From eec94fdb04806790c7b7e6ea347820064cc6d467 Mon Sep 17 00:00:00 2001
From: Vlad Buslov <vladbu@mellanox.com>
Date: Thu, 5 Jul 2018 17:24:23 +0300
Subject: [PATCH 01/11] net: sched: use rcu for action cookie update

Implement functions to atomically update and free action cookie
using rcu mechanism.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/net/act_api.h |  2 +-
 include/net/pkt_cls.h |  1 +
 net/sched/act_api.c   | 44 +++++++++++++++++++++++++++++--------------
 3 files changed, 32 insertions(+), 15 deletions(-)

diff --git a/include/net/act_api.h b/include/net/act_api.h
index 5ff11adbe2a6..ffc3ef321776 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -37,7 +37,7 @@ struct tc_action {
 	spinlock_t			tcfa_lock;
 	struct gnet_stats_basic_cpu __percpu *cpu_bstats;
 	struct gnet_stats_queue __percpu *cpu_qstats;
-	struct tc_cookie	*act_cookie;
+	struct tc_cookie	__rcu *act_cookie;
 	struct tcf_chain	*goto_chain;
 };
 #define tcf_index	common.tcfa_index
diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index 6641584b27f1..2081e4219f81 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -781,6 +781,7 @@ struct tc_mqprio_qopt_offload {
 struct tc_cookie {
 	u8  *data;
 	u32 len;
+	struct rcu_head rcu;
 };
 
 struct tc_qopt_offload_stats {
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 3f4cf930f809..02670c7489e3 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -55,6 +55,24 @@ static void tcf_action_goto_chain_exec(const struct tc_action *a,
 	res->goto_tp = rcu_dereference_bh(chain->filter_chain);
 }
 
+static void tcf_free_cookie_rcu(struct rcu_head *p)
+{
+	struct tc_cookie *cookie = container_of(p, struct tc_cookie, rcu);
+
+	kfree(cookie->data);
+	kfree(cookie);
+}
+
+static void tcf_set_action_cookie(struct tc_cookie __rcu **old_cookie,
+				  struct tc_cookie *new_cookie)
+{
+	struct tc_cookie *old;
+
+	old = xchg(old_cookie, new_cookie);
+	if (old)
+		call_rcu(&old->rcu, tcf_free_cookie_rcu);
+}
+
 /* XXX: For standalone actions, we don't need a RCU grace period either, because
  * actions are always connected to filters and filters are already destroyed in
  * RCU callbacks, so after a RCU grace period actions are already disconnected
@@ -65,10 +83,7 @@ static void free_tcf(struct tc_action *p)
 	free_percpu(p->cpu_bstats);
 	free_percpu(p->cpu_qstats);
 
-	if (p->act_cookie) {
-		kfree(p->act_cookie->data);
-		kfree(p->act_cookie);
-	}
+	tcf_set_action_cookie(&p->act_cookie, NULL);
 	if (p->goto_chain)
 		tcf_action_goto_chain_fini(p);
 
@@ -567,16 +582,22 @@ tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 	int err = -EINVAL;
 	unsigned char *b = skb_tail_pointer(skb);
 	struct nlattr *nest;
+	struct tc_cookie *cookie;
 
 	if (nla_put_string(skb, TCA_KIND, a->ops->kind))
 		goto nla_put_failure;
 	if (tcf_action_copy_stats(skb, a, 0))
 		goto nla_put_failure;
-	if (a->act_cookie) {
-		if (nla_put(skb, TCA_ACT_COOKIE, a->act_cookie->len,
-			    a->act_cookie->data))
+
+	rcu_read_lock();
+	cookie = rcu_dereference(a->act_cookie);
+	if (cookie) {
+		if (nla_put(skb, TCA_ACT_COOKIE, cookie->len, cookie->data)) {
+			rcu_read_unlock();
 			goto nla_put_failure;
+		}
 	}
+	rcu_read_unlock();
 
 	nest = nla_nest_start(skb, TCA_OPTIONS);
 	if (nest == NULL)
@@ -719,13 +740,8 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp,
 	if (err < 0)
 		goto err_mod;
 
-	if (name == NULL && tb[TCA_ACT_COOKIE]) {
-		if (a->act_cookie) {
-			kfree(a->act_cookie->data);
-			kfree(a->act_cookie);
-		}
-		a->act_cookie = cookie;
-	}
+	if (!name && tb[TCA_ACT_COOKIE])
+		tcf_set_action_cookie(&a->act_cookie, cookie);
 
 	/* module count goes up only when brand new policy is created
 	 * if it exists and is only bound to in a_o->init() then

From 036bb44327f50273e85ee4a2c9b56eebce1c0838 Mon Sep 17 00:00:00 2001
From: Vlad Buslov <vladbu@mellanox.com>
Date: Thu, 5 Jul 2018 17:24:24 +0300
Subject: [PATCH 02/11] net: sched: change type of reference and bind counters

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.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 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 ffc3ef321776..2759226527a2 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 20d7d36b2fc9..3536a23f46b5 100644
--- a/net/sched/act_ife.c
+++ b/net/sched/act_ife.c
@@ -596,8 +596,8 @@ 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 e43aef28fdac..889690e0ec39 100644
--- a/net/sched/act_pedit.c
+++ b/net/sched/act_pedit.c
@@ -409,8 +409,8 @@ 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 98c4afe7c15b..c3a761097b01 100644
--- a/net/sched/act_simple.c
+++ b/net/sched/act_simple.c
@@ -145,8 +145,8 @@ 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 dfaf5d8028dd..cfd20d3d2ca9 100644
--- a/net/sched/act_skbedit.c
+++ b/net/sched/act_skbedit.c
@@ -208,8 +208,8 @@ 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 ea203e386a92..2354f07eba15 100644
--- a/net/sched/act_tunnel_key.c
+++ b/net/sched/act_tunnel_key.c
@@ -474,8 +474,8 @@ 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 1fb39e1f9d07..799e3deb44ac 100644
--- a/net/sched/act_vlan.c
+++ b/net/sched/act_vlan.c
@@ -239,8 +239,8 @@ 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,
 	};

From 789871bb2a0381425b106d2a995bde1460d35a34 Mon Sep 17 00:00:00 2001
From: Vlad Buslov <vladbu@mellanox.com>
Date: Thu, 5 Jul 2018 17:24:25 +0300
Subject: [PATCH 03/11] net: sched: implement unlocked action init API

Add additional 'rtnl_held' argument to act API init functions. It is
required to implement actions that need to release rtnl lock before loading
kernel module and reacquire if afterwards.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/net/act_api.h      |  6 ++++--
 net/sched/act_api.c        | 18 +++++++++++-------
 net/sched/act_bpf.c        |  3 ++-
 net/sched/act_connmark.c   |  2 +-
 net/sched/act_csum.c       |  3 ++-
 net/sched/act_gact.c       |  3 ++-
 net/sched/act_ife.c        |  3 ++-
 net/sched/act_ipt.c        |  6 ++++--
 net/sched/act_mirred.c     |  5 +++--
 net/sched/act_nat.c        |  2 +-
 net/sched/act_pedit.c      |  3 ++-
 net/sched/act_police.c     |  2 +-
 net/sched/act_sample.c     |  3 ++-
 net/sched/act_simple.c     |  3 ++-
 net/sched/act_skbedit.c    |  3 ++-
 net/sched/act_skbmod.c     |  3 ++-
 net/sched/act_tunnel_key.c |  3 ++-
 net/sched/act_vlan.c       |  3 ++-
 net/sched/cls_api.c        |  5 +++--
 19 files changed, 50 insertions(+), 29 deletions(-)

diff --git a/include/net/act_api.h b/include/net/act_api.h
index 2759226527a2..27823f4e24c4 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -92,7 +92,8 @@ struct tc_action_ops {
 			  struct netlink_ext_ack *extack);
 	int     (*init)(struct net *net, struct nlattr *nla,
 			struct nlattr *est, struct tc_action **act, int ovr,
-			int bind, struct netlink_ext_ack *extack);
+			int bind, bool rtnl_held,
+			struct netlink_ext_ack *extack);
 	int     (*walk)(struct net *, struct sk_buff *,
 			struct netlink_callback *, int,
 			const struct tc_action_ops *,
@@ -168,10 +169,11 @@ int tcf_action_exec(struct sk_buff *skb, struct tc_action **actions,
 int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
 		    struct nlattr *est, char *name, int ovr, int bind,
 		    struct list_head *actions, size_t *attr_size,
-		    struct netlink_ext_ack *extack);
+		    bool rtnl_held, struct netlink_ext_ack *extack);
 struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp,
 				    struct nlattr *nla, struct nlattr *est,
 				    char *name, int ovr, int bind,
+				    bool rtnl_held,
 				    struct netlink_ext_ack *extack);
 int tcf_action_dump(struct sk_buff *skb, struct list_head *, int, int);
 int tcf_action_dump_old(struct sk_buff *skb, struct tc_action *a, int, int);
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 4f064ecab882..256b0c93916c 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -671,6 +671,7 @@ static struct tc_cookie *nla_memdup_cookie(struct nlattr **tb)
 struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp,
 				    struct nlattr *nla, struct nlattr *est,
 				    char *name, int ovr, int bind,
+				    bool rtnl_held,
 				    struct netlink_ext_ack *extack)
 {
 	struct tc_action *a;
@@ -721,9 +722,11 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp,
 	a_o = tc_lookup_action_n(act_name);
 	if (a_o == NULL) {
 #ifdef CONFIG_MODULES
-		rtnl_unlock();
+		if (rtnl_held)
+			rtnl_unlock();
 		request_module("act_%s", act_name);
-		rtnl_lock();
+		if (rtnl_held)
+			rtnl_lock();
 
 		a_o = tc_lookup_action_n(act_name);
 
@@ -746,9 +749,10 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp,
 	/* backward compatibility for policer */
 	if (name == NULL)
 		err = a_o->init(net, tb[TCA_ACT_OPTIONS], est, &a, ovr, bind,
-				extack);
+				rtnl_held, extack);
 	else
-		err = a_o->init(net, nla, est, &a, ovr, bind, extack);
+		err = a_o->init(net, nla, est, &a, ovr, bind, rtnl_held,
+				extack);
 	if (err < 0)
 		goto err_mod;
 
@@ -800,7 +804,7 @@ static void cleanup_a(struct list_head *actions, int ovr)
 int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
 		    struct nlattr *est, char *name, int ovr, int bind,
 		    struct list_head *actions, size_t *attr_size,
-		    struct netlink_ext_ack *extack)
+		    bool rtnl_held, struct netlink_ext_ack *extack)
 {
 	struct nlattr *tb[TCA_ACT_MAX_PRIO + 1];
 	struct tc_action *act;
@@ -814,7 +818,7 @@ int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
 
 	for (i = 1; i <= TCA_ACT_MAX_PRIO && tb[i]; i++) {
 		act = tcf_action_init_1(net, tp, tb[i], est, name, ovr, bind,
-					extack);
+					rtnl_held, extack);
 		if (IS_ERR(act)) {
 			err = PTR_ERR(act);
 			goto err;
@@ -1173,7 +1177,7 @@ static int tcf_action_add(struct net *net, struct nlattr *nla,
 	LIST_HEAD(actions);
 
 	ret = tcf_action_init(net, NULL, nla, NULL, NULL, ovr, 0, &actions,
-			      &attr_size, extack);
+			      &attr_size, true, extack);
 	if (ret)
 		return ret;
 
diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
index 15a2a53cbde1..8ebf40a3506c 100644
--- a/net/sched/act_bpf.c
+++ b/net/sched/act_bpf.c
@@ -276,7 +276,8 @@ static void tcf_bpf_prog_fill_cfg(const struct tcf_bpf *prog,
 
 static int tcf_bpf_init(struct net *net, struct nlattr *nla,
 			struct nlattr *est, struct tc_action **act,
-			int replace, int bind, struct netlink_ext_ack *extack)
+			int replace, int bind, bool rtnl_held,
+			struct netlink_ext_ack *extack)
 {
 	struct tc_action_net *tn = net_generic(net, bpf_net_id);
 	struct nlattr *tb[TCA_ACT_BPF_MAX + 1];
diff --git a/net/sched/act_connmark.c b/net/sched/act_connmark.c
index 188865034f9a..e3787aa0025a 100644
--- a/net/sched/act_connmark.c
+++ b/net/sched/act_connmark.c
@@ -96,7 +96,7 @@ static const struct nla_policy connmark_policy[TCA_CONNMARK_MAX + 1] = {
 
 static int tcf_connmark_init(struct net *net, struct nlattr *nla,
 			     struct nlattr *est, struct tc_action **a,
-			     int ovr, int bind,
+			     int ovr, int bind, bool rtnl_held,
 			     struct netlink_ext_ack *extack)
 {
 	struct tc_action_net *tn = net_generic(net, connmark_net_id);
diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c
index da865f7b390a..334261943f9f 100644
--- a/net/sched/act_csum.c
+++ b/net/sched/act_csum.c
@@ -46,7 +46,8 @@ static struct tc_action_ops act_csum_ops;
 
 static int tcf_csum_init(struct net *net, struct nlattr *nla,
 			 struct nlattr *est, struct tc_action **a, int ovr,
-			 int bind, struct netlink_ext_ack *extack)
+			 int bind, bool rtnl_held,
+			 struct netlink_ext_ack *extack)
 {
 	struct tc_action_net *tn = net_generic(net, csum_net_id);
 	struct tcf_csum_params *params_old, *params_new;
diff --git a/net/sched/act_gact.c b/net/sched/act_gact.c
index ca83debd5a70..b4dfb2b4addc 100644
--- a/net/sched/act_gact.c
+++ b/net/sched/act_gact.c
@@ -56,7 +56,8 @@ static const struct nla_policy gact_policy[TCA_GACT_MAX + 1] = {
 
