From: Jiri Pirko <jiri@resnulli.us>
To: Vlad Buslov <vladbu@mellanox.com>
Cc: netdev@vger.kernel.org, davem@davemloft.net, jhs@mojatatu.com,
xiyou.wangcong@gmail.com, pablo@netfilter.org,
kadlec@blackhole.kfki.hu, fw@strlen.de, ast@kernel.org,
daniel@iogearbox.net, edumazet@google.com, keescook@chromium.org,
linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org,
coreteam@netfilter.org, kliteyn@mellanox.com
Subject: Re: [PATCH 12/14] net: sched: retry action check-insert on concurrent modification
Date: Wed, 16 May 2018 14:26:00 +0200 [thread overview]
Message-ID: <20180516122600.GM1972@nanopsycho> (raw)
In-Reply-To: <vbf4lj724th.fsf@reg-r-vrt-018-180.mtr.labs.mlnx>
Wed, May 16, 2018 at 01:55:06PM CEST, vladbu@mellanox.com wrote:
>
>On Wed 16 May 2018 at 09:59, Jiri Pirko <jiri@resnulli.us> wrote:
>> 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.
>
>This code uses goto so it can't be easily refactored into standalone
>function. Could you specify which part of this code you suggest to
>extract?
Hmm, looking at the code, I think that what would help is to have a
helper that would atomically check if index exists and if not, it would
allocate one. Something like:
int tcf_idr_check_alloc(struct tc_action_net *tn, u32 *index,
struct tc_action **a, int bind)
{
struct tcf_idrinfo *idrinfo = tn->idrinfo;
struct tc_action *p;
int err;
spin_lock(&idrinfo->lock);
if (*index) {
p = idr_find(&idrinfo->action_idr, *index);
if (p) {
if (bind)
p->tcfa_bindcnt++;
p->tcfa_refcnt++;
*a = p;
err = 0;
} else {
*a = NULL;
err = idr_alloc_u32(idr, NULL, index,
*index, GFP_ATOMIC);
}
} else {
*index = 1;
*a = NULL;
err = idr_alloc_u32(idr, NULL, index, UINT_MAX, GFP_ATOMIC);
}
spin_unlock(&idrinfo->lock);
return err;
}
The act code would just check if "a" is NULL and if so, it would call
tcf_idr_create() with allocated index as arg.
>
>>
>> [...]
>
next prev parent reply other threads:[~2018-05-16 12:26 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-14 14:27 [PATCH 00/14] Modify action API for implementing lockless actions Vlad Buslov
2018-05-14 14:27 ` [PATCH 01/14] net: sched: use rcu for action cookie update Vlad Buslov
2018-05-14 15:10 ` Jiri Pirko
2018-05-14 23:39 ` kbuild test robot
2018-05-14 14:27 ` [PATCH 02/14] net: sched: change type of reference and bind counters Vlad Buslov
2018-05-14 15:11 ` Jiri Pirko
2018-05-19 21:04 ` Marcelo Ricardo Leitner
2018-05-20 10:55 ` Vlad Buslov
2018-05-14 14:27 ` [PATCH 03/14] net: sched: add 'delete' function to action ops Vlad Buslov
2018-05-14 15:12 ` Jiri Pirko
2018-05-14 16:30 ` Jiri Pirko
2018-05-14 14:27 ` [PATCH 04/14] net: sched: implement unlocked action init API Vlad Buslov
2018-05-14 15:16 ` Jiri Pirko
2018-05-19 21:11 ` Marcelo Ricardo Leitner
2018-05-14 14:27 ` [PATCH 05/14] net: sched: always take reference to action Vlad Buslov
2018-05-14 16:23 ` Jiri Pirko
2018-05-14 18:49 ` Vlad Buslov
2018-05-15 8:58 ` Jiri Pirko
2018-05-15 11:52 ` Vlad Buslov
