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From: "Jesper Juhl" <jesper.juhl@gmail.com>
To: "Jan Engelhardt" <jengelh@computergmbh.de>
Cc: Denys Vlasenko <vda.linux@googlemail.com>,
	David Woodhouse <dwmw2@infradead.org>,
	linux-mtd@lists.infradead.org,
	"Robert P. J. Day" <rpjday@mindspring.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 09/30] mtd: Don't cast kmalloc() return value in drivers/mtd/maps/pmcmsp-flash.c
Date: Mon, 27 Aug 2007 00:10:17 +0200	[thread overview]
Message-ID: <9a8748490708261510u6f373d2s760bef86e81bbe02@mail.gmail.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0708261635080.15614@fbirervta.pbzchgretzou.qr>

On 26/08/07, Jan Engelhardt <jengelh@computergmbh.de> wrote:
>
> On Aug 26 2007 15:28, Denys Vlasenko wrote:
> >> >
> >> > What exactely would using kcalloc() over kzalloc() here buy us?
> >>
> >> technically, nothing.
> >
> >The idea of calloc is that it can check for underflow in parameter.
>
> Actually, overflow.
>
> calloc(0xFFFF0000,  0x1000) => will return NULL
> malloc(0xFFFF0000 * 0x1000) => silent 32 bit multiplication/truncation,
> will allocate less than requested.
>
> >calloc(-1, 10000000) => easy to detect
> >malloc(-1 * 10000000) => malloc(-10000000) => not so trivial
>
Ok, that makes a bit of sense. Thank you.


-- 
Jesper Juhl <jesper.juhl@gmail.com>
Don't top-post  http://www.catb.org/~esr/jargon/html/T/top-post.html
Plain text mails only, please      http://www.expita.com/nomime.html

  reply	other threads:[~2007-08-26 22:10 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1554af80879a7ef2f78a4d654f23c248203500d9.1187912217.git.jesper.juhl@gmail.com>
2007-08-23 23:50 ` [PATCH 07/30] mtd: Get rid of pointless cast of kzalloc() return value in AT26xxx driver Jesper Juhl
2007-08-23 23:51 ` [PATCH 08/30] mtd: Avoid a pointless kmalloc() return value cast in TQM8xxL mapping handling code Jesper Juhl
2007-08-23 23:52 ` [PATCH 09/30] mtd: Don't cast kmalloc() return value in drivers/mtd/maps/pmcmsp-flash.c Jesper Juhl
2007-08-24 10:41   ` Denys Vlasenko
2007-08-24 10:43     ` Robert P. J. Day
2007-08-25 22:27       ` Jesper Juhl
2007-08-25 23:59         ` Robert P. J. Day
2007-08-26  0:28           ` Jesper Juhl
2007-08-26  0:23             ` Robert P. J. Day
2007-08-26  0:36               ` Jesper Juhl
2007-08-26  1:52                 ` Kyle Moffett
2007-08-26 14:28               ` Denys Vlasenko
2007-08-26 14:37                 ` Jan Engelhardt
2007-08-26 22:10                   ` Jesper Juhl [this message]
2007-08-24 10:48     ` Jesper Juhl

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