Re: [PATCH v3 02/11] net: sched: change type of reference and bind counters

Marcelo Ricardo Leitner
2018-05-28T21:37:57Z

On Mon, May 28, 2018 at 12:17:20AM +0300, Vlad Buslov wrote:
> Change type of action reference counter to refcount_t.
>
> Change type of action bind counter to atomic_t.
> This type is used to allow decrementing bind counter without testing
> for 0 result.
>
> Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
> Signed-off-by: Jiri Pirko <jiri@mellanox.com>

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

> ---
> include/net/act_api.h | 5 +++--
> net/sched/act_api.c | 32 ++++++++++++++++++++++----------
> net/sched/act_bpf.c | 4 ++--
> net/sched/act_connmark.c | 4 ++--
> net/sched/act_csum.c | 4 ++--
> net/sched/act_gact.c | 4 ++--
> net/sched/act_ife.c | 4 ++--
> net/sched/act_ipt.c | 4 ++--
> net/sched/act_mirred.c | 4 ++--
> net/sched/act_nat.c | 4 ++--
> net/sched/act_pedit.c | 4 ++--
> net/sched/act_police.c | 4 ++--
> net/sched/act_sample.c | 4 ++--
> net/sched/act_simple.c | 4 ++--
> net/sched/act_skbedit.c | 4 ++--
> net/sched/act_skbmod.c | 4 ++--
> net/sched/act_tunnel_key.c | 4 ++--
> net/sched/act_vlan.c | 4 ++--
> 18 files changed, 57 insertions(+), 44 deletions(-)
>
> diff --git a/include/net/act_api.h b/include/net/act_api.h
> index f7b59ef7303d..e634014605cb 100644
> --- a/include/net/act_api.h
> +++ b/include/net/act_api.h
> @@ -6,6 +6,7 @@
> * Public action API for classifiers/qdiscs
> */
>
> +#include <linux/refcount.h>
> #include <net/sch_generic.h>
> #include <net/pkt_sched.h>
> #include <net/net_namespace.h>
> @@ -26,8 +27,8 @@ struct tc_action {
> struct tcf_idrinfo *idrinfo;
>
> u32 tcfa_index;
> - int tcfa_refcnt;
> - int tcfa_bindcnt;
> + refcount_t tcfa_refcnt;
> + atomic_t tcfa_bindcnt;
> u32 tcfa_capab;
> int tcfa_action;
> struct tcf_t tcfa_tm;
> diff --git a/net/sched/act_api.c b/net/sched/act_api.c
> index 02670c7489e3..4f064ecab882 100644
> --- a/net/sched/act_api.c
> +++ b/net/sched/act_api.c
> @@ -105,14 +105,26 @@ int __tcf_idr_release(struct tc_action *p, bool bind, bool strict)
>
> ASSERT_RTNL();
>
> + /* Release with strict==1 and bind==0 is only called through act API
> + * interface (classifiers always bind). Only case when action with
> + * positive reference count and zero bind count can exist is when it was
> + * also created with act API (unbinding last classifier will destroy the
> + * action if it was created by classifier). So only case when bind count
> + * can be changed after initial check is when unbound action is
> + * destroyed by act API while classifier binds to action with same id
> + * concurrently. This result either creation of new action(same behavior
> + * as before), or reusing existing action if concurrent process
> + * increments reference count before action is deleted. Both scenarios
> + * are acceptable.
