On Fri, Feb 07, 2020 at 12:11:34PM +0800, Baoquan He wrote:
>On 02/07/20 at 07:16am, Wei Yang wrote:
>> memmap should be the physical address to page struct instead of virtual
>> address to pfn.
>
>Maybe not, memmap stores a virtual address.
>
>>
>> Since we call this only for SPARSEMEM_VMEMMAP, pfn_to_page() is valid at
>> this point.
>>
>> Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug")
>> Signed-off-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
>> CC: Dan Williams <dan.j.williams@xxxxxxxxx>
>> ---
>> mm/sparse.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/mm/sparse.c b/mm/sparse.c
>> index b5da121bdd6e..56816f653588 100644
>> --- a/mm/sparse.c
>> +++ b/mm/sparse.c
>> @@ -888,7 +888,7 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn,
>> /* Align memmap to section boundary in the subsection case */
>> if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP) &&
>> section_nr_to_pfn(section_nr) != start_pfn)
>> - memmap = pfn_to_kaddr(section_nr_to_pfn(section_nr));
>> + memmap = pfn_to_page(section_nr_to_pfn(section_nr));
>
>With Dan's confirmation, sub-section is only valid in vmemmap case. I
>think the old if (section_nr_to_pfn(section_nr) != start_pfn) is enough
>to filter out non vmemmap case. So only below code is good:
>
> + memmap = pfn_to_page(section_nr_to_pfn(section_nr));
>
You mean replace pfn_to_kaddr with pfn_to_page ?
>> sparse_init_one_section(ms, section_nr, memmap, ms->usage, 0);
>>
>> return 0;
>> --
>> 2.17.1
>>
--
Wei Yang
Help you, Help me
