockid;
>> > +     p->tcfg_flags = gflags;
>> > +
>> > +     gact->tk_offset = tk_offset;
>> > +     spin_lock_init(&gact->entry_lock);
>> > +     hrtimer_init(&gact->hitimer, clockid, HRTIMER_MODE_ABS);
>> > +     gact->hitimer.function = gate_timer_func;
>> > +
>> > +     err = gate_get_start_time(gact, &start);
>> > +     if (err < 0) {
>> > +             NL_SET_ERR_MSG(extack,
>> > +                            "Internal error: failed get start time");
>> > +             goto release_mem;
>> > +     }
>> > +
>> > +     gact->current_close_time = start;
>> > +     gact->current_gate_status = GATE_ACT_GATE_OPEN |
>> > + GATE_ACT_PENDING;
>> > +
>> > +     next = list_first_entry(&p->entries, struct tcfg_gate_entry, list);
>> > +     rcu_assign_pointer(gact->next_entry, next);
>> > +
>> > +     gate_start_timer(gact, start);
>> > +
>> > +     spin_lock_bh(&g->tcf_lock);
>> > +     goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
>> > +     gact = rcu_replace_pointer(g->actg, gact,
>> > +                                lockdep_is_held(&g->tcf_lock));
>> > +     spin_unlock_bh(&g->tcf_lock);
>> > +
>> > +     if (goto_ch)
>> > +             tcf_chain_put_by_act(goto_ch);
>> > +     if (gact)
>> > +             kfree_rcu(gact, rcu);
>> 
>> This leaks entries. For example, tunnel key action implements
>> tunnel_key_release_params() helper that is used by both init and release
>> code. I guess that would be the best approach here as well.
>> 
>
> Will refer the tunnel action. Thanks for pointing out.
>
>> > +
>> > +     if (ret == ACT_P_CREATED)
>> > +             tcf_idr_insert(tn, *a);
>> > +     return ret;
>> > +
>> > +release_mem:
>> > +     kfree(gact);
>> > +put_chain:
>> > +     if (goto_ch)
>> > +             tcf_chain_put_by_act(goto_ch);
>> > +release_idr:
>> > +     tcf_idr_release(*a, bind);
>> > +     return err;
>> > +}
>> > +
>> > +static void tcf_gate_cleanup(struct tc_action *a) {
>> > +     struct tcf_gate *g = to_gate(a);
>> > +     struct tcfg_gate_entry *entry, *n;
>> > +     struct tcf_gate_params *p;
>> > +     struct gate_action *gact;
>> > +
>> > +     spin_lock_bh(&g->tcf_lock);
>> > +     gact = rcu_dereference_protected(g->actg,
>> > +                                      lockdep_is_held(&g->tcf_lock));
>> > +     hrtimer_cancel(&gact->hitimer);
>> > +
>> > +     p = get_gate_param(gact);
>> > +     list_for_each_entry_safe(entry, n, &p->entries, list) {
>> > +             list_del(&entry->list);
>> > +             kfree(entry);
>> > +     }
>> > +     spin_unlock_bh(&g->tcf_lock);
>> > +
>> > +     kfree_rcu(gact, rcu);
>> > +}
>> > +
>> > +static int dumping_entry(struct sk_buff *skb,
>> > +                      struct tcfg_gate_entry *entry) {
>> > +     struct nlattr *item;
>> > +
>> > +     item = nla_nest_start_noflag(skb, TCA_GATE_ONE_ENTRY);
>> > +     if (!item)
>> > +             return -ENOSPC;
>> > +
>> > +     if (nla_put_u32(skb, TCA_GATE_ENTRY_INDEX, entry->index))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (entry->gate_state && nla_put_flag(skb, TCA_GATE_ENTRY_GATE))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_u32(skb, TCA_GATE_ENTRY_INTERVAL, entry->interval))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_s32(skb, TCA_GATE_ENTRY_MAX_OCTETS, entry-
>> >maxoctets))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_s32(skb, TCA_GATE_ENTRY_IPV, entry->ipv))
>> > +             goto nla_put_failure;
>> > +
>> > +     return nla_nest_end(skb, item);
>> > +
>> > +nla_put_failure:
>> > +     nla_nest_cancel(skb, item);
>> > +     return -1;
>> > +}
>> > +
>> > +static int tcf_gate_dump(struct sk_buff *skb, struct tc_action *a,
>> > +                      int bind, int ref) {
>> > +     unsigned char *b = skb_tail_pointer(skb);
>> > +     struct tcf_gate *g = to_gate(a);
>> > +     struct tc_gate opt = {
>> > +             .index    = g->tcf_index,
>> > +             .refcnt   = refcount_read(&g->tcf_refcnt) - ref,
>> > +             .bindcnt  = atomic_read(&g->tcf_bindcnt) - bind,
>> > +     };
>> > +     struct tcfg_gate_entry *entry;
>> > +     struct gate_action *gact;
>> > +     struct tcf_gate_params *p;
>> > +     struct nlattr *entry_list;
>> > +     struct tcf_t t;
>> > +
>> > +     spin_lock_bh(&g->tcf_lock);
>> > +     opt.action = g->tcf_action;
>> > +     gact = rcu_dereference_protected(g->actg,
>> > +                                      lockdep_is_held(&g->tcf_lock));
>> > +
>> > +     p = get_gate_param(gact);
