From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Hua Zhong <hzhong@gmail.com>
Cc: "'Paul Mackerras'" <paulus@samba.org>,
"'Pekka Enberg'" <penberg@cs.helsinki.fi>,
"'Andrew Morton'" <akpm@osdl.org>,
"'James Morris'" <jmorris@namei.org>,
dwalker@mvista.com, linux-kernel@vger.kernel.org
Subject: Re: kfree(NULL)
Date: Sun, 23 Apr 2006 05:05:41 +1000 [thread overview]
Message-ID: <444A7E85.4030803@yahoo.com.au> (raw)
In-Reply-To: <001201c6663e$983f7960$0200a8c0@nuitysystems.com>
Hua Zhong wrote:
> > There is a judgement to be made at each call site of kfree
>
>>(and similar functions) about whether the argument is rarely
>>NULL, or could often be NULL. If the janitors have been
>>making this judgement, I apologise, but I haven't seen them
>>doing that.
>>
>>Paul.
>
>
> Even if the caller passes NULL most of the time, the check should be removed.
>
> It's just crazy talk to say "you should not check NULL before calling kfree, as long as you make sure it's not NULL most of the
> time".
It can reduce readability of the code [unless it is used in error path
simplification, kfree(something) usually suggests kfree-an-object].
If the caller passes NULL most of the time, it could be in need of
redesign.
I don't actually like kfree(NULL) any time except error paths. It is
subjective, not crazy talk.
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
next prev parent reply other threads:[~2006-04-22 19:05 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-21 7:03 kfree(NULL) Daniel Walker
2006-04-21 7:22 ` kfree(NULL) James Morris
2006-04-21 8:54 ` kfree(NULL) Andrew Morton
2006-04-21 13:56 ` kfree(NULL) Vernon Mauery
2006-04-21 14:07 ` kfree(NULL) Dmitry Fedorov
2006-04-21 15:07 ` kfree(NULL) Jan Engelhardt
2006-04-21 19:22 ` kfree(NULL) Adrian Bunk
2006-04-21 20:30 ` kfree(NULL) Vernon Mauery
2006-04-21 20:54 ` kfree(NULL) Steven Rostedt
2006-04-21 21:38 ` kfree(NULL) Adrian Bunk
2006-04-22 11:56 ` kfree(NULL) Jörn Engel
2006-04-21 23:55 ` kfree(NULL) Paul Mackerras
2006-04-22 7:43 ` kfree(NULL) Pekka Enberg
2006-04-22 8:48 ` kfree(NULL) Paul Mackerras
2006-04-22 15:02 ` kfree(NULL) Pekka Enberg
2006-04-22 18:57 ` kfree(NULL) Hua Zhong
2006-04-22 19:05 ` Nick Piggin [this message]
2006-04-22 19:22 ` kfree(NULL) Hua Zhong
2006-04-22 19:25 ` kfree(NULL) Nick Piggin
2006-04-22 20:18 ` kfree(NULL) Jan Engelhardt
2006-04-23 16:50 ` kfree(NULL) Steven Rostedt
2006-04-22 11:34 ` kfree(NULL) Jesper Juhl
2006-04-21 14:06 ` kfree(NULL) Daniel Walker
[not found] <63XWg-1IL-5@gated-at.bofh.it>
[not found] ` <63YfP-26I-11@gated-at.bofh.it>
[not found] ` <63ZEY-45n-27@gated-at.bofh.it>
2006-04-21 15:25 ` kfree(NULL) Tilman Schmidt
2006-04-21 16:03 ` kfree(NULL) Daniel Walker
2006-04-21 17:48 ` kfree(NULL) Jörn Engel
2006-04-21 18:00 ` kfree(NULL) Steven Rostedt
2006-04-21 18:42 ` kfree(NULL) Daniel Walker
2006-04-21 18:56 ` kfree(NULL) Steven Rostedt
2006-04-21 19:26 ` kfree(NULL) Andrew Morton
-- strict thread matches above, loose matches on Subject: below --
2006-04-21 21:02 kfree(NULL) Hua Zhong
2006-04-21 21:11 ` kfree(NULL) Daniel Walker
2006-04-21 21:36 ` kfree(NULL) Michael Buesch
2006-04-21 21:42 ` kfree(NULL) Andrew Morton
2006-04-21 21:48 ` kfree(NULL) Andrew Morton
2006-04-21 22:53 ` kfree(NULL) Hua Zhong
2006-04-21 22:58 ` kfree(NULL) Daniel Walker
2006-04-21 23:03 ` kfree(NULL) Hua Zhong
2006-04-21 23:25 ` kfree(NULL) Andrew Morton
2006-04-21 23:27 ` kfree(NULL) Andrew Morton
2006-04-22 11:18 ` kfree(NULL) Jan Engelhardt
2006-04-22 12:05 kfree(NULL) linux
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