net_sched: act: use standard struct list_head

Currently actions are chained by a singly linked list,
therefore it is a bit hard to add and remove a specific
entry. Convert it to struct list_head so that in the
latter patch we can remove an action without finding
its head.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 26 insertions, 28 deletions

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 8e118af90973..3c056d73d394 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -500,10 +500,8 @@ out:
 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
 {
 #ifdef CONFIG_NET_CLS_ACT
-        if (exts->action) {
-                tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
-                exts->action = NULL;
-        }
+        tcf_action_destroy(&exts->actions, TCA_ACT_UNBIND);
+        INIT_LIST_HEAD(&exts->actions);
 #endif
 }
 EXPORT_SYMBOL(tcf_exts_destroy);
@@ -518,6 +516,7 @@ int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
         {
                 struct tc_action *act;
 
+                INIT_LIST_HEAD(&exts->actions);
                 if (map->police && tb[map->police]) {
                         act = tcf_action_init_1(net, tb[map->police], rate_tlv,
                                                 "police", TCA_ACT_NOREPLACE,
@@ -525,16 +524,15 @@ int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
                         if (IS_ERR(act))
                                 return PTR_ERR(act);
 
-                        act->type = TCA_OLD_COMPAT;
-                        exts->action = act;
+                        act->type = exts->type = TCA_OLD_COMPAT;
+                        list_add(&act->list, &exts->actions);
                 } else if (map->action && tb[map->action]) {
-                        act = tcf_action_init(net, tb[map->action], rate_tlv,
+                        int err;
+                        err = tcf_action_init(net, tb[map->action], rate_tlv,
                                               NULL, TCA_ACT_NOREPLACE,
-                                              TCA_ACT_BIND);
-                        if (IS_ERR(act))
-                                return PTR_ERR(act);
-
-                        exts->action = act;
+                                              TCA_ACT_BIND, &exts->actions);
+                        if (err)
+                                return err;
                 }
         }
 #else
@@ -551,43 +549,45 @@ void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
                      struct tcf_exts *src)
 {
 #ifdef CONFIG_NET_CLS_ACT
-        if (src->action) {
-                struct tc_action *act;
+        if (!list_empty(&src->actions)) {
+                LIST_HEAD(tmp);
                 tcf_tree_lock(tp);
-                act = dst->action;
-                dst->action = src->action;
+                list_splice_init(&dst->actions, &tmp);
+                list_splice(&src->actions, &dst->actions);
                 tcf_tree_unlock(tp);
-                if (act)
-                        tcf_action_destroy(act, TCA_ACT_UNBIND);
+                tcf_action_destroy(&tmp, TCA_ACT_UNBIND);
         }
 #endif
 }
 EXPORT_SYMBOL(tcf_exts_change);
 
+#define tcf_exts_first_act(ext) \
+                list_first_entry(&(exts)->actions, struct tc_action, list)
+
 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
                   const struct tcf_ext_map *map)
 {
 #ifdef CONFIG_NET_CLS_ACT
-        if (map->action && exts->action) {
+        if (map->action && !list_empty(&exts->actions)) {
                 /*
                  * again for backward compatible mode - we want
                  * to work with both old and new modes of entering
                  * tc data even if iproute2  was newer - jhs
                  */
                 struct nlattr *nest;
-
-                if (exts->action->type != TCA_OLD_COMPAT) {
+                if (exts->type != TCA_OLD_COMPAT) {
                         nest = nla_nest_start(skb, map->action);
                         if (nest == NULL)
                                 goto nla_put_failure;
-                        if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
+                        if (tcf_action_dump(skb, &exts->actions, 0, 0) < 0)
                                 goto nla_put_failure;
                         nla_nest_end(skb, nest);
                 } else if (map->police) {
+                        struct tc_action *act = tcf_exts_first_act(exts);
                         nest = nla_nest_start(skb, map->police);
                         if (nest == NULL)
                                 goto nla_put_failure;
-                        if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
+                        if (tcf_action_dump_old(skb, act, 0, 0) < 0)
                                 goto nla_put_failure;
                         nla_nest_end(skb, nest);
                 }
@@ -604,13 +604,11 @@ int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
                         const struct tcf_ext_map *map)
 {
 #ifdef CONFIG_NET_CLS_ACT
-        if (exts->action)
-                if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
-                        goto nla_put_failure;
+        struct tc_action *a = tcf_exts_first_act(exts);
+        if (tcf_action_copy_stats(skb, a, 1) < 0)
+                return -1;
 #endif
         return 0;
-nla_put_failure: __attribute__ ((unused))
-        return -1;
 }
 EXPORT_SYMBOL(tcf_exts_dump_stats);