2018-05-15 1:38 ` kbuild test robot
2018-05-15 1:38 ` [RFC PATCH] net: sched: __tcf_idr_check() can be static kbuild test robot
2018-05-14 14:27 ` [PATCH 06/14] net: sched: implement reference counted action release Vlad Buslov
2018-05-14 16:28 ` Jiri Pirko
2018-05-14 16:47 ` Jiri Pirko
2018-05-14 19:07 ` Vlad Buslov
2018-05-15 9:03 ` Jiri Pirko
2018-05-15 9:16 ` Vlad Buslov
2018-05-19 21:43 ` Marcelo Ricardo Leitner
2018-05-20 6:22 ` Jiri Pirko
2018-05-20 10:59 ` Vlad Buslov
2018-05-14 14:27 ` [PATCH 07/14] net: sched: use reference counting action init Vlad Buslov
2018-05-15 11:24 ` Jiri Pirko
2018-05-15 11:32 ` Vlad Buslov
2018-05-15 11:39 ` Jiri Pirko
2018-05-15 11:41 ` Vlad Buslov
2018-05-15 11:57 ` Jiri Pirko
2018-05-15 12:00 ` Vlad Buslov
2018-05-14 14:27 ` [PATCH 08/14] net: sched: account for temporary action reference Vlad Buslov
2018-05-16 7:12 ` Jiri Pirko
2018-05-14 14:27 ` [PATCH 09/14] net: sched: don't release reference on action overwrite Vlad Buslov
2018-05-16 7:43 ` Jiri Pirko
2018-05-16 7:47 ` Vlad Buslov
2018-05-16 7:50 ` Jiri Pirko
2018-05-19 21:52 ` Marcelo Ricardo Leitner
2018-05-20 18:42 ` Vlad Buslov
2018-05-14 14:27 ` [PATCH 10/14] net: sched: extend act API for lockless actions Vlad Buslov
2018-05-16 7:50 ` Jiri Pirko
2018-05-16 8:16 ` Vlad Buslov
2018-05-16 8:56 ` Jiri Pirko
2018-05-16 9:39 ` Vlad Buslov
2018-05-19 22:17 ` Marcelo Ricardo Leitner
2018-05-14 14:27 ` [PATCH 11/14] net: core: add new/replace rate estimator lock parameter Vlad Buslov
2018-05-16 9:54 ` Jiri Pirko
2018-05-16 10:00 ` Vlad Buslov
2018-05-16 10:11 ` Jiri Pirko
2018-05-14 14:27 ` [PATCH 12/14] net: sched: retry action check-insert on concurrent modification Vlad Buslov
2018-05-16 9:59 ` Jiri Pirko
2018-05-16 11:55 ` Vlad Buslov
2018-05-16 12:26 ` Jiri Pirko [this message]
2018-05-16 12:43 ` Vlad Buslov
2018-05-16 13:21 ` Jiri Pirko
2018-05-16 13:52 ` Vlad Buslov
2018-05-16 14:13 ` Jiri Pirko
2018-05-16 14:26 ` Vlad Buslov
2018-05-16 14:55 ` Jiri Pirko
2018-05-19 22:35 ` Marcelo Ricardo Leitner
2018-05-14 14:27 ` [PATCH 13/14] net: sched: use unique idr insert function in unlocked actions Vlad Buslov
2018-05-16 9:50 ` Jiri Pirko
2018-05-16 9:54 ` Vlad Buslov
2018-05-19 22:20 ` Marcelo Ricardo Leitner
2018-05-20 21:13 ` Or Gerlitz
2018-05-20 21:33 ` Marcelo Ricardo Leitner
2018-05-20 21:40 ` Or Gerlitz
2018-05-20 22:43 ` Marcelo Ricardo Leitner
2018-05-14 14:27 ` [PATCH 14/14] net: sched: implement delete for all actions Vlad Buslov
2018-05-16 9:48 ` Jiri Pirko
2018-05-16 9:58 ` Vlad Buslov
2018-05-19 22:45 ` Marcelo Ricardo Leitner
2018-05-14 18:03 ` [PATCH 00/14] Modify action API for implementing lockless actions Jamal Hadi Salim
2018-05-14 20:46 ` Vlad Buslov
2018-05-15 18:25 ` Jamal Hadi Salim
2018-05-15 21:21 ` Vlad Buslov
2018-05-15 8:20 ` Jiri Pirko
2018-05-24 23:34 ` Cong Wang
2018-05-25 20:39 ` Vlad Buslov
2018-05-25 21:40 ` Cong Wang
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