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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Tue, 29 Aug 2017 10:12:22 -0700
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Subject: Re: printk: what is going on with additional newlines?
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
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        Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Tue, Aug 29, 2017 at 10:00 AM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> I refuse to help those things. We mis-designed things

Actually, let me rephrase that:

It might actually be a good idea to help those things, by making
helper functions available that do the marshalling.

So not calling "printk()" directly, but having a set of simple
"buffer_print()" functions where each user has its own buffer, and
then the "buffer_print()" functions will help people do nicely output
data.

So if the issue is that people want to print (for example) hex dumps
one character at a time, but don't want to have each character show up
on a line of their own, I think we might well add a few functions to
help dop that.

But they wouldn't be "printk". They would be the buffering functions
that then call printk when tyhey have buffered a line.

That avoids the whole nasty issue with printk - printk wants to show
stuff early (because _maybe_ it's critical) and printk wants to make
log records with timestamps and loglevels. And printk has serious
locking issues that are really nasty and fundamental.

A private buffer has none of those issues.

                 Linus