> + */
> if (p) {
> if (bind)
> - p->tcfa_bindcnt--;
> - else if (strict && p->tcfa_bindcnt > 0)
> + atomic_dec(&p->tcfa_bindcnt);
> + else if (strict && atomic_read(&p->tcfa_bindcnt) > 0)
> return -EPERM;
>
> - p->tcfa_refcnt--;
> - if (p->tcfa_bindcnt <= 0 && p->tcfa_refcnt <= 0) {
> + if (atomic_read(&p->tcfa_bindcnt) <= 0 &&
> + refcount_dec_and_test(&p->tcfa_refcnt)) {
> if (p->ops->cleanup)
> p->ops->cleanup(p);
> tcf_idr_remove(p->idrinfo, p);
> @@ -304,8 +316,8 @@ bool tcf_idr_check(struct tc_action_net *tn, u32 index, struct tc_action **a,
>
> if (index && p) {
> if (bind)
> - p->tcfa_bindcnt++;
> - p->tcfa_refcnt++;
> + atomic_inc(&p->tcfa_bindcnt);
> + refcount_inc(&p->tcfa_refcnt);
> *a = p;
> return true;
> }
> @@ -324,9 +336,9 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
>
> if (unlikely(!p))
> return -ENOMEM;
> - p->tcfa_refcnt = 1;
> + refcount_set(&p->tcfa_refcnt, 1);
> if (bind)
> - p->tcfa_bindcnt = 1;
> + atomic_set(&p->tcfa_bindcnt, 1);
>
> if (cpustats) {
> p->cpu_bstats = netdev_alloc_pcpu_stats(struct gnet_stats_basic_cpu);
> @@ -782,7 +794,7 @@ static void cleanup_a(struct list_head *actions, int ovr)
> return;
>
> list_for_each_entry(a, actions, list)
> - a->tcfa_refcnt--;
> + refcount_dec(&a->tcfa_refcnt);
> }
>
> int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
> @@ -810,7 +822,7 @@ int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
> act->order = i;
> sz += tcf_action_fill_size(act);
> if (ovr)
> - act->tcfa_refcnt++;
> + refcount_inc(&act->tcfa_refcnt);
> list_add_tail(&act->list, actions);
> }
>
> diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
> index 18089c02e557..15a2a53cbde1 100644
> --- a/net/sched/act_bpf.c
> +++ b/net/sched/act_bpf.c
> @@ -141,8 +141,8 @@ static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act,
> struct tcf_bpf *prog = to_bpf(act);
> struct tc_act_bpf opt = {
> .index = prog->tcf_index,
> - .refcnt = prog->tcf_refcnt - ref,
> - .bindcnt = prog->tcf_bindcnt - bind,
> + .refcnt = refcount_read(&prog->tcf_refcnt) - ref,
> + .bindcnt = atomic_read(&prog->tcf_bindcnt) - bind,
> .action = prog->tcf_action,
> };
> struct tcf_t tm;
> diff --git a/net/sched/act_connmark.c b/net/sched/act_connmark.c
> index e4b880fa51fe..188865034f9a 100644
> --- a/net/sched/act_connmark.c
> +++ b/net/sched/act_connmark.c
> @@ -154,8 +154,8 @@ static inline int tcf_connmark_dump(struct sk_buff *skb, struct tc_action *a,
>
> struct tc_connmark opt = {
> .index = ci->tcf_index,
> - .refcnt = ci->tcf_refcnt - ref,
> - .bindcnt = ci->tcf_bindcnt - bind,
> + .refcnt = refcount_read(&ci->tcf_refcnt) - ref,
> + .bindcnt = atomic_read(&ci->tcf_bindcnt) - bind,
> .action = ci->tcf_action,
> .zone = ci->zone,
> };
> diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c
> index 526a8e491626..da865f7b390a 100644
> --- a/net/sched/act_csum.c
> +++ b/net/sched/act_csum.c
> @@ -597,8 +597,8 @@ static int tcf_csum_dump(struct sk_buff *skb, struct tc_action *a, int bind,
> struct tcf_csum_params *params;
> struct tc_csum opt = {
> .index = p->tcf_index,
> - .refcnt = p->tcf_refcnt - ref,
> - .bindcnt = p->tcf_bindcnt - bind,
> + .refcnt = refcount_read(&p->tcf_refcnt) - ref,
> + .bindcnt = atomic_read(&p->tcf_bindcnt) - bind,
> };
> struct tcf_t t;
>
> diff --git a/net/sched/act_gact.c b/net/sched/act_gact.c
> index 4dc4f153cad8..ca83debd5a70 100644
> --- a/net/sched/act_gact.c
> +++ b/net/sched/act_gact.c
> @@ -169,8 +169,8 @@ static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a,
> struct tcf_gact *gact = to_gact(a);
> struct tc_gact opt = {
> .index = gact->tcf_index,
