[patch net-next] net: sched: cls_matchall: allow to delete filter

[Jiri Pirko]

From: Jiri Pirko <j...@mellanox.com>

Currently user is unable to delete the filter. See following example:
$ tc filter add dev ens16np1 ingress pref 1 handle 1 matchall action drop
$ tc filter show dev ens16np1 ingress
filter protocol all pref 1 matchall chain 0
filter protocol all pref 1 matchall chain 0 handle 0x1
  in_hw
        action order 1: gact action drop
         random type none pass val 0
         index 1 ref 1 bind 1

$ tc filter del dev ens16np1 ingress pref 1 handle 1 matchall action drop
RTNETLINK answers: Operation not supported

Implement tcf_proto_ops->delete() op and allow user to delete the filter.

Reported-by: Eli Cohen <e...@mellanox.com>
Signed-off-by: Jiri Pirko <j...@mellanox.com>
---
 net/sched/cls_matchall.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/sched/cls_matchall.c b/net/sched/cls_matchall.c
index 38c0a9f0f296..a30d2f8feb32 100644
--- a/net/sched/cls_matchall.c
+++ b/net/sched/cls_matchall.c
@@ -21,6 +21,7 @@ struct cls_mall_head {
        unsigned int in_hw_count;
        struct tc_matchall_pcnt __percpu *pf;
        struct rcu_work rwork;
+       bool deleting;
 };
 
 static int mall_classify(struct sk_buff *skb, const struct tcf_proto *tp,
@@ -258,7 +259,11 @@ static int mall_change(struct net *net, struct sk_buff 
*in_skb,
 static int mall_delete(struct tcf_proto *tp, void *arg, bool *last,
                       bool rtnl_held, struct netlink_ext_ack *extack)
 {
-       return -EOPNOTSUPP;
+       struct cls_mall_head *head = rtnl_dereference(tp->root);
+
+       head->deleting = true;
+       *last = true;
+       return 0;
 }
 
 static void mall_walk(struct tcf_proto *tp, struct tcf_walker *arg,
@@ -269,7 +274,7 @@ static void mall_walk(struct tcf_proto *tp, struct 
tcf_walker *arg,
        if (arg->count < arg->skip)
                goto skip;
 
-       if (!head)
+       if (!head || head->deleting)
                return;
        if (arg->fn(tp, head, arg) < 0)
                arg->stop = 1;
-- 
2.20.1