linux-kernel - Re: [PATCHv7 4/8] printk: always use deferred printk when flush printk

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Date:   Thu, 2 Feb 2017 15:05:38 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     Steven Rostedt <rostedt@...dmis.org>,
        Petr Mladek <pmladek@...e.com>
Cc:     Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Jan Kara <jack@...e.cz>, Tejun Heo <tj@...nel.org>,
        Calvin Owens <calvinowens@...com>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Hurley <peter@...leysoftware.com>,
        linux-kernel@...r.kernel.org,
        Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Subject: Re: [PATCHv7 4/8] printk: always use deferred printk when flush
 printk_safe lines

On (02/01/17 11:06), Steven Rostedt wrote:
[..]
> >  static void printk_safe_flush_line(const char *text, int len)
> >  {
> >  	/*
> > -	 * The buffers are flushed in NMI only on panic.  The messages must
> > -	 * go only into the ring buffer at this stage.  Consoles will get
> > -	 * explicitly called later when a crashdump is not generated.
> > +	 * Avoid any console drivers calls from here, because we may be
> > +	 * in NMI or printk_safe context (when in panic). The messages
> > +	 * must go only into the ring buffer at this stage.  Consoles will
> > +	 * get explicitly called later when a crashdump is not generated.
> >  	 */
> > -	if (in_nmi())
> > -		printk_deferred("%.*s", len, text);
> > -	else
> > -		printk("%.*s", len, text);
> > +	printk_deferred("%.*s", len, text);
> >  }
> 
> The helper function was there because of the if statement. Just nuke
> this function and call printk_deferred() directly. You can move the
> comment to the caller.

indeed. thanks.

Petr, how would you prefer to handle this?

	-ss