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From: Jiri Pirko <jiri@resnulli.us>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>,
	David Miller <davem@davemloft.net>,
	Jamal Hadi Salim <jhs@mojatatu.com>,
	Eric Dumazet <edumazet@google.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Simon Horman <simon.horman@netronome.com>,
	mlxsw@mellanox.com, Colin King <colin.king@canonical.com>
Subject: Re: [patch net-next 2/2] net/sched: fix filter flushing
Date: Sun, 21 May 2017 07:54:16 +0200	[thread overview]
Message-ID: <20170521055416.GA1848@nanopsycho> (raw)
In-Reply-To: <CAM_iQpWha6aCV3kOfCEFsBLNiC7LFTh=K=QaL17rH4=PUoeUmQ@mail.gmail.com>

Sun, May 21, 2017 at 02:16:45AM CEST, xiyou.wangcong@gmail.com wrote:
>On Sat, May 20, 2017 at 6:01 AM, Jiri Pirko <jiri@resnulli.us> wrote:
>> +static void tcf_chain_destroy(struct tcf_chain *chain)
>> +{
>> +       list_del(&chain->list);
>> +       tcf_chain_flush(chain);
>>         kfree(chain);
>>  }
>>
>> @@ -510,7 +517,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
>>
>>         if (n->nlmsg_type == RTM_DELTFILTER && prio == 0) {
>>                 tfilter_notify_chain(net, skb, n, chain, RTM_DELTFILTER);
>> -               tcf_chain_destroy(chain);
>> +               tcf_chain_flush(chain);
>
>
>I wonder if we should return EBUSY and do nothing in case of busy?
>The chain is no longer visual to new actions after your list_del(), but
>the old one could still use and see it.

No. User request to flush the chain, that is what happens in the past
and that is what should happen now.
If there is still a reference, the chain_put will keep the empty chain.
If there is no longer a reference, chain_put will destroy the chain. All
good.

  reply	other threads:[~2017-05-21  5:54 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-20 13:01 [patch net-next 1/2] net/sched: properly assign RCU pointer in tcf_chain_tp_insert/remove Jiri Pirko
2017-05-20 13:01 ` [patch net-next 2/2] net/sched: fix filter flushing Jiri Pirko
2017-05-21  0:16   ` Cong Wang
2017-05-21  5:54     ` Jiri Pirko [this message]
2017-05-21 18:27       ` Cong Wang
2017-05-21 19:19         ` Jiri Pirko
2017-05-22 10:42           ` Jamal Hadi Salim
2017-05-22 12:36             ` Jiri Pirko
2017-05-22 20:54           ` Cong Wang
2017-05-22 21:04             ` Cong Wang
2017-05-23  5:17               ` Jiri Pirko
2017-05-23  5:39                 ` Cong Wang
2017-05-23  5:40   ` Cong Wang
2017-05-23 15:00   ` David Miller
2017-05-23 15:00 ` [patch net-next 1/2] net/sched: properly assign RCU pointer in tcf_chain_tp_insert/remove David Miller

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