> - .refcnt = gact->tcf_refcnt - ref,
> - .bindcnt = gact->tcf_bindcnt - bind,
> + .refcnt = refcount_read(&gact->tcf_refcnt) - ref,
> + .bindcnt = atomic_read(&gact->tcf_bindcnt) - bind,
> .action = gact->tcf_action,
> };
> struct tcf_t t;
> diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c
> index 8527cfdc446d..706e84d6f912 100644
> --- a/net/sched/act_ife.c
> +++ b/net/sched/act_ife.c
> @@ -598,8 +598,8 @@ static int tcf_ife_dump(struct sk_buff *skb, struct tc_action *a, int bind,
> struct tcf_ife_params *p = rtnl_dereference(ife->params);
> struct tc_ife opt = {
> .index = ife->tcf_index,
> - .refcnt = ife->tcf_refcnt - ref,
> - .bindcnt = ife->tcf_bindcnt - bind,
> + .refcnt = refcount_read(&ife->tcf_refcnt) - ref,
> + .bindcnt = atomic_read(&ife->tcf_bindcnt) - bind,
> .action = ife->tcf_action,
> .flags = p->flags,
> };
> diff --git a/net/sched/act_ipt.c b/net/sched/act_ipt.c
> index 14c312d7908f..7bce88dc11c9 100644
> --- a/net/sched/act_ipt.c
> +++ b/net/sched/act_ipt.c
> @@ -280,8 +280,8 @@ static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind,
> if (unlikely(!t))
> goto nla_put_failure;
>
> - c.bindcnt = ipt->tcf_bindcnt - bind;
> - c.refcnt = ipt->tcf_refcnt - ref;
> + c.bindcnt = atomic_read(&ipt->tcf_bindcnt) - bind;
> + c.refcnt = refcount_read(&ipt->tcf_refcnt) - ref;
> strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
>
> if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
> diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
> index fd34015331ab..82a8bdd67c47 100644
> --- a/net/sched/act_mirred.c
> +++ b/net/sched/act_mirred.c
> @@ -250,8 +250,8 @@ static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind,
> struct tc_mirred opt = {
> .index = m->tcf_index,
> .action = m->tcf_action,
> - .refcnt = m->tcf_refcnt - ref,
> - .bindcnt = m->tcf_bindcnt - bind,
> + .refcnt = refcount_read(&m->tcf_refcnt) - ref,
> + .bindcnt = atomic_read(&m->tcf_bindcnt) - bind,
> .eaction = m->tcfm_eaction,
> .ifindex = dev ? dev->ifindex : 0,
> };
> diff --git a/net/sched/act_nat.c b/net/sched/act_nat.c
> index 4b5848b6c252..457c2ae3de46 100644
> --- a/net/sched/act_nat.c
> +++ b/net/sched/act_nat.c
> @@ -257,8 +257,8 @@ static int tcf_nat_dump(struct sk_buff *skb, struct tc_action *a,
>
> .index = p->tcf_index,
> .action = p->tcf_action,
> - .refcnt = p->tcf_refcnt - ref,
> - .bindcnt = p->tcf_bindcnt - bind,
> + .refcnt = refcount_read(&p->tcf_refcnt) - ref,
> + .bindcnt = atomic_read(&p->tcf_bindcnt) - bind,
> };
> struct tcf_t t;
>
> diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
> index 8a925c72db5f..0102b2935fdb 100644
> --- a/net/sched/act_pedit.c
> +++ b/net/sched/act_pedit.c
> @@ -391,8 +391,8 @@ static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
> opt->nkeys = p->tcfp_nkeys;
> opt->flags = p->tcfp_flags;
> opt->action = p->tcf_action;
> - opt->refcnt = p->tcf_refcnt - ref;
> - opt->bindcnt = p->tcf_bindcnt - bind;
> + opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
> + opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
>
> if (p->tcfp_keys_ex) {
> tcf_pedit_key_ex_dump(skb, p->tcfp_keys_ex, p->tcfp_nkeys);
> diff --git a/net/sched/act_police.c b/net/sched/act_police.c
> index 4e72bc2a0dfb..a789b8060968 100644
> --- a/net/sched/act_police.c
> +++ b/net/sched/act_police.c
> @@ -274,8 +274,8 @@ static int tcf_act_police_dump(struct sk_buff *skb, struct tc_action *a,
> .action = police->tcf_action,
> .mtu = police->tcfp_mtu,
> .burst = PSCHED_NS2TICKS(police->tcfp_burst),
> - .refcnt = police->tcf_refcnt - ref,
> - .bindcnt = police->tcf_bindcnt - bind,