 static int tcf_gact_init(struct net *net, struct nlattr *nla,
 			 struct nlattr *est, struct tc_action **a,
-			 int ovr, int bind, struct netlink_ext_ack *extack)
+			 int ovr, int bind, bool rtnl_held,
+			 struct netlink_ext_ack *extack)
 {
 	struct tc_action_net *tn = net_generic(net, gact_net_id);
 	struct nlattr *tb[TCA_GACT_MAX + 1];
diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c
index 3536a23f46b5..576ffbba61c3 100644
--- a/net/sched/act_ife.c
+++ b/net/sched/act_ife.c
@@ -448,7 +448,8 @@ static int populate_metalist(struct tcf_ife_info *ife, struct nlattr **tb,
 
 static int tcf_ife_init(struct net *net, struct nlattr *nla,
 			struct nlattr *est, struct tc_action **a,
-			int ovr, int bind, struct netlink_ext_ack *extack)
+			int ovr, int bind, bool rtnl_held,
+			struct netlink_ext_ack *extack)
 {
 	struct tc_action_net *tn = net_generic(net, ife_net_id);
 	struct nlattr *tb[TCA_IFE_MAX + 1];
diff --git a/net/sched/act_ipt.c b/net/sched/act_ipt.c
index 7bce88dc11c9..9c21663a86a6 100644
--- a/net/sched/act_ipt.c
+++ b/net/sched/act_ipt.c
@@ -196,7 +196,8 @@ err1:
 
 static int tcf_ipt_init(struct net *net, struct nlattr *nla,
 			struct nlattr *est, struct tc_action **a, int ovr,
-			int bind, struct netlink_ext_ack *extack)
+			int bind, bool rtnl_held,
+			struct netlink_ext_ack *extack)
 {
 	return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, ovr,
 			      bind);
@@ -204,7 +205,8 @@ static int tcf_ipt_init(struct net *net, struct nlattr *nla,
 
 static int tcf_xt_init(struct net *net, struct nlattr *nla,
 		       struct nlattr *est, struct tc_action **a, int ovr,
-		       int bind, struct netlink_ext_ack *extack)
+		       int bind, bool unlocked,
+		       struct netlink_ext_ack *extack)
 {
 	return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, ovr,
 			      bind);
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index 82a8bdd67c47..5434f08f2eb7 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -68,8 +68,9 @@ static unsigned int mirred_net_id;
 static struct tc_action_ops act_mirred_ops;
 
 static int tcf_mirred_init(struct net *net, struct nlattr *nla,
-			   struct nlattr *est, struct tc_action **a, int ovr,
-			   int bind, struct netlink_ext_ack *extack)
+			   struct nlattr *est, struct tc_action **a,
+			   int ovr, int bind, bool rtnl_held,
+			   struct netlink_ext_ack *extack)
 {
 	struct tc_action_net *tn = net_generic(net, mirred_net_id);
 	struct nlattr *tb[TCA_MIRRED_MAX + 1];
diff --git a/net/sched/act_nat.c b/net/sched/act_nat.c
index 457c2ae3de46..e6487ad1e4a8 100644
--- a/net/sched/act_nat.c
+++ b/net/sched/act_nat.c
@@ -38,7 +38,7 @@ static const struct nla_policy nat_policy[TCA_NAT_MAX + 1] = {
 
 static int tcf_nat_init(struct net *net, struct nlattr *nla, struct nlattr *est,
 			struct tc_action **a, int ovr, int bind,
-			struct netlink_ext_ack *extack)
+			bool rtnl_held, struct netlink_ext_ack *extack)
 {
 	struct tc_action_net *tn = net_generic(net, nat_net_id);
 	struct nlattr *tb[TCA_NAT_MAX + 1];
diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
index 889690e0ec39..f7965f35585b 100644
--- a/net/sched/act_pedit.c
+++ b/net/sched/act_pedit.c
@@ -132,7 +132,8 @@ static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
 
 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 			  struct nlattr *est, struct tc_action **a,
-			  int ovr, int bind, struct netlink_ext_ack *extack)
+			  int ovr, int bind, bool rtnl_held,
+			  struct netlink_ext_ack *extack)
 {
 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
 	struct nlattr *tb[TCA_PEDIT_MAX + 1];
diff --git a/net/sched/act_police.c b/net/sched/act_police.c
index a789b8060968..0e1c2fb0ebea 100644
--- a/net/sched/act_police.c
+++ b/net/sched/act_police.c
@@ -75,7 +75,7 @@ static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = {
 
 static int tcf_act_police_init(struct net *net, struct nlattr *nla,
 			       struct nlattr *est, struct tc_action **a,
-			       int ovr, int bind,
+			       int ovr, int bind, bool rtnl_held,
 			       struct netlink_ext_ack *extack)
 {
 	int ret = 0, err;
diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c
index 4a46978db092..316fc645595d 100644
--- a/net/sched/act_sample.c
+++ b/net/sched/act_sample.c
@@ -37,7 +37,8 @@ static const struct nla_policy sample_policy[TCA_SAMPLE_MAX + 1] = {
 
 static int tcf_sample_init(struct net *net, struct nlattr *nla,
 			   struct nlattr *est, struct tc_action **a, int ovr,
-			   int bind, struct netlink_ext_ack *extack)
+			   int bind, bool rtnl_held,
+			   struct netlink_ext_ack *extack)
 {
 	struct tc_action_net *tn = net_generic(net, sample_net_id);
 	struct nlattr *tb[TCA_SAMPLE_MAX + 1];
diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c
index c3a761097b01..dc591cc87f4a 100644
--- a/net/sched/act_simple.c
+++ b/net/sched/act_simple.c
@@ -79,7 +79,8 @@ static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
 
 static int tcf_simp_init(struct net *net, struct nlattr *nla,
 			 struct nlattr *est, struct tc_action **a,
-			 int ovr, int bind, struct netlink_ext_ack *extack)
+			 int ovr, int bind, bool rtnl_held,
+			 struct netlink_ext_ack *extack)
 {
 	struct tc_action_net *tn = net_generic(net, simp_net_id);
 	struct nlattr *tb[TCA_DEF_MAX + 1];
diff --git a/net/sched/act_skbedit.c b/net/sched/act_skbedit.c
index cfd20d3d2ca9..c4ae4bd830aa 100644
--- a/net/sched/act_skbedit.c
+++ b/net/sched/act_skbedit.c
@@ -94,7 +94,8 @@ static const struct nla_policy skbedit_policy[TCA_SKBEDIT_MAX + 1] = {
 
 static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
 			    struct nlattr *est, struct tc_action **a,
-			    int ovr, int bind, struct netlink_ext_ack *extack)
+			    int ovr, int bind, bool rtnl_held,
+			    struct netlink_ext_ack *extack)
 {
 	struct tc_action_net *tn = net_generic(net, skbedit_net_id);
 	struct nlattr *tb[TCA_SKBEDIT_MAX + 1];
diff --git a/net/sched/act_skbmod.c b/net/sched/act_skbmod.c
index ff90d720eda3..026d6f58eda1 100644
--- a/net/sched/act_skbmod.c
+++ b/net/sched/act_skbmod.c
@@ -84,7 +84,8 @@ static const struct nla_policy skbmod_policy[TCA_SKBMOD_MAX + 1] = {
 
 static int tcf_skbmod_init(struct net *net, struct nlattr *nla,
 			   struct nlattr *est, struct tc_action **a,
-			   int ovr, int bind, struct netlink_ext_ack *extack)
+			   int ovr, int bind, bool rtnl_held,
+			   struct netlink_ext_ack *extack)
 {
 	struct tc_action_net *tn = net_generic(net, skbmod_net_id);
 	struct nlattr *tb[TCA_SKBMOD_MAX + 1];
diff --git a/net/sched/act_tunnel_key.c b/net/sched/act_tunnel_key.c
index 2354f07eba15..15ea5ce0f9ed 100644
--- a/net/sched/act_tunnel_key.c
+++ b/net/sched/act_tunnel_key.c
@@ -201,7 +201,8 @@ static const struct nla_policy tunnel_key_policy[TCA_TUNNEL_KEY_MAX + 1] = {
 
 static int tunnel_key_init(struct net *net, struct nlattr *nla,
 			   struct nlattr *est, struct tc_action **a,
-			   int ovr, int bind, struct netlink_ext_ack *extack)
+			   int ovr, int bind, bool rtnl_held,
+			   struct netlink_ext_ack *extack)
 {
 	struct tc_action_net *tn = net_generic(net, tunnel_key_net_id);
 	struct nlattr *tb[TCA_TUNNEL_KEY_MAX + 1];
diff --git a/net/sched/act_vlan.c b/net/sched/act_vlan.c
index 799e3deb44ac..c61775250722 100644
--- a/net/sched/act_vlan.c
+++ b/net/sched/act_vlan.c
@@ -109,7 +109,8 @@ static const struct nla_policy vlan_policy[TCA_VLAN_MAX + 1] = {
 
 static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 			 struct nlattr *est, struct tc_action **a,
-			 int ovr, int bind, struct netlink_ext_ack *extack)
+			 int ovr, int bind, bool rtnl_held,
+			 struct netlink_ext_ack *extack)
 {
 	struct tc_action_net *tn = net_generic(net, vlan_net_id);
 	struct nlattr *tb[TCA_VLAN_MAX + 1];
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index bbf8dda96b0e..ebc2b9dd783f 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -1632,7 +1632,7 @@ int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
 		if (exts->police && tb[exts->police]) {
 			act = tcf_action_init_1(net, tp, tb[exts->police],
 						rate_tlv, "police", ovr,
-						TCA_ACT_BIND, extack);
+						TCA_ACT_BIND, true, extack);
 			if (IS_ERR(act))
 				return PTR_ERR(act);
 
@@ -1645,7 +1645,8 @@ int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
 
 			err = tcf_action_init(net, tp, tb[exts->action],
 					      rate_tlv, NULL, ovr, TCA_ACT_BIND,
-					      &actions, &attr_size, extack);
+					      &actions, &attr_size, true,
+					      extack);
 			if (err)
 				return err;
 			list_for_each_entry(act, &actions, list)

From 3f7c72bc4227b169ba2c924a7987324e24bbc4b2 Mon Sep 17 00:00:00 2001
From: Vlad Buslov <vladbu@mellanox.com>
Date: Thu, 5 Jul 2018 17:24:26 +0300
Subject: [PATCH 04/11] net: sched: always take reference to action

Without rtnl lock protection it is no longer safe to use pointer to tc
action without holding reference to it. (it can be destroyed concurrently)

Remove unsafe action idr lookup function. Instead of it, implement safe tcf
idr check function that atomically looks up action in idr and increments
its reference and bind counters. Implement both action search and check
using new safe function

Reference taken by idr check is temporal and should not be accounted by
userspace clients (both logically and to preserver current API behavior).
Subtract temporal reference when dumping action to userspace using existing
tca_get_fill function arguments.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/sched/act_api.c | 46 ++++++++++++++++++++-------------------------
 1 file changed, 20 insertions(+), 26 deletions(-)

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 256b0c93916c..aa304d36fee0 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -284,44 +284,38 @@ int tcf_generic_walker(struct tc_action_net *tn, struct sk_buff *skb,
 }
 EXPORT_SYMBOL(tcf_generic_walker);
 
-static struct tc_action *tcf_idr_lookup(u32 index, struct tcf_idrinfo *idrinfo)
+static bool __tcf_idr_check(struct tc_action_net *tn, u32 index,
+			    struct tc_action **a, int bind)
 {
-	struct tc_action *p = NULL;
+	struct tcf_idrinfo *idrinfo = tn->idrinfo;
+	struct tc_action *p;
 
 	spin_lock(&idrinfo->lock);
 	p = idr_find(&idrinfo->action_idr, index);
+	if (p) {
+		refcount_inc(&p->tcfa_refcnt);
+		if (bind)
+			atomic_inc(&p->tcfa_bindcnt);
+	}
 	spin_unlock(&idrinfo->lock);
 
-	return p;
+	if (p) {
+		*a = p;
+		return true;
+	}
+	return false;
 }
 
 int tcf_idr_search(struct tc_action_net *tn, struct tc_action **a, u32 index)
 {
-	struct tcf_idrinfo *idrinfo = tn->idrinfo;
-	struct tc_action *p = tcf_idr_lookup(index, idrinfo);
-
-	if (p) {
-		*a = p;
-		return 1;
-	}
-	return 0;
+	return __tcf_idr_check(tn, index, a, 0);
 }
 EXPORT_SYMBOL(tcf_idr_search);
 
 bool tcf_idr_check(struct tc_action_net *tn, u32 index, struct tc_action **a,
 		   int bind)
 {
-	struct tcf_idrinfo *idrinfo = tn->idrinfo;
-	struct tc_action *p = tcf_idr_lookup(index, idrinfo);
-
-	if (index && p) {
-		if (bind)
-			atomic_inc(&p->tcfa_bindcnt);
-		refcount_inc(&p->tcfa_refcnt);
-		*a = p;
-		return true;
-	}
-	return false;
+	return __tcf_idr_check(tn, index, a, bind);
 }
 EXPORT_SYMBOL(tcf_idr_check);
 
@@ -932,7 +926,7 @@ tcf_get_notify(struct net *net, u32 portid, struct nlmsghdr *n,
 	if (!skb)
 		return -ENOBUFS;
 	if (tca_get_fill(skb, actions, portid, n->nlmsg_seq, 0, event,
-			 0, 0) <= 0) {
+			 0, 1) <= 0) {
 		NL_SET_ERR_MSG(extack, "Failed to fill netlink attributes while adding TC action");
 		kfree_skb(skb);
 		return -EINVAL;
@@ -1072,7 +1066,7 @@ tcf_del_notify(struct net *net, struct nlmsghdr *n, struct list_head *actions,
 		return -ENOBUFS;
 
 	if (tca_get_fill(skb, actions, portid, n->nlmsg_seq, 0, RTM_DELACTION,
-			 0, 1) <= 0) {
+			 0, 2) <= 0) {
 		NL_SET_ERR_MSG(extack, "Failed to fill netlink TC action attributes");
 		kfree_skb(skb);
 		return -EINVAL;
@@ -1131,14 +1125,14 @@ tca_action_gd(struct net *net, struct nlattr *nla, struct nlmsghdr *n,
 	if (event == RTM_GETACTION)
 		ret = tcf_get_notify(net, portid, n, &actions, event, extack);
 	else { /* delete */
+		cleanup_a(&actions, 1); /* lookup took reference */
 		ret = tcf_del_notify(net, n, &actions, portid, attr_size, extack);
 		if (ret)
 			goto err;
 		return ret;
 	}
 err:
-	if (event != RTM_GETACTION)
-		tcf_action_destroy(&actions, 0);
+	tcf_action_destroy(&actions, 0);
 	return ret;
 }
 

