Re: [PATCH] ACPI: add missing KERN_* constants to printks

From: Geert Uytterhoeven
Date: Wed Feb 04 2009 - 11:48:38 EST


On Wed, 4 Feb 2009, Frans Pop wrote:
> On Wednesday 04 February 2009, Geert Uytterhoeven wrote:
> > > This patch looks broken to me, at least for some of your changes.
> > > For example, in the bit quoted above all printks together make up
> > > *one single* message, which means that only the _first_ of the
> > > printks should have the KERN_* prefix. printks that are continuations
> > > should not have the prefix.
> >
> > Actually they should, but the right prefix :-)
>
> Hmm. I was going by memory and from what I've seen in existing code, but
> also found this (somewhat old) post:
> https://lists.linux-foundation.org/pipermail/kernel-janitors/2005-October/014375.html

That one predates KERN_CONT.

> > Quoting include/linux/kernel.h:
> > | /*
> > | * Annotation for a "continued" line of log printout (only done after a
> > | * line that had no enclosing \n). Only to be used by core/arch code
> > | * during early bootup (a continued line is not SMP-safe otherwise).
> > | */
> > | #define KERN_CONT ""
> >
> > Please also consider the note about SMP-safeness.
>
> From that it looks like KERN_CONT should only be used in a very limited
> context, but I guess this example qualifies.

Yep, the general advise is to avoid using continuations.

With kind regards,

Geert Uytterhoeven
Software Architect

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