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Subject: Re: [-mm patch] make kcalloc() a static inline
From: Arjan van de Ven <arjan@infradead.org>
To: Denis Vlasenko <vda@ilport.com.ua>
Cc: Adrian Bunk <bunk@stusta.de>, Pekka J Enberg <penberg@cs.Helsinki.FI>,
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Date: Mon, 15 Aug 2005 10:14:20 +0200
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On Mon, 2005-08-15 at 11:06 +0300, Denis Vlasenko wrote:

> > +static inline void *kcalloc(size_t n, size_t size, unsigned int __nocast flags)
> > +{
> > +	if (n != 0 && size > INT_MAX / n)
> > +		return NULL;
> > +	return kzalloc(n * size, flags);
> > +}

> Can you conditionalize it on __builtin_constant_p(n) ?
> Otherwise with variable n you have 3 oprations in inlined
> code, one of them a division.

you can't conditionalize the security check really. If it's constant,
gcc will optimize it anyway, and if it's not constant you for sure want
the check there...