From 2a2ea349704fffade9526d5122299edbbfd122ca Mon Sep 17 00:00:00 2001
From: Vlad Buslov <vladbu@mellanox.com>
Date: Thu, 5 Jul 2018 17:24:27 +0300
Subject: [PATCH 05/11] net: sched: implement action API that deletes action by
 index

Implement new action API function that atomically finds and deletes action
from idr by index. Intended to be used by lockless actions that do not rely
on rtnl lock.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/net/act_api.h |  1 +
 net/sched/act_api.c   | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/include/net/act_api.h b/include/net/act_api.h
index 27823f4e24c4..a8eaae67c264 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -153,6 +153,7 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
 		   int bind, bool cpustats);
 void tcf_idr_insert(struct tc_action_net *tn, struct tc_action *a);
 
+int tcf_idr_delete_index(struct tc_action_net *tn, u32 index);
 int __tcf_idr_release(struct tc_action *a, bool bind, bool strict);
 
 static inline int tcf_idr_release(struct tc_action *a, bool bind)
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index aa304d36fee0..0f31f09946ab 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -319,6 +319,45 @@ bool tcf_idr_check(struct tc_action_net *tn, u32 index, struct tc_action **a,
 }
 EXPORT_SYMBOL(tcf_idr_check);
 
+int tcf_idr_delete_index(struct tc_action_net *tn, u32 index)
+{
+	struct tcf_idrinfo *idrinfo = tn->idrinfo;
+	struct tc_action *p;
+	int ret = 0;
+
+	spin_lock(&idrinfo->lock);
+	p = idr_find(&idrinfo->action_idr, index);
+	if (!p) {
+		spin_unlock(&idrinfo->lock);
+		return -ENOENT;
+	}
+
+	if (!atomic_read(&p->tcfa_bindcnt)) {
+		if (refcount_dec_and_test(&p->tcfa_refcnt)) {
+			struct module *owner = p->ops->owner;
+
+			WARN_ON(p != idr_remove(&idrinfo->action_idr,
+						p->tcfa_index));
+			spin_unlock(&idrinfo->lock);
+
+			if (p->ops->cleanup)
+				p->ops->cleanup(p);
+
+			gen_kill_estimator(&p->tcfa_rate_est);
+			free_tcf(p);
+			module_put(owner);
+			return 0;
+		}
+		ret = 0;
+	} else {
+		ret = -EPERM;
+	}
+
+	spin_unlock(&idrinfo->lock);
+	return ret;
+}
+EXPORT_SYMBOL(tcf_idr_delete_index);
+
 int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
 		   struct tc_action **a, const struct tc_action_ops *ops,
 		   int bind, bool cpustats)

From b409074e6693bcdaa7abbee2a035f22a9eabda53 Mon Sep 17 00:00:00 2001
From: Vlad Buslov <vladbu@mellanox.com>
Date: Thu, 5 Jul 2018 17:24:28 +0300
Subject: [PATCH 06/11] net: sched: add 'delete' function to action ops

Extend action ops with 'delete' function. Each action type to implements
its own delete function that doesn't depend on rtnl lock.

Implement delete function that is required to delete actions without
holding rtnl lock. Use action API function that atomically deletes action
only if it is still in action idr. This implementation prevents concurrent
threads from deleting same action twice.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/net/act_api.h      |  1 +
 net/sched/act_bpf.c        |  8 ++++++++
 net/sched/act_connmark.c   |  8 ++++++++
 net/sched/act_csum.c       |  8 ++++++++
 net/sched/act_gact.c       |  8 ++++++++
 net/sched/act_ife.c        |  8 ++++++++
 net/sched/act_ipt.c        | 16 ++++++++++++++++
 net/sched/act_mirred.c     |  8 ++++++++
 net/sched/act_nat.c        |  8 ++++++++
 net/sched/act_pedit.c      |  8 ++++++++
 net/sched/act_police.c     |  8 ++++++++
 net/sched/act_sample.c     |  8 ++++++++
 net/sched/act_simple.c     |  8 ++++++++
 net/sched/act_skbedit.c    |  8 ++++++++
 net/sched/act_skbmod.c     |  8 ++++++++
 net/sched/act_tunnel_key.c |  8 ++++++++
 net/sched/act_vlan.c       |  8 ++++++++
 17 files changed, 137 insertions(+)

diff --git a/include/net/act_api.h b/include/net/act_api.h
index a8eaae67c264..b9ed2b8256a5 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -101,6 +101,7 @@ struct tc_action_ops {
 	void	(*stats_update)(struct tc_action *, u64, u32, u64);
 	size_t  (*get_fill_size)(const struct tc_action *act);
 	struct net_device *(*get_dev)(const struct tc_action *a);
+	int     (*delete)(struct net *net, u32 index);
 };
 
 struct tc_action_net {
diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
index 8ebf40a3506c..7941dd66ff83 100644
--- a/net/sched/act_bpf.c
+++ b/net/sched/act_bpf.c
@@ -388,6 +388,13 @@ static int tcf_bpf_search(struct net *net, struct tc_action **a, u32 index,
 	return tcf_idr_search(tn, a, index);
 }
 
+static int tcf_bpf_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, bpf_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_bpf_ops __read_mostly = {
 	.kind		=	"bpf",
 	.type		=	TCA_ACT_BPF,
@@ -398,6 +405,7 @@ static struct tc_action_ops act_bpf_ops __read_mostly = {
 	.init		=	tcf_bpf_init,
 	.walk		=	tcf_bpf_walker,
 	.lookup		=	tcf_bpf_search,
+	.delete		=	tcf_bpf_delete,
 	.size		=	sizeof(struct tcf_bpf),
 };
 
diff --git a/net/sched/act_connmark.c b/net/sched/act_connmark.c
index e3787aa0025a..143c2d3de723 100644
--- a/net/sched/act_connmark.c
+++ b/net/sched/act_connmark.c
@@ -193,6 +193,13 @@ static int tcf_connmark_search(struct net *net, struct tc_action **a, u32 index,
 	return tcf_idr_search(tn, a, index);
 }
 
+static int tcf_connmark_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, connmark_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_connmark_ops = {
 	.kind		=	"connmark",
 	.type		=	TCA_ACT_CONNMARK,
@@ -202,6 +209,7 @@ static struct tc_action_ops act_connmark_ops = {
 	.init		=	tcf_connmark_init,
 	.walk		=	tcf_connmark_walker,
 	.lookup		=	tcf_connmark_search,
+	.delete		=	tcf_connmark_delete,
 	.size		=	sizeof(struct tcf_connmark_info),
 };
 
diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c
index 334261943f9f..3768539340e0 100644
--- a/net/sched/act_csum.c
+++ b/net/sched/act_csum.c
@@ -654,6 +654,13 @@ static size_t tcf_csum_get_fill_size(const struct tc_action *act)
 	return nla_total_size(sizeof(struct tc_csum));
 }
 
+static int tcf_csum_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, csum_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_csum_ops = {
 	.kind		= "csum",
 	.type		= TCA_ACT_CSUM,
@@ -665,6 +672,7 @@ static struct tc_action_ops act_csum_ops = {
 	.walk		= tcf_csum_walker,
 	.lookup		= tcf_csum_search,
 	.get_fill_size  = tcf_csum_get_fill_size,
+	.delete		= tcf_csum_delete,
 	.size		= sizeof(struct tcf_csum),
 };
 
diff --git a/net/sched/act_gact.c b/net/sched/act_gact.c
index b4dfb2b4addc..a431a711f0dd 100644
--- a/net/sched/act_gact.c
+++ b/net/sched/act_gact.c
@@ -231,6 +231,13 @@ static size_t tcf_gact_get_fill_size(const struct tc_action *act)
 	return sz;
 }
 
+static int tcf_gact_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, gact_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_gact_ops = {
 	.kind		=	"gact",
 	.type		=	TCA_ACT_GACT,
@@ -242,6 +249,7 @@ static struct tc_action_ops act_gact_ops = {
 	.walk		=	tcf_gact_walker,
 	.lookup		=	tcf_gact_search,
 	.get_fill_size	=	tcf_gact_get_fill_size,
+	.delete		=	tcf_gact_delete,
 	.size		=	sizeof(struct tcf_gact),
 };
 
diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c
index 576ffbba61c3..89a761395c94 100644
--- a/net/sched/act_ife.c
+++ b/net/sched/act_ife.c
@@ -844,6 +844,13 @@ static int tcf_ife_search(struct net *net, struct tc_action **a, u32 index,
 	return tcf_idr_search(tn, a, index);
 }
 
+static int tcf_ife_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, ife_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_ife_ops = {
 	.kind = "ife",
 	.type = TCA_ACT_IFE,
@@ -854,6 +861,7 @@ static struct tc_action_ops act_ife_ops = {
 	.init = tcf_ife_init,
 	.walk = tcf_ife_walker,
 	.lookup = tcf_ife_search,
+	.delete = tcf_ife_delete,
 	.size =	sizeof(struct tcf_ife_info),
 };
 
diff --git a/net/sched/act_ipt.c b/net/sched/act_ipt.c
index 9c21663a86a6..6c234411c771 100644
--- a/net/sched/act_ipt.c
+++ b/net/sched/act_ipt.c
@@ -324,6 +324,13 @@ static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index,
 	return tcf_idr_search(tn, a, index);
 }
 
+static int tcf_ipt_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, ipt_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_ipt_ops = {
 	.kind		=	"ipt",
 	.type		=	TCA_ACT_IPT,
@@ -334,6 +341,7 @@ static struct tc_action_ops act_ipt_ops = {
 	.init		=	tcf_ipt_init,
 	.walk		=	tcf_ipt_walker,
 	.lookup		=	tcf_ipt_search,
+	.delete		=	tcf_ipt_delete,
 	.size		=	sizeof(struct tcf_ipt),
 };
 
@@ -374,6 +382,13 @@ static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index,
 	return tcf_idr_search(tn, a, index);
 }
 
+static int tcf_xt_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, xt_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_xt_ops = {
 	.kind		=	"xt",
 	.type		=	TCA_ACT_XT,
@@ -384,6 +399,7 @@ static struct tc_action_ops act_xt_ops = {
 	.init		=	tcf_xt_init,
 	.walk		=	tcf_xt_walker,
 	.lookup		=	tcf_xt_search,
+	.delete		=	tcf_xt_delete,
 	.size		=	sizeof(struct tcf_ipt),
 };
 
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index 5434f08f2eb7..3d8300bce7e4 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -322,6 +322,13 @@ static struct net_device *tcf_mirred_get_dev(const struct tc_action *a)
 	return rtnl_dereference(m->tcfm_dev);
 }
 
+static int tcf_mirred_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, mirred_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_mirred_ops = {
 	.kind		=	"mirred",
 	.type		=	TCA_ACT_MIRRED,
@@ -335,6 +342,7 @@ static struct tc_action_ops act_mirred_ops = {
 	.lookup		=	tcf_mirred_search,
 	.size		=	sizeof(struct tcf_mirred),
 	.get_dev	=	tcf_mirred_get_dev,
+	.delete		=	tcf_mirred_delete,
 };
 
 static __net_init int mirred_init_net(struct net *net)
diff --git a/net/sched/act_nat.c b/net/sched/act_nat.c
index e6487ad1e4a8..9eb27c89dc46 100644
--- a/net/sched/act_nat.c
+++ b/net/sched/act_nat.c
@@ -294,6 +294,13 @@ static int tcf_nat_search(struct net *net, struct tc_action **a, u32 index,
 	return tcf_idr_search(tn, a, index);
 }
 
+static int tcf_nat_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, nat_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_nat_ops = {
 	.kind		=	"nat",
 	.type		=	TCA_ACT_NAT,
@@ -303,6 +310,7 @@ static struct tc_action_ops act_nat_ops = {
 	.init		=	tcf_nat_init,
 	.walk		=	tcf_nat_walker,
 	.lookup		=	tcf_nat_search,
+	.delete		=	tcf_nat_delete,
 	.size		=	sizeof(struct tcf_nat),
 };
 
diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
index f7965f35585b..45871052840f 100644
--- a/net/sched/act_pedit.c
+++ b/net/sched/act_pedit.c
@@ -454,6 +454,13 @@ static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index,
 	return tcf_idr_search(tn, a, index);
 }
 
+static int tcf_pedit_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, pedit_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_pedit_ops = {
 	.kind		=	"pedit",
 	.type		=	TCA_ACT_PEDIT,
@@ -464,6 +471,7 @@ static struct tc_action_ops act_pedit_ops = {
 	.init		=	tcf_pedit_init,
 	.walk		=	tcf_pedit_walker,
 	.lookup		=	tcf_pedit_search,
+	.delete		=	tcf_pedit_delete,
 	.size		=	sizeof(struct tcf_pedit),
 };
 
diff --git a/net/sched/act_police.c b/net/sched/act_police.c
index 0e1c2fb0ebea..c955fb0d4f3f 100644
--- a/net/sched/act_police.c
+++ b/net/sched/act_police.c
@@ -314,6 +314,13 @@ static int tcf_police_search(struct net *net, struct tc_action **a, u32 index,
 	return tcf_idr_search(tn, a, index);
 }
 
