Re: [PATCH v3 net 1/1] net sched actions: fix GETing actions

[Sergei Shtylyov]

On 9/13/2016 2:07 AM, Jamal Hadi Salim wrote:

From: Jamal Hadi Salim <j...@mojatatu.com>

With the batch changes that translated transient actions into
a temporary list lost in the translation was the fact that
tcf_action_destroy() will eventually delete the action from
the permanent location if the refcount is zero.

Example of what broke:
...add a gact action to drop
sudo $TC actions add action drop index 10
...now retrieve it, looks good
sudo $TC actions get action gact index 10
...retrieve it again and find it is gone!
sudo $TC actions get action gact index 10

Fixes:
commit 22dc13c837c3 ("net_sched: convert tcf_exts from list to pointer array"),
commit 824a7e8863b3 ("net_sched: remove an unnecessary list_del()")
commit f07fed82ad79 ("net_sched: remove the leftover cleanup_a()")

Signed-off-by: Jamal Hadi Salim <j...@mojatatu.com>
---
 net/sched/act_api.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index d09d068..50720b1 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -592,6 +592,16 @@ err_out:
        return ERR_PTR(err);
 }

+static void cleanup_a(struct list_head *actions, int ovr)
+{
+       struct tc_action *a;
+
+       list_for_each_entry(a, actions, list) {
+               if (ovr)
+                       a->tcfa_refcnt -= 1;

                        a->tcfa_refcnt--;

[...]

@@ -612,8 +622,15 @@ int tcf_action_init(struct net *net, struct nlattr *nla,
                        goto err;
                }
                act->order = i;
+               if (ovr)
+                       act->tcfa_refcnt += 1;

                        act->tcfa_refcnt++;

[...]

@@ -883,6 +900,8 @@ tca_action_gd(struct net *net, struct nlattr *nla, struct 
nlmsghdr *n,
                        goto err;
                }
                act->order = i;
+               if (event == RTM_GETACTION)
+                       act->tcfa_refcnt += 1;

                act->tcfa_refcnt++;

[...]

MBR, Sergei