From mboxrd@z Thu Jan  1 00:00:00 1970
From: Vlad Buslov <vladbu@mellanox.com>
Subject: Re: [PATCH net-next v2 05/10] net: sched: use Qdisc rcu API instead of relying on rtnl lock
Date: Thu, 20 Sep 2018 10:20:58 +0300
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References: <1537168660-24032-1-git-send-email-vladbu@mellanox.com> <1537168660-24032-6-git-send-email-vladbu@mellanox.com> <CAM_iQpVKEU_RqxDPaTEo2KShKNATsHGJEa64afT-m6iadptNGw@mail.gmail.com>
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Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>,
        Jamal Hadi Salim <jhs@mojatatu.com>,
        Jiri Pirko <jiri@resnulli.us>,
        David Miller <davem@davemloft.net>,
        Stephen Hemminger <stephen@networkplumber.org>,
        Kirill Tkhai <ktkhai@virtuozzo.com>,
        Nicolas Dichtel <nicolas.dichtel@6wind.com>,
        Greg KH <gregkh@linuxfoundation.org>, mark.rutland@arm.com,
        Leon Romanovsky <leon@kernel.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Florian Westphal <fw@strlen.de>,
        David Ahern <dsahern@gmail.com>, christian@brauner.io,
        lucien xin <lucien.xin@gmail.com>,
        Jakub Kicinski <jakub.kicinski@netronome.com>,
        Jiri Benc <jbenc@redhat.com>
To: Cong Wang <xiyou.wangcong@gmail.com>
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On Wed 19 Sep 2018 at 22:04, Cong Wang <xiyou.wangcong@gmail.com> wrote:
> On Mon, Sep 17, 2018 at 12:19 AM Vlad Buslov <vladbu@mellanox.com> wrote:
>> +static void tcf_qdisc_put(struct Qdisc *q, bool rtnl_held)
>> +{
>> +       if (!q)
>> +               return;
>> +
>> +       if (rtnl_held)
>> +               qdisc_put(q);
>> +       else
>> +               qdisc_put_unlocked(q);
>> +}
>
> This is very ugly. You should know whether RTNL is held or
> not when calling it.
>
> What's more, all of your code passes true, so why do you
> need a parameter for rtnl_held?

It passes true because currently rule update handlers still registered
as locked. This is a preparation for next patch set where this would be
changed to proper variable that depends on qdics and classifier type.