+static int tcf_police_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, police_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 MODULE_AUTHOR("Alexey Kuznetsov");
 MODULE_DESCRIPTION("Policing actions");
 MODULE_LICENSE("GPL");
@@ -327,6 +334,7 @@ static struct tc_action_ops act_police_ops = {
 	.init		=	tcf_act_police_init,
 	.walk		=	tcf_act_police_walker,
 	.lookup		=	tcf_police_search,
+	.delete		=	tcf_police_delete,
 	.size		=	sizeof(struct tcf_police),
 };
 
diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c
index 316fc645595d..6f79d2afcba2 100644
--- a/net/sched/act_sample.c
+++ b/net/sched/act_sample.c
@@ -220,6 +220,13 @@ static int tcf_sample_search(struct net *net, struct tc_action **a, u32 index,
 	return tcf_idr_search(tn, a, index);
 }
 
+static int tcf_sample_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, sample_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_sample_ops = {
 	.kind	  = "sample",
 	.type	  = TCA_ACT_SAMPLE,
@@ -230,6 +237,7 @@ static struct tc_action_ops act_sample_ops = {
 	.cleanup  = tcf_sample_cleanup,
 	.walk	  = tcf_sample_walker,
 	.lookup	  = tcf_sample_search,
+	.delete	  = tcf_sample_delete,
 	.size	  = sizeof(struct tcf_sample),
 };
 
diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c
index dc591cc87f4a..446c750f3d3c 100644
--- a/net/sched/act_simple.c
+++ b/net/sched/act_simple.c
@@ -184,6 +184,13 @@ static int tcf_simp_search(struct net *net, struct tc_action **a, u32 index,
 	return tcf_idr_search(tn, a, index);
 }
 
+static int tcf_simp_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, simp_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_simp_ops = {
 	.kind		=	"simple",
 	.type		=	TCA_ACT_SIMP,
@@ -194,6 +201,7 @@ static struct tc_action_ops act_simp_ops = {
 	.init		=	tcf_simp_init,
 	.walk		=	tcf_simp_walker,
 	.lookup		=	tcf_simp_search,
+	.delete		=	tcf_simp_delete,
 	.size		=	sizeof(struct tcf_defact),
 };
 
diff --git a/net/sched/act_skbedit.c b/net/sched/act_skbedit.c
index c4ae4bd830aa..b3eaa120c7f4 100644
--- a/net/sched/act_skbedit.c
+++ b/net/sched/act_skbedit.c
@@ -267,6 +267,13 @@ static int tcf_skbedit_search(struct net *net, struct tc_action **a, u32 index,
 	return tcf_idr_search(tn, a, index);
 }
 
+static int tcf_skbedit_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, skbedit_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_skbedit_ops = {
 	.kind		=	"skbedit",
 	.type		=	TCA_ACT_SKBEDIT,
@@ -276,6 +283,7 @@ static struct tc_action_ops act_skbedit_ops = {
 	.init		=	tcf_skbedit_init,
 	.walk		=	tcf_skbedit_walker,
 	.lookup		=	tcf_skbedit_search,
+	.delete		=	tcf_skbedit_delete,
 	.size		=	sizeof(struct tcf_skbedit),
 };
 
diff --git a/net/sched/act_skbmod.c b/net/sched/act_skbmod.c
index 026d6f58eda1..30be3f767495 100644
--- a/net/sched/act_skbmod.c
+++ b/net/sched/act_skbmod.c
@@ -253,6 +253,13 @@ static int tcf_skbmod_search(struct net *net, struct tc_action **a, u32 index,
 	return tcf_idr_search(tn, a, index);
 }
 
+static int tcf_skbmod_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, skbmod_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_skbmod_ops = {
 	.kind		=	"skbmod",
 	.type		=	TCA_ACT_SKBMOD,
@@ -263,6 +270,7 @@ static struct tc_action_ops act_skbmod_ops = {
 	.cleanup	=	tcf_skbmod_cleanup,
 	.walk		=	tcf_skbmod_walker,
 	.lookup		=	tcf_skbmod_search,
+	.delete		=	tcf_skbmod_delete,
 	.size		=	sizeof(struct tcf_skbmod),
 };
 
diff --git a/net/sched/act_tunnel_key.c b/net/sched/act_tunnel_key.c
index 15ea5ce0f9ed..655ed0b3fc67 100644
--- a/net/sched/act_tunnel_key.c
+++ b/net/sched/act_tunnel_key.c
@@ -534,6 +534,13 @@ static int tunnel_key_search(struct net *net, struct tc_action **a, u32 index,
 	return tcf_idr_search(tn, a, index);
 }
 
+static int tunnel_key_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, tunnel_key_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_tunnel_key_ops = {
 	.kind		=	"tunnel_key",
 	.type		=	TCA_ACT_TUNNEL_KEY,
@@ -544,6 +551,7 @@ static struct tc_action_ops act_tunnel_key_ops = {
 	.cleanup	=	tunnel_key_release,
 	.walk		=	tunnel_key_walker,
 	.lookup		=	tunnel_key_search,
+	.delete		=	tunnel_key_delete,
 	.size		=	sizeof(struct tcf_tunnel_key),
 };
 
diff --git a/net/sched/act_vlan.c b/net/sched/act_vlan.c
index c61775250722..e334d2751784 100644
--- a/net/sched/act_vlan.c
+++ b/net/sched/act_vlan.c
@@ -287,6 +287,13 @@ static int tcf_vlan_search(struct net *net, struct tc_action **a, u32 index,
 	return tcf_idr_search(tn, a, index);
 }
 
+static int tcf_vlan_delete(struct net *net, u32 index)
+{
+	struct tc_action_net *tn = net_generic(net, vlan_net_id);
+
+	return tcf_idr_delete_index(tn, index);
+}
+
 static struct tc_action_ops act_vlan_ops = {
 	.kind		=	"vlan",
 	.type		=	TCA_ACT_VLAN,
@@ -297,6 +304,7 @@ static struct tc_action_ops act_vlan_ops = {
 	.cleanup	=	tcf_vlan_cleanup,
 	.walk		=	tcf_vlan_walker,
 	.lookup		=	tcf_vlan_search,
+	.delete		=	tcf_vlan_delete,
 	.size		=	sizeof(struct tcf_vlan),
 };
 

From 16af6067392c40e454e49eec834843ab03643d96 Mon Sep 17 00:00:00 2001
From: Vlad Buslov <vladbu@mellanox.com>
Date: Thu, 5 Jul 2018 17:24:29 +0300
Subject: [PATCH 07/11] net: sched: implement reference counted action release

Implement helper delete function that uses new action ops 'delete', instead
of destroying action directly. This is required so act API could delete
actions by index, without holding any references to action that is being
deleted.

Implement function __tcf_action_put() that releases reference to action and
frees it, if necessary. Refactor action deletion code to use new put
function and not to rely on rtnl lock. Remove rtnl lock assertions that are
no longer needed.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/sched/act_api.c | 84 +++++++++++++++++++++++++++++++++------------
 net/sched/cls_api.c |  1 -
 2 files changed, 62 insertions(+), 23 deletions(-)

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 0f31f09946ab..a023873db713 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -90,21 +90,39 @@ static void free_tcf(struct tc_action *p)
 	kfree(p);
 }
 
-static void tcf_idr_remove(struct tcf_idrinfo *idrinfo, struct tc_action *p)
+static void tcf_action_cleanup(struct tc_action *p)
 {
-	spin_lock(&idrinfo->lock);
-	idr_remove(&idrinfo->action_idr, p->tcfa_index);
-	spin_unlock(&idrinfo->lock);
+	if (p->ops->cleanup)
+		p->ops->cleanup(p);
+
 	gen_kill_estimator(&p->tcfa_rate_est);
 	free_tcf(p);
 }
 
+static int __tcf_action_put(struct tc_action *p, bool bind)
+{
+	struct tcf_idrinfo *idrinfo = p->idrinfo;
+
+	if (refcount_dec_and_lock(&p->tcfa_refcnt, &idrinfo->lock)) {
+		if (bind)
+			atomic_dec(&p->tcfa_bindcnt);
+		idr_remove(&idrinfo->action_idr, p->tcfa_index);
+		spin_unlock(&idrinfo->lock);
+
+		tcf_action_cleanup(p);
+		return 1;
+	}
+
+	if (bind)
+		atomic_dec(&p->tcfa_bindcnt);
+
+	return 0;
+}
+
 int __tcf_idr_release(struct tc_action *p, bool bind, bool strict)
 {
 	int ret = 0;
 
-	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
@@ -118,18 +136,11 @@ int __tcf_idr_release(struct tc_action *p, bool bind, bool strict)
 	 * are acceptable.
 	 */
 	if (p) {
-		if (bind)
-			atomic_dec(&p->tcfa_bindcnt);
-		else if (strict && atomic_read(&p->tcfa_bindcnt) > 0)
+		if (!bind && strict && atomic_read(&p->tcfa_bindcnt) > 0)
 			return -EPERM;
 
-		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);
+		if (__tcf_action_put(p, bind))
 			ret = ACT_P_DELETED;
-		}
 	}
 
 	return ret;
@@ -340,11 +351,7 @@ int tcf_idr_delete_index(struct tc_action_net *tn, u32 index)
 						p->tcfa_index));
 			spin_unlock(&idrinfo->lock);
 
-			if (p->ops->cleanup)
-				p->ops->cleanup(p);
-
-			gen_kill_estimator(&p->tcfa_rate_est);
-			free_tcf(p);
+			tcf_action_cleanup(p);
 			module_put(owner);
 			return 0;
 		}
@@ -615,6 +622,11 @@ int tcf_action_destroy(struct list_head *actions, int bind)
 	return ret;
 }
 
+static int tcf_action_put(struct tc_action *p)
+{
+	return __tcf_action_put(p, false);
+}
+
 int
 tcf_action_dump_old(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 {
@@ -1092,6 +1104,35 @@ err_out:
 	return err;
 }
 
+static int tcf_action_delete(struct net *net, struct list_head *actions,
+			     struct netlink_ext_ack *extack)
+{
+	struct tc_action *a, *tmp;
+	u32 act_index;
+	int ret;
+
+	list_for_each_entry_safe(a, tmp, actions, list) {
+		const struct tc_action_ops *ops = a->ops;
+
+		/* Actions can be deleted concurrently so we must save their
+		 * type and id to search again after reference is released.
+		 */
+		act_index = a->tcfa_index;
+
+		list_del(&a->list);
+		if (tcf_action_put(a)) {
+			/* last reference, action was deleted concurrently */
+			module_put(ops->owner);
+		} else  {
+			/* now do the delete */
+			ret = ops->delete(net, act_index);
+			if (ret < 0)
+				return ret;
+		}
+	}
+	return 0;
+}
+
 static int
 tcf_del_notify(struct net *net, struct nlmsghdr *n, struct list_head *actions,
 	       u32 portid, size_t attr_size, struct netlink_ext_ack *extack)
@@ -1112,7 +1153,7 @@ tcf_del_notify(struct net *net, struct nlmsghdr *n, struct list_head *actions,
 	}
 
 	/* now do the delete */
-	ret = tcf_action_destroy(actions, 0);
+	ret = tcf_action_delete(net, actions, extack);
 	if (ret < 0) {
 		NL_SET_ERR_MSG(extack, "Failed to delete TC action");
 		kfree_skb(skb);
@@ -1164,7 +1205,6 @@ tca_action_gd(struct net *net, struct nlattr *nla, struct nlmsghdr *n,
 	if (event == RTM_GETACTION)
 		ret = tcf_get_notify(net, portid, n, &actions, event, extack);
 	else { /* delete */
-		cleanup_a(&actions, 1); /* lookup took reference */
 		ret = tcf_del_notify(net, n, &actions, portid, attr_size, extack);
 		if (ret)
 			goto err;
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index ebc2b9dd783f..9041f0e43e9a 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -1611,7 +1611,6 @@ void tcf_exts_destroy(struct tcf_exts *exts)
 #ifdef CONFIG_NET_CLS_ACT
 	LIST_HEAD(actions);
 
-	ASSERT_RTNL();
 	tcf_exts_to_list(exts, &actions);
 	tcf_action_destroy(&actions, TCA_ACT_UNBIND);
 	kfree(exts->actions);

From 4e8ddd7f1758ca4ddd0c1f7cf3e66fce736241d2 Mon Sep 17 00:00:00 2001
From: Vlad Buslov <vladbu@mellanox.com>
Date: Thu, 5 Jul 2018 17:24:30 +0300
Subject: [PATCH 08/11] net: sched: don't release reference on action overwrite

Return from action init function with reference to action taken,
even when overwriting existing action.

Action init API initializes its fourth argument (pointer to pointer to tc
action) to either existing action with same index or newly created action.
In case of existing index(and bind argument is zero), init function returns
without incrementing action reference counter. Caller of action init then
proceeds working with action, without actually holding reference to it.
This means that action could be deleted concurrently.

