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From: Jens Axboe <axboe@kernel.dk>
To: Pekka Enberg <penberg@kernel.org>
Cc: Xi Wang <xi.wang@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dan Carpenter <dan.carpenter@oracle.com>,
	linux-kernel@vger.kernel.org, Christoph Lameter <cl@linux.com>,
	Matt Mackall <mpm@selenic.com>,
	David Rientjes <rientjes@google.com>
Subject: Re: [PATCH RFC] slab: introduce knalloc/kxnalloc
Date: Thu, 09 Feb 2012 14:19:19 +0100	[thread overview]
Message-ID: <4F33C7D7.1060801@kernel.dk> (raw)
In-Reply-To: <CAOJsxLG0Lq7XZQWPxU=ut3Eec6UiRpwhsxU-k5Ooi7H1EBKT2A@mail.gmail.com>

On 02/09/2012 02:05 PM, Pekka Enberg wrote:
> On Thu, Feb 9, 2012 at 2:41 PM, Xi Wang <xi.wang@gmail.com> wrote:
>> This patch introduces knalloc/kxnalloc wrappers that perform integer
>> overflow checks without zeroing the memory.
>>
>> knalloc(n, size, flags) is the non-zeroing version of kcalloc(),
>> which allocates n * size bytes.
>>
>> kxnalloc(xsize, n, size, flags) allocates xsize + n * size bytes.
>> It is useful to allocate a structure ending with a zero-length array,
>> which is a commonly used pattern.  For example, in posix_acl_alloc()
>> to allocate a posix_acl object one could call
>>
>>    kxnalloc(sizeof(struct posix_acl),
>>             count, sizeof(struct posix_acl_entry), flags);
>>
>> to avoid overflowing the allocation size.
>>
>> Suggested-by: Andrew Morton <akpm@linux-foundation.org>
>> Signed-off-by: Xi Wang <xi.wang@gmail.com>
> 
> Are there really enough potential users to justify adding both?

Agree, lets not overdesign. kmalloc_array() sounds good to me, fwiw.

-- 
Jens Axboe


  reply	other threads:[~2012-02-09 13:20 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-07 14:11 integer overflows in kernel/relay.c Dan Carpenter
2012-02-08  8:34 ` Jens Axboe
2012-02-08 22:25   ` Andrew Morton
2012-02-09 12:41     ` Jens Axboe
2012-02-09 17:39       ` Andrew Morton
2012-02-09 12:41     ` [PATCH RFC] slab: introduce knalloc/kxnalloc Xi Wang
2012-02-09 13:05       ` Pekka Enberg
2012-02-09 13:19         ` Jens Axboe [this message]
2012-02-09 13:26           ` Xi Wang
2012-02-09 13:48             ` [PATCH RFC v2] slab: introduce kmalloc_array Xi Wang
2012-02-09 22:42               ` David Rientjes
2012-02-09 23:08                 ` Andrew Morton
2012-02-09 22:47               ` Jesper Juhl
2012-02-09 23:06                 ` Andrew Morton
2012-02-09 23:43                   ` Joe Perches
2012-02-13 15:08                   ` Xi Wang
2012-02-13 16:01                     ` Christoph Lameter
2012-02-13 19:44                       ` Dan Carpenter
2012-02-13 20:27                         ` Christoph Lameter
2012-02-14  7:20                           ` Dan Carpenter
2012-02-14  7:35                             ` Pekka Enberg
2012-02-14 11:12                             ` Xi Wang
2012-02-14 15:02                             ` Christoph Lameter
2012-02-14 16:30                               ` Xi Wang
2012-02-14 16:34                                 ` Christoph Lameter
2012-02-14 16:43                                   ` Xi Wang
2012-02-14 19:33                                     ` Uninline kcalloc Christoph Lameter
2012-02-14 19:37                                       ` Christoph Lameter
2012-02-14 20:46                                         ` Andrew Morton
2012-02-14 20:50                                         ` Nick Bowler
2012-02-14 21:24                                           ` Christoph Lameter
2012-02-15 20:17                                             ` Nick Bowler
2012-02-15 20:24                                               ` Nick Bowler
2012-02-14 20:45                                       ` Andrew Morton
2012-02-14 20:58                                         ` Pekka Enberg
2012-02-14 21:09                                           ` Christoph Lameter
2012-02-14 21:31                                             ` Pekka Enberg
2012-02-14 21:38                                               ` Christoph Lameter
2012-02-14 21:46                                             ` Xi Wang
2012-02-14 22:08                                               ` Christoph Lameter
2012-02-15 19:14                                                 ` Xi Wang
2012-02-15 19:34                                                   ` Christoph Lameter
2012-02-16  3:10                                                     ` Xi Wang
2012-02-16 14:51                                                       ` Christoph Lameter
2012-02-16 18:32                                                         ` Xi Wang
2012-02-16 20:47                                                           ` Christoph Lameter
2012-02-10 13:09               ` [PATCH RFC v2] slab: introduce kmalloc_array Alexey Dobriyan
2012-02-10 13:11                 ` Alexey Dobriyan
2012-02-10 13:55                   ` Xi Wang
2012-02-10 13:58                     ` Alexey Dobriyan
2012-02-10 14:09                       ` Xi Wang
2012-02-11 12:19                         ` Alexey Dobriyan
2012-02-12  5:46                           ` Xi Wang
2012-02-09 12:56     ` integer overflows in kernel/relay.c Pekka Enberg
2012-02-09 10:44   ` [patch] relay: prevent integer overflow in relay_open() Dan Carpenter
2012-02-09 11:55     ` walter harms
2012-02-09 12:36       ` Dan Carpenter

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