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From: Roland Dreier <rdreier@cisco.com>
To: "Pekka Enberg" <penberg@cs.helsinki.fi>
Cc: "Linus Torvalds" <torvalds@linux-foundation.org>,
	"Christoph Lameter" <clameter@sgi.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, jeremy@goop.org
Subject: Re: SLUB: Return ZERO_SIZE_PTR for kmalloc(0)
Date: Mon, 04 Jun 2007 09:43:00 -0700	[thread overview]
Message-ID: <ada6463llgr.fsf@cisco.com> (raw)
In-Reply-To: <84144f020706040937xb06535em543fa887ad65ee8f@mail.gmail.com> (Pekka Enberg's message of "Mon, 4 Jun 2007 19:37:01 +0300")

 > Then we might as well return your regular NULL pointer for zero-length
 > allocations as you can't do anything sane with ZERO_SIZE_PTR either.

No, because as was mentioned earlier in the thread, we want code to be
able to handle 0-sized allocations without special cases.  The goal is
that code like

	buf = kmalloc(nobj * obj_size);
	if (buf == NULL)
		return -ENOMEM;

should work fine if nobj happens to be 0.  But we do want to get an
oops if the code actually tries to read or write *buf.

 - R.

  parent reply	other threads:[~2007-06-04 16:43 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-06-02  1:37 SLUB: Return ZERO_SIZE_PTR for kmalloc(0) Christoph Lameter
2007-06-02  2:09 ` John Anthony Kazos Jr.
2007-06-02  2:15   ` Christoph Lameter
2007-06-02  2:21     ` John Anthony Kazos Jr.
2007-06-02  2:54 ` Linus Torvalds
2007-06-02  3:06   ` Christoph Lameter
2007-06-02  3:41 ` Andrew Morton
2007-06-02  4:01   ` Christoph Lameter
2007-06-02  4:31     ` Andrew Morton
2007-06-02  4:45       ` Christoph Lameter
2007-06-02  4:54         ` Andrew Morton
2007-06-03 16:17           ` Matt Mackall
2007-06-04 17:59           ` William Lee Irwin III
2007-06-03 16:15         ` Matt Mackall
2007-06-04 14:44           ` Alan Cox
2007-06-04 15:08         ` Pekka Enberg
2007-06-04 16:16           ` Christoph Lameter
2007-06-04 16:22             ` Pekka Enberg
2007-06-04 16:26               ` Linus Torvalds
2007-06-04 16:32                 ` Jeremy Fitzhardinge
2007-06-04 16:37                 ` Pekka Enberg
2007-06-04 16:38                   ` Jeremy Fitzhardinge
2007-06-04 16:43                   ` Roland Dreier [this message]
2007-06-04 17:02                     ` Pekka Enberg
2007-06-04 16:48                   ` Linus Torvalds
2007-06-04 18:22                   ` Cyrill Gorcunov
2007-06-04 17:20                 ` Alan Cox
2007-06-04 17:50                   ` Linus Torvalds
2007-06-04 18:05                     ` William Lee Irwin III
2007-06-04 18:47 ` Linus Torvalds
2007-06-04 19:01   ` Christoph Lameter
2007-06-04 19:13     ` Pekka Enberg
2007-06-04 19:14       ` Christoph Lameter
2007-06-04 19:25         ` Pekka Enberg
2007-06-04 22:39           ` Christoph Lameter
2007-06-04 22:53             ` Andrew Morton
2007-06-04 23:09               ` Christoph Lameter
2007-06-05  5:27                 ` Pekka Enberg
2007-06-05 17:23                   ` Christoph Lameter
2007-06-05  8:50                 ` Rene Herman
2007-06-05 12:07                   ` John Anthony Kazos Jr.
2007-06-05 12:54                     ` Rene Herman
2007-06-05 13:58                       ` John Anthony Kazos Jr.
2007-06-05 14:32                         ` Rene Herman
2007-06-05 19:07                           ` Pekka Enberg
2007-06-05 14:40                       ` Jeremy Fitzhardinge
2007-06-05 14:56                         ` Rene Herman
2007-06-06 21:26                           ` Pavel Machek
2007-06-06 21:58                             ` Rene Herman

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