Message-ID: <4FEDAA6A.3000902@net.t-labs.tu-berlin.de> (sfid-20120629_151548_536674_A88F4C50)
Date: Fri, 29 Jun 2012 06:15:22 -0700
From: thomas <thomas@net.t-labs.tu-berlin.de>
MIME-Version: 1.0
To: Schrober <franzschrober@yahoo.de>
CC: Julian Calaby <julian.calaby@gmail.com>,
	linux-wireless@vger.kernel.org, johannes@sipsolutions.net,
	nbd@openwrt.org
Subject: Re: [PATCH] mac80211: correct size the argument to kzalloc in minstrel_ht
References: <1340926085-54416-1-git-send-email-thomas@net.t-labs.tu-berlin.de> <CAGRGNgXCoQNYbs7MVtEsDdoPUgvV+JDP28tCbKWG2cBHcJ60kQ@mail.gmail.com> <4FED3679.4080107@net.t-labs.tu-berlin.de> <1487602.AtWAA39W7Q@bentobox>
In-Reply-To: <1487602.AtWAA39W7Q@bentobox>
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Sender: linux-wireless-owner@vger.kernel.org


Schrober schrieb:

> On Thursday 28 June 2012 22:00:41 thomas wrote:
>> Hi Julian,
>>
>> Compiler wise both of our suggestions will lead to the same machine code.
>> So beside the matter of taste, I just followed the other overall usage
>> pattern of kzalloc in minstrel_ht.
>> And it seems to be explicitly using the struct type.
> 
> http://lxr.linux.no/linux/Documentation/CodingStyle
> 
>                 Chapter 14: Allocating memory
> 
> The kernel provides the following general purpose memory allocators:
> kmalloc(), kzalloc(), kcalloc(), vmalloc(), and vzalloc().  Please refer to
> the API documentation for further information about them.
> 
> The preferred form for passing a size of a struct is the following:
> 
>         p = kmalloc(sizeof(*p), ...);
> 
> The alternative form where struct name is spelled out hurts readability and
> introduces an opportunity for a bug when the pointer variable type is changed
> but the corresponding sizeof that is passed to a memory allocator is not.
> 
> Casting the return value which is a void pointer is redundant. The conversion
> from void pointer to any other pointer type is guaranteed by the C programming
> language.


Good to have this clarified. I will send a version 2.

Thx Thomas