Merge branch 'net-sched-action-init-fixes'

Vlad Buslov says:

====================
Action initalization fixes

This series fixes reference counting of action instances and modules in
several parts of action init code. The first patch reverts previous fix
that didn't properly account for rollback from a failure in the middle of
the loop in tcf_action_init() which is properly fixed by the following
patch.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 42 insertions, 35 deletions

diff --git a/include/net/act_api.h b/include/net/act_api.h
index 2bf3092ae7ecc..086b291e9530b 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -170,12 +170,7 @@ void tcf_idr_insert_many(struct tc_action *actions[]);
 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_release(struct tc_action *a, bool bind, bool strict);
-
-static inline int tcf_idr_release(struct tc_action *a, bool bind)
-{
-	return __tcf_idr_release(a, bind, false);
-}
+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,
@@ -185,7 +180,7 @@ 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 tc_action *actions[], size_t *attr_size,
+		    struct tc_action *actions[], int init_res[], size_t *attr_size,
 		    bool rtnl_held, struct netlink_ext_ack *extack);
 struct tc_action_ops *tc_action_load_ops(char *name, struct nlattr *nla,
 					 bool rtnl_held,
@@ -193,7 +188,8 @@ struct tc_action_ops *tc_action_load_ops(char *name, struct nlattr *nla,
 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,
-				    struct tc_action_ops *ops, bool rtnl_held,
+				    struct tc_action_ops *a_o, int *init_res,
+				    bool rtnl_held,
 				    struct netlink_ext_ack *extack);
 int tcf_action_dump(struct sk_buff *skb, struct tc_action *actions[], int bind,
 		    int ref, bool terse);
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 43cceb924976f..f6d5755d669eb 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -158,7 +158,7 @@ static int __tcf_action_put(struct tc_action *p, bool bind)
 	return 0;
 }
 
-int __tcf_idr_release(struct tc_action *p, bool bind, bool strict)
+static int __tcf_idr_release(struct tc_action *p, bool bind, bool strict)
 {
 	int ret = 0;
 
@@ -184,7 +184,18 @@ int __tcf_idr_release(struct tc_action *p, bool bind, bool strict)
 
 	return ret;
 }
-EXPORT_SYMBOL(__tcf_idr_release);
+
+int tcf_idr_release(struct tc_action *a, bool bind)
+{
+	const struct tc_action_ops *ops = a->ops;
+	int ret;
+
+	ret = __tcf_idr_release(a, bind, false);
+	if (ret == ACT_P_DELETED)
+		module_put(ops->owner);
+	return ret;
+}
+EXPORT_SYMBOL(tcf_idr_release);
 
 static size_t tcf_action_shared_attrs_size(const struct tc_action *act)
 {
@@ -493,6 +504,7 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
 	}
 
 	p->idrinfo = idrinfo;
+	__module_get(ops->owner);
 	p->ops = ops;
 	*a = p;
 	return 0;
@@ -992,7 +1004,8 @@ struct tc_action_ops *tc_action_load_ops(char *name, struct nlattr *nla,
 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,
-				    struct tc_action_ops *a_o, bool rtnl_held,
+				    struct tc_action_ops *a_o, int *init_res,
+				    bool rtnl_held,
 				    struct netlink_ext_ack *extack)
 {
 	struct nla_bitfield32 flags = { 0, 0 };
@@ -1028,6 +1041,7 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp,
 	}
 	if (err < 0)
 		goto err_out;
+	*init_res = err;
 
 	if (!name && tb[TCA_ACT_COOKIE])
 		tcf_set_action_cookie(&a->act_cookie, cookie);
@@ -1035,16 +1049,6 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp,
 	if (!name)
 		a->hw_stats = hw_stats;
 