> + .refcnt = refcount_read(&police->tcf_refcnt) - ref,
> + .bindcnt = atomic_read(&police->tcf_bindcnt) - bind,
> };
> struct tcf_t t;
>
> diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c
> index 5db358497c9e..4a46978db092 100644
> --- a/net/sched/act_sample.c
> +++ b/net/sched/act_sample.c
> @@ -173,8 +173,8 @@ static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a,
> struct tc_sample opt = {
> .index = s->tcf_index,
> .action = s->tcf_action,
> - .refcnt = s->tcf_refcnt - ref,
> - .bindcnt = s->tcf_bindcnt - bind,
> + .refcnt = refcount_read(&s->tcf_refcnt) - ref,
> + .bindcnt = atomic_read(&s->tcf_bindcnt) - bind,
> };
> struct tcf_t t;
>
> diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c
> index 9618b4a83cee..95d5985b8d67 100644
> --- a/net/sched/act_simple.c
> +++ b/net/sched/act_simple.c
> @@ -148,8 +148,8 @@ static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
> struct tcf_defact *d = to_defact(a);
> struct tc_defact opt = {
> .index = d->tcf_index,
> - .refcnt = d->tcf_refcnt - ref,
> - .bindcnt = d->tcf_bindcnt - bind,
> + .refcnt = refcount_read(&d->tcf_refcnt) - ref,
> + .bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
> .action = d->tcf_action,
> };
> struct tcf_t t;
> diff --git a/net/sched/act_skbedit.c b/net/sched/act_skbedit.c
> index 6138d1d71900..d418ec3b0ab9 100644
> --- a/net/sched/act_skbedit.c
> +++ b/net/sched/act_skbedit.c
> @@ -173,8 +173,8 @@ static int tcf_skbedit_dump(struct sk_buff *skb, struct tc_action *a,
> struct tcf_skbedit *d = to_skbedit(a);
> struct tc_skbedit opt = {
> .index = d->tcf_index,
> - .refcnt = d->tcf_refcnt - ref,
> - .bindcnt = d->tcf_bindcnt - bind,
> + .refcnt = refcount_read(&d->tcf_refcnt) - ref,
> + .bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
> .action = d->tcf_action,
> };
> struct tcf_t t;
> diff --git a/net/sched/act_skbmod.c b/net/sched/act_skbmod.c
> index ad050d7d4b46..ff90d720eda3 100644
> --- a/net/sched/act_skbmod.c
> +++ b/net/sched/act_skbmod.c
> @@ -205,8 +205,8 @@ static int tcf_skbmod_dump(struct sk_buff *skb, struct tc_action *a,
> struct tcf_skbmod_params *p = rtnl_dereference(d->skbmod_p);
> struct tc_skbmod opt = {
> .index = d->tcf_index,
> - .refcnt = d->tcf_refcnt - ref,
> - .bindcnt = d->tcf_bindcnt - bind,
> + .refcnt = refcount_read(&d->tcf_refcnt) - ref,
> + .bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
> .action = d->tcf_action,
> };
> struct tcf_t t;
> diff --git a/net/sched/act_tunnel_key.c b/net/sched/act_tunnel_key.c
> index 626dac81a48a..c6e50695414b 100644
> --- a/net/sched/act_tunnel_key.c
> +++ b/net/sched/act_tunnel_key.c
> @@ -252,8 +252,8 @@ static int tunnel_key_dump(struct sk_buff *skb, struct tc_action *a,
> struct tcf_tunnel_key_params *params;
> struct tc_tunnel_key opt = {
> .index = t->tcf_index,
> - .refcnt = t->tcf_refcnt - ref,
> - .bindcnt = t->tcf_bindcnt - bind,
> + .refcnt = refcount_read(&t->tcf_refcnt) - ref,
> + .bindcnt = atomic_read(&t->tcf_bindcnt) - bind,
> };
> struct tcf_t tm;
>
> diff --git a/net/sched/act_vlan.c b/net/sched/act_vlan.c
> index 853604685965..8dda78473004 100644
> --- a/net/sched/act_vlan.c
> +++ b/net/sched/act_vlan.c
> @@ -237,8 +237,8 @@ static int tcf_vlan_dump(struct sk_buff *skb, struct tc_action *a,
> struct tcf_vlan_params *p = rtnl_dereference(v->vlan_p);
> struct tc_vlan opt = {
> .index = v->tcf_index,
> - .refcnt = v->tcf_refcnt - ref,
> - .bindcnt = v->tcf_bindcnt - bind,
> + .refcnt = refcount_read(&v->tcf_refcnt) - ref,
> + .bindcnt = atomic_read(&v->tcf_bindcnt) - bind,
> .action = v->tcf_action,
> .v_action = p->tcfv_action,
> };
> --
> 2.7.5
>