From: Finn Thain <fthain@telegraphics.com.au>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>, Sam Creasey <sammy@sammy.net>,
Joshua Thompson <funaho@jurai.org>,
linux-m68k@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 18/22] m68k/mm: kmap - Modernize printing of kernel messages
Date: Sat, 10 Dec 2016 09:50:09 +1100 (AEDT) [thread overview]
Message-ID: <alpine.LNX.2.00.1612100948260.22611@nippy.intranet> (raw)
In-Reply-To: <alpine.LNX.2.00.1612081022280.9219@nippy.intranet>
On Thu, 8 Dec 2016, I wrote:
>
> On Wed, 7 Dec 2016, Geert Uytterhoeven wrote:
>
> > - Convert from printk() to pr_*(),
> > - Add missing continuations,
> > - Remove #undef DEBUG.
> >
> > Note that "#ifdef DEBUG" is sometimes retained because pr_cont() is
> > not optimized away when debugging is disabled.
> >
>
> I think that argues for using printk(KERN_DEBUG ...) and print(KERN_CONT
> ...) inside #ifdef DEBUG, which would need no explanation.
>
> If instead you use a combination of pr_debug and pr_cont and #ifdef
> DEBUG, perhaps the explanation should be moved from the commit log to a
> comment in the code?
>
Perhaps a better solution than these alternatives would be,
#if defined(DEBUG)
#define pr_debug_cont pr_cont
#else
#define pr_debug_cont no_printk
#endif
But this API is still surprising and ugly. It doesn't work with
CONFIG_DYNAMIC_DEBUG but that's not so important.
IMO, a far better linux/printk.h would have provided us with these
definitions:
#define pr_emerg(fmt, ...) \
printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
/* ... */
#define pr_debug(fmt, ...) \
printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
#define pr_cont(fmt, ...) \
printk(KERN_CONT fmt, ##__VA_ARGS__)
#if defined(CONFIG_DYNAMIC_DEBUG)
#define pr_debug_cond(fmt, ...) \
dynamic_pr_debug(fmt, ##__VA_ARGS__)
#define pr_cont_cond(fmt, ...) \
dynamic_pr_cont(fmt, ##__VA_ARGS__)
#elif defined(DEBUG)
#define pr_debug_cond(fmt, ...) \
printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
#define pr_cont_cond(fmt, ...) \
no_printk(KERN_CONT pr_fmt(fmt), ##__VA_ARGS__)
#else
#define pr_debug_cond(fmt, ...) \
no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
#define pr_cont_cond(fmt, ...) \
no_printk(KERN_CONT pr_fmt(fmt), ##__VA_ARGS__)
#endif
Which have the virtues of symmetry and least surprise.
--
next prev parent reply other threads:[~2016-12-09 22:50 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-07 15:08 [PATCH 00/22] m68k: Modernize printing of kernel messages Geert Uytterhoeven
2016-12-07 15:08 ` [PATCH 01/22] m68k/atari: " Geert Uytterhoeven
2016-12-07 22:36 ` Finn Thain
2016-12-08 12:22 ` Geert Uytterhoeven
2016-12-08 22:55 ` Finn Thain
2016-12-10 0:44 ` Michael Schmitz
2017-02-09 11:59 ` Geert Uytterhoeven
2016-12-07 15:09 ` [PATCH 02/22] m68k/mac: macints - " Geert Uytterhoeven
2016-12-07 22:45 ` Finn Thain
2016-12-08 12:25 ` Geert Uytterhoeven
2016-12-08 23:11 ` Finn Thain
2016-12-07 15:09 ` [PATCH 03/22] m68k/mac: via " Geert Uytterhoeven
2016-12-07 22:48 ` Finn Thain
2016-12-07 15:09 ` [PATCH 04/22] m68k/68000: " Geert Uytterhoeven
2016-12-09 12:00 ` Greg Ungerer
2016-12-07 15:09 ` [PATCH 05/22] m68k/bvme6000: " Geert Uytterhoeven
2016-12-07 15:09 ` [PATCH 06/22] m68k/coldfire: " Geert Uytterhoeven
2016-12-07 22:53 ` Finn Thain
2016-12-09 12:09 ` Greg Ungerer
2016-12-07 15:09 ` [PATCH 07/22] m68k/mac: baboon - " Geert Uytterhoeven
2016-12-07 22:54 ` Finn Thain
2016-12-07 15:09 ` [PATCH 08/22] m68k/mac: iop " Geert Uytterhoeven
2016-12-07 23:06 ` Finn Thain
2016-12-07 15:09 ` [PATCH 09/22] m68k/mac: oss " Geert Uytterhoeven
2016-12-07 23:08 ` Finn Thain
2016-12-07 15:09 ` [PATCH 10/22] m68k/mac: psc " Geert Uytterhoeven
2016-12-07 23:10 ` Finn Thain
2016-12-07 15:09 ` [PATCH 11/22] m68k/mac: " Geert Uytterhoeven
2016-12-07 23:17 ` Finn Thain
2016-12-07 15:09 ` [PATCH 12/22] m68k/mvme147: " Geert Uytterhoeven
2016-12-07 15:09 ` [PATCH 13/22] m68k/mvme16x: " Geert Uytterhoeven
2016-12-07 15:09 ` [PATCH 14/22] m68k/q40: " Geert Uytterhoeven
2016-12-07 15:09 ` [PATCH 15/22] m68k/sun3: " Geert Uytterhoeven
2016-12-07 15:09 ` [PATCH 16/22] m68k/sun3x: " Geert Uytterhoeven
2016-12-07 15:09 ` [PATCH 17/22] m68k/kernel: " Geert Uytterhoeven
2016-12-07 15:09 ` [PATCH 18/22] m68k/mm: kmap - " Geert Uytterhoeven
2016-12-07 23:26 ` Finn Thain
2016-12-09 22:50 ` Finn Thain [this message]
2016-12-07 15:09 ` [PATCH 19/22] m68k/mm: motorola " Geert Uytterhoeven
2016-12-07 15:09 ` [PATCH 20/22] m68k/mm: sun3 " Geert Uytterhoeven
2016-12-07 15:09 ` [PATCH 21/22] m68k/mm: " Geert Uytterhoeven
2016-12-07 15:09 ` [PATCH 22/22] m68k/include: " Geert Uytterhoeven
2017-02-09 13:25 ` [PATCH 00/22] m68k: " Geert Uytterhoeven
2017-02-12 9:43 ` Geert Uytterhoeven
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