[PATCH net-next v6 05/11] net: sched: implement action API that deletes action by index

[Vlad Buslov <vladbu@mellanox.com>]

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>
---
Changes from V1 to V2:
- Rename tcf_idr_find_delete to tcf_idr_delete_index.

 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)
-- 
2.7.5