Change action init behavior to always take reference to action before
returning successfully, in order to protect from concurrent deletion.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/sched/act_api.c        |  2 --
 net/sched/act_bpf.c        |  8 ++++----
 net/sched/act_connmark.c   |  5 +++--
 net/sched/act_csum.c       |  8 ++++----
 net/sched/act_gact.c       |  5 +++--
 net/sched/act_ife.c        | 10 +++++-----
 net/sched/act_ipt.c        |  5 +++--
 net/sched/act_mirred.c     |  5 ++---
 net/sched/act_nat.c        |  5 +++--
 net/sched/act_pedit.c      |  2 +-
 net/sched/act_police.c     |  8 +++-----
 net/sched/act_sample.c     |  8 +++-----
 net/sched/act_simple.c     |  5 +++--
 net/sched/act_skbedit.c    |  5 +++--
 net/sched/act_skbmod.c     |  8 +++-----
 net/sched/act_tunnel_key.c | 11 ++++-------
 net/sched/act_vlan.c       |  8 +++-----
 17 files changed, 50 insertions(+), 58 deletions(-)

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index a023873db713..f019f0464cec 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -870,8 +870,6 @@ 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)
-			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 7941dd66ff83..d3f4ac6f2c4b 100644
--- a/net/sched/act_bpf.c
+++ b/net/sched/act_bpf.c
@@ -311,9 +311,10 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
 		if (bind)
 			return 0;
 
-		tcf_idr_release(*act, bind);
-		if (!replace)
+		if (!replace) {
+			tcf_idr_release(*act, bind);
 			return -EEXIST;
+		}
 	}
 
 	is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS];
@@ -356,8 +357,7 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
 
 	return res;
 out:
-	if (res == ACT_P_CREATED)
-		tcf_idr_release(*act, bind);
+	tcf_idr_release(*act, bind);
 
 	return ret;
 }
diff --git a/net/sched/act_connmark.c b/net/sched/act_connmark.c
index 143c2d3de723..701e90244eff 100644
--- a/net/sched/act_connmark.c
+++ b/net/sched/act_connmark.c
@@ -135,9 +135,10 @@ static int tcf_connmark_init(struct net *net, struct nlattr *nla,
 		ci = to_connmark(*a);
 		if (bind)
 			return 0;
-		tcf_idr_release(*a, bind);
-		if (!ovr)
+		if (!ovr) {
+			tcf_idr_release(*a, bind);
 			return -EEXIST;
+		}
 		/* replacing action and zone */
 		ci->tcf_action = parm->action;
 		ci->zone = parm->zone;
diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c
index 3768539340e0..5dbee136b0a1 100644
--- a/net/sched/act_csum.c
+++ b/net/sched/act_csum.c
@@ -76,9 +76,10 @@ static int tcf_csum_init(struct net *net, struct nlattr *nla,
 	} else {
 		if (bind)/* dont override defaults */
 			return 0;
-		tcf_idr_release(*a, bind);
-		if (!ovr)
+		if (!ovr) {
+			tcf_idr_release(*a, bind);
 			return -EEXIST;
+		}
 	}
 
 	p = to_tcf_csum(*a);
@@ -86,8 +87,7 @@ static int tcf_csum_init(struct net *net, struct nlattr *nla,
 
 	params_new = kzalloc(sizeof(*params_new), GFP_KERNEL);
 	if (unlikely(!params_new)) {
-		if (ret == ACT_P_CREATED)
-			tcf_idr_release(*a, bind);
+		tcf_idr_release(*a, bind);
 		return -ENOMEM;
 	}
 	params_old = rtnl_dereference(p->params);
diff --git a/net/sched/act_gact.c b/net/sched/act_gact.c
index a431a711f0dd..11c4de3f344e 100644
--- a/net/sched/act_gact.c
+++ b/net/sched/act_gact.c
@@ -100,9 +100,10 @@ static int tcf_gact_init(struct net *net, struct nlattr *nla,
 	} else {
 		if (bind)/* dont override defaults */
 			return 0;
-		tcf_idr_release(*a, bind);
-		if (!ovr)
+		if (!ovr) {
+			tcf_idr_release(*a, bind);
 			return -EEXIST;
+		}
 	}
 
 	gact = to_gact(*a);
diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c
index 89a761395c94..acea3feae762 100644
--- a/net/sched/act_ife.c
+++ b/net/sched/act_ife.c
@@ -498,12 +498,10 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
 			return ret;
 		}
 		ret = ACT_P_CREATED;
-	} else {
+	} else if (!ovr) {
 		tcf_idr_release(*a, bind);
-		if (!ovr) {
-			kfree(p);
-			return -EEXIST;
-		}
+		kfree(p);
+		return -EEXIST;
 	}
 
 	ife = to_ife(*a);
@@ -548,6 +546,8 @@ metadata_parse_err:
 
 			if (exists)
 				spin_unlock_bh(&ife->tcf_lock);
+			tcf_idr_release(*a, bind);
+
 			kfree(p);
 			return err;
 		}
diff --git a/net/sched/act_ipt.c b/net/sched/act_ipt.c
index 6c234411c771..85e85dfba401 100644
--- a/net/sched/act_ipt.c
+++ b/net/sched/act_ipt.c
@@ -145,10 +145,11 @@ static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla,
 	} else {
 		if (bind)/* dont override defaults */
 			return 0;
-		tcf_idr_release(*a, bind);
 
-		if (!ovr)
+		if (!ovr) {
+			tcf_idr_release(*a, bind);
 			return -EEXIST;
+		}
 	}
 	hook = nla_get_u32(tb[TCA_IPT_HOOK]);
 
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index 3d8300bce7e4..e08aed06d7f8 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -132,10 +132,9 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 		if (ret)
 			return ret;
 		ret = ACT_P_CREATED;
-	} else {
+	} else if (!ovr) {
 		tcf_idr_release(*a, bind);
-		if (!ovr)
-			return -EEXIST;
+		return -EEXIST;
 	}
 	m = to_mirred(*a);
 
diff --git a/net/sched/act_nat.c b/net/sched/act_nat.c
index 9eb27c89dc46..1f91e8e66c0f 100644
--- a/net/sched/act_nat.c
+++ b/net/sched/act_nat.c
@@ -66,9 +66,10 @@ static int tcf_nat_init(struct net *net, struct nlattr *nla, struct nlattr *est,
 	} else {
 		if (bind)
 			return 0;
-		tcf_idr_release(*a, bind);
-		if (!ovr)
+		if (!ovr) {
+			tcf_idr_release(*a, bind);
 			return -EEXIST;
+		}
 	}
 	p = to_tcf_nat(*a);
 
diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
index 45871052840f..3a0e2f762f4e 100644
--- a/net/sched/act_pedit.c
+++ b/net/sched/act_pedit.c
@@ -194,8 +194,8 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 	} else {
 		if (bind)
 			goto out_free;
-		tcf_idr_release(*a, bind);
 		if (!ovr) {
+			tcf_idr_release(*a, bind);
 			ret = -EEXIST;
 			goto out_free;
 		}
diff --git a/net/sched/act_police.c b/net/sched/act_police.c
index c955fb0d4f3f..99335cca739e 100644
--- a/net/sched/act_police.c
+++ b/net/sched/act_police.c
@@ -111,10 +111,9 @@ static int tcf_act_police_init(struct net *net, struct nlattr *nla,
 		if (ret)
 			return ret;
 		ret = ACT_P_CREATED;
-	} else {
+	} else if (!ovr) {
 		tcf_idr_release(*a, bind);
-		if (!ovr)
-			return -EEXIST;
+		return -EEXIST;
 	}
 
 	police = to_police(*a);
@@ -195,8 +194,7 @@ static int tcf_act_police_init(struct net *net, struct nlattr *nla,
 failure:
 	qdisc_put_rtab(P_tab);
 	qdisc_put_rtab(R_tab);
-	if (ret == ACT_P_CREATED)
-		tcf_idr_release(*a, bind);
+	tcf_idr_release(*a, bind);
 	return err;
 }
 
diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c
index 6f79d2afcba2..a8582e1347db 100644
--- a/net/sched/act_sample.c
+++ b/net/sched/act_sample.c
@@ -69,10 +69,9 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla,
 		if (ret)
 			return ret;
 		ret = ACT_P_CREATED;
-	} else {
+	} else if (!ovr) {
 		tcf_idr_release(*a, bind);
-		if (!ovr)
-			return -EEXIST;
+		return -EEXIST;
 	}
 	s = to_sample(*a);
 
@@ -81,8 +80,7 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla,
 	s->psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]);
 	psample_group = psample_group_get(net, s->psample_group_num);
 	if (!psample_group) {
-		if (ret == ACT_P_CREATED)
-			tcf_idr_release(*a, bind);
+		tcf_idr_release(*a, bind);
 		return -ENOMEM;
 	}
 	RCU_INIT_POINTER(s->psample_group, psample_group);
diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c
index 446c750f3d3c..2da47c682a30 100644
--- a/net/sched/act_simple.c
+++ b/net/sched/act_simple.c
@@ -127,9 +127,10 @@ static int tcf_simp_init(struct net *net, struct nlattr *nla,
 	} else {
 		d = to_defact(*a);
 
-		tcf_idr_release(*a, bind);
-		if (!ovr)
+		if (!ovr) {
+			tcf_idr_release(*a, bind);
 			return -EEXIST;
+		}
 
 		reset_policy(d, tb[TCA_DEF_DATA], parm);
 	}
diff --git a/net/sched/act_skbedit.c b/net/sched/act_skbedit.c
index b3eaa120c7f4..4616a2c1821f 100644
--- a/net/sched/act_skbedit.c
+++ b/net/sched/act_skbedit.c
@@ -172,9 +172,10 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
 		ret = ACT_P_CREATED;
 	} else {
 		d = to_skbedit(*a);
-		tcf_idr_release(*a, bind);
-		if (!ovr)
+		if (!ovr) {
+			tcf_idr_release(*a, bind);
 			return -EEXIST;
+		}
 	}
 
 	spin_lock_bh(&d->tcf_lock);
diff --git a/net/sched/act_skbmod.c b/net/sched/act_skbmod.c
index 30be3f767495..e844381af066 100644
--- a/net/sched/act_skbmod.c
+++ b/net/sched/act_skbmod.c
@@ -145,10 +145,9 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla,
 			return ret;
 
 		ret = ACT_P_CREATED;
-	} else {
+	} else if (!ovr) {
 		tcf_idr_release(*a, bind);
-		if (!ovr)
-			return -EEXIST;
+		return -EEXIST;
 	}
 
 	d = to_skbmod(*a);
@@ -156,8 +155,7 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla,
 	ASSERT_RTNL();
 	p = kzalloc(sizeof(struct tcf_skbmod_params), GFP_KERNEL);
 	if (unlikely(!p)) {
-		if (ret == ACT_P_CREATED)
-			tcf_idr_release(*a, bind);
+		tcf_idr_release(*a, bind);
 		return -ENOMEM;
 	}
 
diff --git a/net/sched/act_tunnel_key.c b/net/sched/act_tunnel_key.c
index 655ed0b3fc67..ab5bf5c13f87 100644
--- a/net/sched/act_tunnel_key.c
+++ b/net/sched/act_tunnel_key.c
@@ -329,12 +329,10 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla,
 		}
 
 		ret = ACT_P_CREATED;
-	} else {
+	} else if (!ovr) {
 		tcf_idr_release(*a, bind);
-		if (!ovr) {
-			NL_SET_ERR_MSG(extack, "TC IDR already exists");
-			return -EEXIST;
-		}
+		NL_SET_ERR_MSG(extack, "TC IDR already exists");
+		return -EEXIST;
 	}
 
 	t = to_tunnel_key(*a);
@@ -342,8 +340,7 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla,
 	ASSERT_RTNL();
 	params_new = kzalloc(sizeof(*params_new), GFP_KERNEL);
 	if (unlikely(!params_new)) {
-		if (ret == ACT_P_CREATED)
-			tcf_idr_release(*a, bind);
+		tcf_idr_release(*a, bind);
 		NL_SET_ERR_MSG(extack, "Cannot allocate tunnel key parameters");
 		return -ENOMEM;
 	}
diff --git a/net/sched/act_vlan.c b/net/sched/act_vlan.c
index e334d2751784..9b600faaccbb 100644
--- a/net/sched/act_vlan.c
+++ b/net/sched/act_vlan.c
@@ -187,10 +187,9 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 			return ret;
 
 		ret = ACT_P_CREATED;
-	} else {
+	} else if (!ovr) {
 		tcf_idr_release(*a, bind);
-		if (!ovr)
-			return -EEXIST;
+		return -EEXIST;
 	}
 
 	v = to_vlan(*a);
@@ -198,8 +197,7 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 	ASSERT_RTNL();
 	p = kzalloc(sizeof(*p), GFP_KERNEL);
 	if (!p) {
-		if (ret == ACT_P_CREATED)
-			tcf_idr_release(*a, bind);
+		tcf_idr_release(*a, bind);
 		return -ENOMEM;
 	}
 

From cae422f379f37fe9105d2a113259788f989e7df5 Mon Sep 17 00:00:00 2001
From: Vlad Buslov <vladbu@mellanox.com>
Date: Thu, 5 Jul 2018 17:24:31 +0300
Subject: [PATCH 09/11] net: sched: use reference counting action init

Change action API to assume that action init function always takes
reference to action, even when overwriting existing action. This is
necessary because action API continues to use action pointer after init
function is done. At this point action becomes accessible for concurrent
modifications, so user must always hold reference to it.

Implement helper put list function to atomically release list of actions
after action API init code is done using them.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/sched/act_api.c | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index f019f0464cec..eefe8c2fe667 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -627,6 +627,18 @@ static int tcf_action_put(struct tc_action *p)
 	return __tcf_action_put(p, false);
 }
 
+static void tcf_action_put_lst(struct list_head *actions)
+{
+	struct tc_action *a, *tmp;
+
+	list_for_each_entry_safe(a, tmp, actions, list) {
+		const struct tc_action_ops *ops = a->ops;
+
+		if (tcf_action_put(a))
+			module_put(ops->owner);
+	}
+}
+
 int
 tcf_action_dump_old(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 {
@@ -835,17 +847,6 @@ err_out:
 	return ERR_PTR(err);
 }
 
-static void cleanup_a(struct list_head *actions, int ovr)
-{
-	struct tc_action *a;
-
-	if (!ovr)
-		return;
-
-	list_for_each_entry(a, actions, list)
-		refcount_dec(&a->tcfa_refcnt);
-}
-
 int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
 		    struct nlattr *est, char *name, int ovr, int bind,
 		    struct list_head *actions, size_t *attr_size,
@@ -874,11 +875,6 @@ int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
 	}
 
 	*attr_size = tcf_action_full_attrs_size(sz);
-
-	/* Remove the temp refcnt which was necessary to protect against
-	 * destroying an existing action which was being replaced
-	 */
-	cleanup_a(actions, ovr);
 	return 0;
 
 err:
@@ -1209,7 +1205,7 @@ tca_action_gd(struct net *net, struct nlattr *nla, struct nlmsghdr *n,
 		return ret;
 	}
 err:
-	tcf_action_destroy(&actions, 0);
+	tcf_action_put_lst(&actions);
 	return ret;
 }
 
@@ -1251,8 +1247,11 @@ static int tcf_action_add(struct net *net, struct nlattr *nla,
 			      &attr_size, true, extack);
 	if (ret)
 		return ret;
+	ret = tcf_add_notify(net, n, &actions, portid, attr_size, extack);
+	if (ovr)
+		tcf_action_put_lst(&actions);
 
-	return tcf_add_notify(net, n, &actions, portid, attr_size, extack);
+	return ret;
 }
 
 static u32 tcaa_root_flags_allowed = TCA_FLAG_LARGE_DUMP_ON;

From 0190c1d452a91c38a3462abdd81752be1b9006a8 Mon Sep 17 00:00:00 2001
From: Vlad Buslov <vladbu@mellanox.com>
Date: Thu, 5 Jul 2018 17:24:32 +0300
Subject: [PATCH 10/11] net: sched: atomically check-allocate action

Implement function that atomically checks if action exists and either takes
reference to it, or allocates idr slot for action index to prevent
concurrent allocations of actions with same index. Use EBUSY error pointer
to indicate that idr slot is reserved.

