Date: Thu, 30 Mar 2017 14:55:46 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Aleksey Makarov <aleksey.makarov@linaro.org>,
        linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
        Sudeep Holla <sudeep.holla@arm.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Peter Hurley <peter@hurleysoftware.com>, Jiri Slaby <jslaby@suse.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        "Nair, Jayachandran" <Jayachandran.Nair@cavium.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: Re: [PATCH v8 3/3] printk: fix double printing with earlycon
Message-ID: <20170330055546.GD513@jagdpanzerIV.localdomain>
References: <20170315102854.1763-1-aleksey.makarov@linaro.org>
 <20170320100302.8656-1-aleksey.makarov@linaro.org>
 <20170327141432.GH2846@pathway.suse.cz>
 <4b561f81-67af-f6a3-76c9-d0d8499c52bd@linaro.org>
 <20170328020404.GA10573@jagdpanzerIV.localdomain>
 <20170328125657.GJ2846@pathway.suse.cz>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20170328125657.GJ2846@pathway.suse.cz>
User-Agent: Mutt/1.8.0 (2017-02-23)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1181
Lines: 33

On (03/28/17 14:56), Petr Mladek wrote:
[..]
> > > Is it better?  If not, I will send a version with console_cmdline_last.
> > 
> > personally I'm fine with the nested loop. the latest version
> > 	"for (last = MAX_CMDLINECONSOLES - 1; last >= 0;..."
> > 
> > is even easier to read.
> 
> The number of elements is bumped on a single location, so there
> is not much to synchronize. The old approach was fine because
> the for cycles were needed anyway, they started on the 0th element,
> and NULL ended arrays are rather common practice.
> 
> But we are searching the array from the end now. Also we use the
> for cycle just to get the number here. This is not a common
> practice and it makes the code more complicated and strange from
> my point of view.

I'm fine with either way :)

[..]
> > neither add_preferred_console() nor __add_preferred_console() have any
> > serialization. and I assume that we can call add_preferred_console()
> > concurrently, can't we?
[..]
> If I did not miss anything, it would seem that
> __add_preferred_console() are called synchronously
> and only during boot by design.

thanks. I think you are right. it's console_initcall or __init.

	-ss