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Date: Tue, 29 May 2007 17:45:56 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
       linux-kernel@vger.kernel.org, linux-m68k@vger.kernel.org,
       Roman Zippel <zippel@linux-m68k.org>
Subject: Re: [patch 2/2] m68k: Discontinuous memory support
Message-Id: <20070529174556.20c551a0.akpm@linux-foundation.org>
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	<20070528191715.597623909@mail.of.borg>
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On Mon, 28 May 2007 21:16:32 +0200
Geert Uytterhoeven <geert@linux-m68k.org> wrote:

> -#define __page_address(page)	(PAGE_OFFSET + (((page) - mem_map) << PAGE_SHIFT))
> -#define page_to_phys(page)	virt_to_phys((void *)__page_address(page))
> +#ifdef CONFIG_SINGLE_MEMORY_CHUNK
> +#define page_to_phys(page) \
> +	__pa(PAGE_OFFSET + (((page) - pg_data_map[0].node_mem_map) << PAGE_SHIFT))
> +#else
> +#define page_to_phys(page) ({						\
> +	struct pglist_data *pgdat;					\
> +	pgdat = pg_data_table[page_to_nid(page)];			\
> +	page_to_pfn(page) << PAGE_SHIFT;				\
> +})
> +#endif

macros which evaluate their args more than once are dangerous.