Implement cleanup helper function that removes temporary error pointer from
idr. (in case of error between idr allocation and insertion of newly
created action to specified index)

Refactor all action init functions to insert new action to idr using this
API.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/net/act_api.h      |  3 ++
 net/sched/act_api.c        | 92 +++++++++++++++++++++++++++++---------
 net/sched/act_bpf.c        | 11 +++--
 net/sched/act_connmark.c   | 10 +++--
 net/sched/act_csum.c       | 11 +++--
 net/sched/act_gact.c       | 11 +++--
 net/sched/act_ife.c        |  6 ++-
 net/sched/act_ipt.c        | 13 +++++-
 net/sched/act_mirred.c     | 16 +++++--
 net/sched/act_nat.c        | 11 +++--
 net/sched/act_pedit.c      | 12 +++--
 net/sched/act_police.c     |  9 +++-
 net/sched/act_sample.c     | 11 +++--
 net/sched/act_simple.c     | 11 ++++-
 net/sched/act_skbedit.c    | 11 ++++-
 net/sched/act_skbmod.c     | 11 ++++-
 net/sched/act_tunnel_key.c |  9 +++-
 net/sched/act_vlan.c       | 17 ++++++-
 18 files changed, 216 insertions(+), 59 deletions(-)

diff --git a/include/net/act_api.h b/include/net/act_api.h
index b9ed2b8256a5..8090de2edab7 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -154,6 +154,9 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
 		   int bind, bool cpustats);
 void tcf_idr_insert(struct tc_action_net *tn, struct tc_action *a);
 
+void tcf_idr_cleanup(struct tc_action_net *tn, u32 index);
+int tcf_idr_check_alloc(struct tc_action_net *tn, u32 *index,
+			struct tc_action **a, int bind);
 int tcf_idr_delete_index(struct tc_action_net *tn, u32 index);
 int __tcf_idr_release(struct tc_action *a, bool bind, bool strict);
 
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index eefe8c2fe667..9511502e1cbb 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -303,7 +303,9 @@ static bool __tcf_idr_check(struct tc_action_net *tn, u32 index,
 
 	spin_lock(&idrinfo->lock);
 	p = idr_find(&idrinfo->action_idr, index);
-	if (p) {
+	if (IS_ERR(p)) {
+		p = NULL;
+	} else if (p) {
 		refcount_inc(&p->tcfa_refcnt);
 		if (bind)
 			atomic_inc(&p->tcfa_bindcnt);
@@ -371,7 +373,6 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
 {
 	struct tc_action *p = kzalloc(ops->size, GFP_KERNEL);
 	struct tcf_idrinfo *idrinfo = tn->idrinfo;
-	struct idr *idr = &idrinfo->action_idr;
 	int err = -ENOMEM;
 
 	if (unlikely(!p))
@@ -389,20 +390,6 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
 			goto err2;
 	}
 	spin_lock_init(&p->tcfa_lock);
-	idr_preload(GFP_KERNEL);
-	spin_lock(&idrinfo->lock);
-	/* user doesn't specify an index */
-	if (!index) {
-		index = 1;
-		err = idr_alloc_u32(idr, NULL, &index, UINT_MAX, GFP_ATOMIC);
-	} else {
-		err = idr_alloc_u32(idr, NULL, &index, index, GFP_ATOMIC);
-	}
-	spin_unlock(&idrinfo->lock);
-	idr_preload_end();
-	if (err)
-		goto err3;
-
 	p->tcfa_index = index;
 	p->tcfa_tm.install = jiffies;
 	p->tcfa_tm.lastuse = jiffies;
@@ -412,7 +399,7 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
 					&p->tcfa_rate_est,
 					&p->tcfa_lock, NULL, est);
 		if (err)
-			goto err4;
+			goto err3;
 	}
 
 	p->idrinfo = idrinfo;
@@ -420,8 +407,6 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
 	INIT_LIST_HEAD(&p->list);
 	*a = p;
 	return 0;
-err4:
-	idr_remove(idr, index);
 err3:
 	free_percpu(p->cpu_qstats);
 err2:
@@ -437,11 +422,78 @@ void tcf_idr_insert(struct tc_action_net *tn, struct tc_action *a)
 	struct tcf_idrinfo *idrinfo = tn->idrinfo;
 
 	spin_lock(&idrinfo->lock);
-	idr_replace(&idrinfo->action_idr, a, a->tcfa_index);
+	/* Replace ERR_PTR(-EBUSY) allocated by tcf_idr_check_alloc */
+	WARN_ON(!IS_ERR(idr_replace(&idrinfo->action_idr, a, a->tcfa_index)));
 	spin_unlock(&idrinfo->lock);
 }
 EXPORT_SYMBOL(tcf_idr_insert);
 
+/* Cleanup idr index that was allocated but not initialized. */
+
+void tcf_idr_cleanup(struct tc_action_net *tn, u32 index)
+{
+	struct tcf_idrinfo *idrinfo = tn->idrinfo;
+
+	spin_lock(&idrinfo->lock);
+	/* Remove ERR_PTR(-EBUSY) allocated by tcf_idr_check_alloc */
+	WARN_ON(!IS_ERR(idr_remove(&idrinfo->action_idr, index)));
+	spin_unlock(&idrinfo->lock);
+}
+EXPORT_SYMBOL(tcf_idr_cleanup);
+
+/* Check if action with specified index exists. If actions is found, increments
+ * its reference and bind counters, and return 1. Otherwise insert temporary
+ * error pointer (to prevent concurrent users from inserting actions with same
+ * index) and return 0.
+ */
+
+int tcf_idr_check_alloc(struct tc_action_net *tn, u32 *index,
+			struct tc_action **a, int bind)
+{
+	struct tcf_idrinfo *idrinfo = tn->idrinfo;
+	struct tc_action *p;
+	int ret;
+
+again:
+	spin_lock(&idrinfo->lock);
+	if (*index) {
+		p = idr_find(&idrinfo->action_idr, *index);
+		if (IS_ERR(p)) {
+			/* This means that another process allocated
+			 * index but did not assign the pointer yet.
+			 */
+			spin_unlock(&idrinfo->lock);
+			goto again;
+		}
+
+		if (p) {
+			refcount_inc(&p->tcfa_refcnt);
+			if (bind)
+				atomic_inc(&p->tcfa_bindcnt);
+			*a = p;
+			ret = 1;
+		} else {
+			*a = NULL;
+			ret = idr_alloc_u32(&idrinfo->action_idr, NULL, index,
+					    *index, GFP_ATOMIC);
+			if (!ret)
+				idr_replace(&idrinfo->action_idr,
+					    ERR_PTR(-EBUSY), *index);
+		}
+	} else {
+		*index = 1;
+		*a = NULL;
+		ret = idr_alloc_u32(&idrinfo->action_idr, NULL, index,
+				    UINT_MAX, GFP_ATOMIC);
+		if (!ret)
+			idr_replace(&idrinfo->action_idr, ERR_PTR(-EBUSY),
+				    *index);
+	}
+	spin_unlock(&idrinfo->lock);
+	return ret;
+}
+EXPORT_SYMBOL(tcf_idr_check_alloc);
+
 void tcf_idrinfo_destroy(const struct tc_action_ops *ops,
 			 struct tcf_idrinfo *idrinfo)
 {
diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
index d3f4ac6f2c4b..06f743d8ed41 100644
--- a/net/sched/act_bpf.c
+++ b/net/sched/act_bpf.c
@@ -299,14 +299,17 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
 
 	parm = nla_data(tb[TCA_ACT_BPF_PARMS]);
 
-	if (!tcf_idr_check(tn, parm->index, act, bind)) {
+	ret = tcf_idr_check_alloc(tn, &parm->index, act, bind);
+	if (!ret) {
 		ret = tcf_idr_create(tn, parm->index, est, act,
 				     &act_bpf_ops, bind, true);
-		if (ret < 0)
+		if (ret < 0) {
+			tcf_idr_cleanup(tn, parm->index);
 			return ret;
+		}
 
 		res = ACT_P_CREATED;
-	} else {
+	} else if (ret > 0) {
 		/* Don't override defaults. */
 		if (bind)
 			return 0;
@@ -315,6 +318,8 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
 			tcf_idr_release(*act, bind);
 			return -EEXIST;
 		}
+	} else {
+		return ret;
 	}
 
 	is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS];
diff --git a/net/sched/act_connmark.c b/net/sched/act_connmark.c
index 701e90244eff..1e31f0e448e2 100644
--- a/net/sched/act_connmark.c
+++ b/net/sched/act_connmark.c
@@ -118,11 +118,14 @@ static int tcf_connmark_init(struct net *net, struct nlattr *nla,
 
 	parm = nla_data(tb[TCA_CONNMARK_PARMS]);
 
-	if (!tcf_idr_check(tn, parm->index, a, bind)) {
+	ret = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	if (!ret) {
 		ret = tcf_idr_create(tn, parm->index, est, a,
 				     &act_connmark_ops, bind, false);
-		if (ret)
+		if (ret) {
+			tcf_idr_cleanup(tn, parm->index);
 			return ret;
+		}
 
 		ci = to_connmark(*a);
 		ci->tcf_action = parm->action;
@@ -131,7 +134,7 @@ static int tcf_connmark_init(struct net *net, struct nlattr *nla,
 
 		tcf_idr_insert(tn, *a);
 		ret = ACT_P_CREATED;
-	} else {
+	} else if (ret > 0) {
 		ci = to_connmark(*a);
 		if (bind)
 			return 0;
@@ -142,6 +145,7 @@ static int tcf_connmark_init(struct net *net, struct nlattr *nla,
 		/* replacing action and zone */
 		ci->tcf_action = parm->action;
 		ci->zone = parm->zone;
+		ret = 0;
 	}
 
 	return ret;
diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c
index 5dbee136b0a1..bd232d3bd022 100644
--- a/net/sched/act_csum.c
+++ b/net/sched/act_csum.c
@@ -67,19 +67,24 @@ static int tcf_csum_init(struct net *net, struct nlattr *nla,
 		return -EINVAL;
 	parm = nla_data(tb[TCA_CSUM_PARMS]);
 
-	if (!tcf_idr_check(tn, parm->index, a, bind)) {
+	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	if (!err) {
 		ret = tcf_idr_create(tn, parm->index, est, a,
 				     &act_csum_ops, bind, true);
-		if (ret)
+		if (ret) {
+			tcf_idr_cleanup(tn, parm->index);
 			return ret;
+		}
 		ret = ACT_P_CREATED;
-	} else {
+	} else if (err > 0) {
 		if (bind)/* dont override defaults */
 			return 0;
 		if (!ovr) {
 			tcf_idr_release(*a, bind);
 			return -EEXIST;
 		}
+	} else {
+		return err;
 	}
 
 	p = to_tcf_csum(*a);
diff --git a/net/sched/act_gact.c b/net/sched/act_gact.c
index 11c4de3f344e..661b72b9147d 100644
--- a/net/sched/act_gact.c
+++ b/net/sched/act_gact.c
@@ -91,19 +91,24 @@ static int tcf_gact_init(struct net *net, struct nlattr *nla,
 	}
 #endif
 
-	if (!tcf_idr_check(tn, parm->index, a, bind)) {
+	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	if (!err) {
 		ret = tcf_idr_create(tn, parm->index, est, a,
 				     &act_gact_ops, bind, true);
-		if (ret)
+		if (ret) {
+			tcf_idr_cleanup(tn, parm->index);
 			return ret;
+		}
 		ret = ACT_P_CREATED;
-	} else {
+	} else if (err > 0) {
 		if (bind)/* dont override defaults */
 			return 0;
 		if (!ovr) {
 			tcf_idr_release(*a, bind);
 			return -EEXIST;
 		}
+	} else {
+		return err;
 	}
 
 	gact = to_gact(*a);
diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c
index acea3feae762..a3eef00cd711 100644
--- a/net/sched/act_ife.c
+++ b/net/sched/act_ife.c
@@ -484,7 +484,10 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
 	if (!p)
 		return -ENOMEM;
 
-	exists = tcf_idr_check(tn, parm->index, a, bind);
+	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	if (err < 0)
+		return err;
+	exists = err;
 	if (exists && bind) {
 		kfree(p);
 		return 0;
@@ -494,6 +497,7 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
 		ret = tcf_idr_create(tn, parm->index, est, a, &act_ife_ops,
 				     bind, true);
 		if (ret) {
+			tcf_idr_cleanup(tn, parm->index);
 			kfree(p);
 			return ret;
 		}
diff --git a/net/sched/act_ipt.c b/net/sched/act_ipt.c
index 85e85dfba401..0dc787a57798 100644
--- a/net/sched/act_ipt.c
+++ b/net/sched/act_ipt.c
@@ -119,13 +119,18 @@ static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla,
 	if (tb[TCA_IPT_INDEX] != NULL)
 		index = nla_get_u32(tb[TCA_IPT_INDEX]);
 
