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From: Johannes Stezenbach <js@linuxtv.org>
To: Jonathan Corbet <corbet@lwn.net>
Cc: Randy Dunlap <randy.dunlap@oracle.com>,
	Paul Sokolovsky <pmiscml@gmail.com>,
	linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC/PATCH] doc: volatile considered evil
Date: Wed, 9 May 2007 11:43:05 +0200	[thread overview]
Message-ID: <20070509094305.GC28774@linuxtv.org> (raw)
In-Reply-To: <16987.1178675251@lwn.net>

On Tue, May 08, 2007, Jonathan Corbet wrote:
> 
> I just took a shot at turning this into something more like a normal
> document:
> 
> 	http://lwn.net/Articles/233479/

I think the "jiffies variable is special" part misses the
"for stupid legacy reasons" explanation.

According to the other volatile rules one should use
something like that:

extern unsigned long __jiffies;
static inline unsigned long read_ulong(unsigned long *addr)
{
	return *(volatile unsigned long *)addr;
}
static inline unsigned long get_jiffies(void)
{
	return read_ulong(&__jiffies);
}

But of course changing all references to jiffies in the kernel would
be insane, thus jiffies is special "for stupid legacy reasons".

Right?


Johannes

  reply	other threads:[~2007-05-09  9:43 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-05-01  5:08 [RFC, PATCH 2/4] SoC base drivers: ASIC3 SoC hardware definitions Paul Sokolovsky
2007-05-01  6:56 ` Andrew Morton
2007-05-01 10:27   ` Alan Cox
2007-05-01 12:04     ` Paul Sokolovsky
2007-05-01 12:21       ` Jamey Hicks
2007-05-08 19:14   ` [RFC/PATCH] doc: volatile considered evil Randy Dunlap
2007-05-08 19:18     ` David Rientjes
2007-05-08 20:00       ` Krzysztof Halasa
2007-05-08 20:20         ` David Rientjes
2007-05-08 23:13           ` Randy Dunlap
2007-05-08 23:54             ` David Rientjes
2007-05-09  0:00               ` Randy Dunlap
2007-05-08 21:05         ` Jeremy Fitzhardinge
2007-05-08 21:10           ` Krzysztof Halasa
2007-05-08 21:16           ` Jeff Garzik
2007-05-08 21:26             ` Randy Dunlap
2007-05-08 21:25               ` Jeff Garzik
2007-05-08 21:20       ` Jeremy Fitzhardinge
2007-05-08 21:27         ` David Rientjes
2007-05-08 21:37           ` Jeremy Fitzhardinge
2007-05-08 21:59             ` David Rientjes
2007-05-08 22:04               ` Jeremy Fitzhardinge
2007-05-08 22:19                 ` David Rientjes
2007-05-08 22:29                   ` Jeremy Fitzhardinge
2007-05-08 22:35                     ` David Rientjes
2007-05-08 23:09           ` Randy Dunlap
2007-05-08 21:29         ` Randy Dunlap
2007-05-08 20:07     ` Satyam Sharma
2007-05-08 23:34       ` [PATCH] " Randy Dunlap
2007-05-09  0:06         ` David Rientjes
2007-05-09  2:08           ` Randy Dunlap
2007-05-09  2:38             ` David Rientjes
2007-05-09  3:15               ` Randy Dunlap
2007-05-09  9:21               ` Alan Cox
2007-05-09  9:26                 ` Nick Piggin
2007-05-09 13:31                   ` Alan Cox
2007-05-09 10:25                 ` David Rientjes
2007-05-09 13:36                   ` Alan Cox
2007-05-09 18:41                     ` David Rientjes
2007-05-09 20:23                       ` Alan Cox
2007-05-09 20:25                         ` David Rientjes
2007-05-09 22:47                         ` Rob Landley
2007-05-09  8:50         ` Stefan Richter
2007-05-09 15:52           ` Randy Dunlap
2007-05-09 19:04             ` Satyam Sharma
2007-05-09  1:47     ` [RFC/PATCH] " Jonathan Corbet
2007-05-09  9:43       ` Johannes Stezenbach [this message]
2007-05-09 19:34         ` Satyam Sharma

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