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>

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),
 };