-	/* module count goes up only when brand new policy is created
-	 * if it exists and is only bound to in a_o->init() then
-	 * ACT_P_CREATED is not returned (a zero is).
-	 */
-	if (err != ACT_P_CREATED)
-		module_put(a_o->owner);
-
-	if (!bind && ovr && err == ACT_P_CREATED)
-		refcount_set(&a->tcfa_refcnt, 2);
-
 	return a;
 
 err_out:
@@ -1059,7 +1063,7 @@ err_out:
 
 int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
 		    struct nlattr *est, char *name, int ovr, int bind,
-		    struct tc_action *actions[], size_t *attr_size,
+		    struct tc_action *actions[], int init_res[], size_t *attr_size,
 		    bool rtnl_held, struct netlink_ext_ack *extack)
 {
 	struct tc_action_ops *ops[TCA_ACT_MAX_PRIO] = {};
@@ -1087,7 +1091,8 @@ 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,
-					ops[i - 1], rtnl_held, extack);
+					ops[i - 1], &init_res[i - 1], rtnl_held,
+					extack);
 		if (IS_ERR(act)) {
 			err = PTR_ERR(act);
 			goto err;
@@ -1103,7 +1108,8 @@ int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
 	tcf_idr_insert_many(actions);
 
 	*attr_size = tcf_action_full_attrs_size(sz);
-	return i - 1;
+	err = i - 1;
+	goto err_mod;
 
 err:
 	tcf_action_destroy(actions, bind);
@@ -1500,12 +1506,13 @@ static int tcf_action_add(struct net *net, struct nlattr *nla,
 			  struct netlink_ext_ack *extack)
 {
 	size_t attr_size = 0;
-	int loop, ret;
+	int loop, ret, i;
 	struct tc_action *actions[TCA_ACT_MAX_PRIO] = {};
+	int init_res[TCA_ACT_MAX_PRIO] = {};
 
 	for (loop = 0; loop < 10; loop++) {
 		ret = tcf_action_init(net, NULL, nla, NULL, NULL, ovr, 0,
-				      actions, &attr_size, true, extack);
+				      actions, init_res, &attr_size, true, extack);
 		if (ret != -EAGAIN)
 			break;
 	}
@@ -1513,8 +1520,12 @@ static int tcf_action_add(struct net *net, struct nlattr *nla,
 	if (ret < 0)
 		return ret;
 	ret = tcf_add_notify(net, n, actions, portid, attr_size, extack);
-	if (ovr)
-		tcf_action_put_many(actions);
+
+	/* only put existing actions */
+	for (i = 0; i < TCA_ACT_MAX_PRIO; i++)
+		if (init_res[i] == ACT_P_CREATED)
+			actions[i] = NULL;
+	tcf_action_put_many(actions);
 
 	return ret;
 }
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 9332ec6863e8e..340d5af86e87f 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -3040,6 +3040,7 @@ int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
 {
 #ifdef CONFIG_NET_CLS_ACT
 	{
+		int init_res[TCA_ACT_MAX_PRIO] = {};
 		struct tc_action *act;
 		size_t attr_size = 0;
 
@@ -3051,12 +3052,11 @@ int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
 				return PTR_ERR(a_o);
 			act = tcf_action_init_1(net, tp, tb[exts->police],
 						rate_tlv, "police", ovr,
-						TCA_ACT_BIND, a_o, rtnl_held,
-						extack);
-			if (IS_ERR(act)) {
-				module_put(a_o->owner);
+						TCA_ACT_BIND, a_o, init_res,
+						rtnl_held, extack);
+			module_put(a_o->owner);
+			if (IS_ERR(act))
 				return PTR_ERR(act);
-			}
 
 			act->type = exts->type = TCA_OLD_COMPAT;
 			exts->actions[0] = act;
@@ -3067,8 +3067,8 @@ 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,
-					      exts->actions, &attr_size,
-					      rtnl_held, extack);
+					      exts->actions, init_res,
+					      &attr_size, rtnl_held, extack);
 			if (err < 0)
 				return err;
 			exts->nr_actions = err;