Re: [PATCH v8 3/3] printk: fix double printing with earlycon

From: Sergey Senozhatsky
Date: Thu Mar 30 2017 - 01:56:12 EST


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