linux-kernel - Re: [PATCH 1/3] xen: off by one error in xen/setup.c

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Date:	Wed, 03 Aug 2011 08:31:52 +0200
From:	Igor Mammedov <imammedo@...hat.com>
To:	Jesper Juhl <jj@...osbits.net>
CC:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] xen: off by one error in xen/setup.c

On 08/03/2011 08:23 AM, Jesper Juhl wrote:
> On Wed, 3 Aug 2011, Igor Mammedov wrote:
>
>> On 08/02/2011 07:07 PM, Konrad Rzeszutek Wilk wrote:
>>> On Tue, Aug 02, 2011 at 11:45:23AM +0200, Igor Mammedov wrote:
>>>> Do not try to initialize pfn beyond of available address space.
>>>>
>>>> Signed-off-by: Igor Mammedov<imammedo@...hat.com>
>>>> ---
>>>>    arch/x86/xen/setup.c |    2 +-
>>>>    1 files changed, 1 insertions(+), 1 deletions(-)
>>>>
>>>> diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
>>>> index 60aeeb5..2221b05 100644
>>>> --- a/arch/x86/xen/setup.c
>>>> +++ b/arch/x86/xen/setup.c
>>>> @@ -69,7 +69,7 @@ static void __init xen_add_extra_mem(unsigned long
>>>> pages)
>>>>
>>>>    	xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
>>>>
>>>> -	for (pfn = PFN_DOWN(extra_start); pfn<= xen_max_p2m_pfn; pfn++)
>>>> +	for (pfn = PFN_DOWN(extra_start); pfn<   xen_max_p2m_pfn; ++pfn)
>>>>    		__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
>>>
>>> Did this actually break anything?
>>
>> Not really, but for the sake of correctness and as cleanup it's good idea.
>>
>
> Ok I'm really, really nitpicking here, but if it's supposed to "clean up",
> wouldn't this:
>
>    for (pfn = PFN_DOWN(extra_start); pfn<  xen_max_p2m_pfn; ++pfn)
>
> be preferable (note the spacing around '<') ?

It is correct. Checkout https://lkml.org/lkml/2011/8/2/82

-- 
Thanks,
  Igor
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