-	exists = tcf_idr_check(tn, index, a, bind);
+	err = tcf_idr_check_alloc(tn, &index, a, bind);
+	if (err < 0)
+		return err;
+	exists = err;
 	if (exists && bind)
 		return 0;
 
 	if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) {
 		if (exists)
 			tcf_idr_release(*a, bind);
+		else
+			tcf_idr_cleanup(tn, index);
 		return -EINVAL;
 	}
 
@@ -133,14 +138,18 @@ static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla,
 	if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size) {
 		if (exists)
 			tcf_idr_release(*a, bind);
+		else
+			tcf_idr_cleanup(tn, index);
 		return -EINVAL;
 	}
 
 	if (!exists) {
 		ret = tcf_idr_create(tn, index, est, a, ops, bind,
 				     false);
-		if (ret)
+		if (ret) {
+			tcf_idr_cleanup(tn, index);
 			return ret;
+		}
 		ret = ACT_P_CREATED;
 	} else {
 		if (bind)/* dont override defaults */
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index e08aed06d7f8..6afd89a36c69 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -79,7 +79,7 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 	struct tcf_mirred *m;
 	struct net_device *dev;
 	bool exists = false;
-	int ret;
+	int ret, err;
 
 	if (!nla) {
 		NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed");
@@ -94,7 +94,10 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 	}
 	parm = nla_data(tb[TCA_MIRRED_PARMS]);
 
-	exists = tcf_idr_check(tn, parm->index, a, bind);
+	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	if (err < 0)
+		return err;
+	exists = err;
 	if (exists && bind)
 		return 0;
 
@@ -107,6 +110,8 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 	default:
 		if (exists)
 			tcf_idr_release(*a, bind);
+		else
+			tcf_idr_cleanup(tn, parm->index);
 		NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
 		return -EINVAL;
 	}
@@ -115,6 +120,8 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 		if (dev == NULL) {
 			if (exists)
 				tcf_idr_release(*a, bind);
+			else
+				tcf_idr_cleanup(tn, parm->index);
 			return -ENODEV;
 		}
 		mac_header_xmit = dev_is_mac_header_xmit(dev);
@@ -124,13 +131,16 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 
 	if (!exists) {
 		if (!dev) {
+			tcf_idr_cleanup(tn, parm->index);
 			NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist");
 			return -EINVAL;
 		}
 		ret = tcf_idr_create(tn, parm->index, est, a,
 				     &act_mirred_ops, bind, true);
-		if (ret)
+		if (ret) {
+			tcf_idr_cleanup(tn, parm->index);
 			return ret;
+		}
 		ret = ACT_P_CREATED;
 	} else if (!ovr) {
 		tcf_idr_release(*a, bind);
diff --git a/net/sched/act_nat.c b/net/sched/act_nat.c
index 1f91e8e66c0f..4dd9188a72fd 100644
--- a/net/sched/act_nat.c
+++ b/net/sched/act_nat.c
@@ -57,19 +57,24 @@ static int tcf_nat_init(struct net *net, struct nlattr *nla, struct nlattr *est,
 		return -EINVAL;
 	parm = nla_data(tb[TCA_NAT_PARMS]);
 
-	if (!tcf_idr_check(tn, parm->index, a, bind)) {
+	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	if (!err) {
 		ret = tcf_idr_create(tn, parm->index, est, a,
 				     &act_nat_ops, bind, false);
-		if (ret)
+		if (ret) {
+			tcf_idr_cleanup(tn, parm->index);
 			return ret;
+		}
 		ret = ACT_P_CREATED;
-	} else {
+	} else if (err > 0) {
 		if (bind)
 			return 0;
 		if (!ovr) {
 			tcf_idr_release(*a, bind);
 			return -EEXIST;
 		}
+	} else {
+		return err;
 	}
 	p = to_tcf_nat(*a);
 
diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
index 3a0e2f762f4e..cc8ffcd1ddb5 100644
--- a/net/sched/act_pedit.c
+++ b/net/sched/act_pedit.c
@@ -173,16 +173,20 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 	if (IS_ERR(keys_ex))
 		return PTR_ERR(keys_ex);
 
-	if (!tcf_idr_check(tn, parm->index, a, bind)) {
+	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	if (!err) {
 		if (!parm->nkeys) {
+			tcf_idr_cleanup(tn, parm->index);
 			NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
 			ret = -EINVAL;
 			goto out_free;
 		}
 		ret = tcf_idr_create(tn, parm->index, est, a,
 				     &act_pedit_ops, bind, false);
-		if (ret)
+		if (ret) {
+			tcf_idr_cleanup(tn, parm->index);
 			goto out_free;
+		}
 		p = to_pedit(*a);
 		keys = kmalloc(ksize, GFP_KERNEL);
 		if (!keys) {
@@ -191,7 +195,7 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 			goto out_free;
 		}
 		ret = ACT_P_CREATED;
-	} else {
+	} else if (err > 0) {
 		if (bind)
 			goto out_free;
 		if (!ovr) {
@@ -207,6 +211,8 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 				goto out_free;
 			}
 		}
+	} else {
+		return err;
 	}
 
 	spin_lock_bh(&p->tcf_lock);
diff --git a/net/sched/act_police.c b/net/sched/act_police.c
index 99335cca739e..1f3192ea8df7 100644
--- a/net/sched/act_police.c
+++ b/net/sched/act_police.c
@@ -101,15 +101,20 @@ static int tcf_act_police_init(struct net *net, struct nlattr *nla,
 		return -EINVAL;
 
 	parm = nla_data(tb[TCA_POLICE_TBF]);
-	exists = tcf_idr_check(tn, parm->index, a, bind);
+	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	if (err < 0)
+		return err;
+	exists = err;
 	if (exists && bind)
 		return 0;
 
 	if (!exists) {
 		ret = tcf_idr_create(tn, parm->index, NULL, a,
 				     &act_police_ops, bind, false);
-		if (ret)
+		if (ret) {
+			tcf_idr_cleanup(tn, parm->index);
 			return ret;
+		}
 		ret = ACT_P_CREATED;
 	} else if (!ovr) {
 		tcf_idr_release(*a, bind);
diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c
index a8582e1347db..3079e7be5bde 100644
--- a/net/sched/act_sample.c
+++ b/net/sched/act_sample.c
@@ -46,7 +46,7 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla,
 	struct tc_sample *parm;
 	struct tcf_sample *s;
 	bool exists = false;
-	int ret;
+	int ret, err;
 
 	if (!nla)
 		return -EINVAL;
@@ -59,15 +59,20 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla,
 
 	parm = nla_data(tb[TCA_SAMPLE_PARMS]);
 
-	exists = tcf_idr_check(tn, parm->index, a, bind);
+	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	if (err < 0)
+		return err;
+	exists = err;
 	if (exists && bind)
 		return 0;
 
 	if (!exists) {
 		ret = tcf_idr_create(tn, parm->index, est, a,
 				     &act_sample_ops, bind, false);
-		if (ret)
+		if (ret) {
+			tcf_idr_cleanup(tn, parm->index);
 			return ret;
+		}
 		ret = ACT_P_CREATED;
 	} else if (!ovr) {
 		tcf_idr_release(*a, bind);
diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c
index 2da47c682a30..aa51152e0066 100644
--- a/net/sched/act_simple.c
+++ b/net/sched/act_simple.c
@@ -100,21 +100,28 @@ static int tcf_simp_init(struct net *net, struct nlattr *nla,
 		return -EINVAL;
 
 	parm = nla_data(tb[TCA_DEF_PARMS]);
-	exists = tcf_idr_check(tn, parm->index, a, bind);
+	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	if (err < 0)
+		return err;
+	exists = err;
 	if (exists && bind)
 		return 0;
 
 	if (tb[TCA_DEF_DATA] == NULL) {
 		if (exists)
 			tcf_idr_release(*a, bind);
+		else
+			tcf_idr_cleanup(tn, parm->index);
 		return -EINVAL;
 	}
 
 	if (!exists) {
 		ret = tcf_idr_create(tn, parm->index, est, a,
 				     &act_simp_ops, bind, false);
-		if (ret)
+		if (ret) {
+			tcf_idr_cleanup(tn, parm->index);
 			return ret;
+		}
 
 		d = to_defact(*a);
 		ret = alloc_defdata(d, tb[TCA_DEF_DATA]);
diff --git a/net/sched/act_skbedit.c b/net/sched/act_skbedit.c
index 4616a2c1821f..86521a74ecdd 100644
--- a/net/sched/act_skbedit.c
+++ b/net/sched/act_skbedit.c
@@ -152,21 +152,28 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
 
 	parm = nla_data(tb[TCA_SKBEDIT_PARMS]);
 
-	exists = tcf_idr_check(tn, parm->index, a, bind);
+	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	if (err < 0)
+		return err;
+	exists = err;
 	if (exists && bind)
 		return 0;
 
 	if (!flags) {
 		if (exists)
 			tcf_idr_release(*a, bind);
+		else
+			tcf_idr_cleanup(tn, parm->index);
 		return -EINVAL;
 	}
 
 	if (!exists) {
 		ret = tcf_idr_create(tn, parm->index, est, a,
 				     &act_skbedit_ops, bind, false);
-		if (ret)
+		if (ret) {
+			tcf_idr_cleanup(tn, parm->index);
 			return ret;
+		}
 
 		d = to_skbedit(*a);
 		ret = ACT_P_CREATED;
diff --git a/net/sched/act_skbmod.c b/net/sched/act_skbmod.c
index e844381af066..cdc6bacfb190 100644
--- a/net/sched/act_skbmod.c
+++ b/net/sched/act_skbmod.c
@@ -128,21 +128,28 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla,
 	if (parm->flags & SKBMOD_F_SWAPMAC)
 		lflags = SKBMOD_F_SWAPMAC;
 
-	exists = tcf_idr_check(tn, parm->index, a, bind);
+	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	if (err < 0)
+		return err;
+	exists = err;
 	if (exists && bind)
 		return 0;
 
 	if (!lflags) {
 		if (exists)
 			tcf_idr_release(*a, bind);
+		else
+			tcf_idr_cleanup(tn, parm->index);
 		return -EINVAL;
 	}
 
 	if (!exists) {
 		ret = tcf_idr_create(tn, parm->index, est, a,
 				     &act_skbmod_ops, bind, true);
-		if (ret)
+		if (ret) {
+			tcf_idr_cleanup(tn, parm->index);
 			return ret;
+		}
 
 		ret = ACT_P_CREATED;
 	} else if (!ovr) {
diff --git a/net/sched/act_tunnel_key.c b/net/sched/act_tunnel_key.c
index ab5bf5c13f87..3ec585d58762 100644
--- a/net/sched/act_tunnel_key.c
+++ b/net/sched/act_tunnel_key.c
@@ -237,7 +237,10 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla,
 	}
 
 	parm = nla_data(tb[TCA_TUNNEL_KEY_PARMS]);
-	exists = tcf_idr_check(tn, parm->index, a, bind);
+	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	if (err < 0)
+		return err;
+	exists = err;
 	if (exists && bind)
 		return 0;
 
@@ -325,7 +328,7 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla,
 				     &act_tunnel_key_ops, bind, true);
 		if (ret) {
 			NL_SET_ERR_MSG(extack, "Cannot create TC IDR");
-			return ret;
+			goto err_out;
 		}
 
 		ret = ACT_P_CREATED;
@@ -364,6 +367,8 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla,
 err_out:
 	if (exists)
 		tcf_idr_release(*a, bind);
+	else
+		tcf_idr_cleanup(tn, parm->index);
 	return ret;
 }
 
diff --git a/net/sched/act_vlan.c b/net/sched/act_vlan.c
index 9b600faaccbb..ad37f308175a 100644
--- a/net/sched/act_vlan.c
+++ b/net/sched/act_vlan.c
@@ -134,7 +134,10 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 	if (!tb[TCA_VLAN_PARMS])
 		return -EINVAL;
 	parm = nla_data(tb[TCA_VLAN_PARMS]);
-	exists = tcf_idr_check(tn, parm->index, a, bind);
+	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
+	if (err < 0)
+		return err;
+	exists = err;
 	if (exists && bind)
 		return 0;
 
@@ -146,12 +149,16 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 		if (!tb[TCA_VLAN_PUSH_VLAN_ID]) {
 			if (exists)
 				tcf_idr_release(*a, bind);
+			else
+				tcf_idr_cleanup(tn, parm->index);
 			return -EINVAL;
 		}
 		push_vid = nla_get_u16(tb[TCA_VLAN_PUSH_VLAN_ID]);
 		if (push_vid >= VLAN_VID_MASK) {
 			if (exists)
 				tcf_idr_release(*a, bind);
+			else
+				tcf_idr_cleanup(tn, parm->index);
 			return -ERANGE;
 		}
 
@@ -164,6 +171,8 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 			default:
 				if (exists)
 					tcf_idr_release(*a, bind);
+				else
+					tcf_idr_cleanup(tn, parm->index);
 				return -EPROTONOSUPPORT;
 			}
 		} else {
@@ -176,6 +185,8 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 	default:
 		if (exists)
 			tcf_idr_release(*a, bind);
+		else
+			tcf_idr_cleanup(tn, parm->index);
 		return -EINVAL;
 	}
 	action = parm->v_action;
@@ -183,8 +194,10 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 	if (!exists) {
 		ret = tcf_idr_create(tn, parm->index, est, a,
 				     &act_vlan_ops, bind, true);
-		if (ret)
+		if (ret) {
+			tcf_idr_cleanup(tn, parm->index);
 			return ret;
+		}
 
 		ret = ACT_P_CREATED;
 	} else if (!ovr) {

From 90b73b77d08ec395311411b545c756ca710aae59 Mon Sep 17 00:00:00 2001
From: Vlad Buslov <vladbu@mellanox.com>
Date: Thu, 5 Jul 2018 17:24:33 +0300
Subject: [PATCH 11/11] net: sched: change action API to use array of pointers
 to actions

Act API used linked list to pass set of actions to functions. It is
intrusive data structure that stores list nodes inside action structure
itself, which means it is not safe to modify such list concurrently.
However, action API doesn't use any linked list specific operations on this
set of actions, so it can be safely refactored into plain pointer array.

