netdev - Re: [PATCH net-next v2 05/10] net: sched: use Qdisc rcu API instead of relying on rtnl lock

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Message-ID: <CAM_iQpVKEU_RqxDPaTEo2KShKNATsHGJEa64afT-m6iadptNGw@mail.gmail.com>
Date:   Wed, 19 Sep 2018 15:04:47 -0700
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     Vlad Buslov <vladbu@...lanox.com>
Cc:     Linux Kernel Network Developers <netdev@...r.kernel.org>,
        Jamal Hadi Salim <jhs@...atatu.com>,
        Jiri Pirko <jiri@...nulli.us>,
        David Miller <davem@...emloft.net>,
        Stephen Hemminger <stephen@...workplumber.org>,
        Kirill Tkhai <ktkhai@...tuozzo.com>,
        Nicolas Dichtel <nicolas.dichtel@...nd.com>,
        Greg KH <gregkh@...uxfoundation.org>, mark.rutland@....com,
        Leon Romanovsky <leon@...nel.org>,
        "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
        Florian Westphal <fw@...len.de>,
        David Ahern <dsahern@...il.com>, christian@...uner.io,
        lucien xin <lucien.xin@...il.com>,
        Jakub Kicinski <jakub.kicinski@...ronome.com>,
        Jiri Benc <jbenc@...hat.com>
Subject: Re: [PATCH net-next v2 05/10] net: sched: use Qdisc rcu API instead
 of relying on rtnl lock

On Mon, Sep 17, 2018 at 12:19 AM Vlad Buslov <vladbu@...lanox.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?