From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Beulich" <jbeulich@novell.com>
Subject: Re: [PATCH] fix ia64 breakage with PHYSDEVOP_pirq_eoi_mfn (was
	Re:[PATCH 2/2] linux/x86: use shared page
	indicatingthe need for an EOI notification)
Date: Wed, 10 Dec 2008 09:21:30 +0000
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	<C56401D2.1FFE2%keir.fraser@eu.citrix.com>
	<20081210040824.GD15447%yamahata@valinux.co.jp>
	<20081210041650.GF15447%yamahata@valinux.co.jp>
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To: Isaku Yamahata <yamahata@valinux.co.jp>
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>>> Isaku Yamahata <yamahata@valinux.co.jp> 10.12.08 05:16 >>>
>Sorry I sent out the old one. Here is the corrected one.
>NULL check must be before its use.

Not really - alloc_bootmem() etc panic for themselves unless you use the
_nopanic variants.
Also, alloc_bootmem() etc zero the allocated memory, so no need for
memset(), and the subsequent BUG_ON() can obviously go away.
And finally, PAGE_SIZE isn't correct, you should use the size originally
used, just slightly modified:

BITS_TO_LONGS(ALIGN(NR_PIRQS, PAGE_SIZE * 8))

I was about to put together a patch for this myself...

Jan