Re: [Part1 PATCH v5 03/22] x86, ACPI, mm: Kill max_low_pfn_mapped

[Yinghai Lu <yinghai@kernel.org>]

On Mon, Jun 17, 2013 at 2:04 PM, Tejun Heo <tj@kernel.org> wrote:
> Hello,
>
> On Thu, Jun 13, 2013 at 09:02:50PM +0800, Tang Chen wrote:
>> From: Yinghai Lu <yinghai@kernel.org>
>>
>> Now we have pfn_mapped[] array, and max_low_pfn_mapped should not
>> be used anymore. Users should use pfn_mapped[] or just
>> 1UL<<(32-PAGE_SHIFT) instead.
>>
>> The only user of max_low_pfn_mapped is ACPI_INITRD_TABLE_OVERRIDE.
>> We could change to use 1U<<(32_PAGE_SHIFT) with it, aka under 4G.
>
>                                 ^ typo

ok.

>
> ...
>> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
>> index e721863..93e3194 100644
>> --- a/drivers/acpi/osl.c
>> +++ b/drivers/acpi/osl.c
>> @@ -624,9 +624,9 @@ void __init acpi_initrd_override(void *data, size_t size)
>>       if (table_nr == 0)
>>               return;
>>
>> -     acpi_tables_addr =
>> -             memblock_find_in_range(0, max_low_pfn_mapped << PAGE_SHIFT,
>> -                                    all_tables_size, PAGE_SIZE);
>> +     /* under 4G at first, then above 4G */
>> +     acpi_tables_addr = memblock_find_in_range(0, (1ULL<<32) - 1,
>> +                                     all_tables_size, PAGE_SIZE);
>
> No bigge, but why (1ULL << 32) - 1?  Shouldn't it be just 1ULL << 32?
> memblock deals with [@start, @end) areas, right?

that is for 32bit, when phys_addr_t is 32bit, in that case
(1ULL<<32) cast to 32bit would be 0.

>
> Other than that,
>
>  Acked-by: Tejun Heo <tj@kernel.org>

Thanks

Yinghai