Message-ID: <1449676073.25389.5.camel@perches.com>
Subject: Re: [PATCH v2] printk: help pr_debug and pr_devel to optimize out
 arguments
From: Joe Perches <joe@perches.com>
To: Arnd Bergmann <arnd@arndb.de>, Aaron Conole <aconole@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org,
        Jason Baron <jbaron@akamai.com>
Date: Wed, 09 Dec 2015 07:47:53 -0800
In-Reply-To: <1652262.soph10NRXK@wuerfel>
References: <5661BFEE.1050103@akamai.com>
	 <1449265902-21781-1-git-send-email-aconole@redhat.com>
	 <1652262.soph10NRXK@wuerfel>
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On Wed, 2015-12-09 at 12:52 +0100, Arnd Bergmann wrote:
> On Friday 04 December 2015 16:51:42 Aaron Conole wrote:
> > --- a/include/linux/printk.h
> > +++ b/include/linux/printk.h
> > @@ -106,13 +106,14 @@ struct va_format {
> > ?
> > ?/*
> > ? * Dummy printk for disabled debugging statements to use whilst maintaining
> > - * gcc's format and side-effect checking.
> > + * gcc's format checking.
> > ? */
> > -static inline __printf(1, 2)
> > -int no_printk(const char *fmt, ...)
> > -{
> > -???????return 0;
> > -}
> > +#define no_printk(fmt, ...)????????????????????\
> > +do {???????????????????????????????????????????\
> > +???????if (0) {????????????????????????????????\
> > +???????????????printk(fmt, ##__VA_ARGS__);?????\
> > +???????}???????????????????????????????????????\
> > +} while (0)
> > ?
> 
> This change breaks compiling lib/842/, at least in some configurations:
> 
> lib/842/842_decompress.c: In function '__do_index':
> lib/842/842_decompress.c:205:12422: error: implicit declaration of function 'no_printk'

Please specify a configuration that fails.

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