>> > +
>> > +     if (nla_put(skb, TCA_GATE_PARMS, sizeof(opt), &opt))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_u64_64bit(skb, TCA_GATE_BASE_TIME,
>> > +                           p->tcfg_basetime, TCA_GATE_PAD))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_u64_64bit(skb, TCA_GATE_CYCLE_TIME,
>> > +                           p->tcfg_cycletime, TCA_GATE_PAD))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_u64_64bit(skb, TCA_GATE_CYCLE_TIME_EXT,
>> > +                           p->tcfg_cycletime_ext, TCA_GATE_PAD))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_s32(skb, TCA_GATE_CLOCKID, p->tcfg_clockid))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_u32(skb, TCA_GATE_FLAGS, p->tcfg_flags))
>> > +             goto nla_put_failure;
>> > +
>> > +     if (nla_put_s32(skb, TCA_GATE_PRIORITY, p->tcfg_priority))
>> > +             goto nla_put_failure;
>> > +
>> > +     entry_list = nla_nest_start_noflag(skb, TCA_GATE_ENTRY_LIST);
>> > +     if (!entry_list)
>> > +             goto nla_put_failure;
>> > +
>> > +     list_for_each_entry(entry, &p->entries, list) {
>> > +             if (dumping_entry(skb, entry) < 0)
>> > +                     goto nla_put_failure;
>> > +     }
>> > +
>> > +     nla_nest_end(skb, entry_list);
>> > +
>> > +     tcf_tm_dump(&t, &g->tcf_tm);
>> > +     if (nla_put_64bit(skb, TCA_GATE_TM, sizeof(t), &t, TCA_GATE_PAD))
>> > +             goto nla_put_failure;
>> > +     spin_unlock_bh(&g->tcf_lock);
>> > +
>> > +     return skb->len;
>> > +
>> > +nla_put_failure:
>> > +     spin_unlock_bh(&g->tcf_lock);
>> > +     nlmsg_trim(skb, b);
>> > +     return -1;
>> > +}
>> > +
>> > +static int tcf_gate_walker(struct net *net, struct sk_buff *skb,
>> > +                        struct netlink_callback *cb, int type,
>> > +                        const struct tc_action_ops *ops,
>> > +                        struct netlink_ext_ack *extack) {
>> > +     struct tc_action_net *tn = net_generic(net, gate_net_id);
>> > +
>> > +     return tcf_generic_walker(tn, skb, cb, type, ops, extack); }
>> > +
>> > +static void tcf_gate_stats_update(struct tc_action *a, u64 bytes, u32
>> packets,
>> > +                               u64 lastuse, bool hw) {
>> > +     struct tcf_gate *g = to_gate(a);
>> > +     struct tcf_t *tm = &g->tcf_tm;
>> > +
>> > +     tcf_action_update_stats(a, bytes, packets, false, hw);
>> > +     tm->lastuse = max_t(u64, tm->lastuse, lastuse); }
>> > +
>> > +static int tcf_gate_search(struct net *net, struct tc_action **a, u32
>> > +index) {
>> > +     struct tc_action_net *tn = net_generic(net, gate_net_id);
>> > +
>> > +     return tcf_idr_search(tn, a, index); }
>> > +
>> > +static size_t tcf_gate_get_fill_size(const struct tc_action *act) {
>> > +     return nla_total_size(sizeof(struct tc_gate)); }
>> > +
>> > +static struct tc_action_ops act_gate_ops = {
>> > +     .kind           =       "gate",
>> > +     .id             =       TCA_ID_GATE,
>> > +     .owner          =       THIS_MODULE,
>> > +     .act            =       tcf_gate_act,
>> > +     .dump           =       tcf_gate_dump,
>> > +     .init           =       tcf_gate_init,
>> > +     .cleanup        =       tcf_gate_cleanup,
>> > +     .walk           =       tcf_gate_walker,
>> > +     .stats_update   =       tcf_gate_stats_update,
>> > +     .get_fill_size  =       tcf_gate_get_fill_size,
>> > +     .lookup         =       tcf_gate_search,
>> > +     .size           =       sizeof(struct gate_action),
>> > +};
>> > +
>> > +static __net_init int gate_init_net(struct net *net) {
>> > +     struct tc_action_net *tn = net_generic(net, gate_net_id);
>> > +
>> > +     return tc_action_net_init(net, tn, &act_gate_ops); }
>> > +
>> > +static void __net_exit gate_exit_net(struct list_head *net_list) {
>> > +     tc_action_net_exit(net_list, gate_net_id); }
>> > +
>> > +static struct pernet_operations gate_net_ops = {
>> > +     .init = gate_init_net,
>> > +     .exit_batch = gate_exit_net,
>> > +     .id   = &gate_net_id,
>> > +     .size = sizeof(struct tc_action_net), };
>> > +
>> > +static int __init gate_init_module(void) {
>> > +     return tcf_register_action(&act_gate_ops, &gate_net_ops); }
>> > +
>> > +static void __exit gate_cleanup_module(void) {
>> > +     tcf_unregister_action(&act_gate_ops, &gate_net_ops); }
>> > +
>> > +module_init(gate_init_module);
>> > +module_exit(gate_cleanup_module);
>> > +MODULE_LICENSE("GPL v2");
>
> Thanks a lot.
>
> Br,
> Po Liu