Re: [PATCH 12/14] net: sched: retry action check-insert on concurrent modification

Jiri Pirko
2018-05-16T09:59:58Z

Mon, May 14, 2018 at 04:27:13PM CEST, vladbu@mellanox.com wrote:
>Retry check-insert sequence in action init functions if action with same
>index was inserted concurrently.
>
>Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
>---
> net/sched/act_bpf.c | 8 +++++++-
> net/sched/act_connmark.c | 8 +++++++-
> net/sched/act_csum.c | 8 +++++++-
> net/sched/act_gact.c | 8 +++++++-
> net/sched/act_ife.c | 8 +++++++-
> net/sched/act_ipt.c | 8 +++++++-
> net/sched/act_mirred.c | 8 +++++++-
> net/sched/act_nat.c | 8 +++++++-
> net/sched/act_pedit.c | 8 +++++++-
> net/sched/act_police.c | 9 ++++++++-
> net/sched/act_sample.c | 8 +++++++-
> net/sched/act_simple.c | 9 ++++++++-
> net/sched/act_skbedit.c | 8 +++++++-
> net/sched/act_skbmod.c | 8 +++++++-
> net/sched/act_tunnel_key.c | 9 ++++++++-
> net/sched/act_vlan.c | 9 ++++++++-
> 16 files changed, 116 insertions(+), 16 deletions(-)
>
>diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
>index 5554bf7..7e20fdc 100644
>--- a/net/sched/act_bpf.c
>+++ b/net/sched/act_bpf.c
>@@ -299,10 +299,16 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
>
> parm = nla_data(tb[TCA_ACT_BPF_PARMS]);
>
>+replay:
> if (!tcf_idr_check(tn, parm->index, act, bind)) {
> ret = tcf_idr_create(tn, parm->index, est, act,
> &act_bpf_ops, bind, true);
>- if (ret < 0)
>+ /* Action with specified index was created concurrently.
>+ * Check again.
>+ */
>+ if (parm->index && ret == -ENOSPC)
>+ goto replay;
>+ else if (ret)

Hmm, looks like you are doing the same/very similar thing in every act
code. I think it would make sense to introduce a helper function for
this purpose. …