From: Giacomo Catenazzi <cate@cateee.net>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: David Schwartz <davids@webmaster.com>,
Johannes Weiner <hannes@saeurebad.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
clameter@sgi.com, penberg@cs.helsinki.fi
Subject: Re: Why is the kfree() argument const?
Date: Fri, 18 Jan 2008 08:51:49 +0100 [thread overview]
Message-ID: <47905A95.4030500@cateee.net> (raw)
In-Reply-To: <alpine.LFD.1.00.0801171710160.2957@woody.linux-foundation.org>
Linus Torvalds wrote:
>
> On Thu, 17 Jan 2008, David Schwartz wrote:
>>> "const" has nothing to do with "logical state". It has one meaning, and
>>> one meaning only: the compiler should complain if that particular type is
>>> used to do a write access.
>> Right, exactly.
>
> So why do you complain?
>
> kfree() literally doesn't write to the object.
>
>> You are the only one who has suggested it has anything to do with changes
>> through other pointers or in other ways. So you are arguing against only
>> yourself here.
>
> No, I'm saying that "const" has absolutely *zero* meaning on writes to an
> object through _other_ pointers (or direct access) to the object.
Hints: "restrict" is the C99 keyword for such requirement (or better
"const restrict")
BTW I think C use non const free as a BIG warning about not to be
to "smart" on optimization.
ciao
cate
next prev parent reply other threads:[~2008-01-18 7:57 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <MDEHLPKNGKAHNMBLJOLKIEGIJJAC.davids@webmaster.com>
2008-01-17 21:25 ` Why is the kfree() argument const? Linus Torvalds
2008-01-17 22:28 ` David Schwartz
2008-01-17 23:10 ` Linus Torvalds
2008-01-18 0:56 ` David Schwartz
2008-01-18 1:15 ` Linus Torvalds
2008-01-18 5:02 ` David Schwartz
2008-01-18 15:38 ` Chris Friesen
2008-01-18 16:10 ` Linus Torvalds
2008-01-18 20:55 ` David Schwartz
2008-01-18 17:37 ` Olivier Galibert
2008-01-18 18:06 ` DM
2008-01-18 7:51 ` Giacomo Catenazzi [this message]
2008-01-18 8:20 ` Giacomo Catenazzi
2008-01-18 13:53 ` Andy Lutomirski
2008-01-18 17:24 ` Olivier Galibert
2008-01-18 22:29 ` J.A. Magallón
2008-01-18 23:44 ` Krzysztof Halasa
2008-01-18 13:54 ` Andy Lutomirski
2008-01-18 19:14 ` Vadim Lobanov
2008-01-18 19:31 ` Zan Lynx
2008-01-18 19:55 ` Vadim Lobanov
2008-01-18 8:30 ` Vadim Lobanov
2008-01-18 9:48 ` Jakob Oestergaard
2008-01-18 11:47 ` Giacomo A. Catenazzi
2008-01-18 14:39 ` Jakob Oestergaard
2008-01-18 19:06 ` Vadim Lobanov
2008-01-18 13:31 ` Björn Steinbrink
2008-01-18 14:53 ` Jakob Oestergaard
[not found] <fa.cHMztHfqJXv7vw5O0nQ8SdTrma0@ifi.uio.no>
[not found] ` <fa.V9M+5l8C/um5KEiBtZOjbJDQmu4@ifi.uio.no>
2013-01-12 19:18 ` antoine.trux
2013-01-13 8:10 ` Chen Gang F T
2013-01-13 17:41 ` Guenter Roeck
2013-01-14 1:45 ` Chen Gang F T
2013-01-13 20:54 ` Cong Ding
2013-01-14 1:18 ` Chen Gang F T
2008-01-18 19:10 ecolbus
-- strict thread matches above, loose matches on Subject: below --
2008-01-18 16:45 ecolbus
2008-01-18 18:20 ` Olivier Galibert
2008-01-18 12:45 ecolbus
2008-01-18 15:20 ` Giacomo A. Catenazzi
2008-01-16 16:32 Johannes Weiner
2008-01-16 16:48 ` Christoph Lameter
2008-01-16 17:34 ` Bernd Petrovitsch
2008-01-16 17:45 ` Pekka J Enberg
2008-01-16 18:39 ` Linus Torvalds
2008-01-16 22:19 ` Johannes Weiner
2008-01-16 22:20 ` Christoph Lameter
2008-01-16 22:37 ` Johannes Weiner
2008-01-16 23:13 ` Johannes Weiner
2008-01-16 23:18 ` Linus Torvalds
2008-01-16 23:16 ` Linus Torvalds
2008-01-16 22:33 ` Steven Rostedt
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