linux-kernel - Re: [PATCH 1/1] FS/JBD:replace count*size kmalloc by kmalloc

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Message-ID: <20140626011751.GA6826@thunk.org>
Date:	Wed, 25 Jun 2014 21:17:51 -0400
From:	Theodore Ts'o <tytso@....edu>
To:	Fabian Frederick <fabf@...net.be>
Cc:	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jan Kara <jack@...e.cz>
Subject: Re: [PATCH 1/1] FS/JBD:replace count*size kmalloc by kmalloc_array

On Wed, Jun 25, 2014 at 08:49:06PM +0200, Fabian Frederick wrote:
> kmalloc_array manages count*sizeof overflow.

Except in these call sites, overflow is impossible.

kmalloc_array() is useful when count is coming from an unvalidated
source.  But in this case, the count is either a fixed, hard-coded
value (256), or the size of n*count is *guaranteed* to be less than
the page size.

So this just adds some extra code which is pointless (assuming the
compiler isn't smart enough to optimize it out).

	       	     	       		   - Ted
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