Refactor action API to use array of pointers to tc_actions instead of
linked list. Change argument 'actions' type of exported action init,
destroy and dump functions.

Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/net/act_api.h |  7 ++--
 net/sched/act_api.c   | 89 ++++++++++++++++++++++++-------------------
 net/sched/cls_api.c   | 21 +++-------
 3 files changed, 60 insertions(+), 57 deletions(-)

diff --git a/include/net/act_api.h b/include/net/act_api.h
index 8090de2edab7..683ce41053d9 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -168,19 +168,20 @@ static inline int tcf_idr_release(struct tc_action *a, bool bind)
 int tcf_register_action(struct tc_action_ops *a, struct pernet_operations *ops);
 int tcf_unregister_action(struct tc_action_ops *a,
 			  struct pernet_operations *ops);
-int tcf_action_destroy(struct list_head *actions, int bind);
+int tcf_action_destroy(struct tc_action *actions[], int bind);
 int tcf_action_exec(struct sk_buff *skb, struct tc_action **actions,
 		    int nr_actions, struct tcf_result *res);
 int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
 		    struct nlattr *est, char *name, int ovr, int bind,
-		    struct list_head *actions, size_t *attr_size,
+		    struct tc_action *actions[], size_t *attr_size,
 		    bool rtnl_held, struct netlink_ext_ack *extack);
 struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp,
 				    struct nlattr *nla, struct nlattr *est,
 				    char *name, int ovr, int bind,
 				    bool rtnl_held,
 				    struct netlink_ext_ack *extack);
-int tcf_action_dump(struct sk_buff *skb, struct list_head *, int, int);
+int tcf_action_dump(struct sk_buff *skb, struct tc_action *actions[], int bind,
+		    int ref);
 int tcf_action_dump_old(struct sk_buff *skb, struct tc_action *a, int, int);
 int tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int, int);
 int tcf_action_copy_stats(struct sk_buff *, struct tc_action *, int);
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 9511502e1cbb..bf1c35f3deb6 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -657,13 +657,15 @@ repeat:
 }
 EXPORT_SYMBOL(tcf_action_exec);
 
-int tcf_action_destroy(struct list_head *actions, int bind)
+int tcf_action_destroy(struct tc_action *actions[], int bind)
 {
 	const struct tc_action_ops *ops;
-	struct tc_action *a, *tmp;
-	int ret = 0;
+	struct tc_action *a;
+	int ret = 0, i;
 
-	list_for_each_entry_safe(a, tmp, actions, list) {
+	for (i = 0; i < TCA_ACT_MAX_PRIO && actions[i]; i++) {
+		a = actions[i];
+		actions[i] = NULL;
 		ops = a->ops;
 		ret = __tcf_idr_release(a, bind, true);
 		if (ret == ACT_P_DELETED)
@@ -679,11 +681,12 @@ static int tcf_action_put(struct tc_action *p)
 	return __tcf_action_put(p, false);
 }
 
-static void tcf_action_put_lst(struct list_head *actions)
+static void tcf_action_put_many(struct tc_action *actions[])
 {
-	struct tc_action *a, *tmp;
+	int i;
 
-	list_for_each_entry_safe(a, tmp, actions, list) {
+	for (i = 0; i < TCA_ACT_MAX_PRIO && actions[i]; i++) {
+		struct tc_action *a = actions[i];
 		const struct tc_action_ops *ops = a->ops;
 
 		if (tcf_action_put(a))
@@ -735,14 +738,15 @@ nla_put_failure:
 }
 EXPORT_SYMBOL(tcf_action_dump_1);
 
-int tcf_action_dump(struct sk_buff *skb, struct list_head *actions,
+int tcf_action_dump(struct sk_buff *skb, struct tc_action *actions[],
 		    int bind, int ref)
 {
 	struct tc_action *a;
-	int err = -EINVAL;
+	int err = -EINVAL, i;
 	struct nlattr *nest;
 
-	list_for_each_entry(a, actions, list) {
+	for (i = 0; i < TCA_ACT_MAX_PRIO && actions[i]; i++) {
+		a = actions[i];
 		nest = nla_nest_start(skb, a->order);
 		if (nest == NULL)
 			goto nla_put_failure;
@@ -878,10 +882,9 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp,
 	if (TC_ACT_EXT_CMP(a->tcfa_action, TC_ACT_GOTO_CHAIN)) {
 		err = tcf_action_goto_chain_init(a, tp);
 		if (err) {
-			LIST_HEAD(actions);
+			struct tc_action *actions[] = { a, NULL };
 
-			list_add_tail(&a->list, &actions);
-			tcf_action_destroy(&actions, bind);
+			tcf_action_destroy(actions, bind);
 			NL_SET_ERR_MSG(extack, "Failed to init TC action chain");
 			return ERR_PTR(err);
 		}
@@ -899,9 +902,11 @@ err_out:
 	return ERR_PTR(err);
 }
 
+/* Returns numbers of initialized actions or negative error. */
+
 int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
 		    struct nlattr *est, char *name, int ovr, int bind,
-		    struct list_head *actions, size_t *attr_size,
+		    struct tc_action *actions[], size_t *attr_size,
 		    bool rtnl_held, struct netlink_ext_ack *extack)
 {
 	struct nlattr *tb[TCA_ACT_MAX_PRIO + 1];
@@ -923,11 +928,12 @@ int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
 		}
 		act->order = i;
 		sz += tcf_action_fill_size(act);
-		list_add_tail(&act->list, actions);
+		/* Start from index 0 */
+		actions[i - 1] = act;
 	}
 
 	*attr_size = tcf_action_full_attrs_size(sz);
-	return 0;
+	return i - 1;
 
 err:
 	tcf_action_destroy(actions, bind);
@@ -978,7 +984,7 @@ errout:
 	return -1;
 }
 
-static int tca_get_fill(struct sk_buff *skb, struct list_head *actions,
+static int tca_get_fill(struct sk_buff *skb, struct tc_action *actions[],
 			u32 portid, u32 seq, u16 flags, int event, int bind,
 			int ref)
 {
@@ -1014,7 +1020,7 @@ out_nlmsg_trim:
 
 static int
 tcf_get_notify(struct net *net, u32 portid, struct nlmsghdr *n,
-	       struct list_head *actions, int event,
+	       struct tc_action *actions[], int event,
 	       struct netlink_ext_ack *extack)
 {
 	struct sk_buff *skb;
@@ -1150,14 +1156,14 @@ err_out:
 	return err;
 }
 
-static int tcf_action_delete(struct net *net, struct list_head *actions,
-			     struct netlink_ext_ack *extack)
+static int tcf_action_delete(struct net *net, struct tc_action *actions[],
+			     int *acts_deleted, struct netlink_ext_ack *extack)
 {
-	struct tc_action *a, *tmp;
 	u32 act_index;
-	int ret;
+	int ret, i;
 
-	list_for_each_entry_safe(a, tmp, actions, list) {
+	for (i = 0; i < TCA_ACT_MAX_PRIO && actions[i]; i++) {
+		struct tc_action *a = actions[i];
 		const struct tc_action_ops *ops = a->ops;
 
 		/* Actions can be deleted concurrently so we must save their
@@ -1165,23 +1171,26 @@ static int tcf_action_delete(struct net *net, struct list_head *actions,
 		 */
 		act_index = a->tcfa_index;
 
-		list_del(&a->list);
 		if (tcf_action_put(a)) {
 			/* last reference, action was deleted concurrently */
 			module_put(ops->owner);
 		} else  {
 			/* now do the delete */
 			ret = ops->delete(net, act_index);
-			if (ret < 0)
+			if (ret < 0) {
+				*acts_deleted = i + 1;
 				return ret;
+			}
 		}
 	}
+	*acts_deleted = i;
 	return 0;
 }
 
 static int
-tcf_del_notify(struct net *net, struct nlmsghdr *n, struct list_head *actions,
-	       u32 portid, size_t attr_size, struct netlink_ext_ack *extack)
+tcf_del_notify(struct net *net, struct nlmsghdr *n, struct tc_action *actions[],
+	       int *acts_deleted, u32 portid, size_t attr_size,
+	       struct netlink_ext_ack *extack)
 {
 	int ret;
 	struct sk_buff *skb;
@@ -1199,7 +1208,7 @@ tcf_del_notify(struct net *net, struct nlmsghdr *n, struct list_head *actions,
 	}
 
 	/* now do the delete */
-	ret = tcf_action_delete(net, actions, extack);
+	ret = tcf_action_delete(net, actions, acts_deleted, extack);
 	if (ret < 0) {
 		NL_SET_ERR_MSG(extack, "Failed to delete TC action");
 		kfree_skb(skb);
@@ -1221,7 +1230,8 @@ tca_action_gd(struct net *net, struct nlattr *nla, struct nlmsghdr *n,
 	struct nlattr *tb[TCA_ACT_MAX_PRIO + 1];
 	struct tc_action *act;
 	size_t attr_size = 0;
-	LIST_HEAD(actions);
+	struct tc_action *actions[TCA_ACT_MAX_PRIO + 1] = {};
+	int acts_deleted = 0;
 
 	ret = nla_parse_nested(tb, TCA_ACT_MAX_PRIO, nla, NULL, extack);
 	if (ret < 0)
@@ -1243,26 +1253,27 @@ tca_action_gd(struct net *net, struct nlattr *nla, struct nlmsghdr *n,
 		}
 		act->order = i;
 		attr_size += tcf_action_fill_size(act);
-		list_add_tail(&act->list, &actions);
+		actions[i - 1] = act;
 	}
 
 	attr_size = tcf_action_full_attrs_size(attr_size);
 
 	if (event == RTM_GETACTION)
-		ret = tcf_get_notify(net, portid, n, &actions, event, extack);
+		ret = tcf_get_notify(net, portid, n, actions, event, extack);
 	else { /* delete */
-		ret = tcf_del_notify(net, n, &actions, portid, attr_size, extack);
+		ret = tcf_del_notify(net, n, actions, &acts_deleted, portid,
+				     attr_size, extack);
 		if (ret)
 			goto err;
 		return ret;
 	}
 err:
-	tcf_action_put_lst(&actions);
+	tcf_action_put_many(&actions[acts_deleted]);
 	return ret;
 }
 
 static int
-tcf_add_notify(struct net *net, struct nlmsghdr *n, struct list_head *actions,
+tcf_add_notify(struct net *net, struct nlmsghdr *n, struct tc_action *actions[],
 	       u32 portid, size_t attr_size, struct netlink_ext_ack *extack)
 {
 	struct sk_buff *skb;
@@ -1293,15 +1304,15 @@ static int tcf_action_add(struct net *net, struct nlattr *nla,
 {
 	size_t attr_size = 0;
 	int ret = 0;
-	LIST_HEAD(actions);
+	struct tc_action *actions[TCA_ACT_MAX_PRIO] = {};
 
-	ret = tcf_action_init(net, NULL, nla, NULL, NULL, ovr, 0, &actions,
+	ret = tcf_action_init(net, NULL, nla, NULL, NULL, ovr, 0, actions,
 			      &attr_size, true, extack);
-	if (ret)
+	if (ret < 0)
 		return ret;
-	ret = tcf_add_notify(net, n, &actions, portid, attr_size, extack);
+	ret = tcf_add_notify(net, n, actions, portid, attr_size, extack);
 	if (ovr)
-		tcf_action_put_lst(&actions);
+		tcf_action_put_many(actions);
 
 	return ret;
 }
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 9041f0e43e9a..73d9967c3739 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -1609,10 +1609,7 @@ out:
 void tcf_exts_destroy(struct tcf_exts *exts)
 {
 #ifdef CONFIG_NET_CLS_ACT
-	LIST_HEAD(actions);
-
-	tcf_exts_to_list(exts, &actions);
-	tcf_action_destroy(&actions, TCA_ACT_UNBIND);
+	tcf_action_destroy(exts->actions, TCA_ACT_UNBIND);
 	kfree(exts->actions);
 	exts->nr_actions = 0;
 #endif
@@ -1639,18 +1636,15 @@ int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
 			exts->actions[0] = act;
 			exts->nr_actions = 1;
 		} else if (exts->action && tb[exts->action]) {
-			LIST_HEAD(actions);
-			int err, i = 0;
+			int err;
 
 			err = tcf_action_init(net, tp, tb[exts->action],
 					      rate_tlv, NULL, ovr, TCA_ACT_BIND,
-					      &actions, &attr_size, true,
+					      exts->actions, &attr_size, true,
 					      extack);
-			if (err)
+			if (err < 0)
 				return err;
-			list_for_each_entry(act, &actions, list)
-				exts->actions[i++] = act;
-			exts->nr_actions = i;
+			exts->nr_actions = err;
 		}
 		exts->net = net;
 	}
@@ -1699,14 +1693,11 @@ int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts)
 		 * tc data even if iproute2  was newer - jhs
 		 */
 		if (exts->type != TCA_OLD_COMPAT) {
-			LIST_HEAD(actions);
-
 			nest = nla_nest_start(skb, exts->action);
 			if (nest == NULL)
 				goto nla_put_failure;
 
-			tcf_exts_to_list(exts, &actions);
-			if (tcf_action_dump(skb, &actions, 0, 0) < 0)
+			if (tcf_action_dump(skb, exts->actions, 0, 0) < 0)
 				goto nla_put_failure;
 			nla_nest_end(skb, nest);
 		} else if (exts->police) {