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Date:   Fri, 30 Sep 2022 19:27:04 +0200
From:   Petr Mladek <pmladek@suse.com>
To:     John Ogness <john.ogness@linutronix.de>
Cc:     Doug Anderson <dianders@chromium.org>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>,
        Jason Wessel <jason.wessel@windriver.com>,
        Daniel Thompson <daniel.thompson@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jirislaby@kernel.org>,
        Aaron Tomlin <atomlin@redhat.com>,
        Luis Chamberlain <mcgrof@kernel.org>,
        kgdb-bugreport@lists.sourceforge.net, linux-serial@vger.kernel.org
Subject: Re: [PATCH printk 10/18] kgbd: Pretend that console list walk is safe
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References: <20220924000454.3319186-1-john.ogness@linutronix.de>
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On Fri 2022-09-30 15:50:56, John Ogness wrote:
> On 2022-09-30, Petr Mladek <pmladek@suse.com> wrote:
> > Anyway, what about using the later added SRCU walk here?
> > After all, this is exactly what RCU is for, isn't it?
> 
> So I think a lot of the problems with this series is that SRCU is
> introduced too late. We are debating things in patch 6 that are
> irrelevant by patch 12.

> I will rework the series so that the changes come in the following
> order:
> 
> 1. provide an atomic console_is_enabled()
>
> 2. convert the list to SRCU
> 
> 3. move all iterators from console_lock()/console_trylock() to SRCU
> 
> Step 3 may result in console_lock()/console_trylock() calls disappearing
> or relocating to where they are needed for non-list-synchronization
> purposes.

I agree that introding SRCU as early as possible would
help. The current patchset converts the same code several times...

Best Regards,
Petr