From: Wei Yang <richard.weiyang@gmail.com>
To: Baoquan He <bhe@redhat.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>,
akpm@linux-foundation.org, osalvador@suse.de,
dan.j.williams@intel.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, david@redhat.com
Subject: Re: [PATCH 2/3] mm/sparsemem: get physical address to page struct instead of virtual address to pfn
Date: Fri, 7 Feb 2020 10:53:14 +0000 [thread overview]
Message-ID: <20200207105314.axkvp4b5glm2snfw@master> (raw)
In-Reply-To: <20200207041134.GC25537@MiWiFi-R3L-srv>
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@linux.intel.com>
>> CC: Dan Williams <dan.j.williams@intel.com>
>> ---
>> 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
next prev parent reply other threads:[~2020-02-07 10:53 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-06 23:16 [PATCH 0/3] Fixes "mm/sparsemem: support sub-section hotplug" Wei Yang
2020-02-06 23:16 ` [PATCH 1/3] mm/sparsemem: adjust memmap only for SPARSEMEM_VMEMMAP Wei Yang
2020-02-07 2:00 ` Dan Williams
2020-02-07 11:06 ` Wei Yang
2020-02-06 23:16 ` [PATCH 2/3] mm/sparsemem: get physical address to page struct instead of virtual address to pfn Wei Yang
2020-02-07 2:19 ` Dan Williams
2020-02-07 3:10 ` Baoquan He
2020-02-07 3:21 ` Dan Williams
2020-02-07 3:36 ` Baoquan He
2020-02-07 4:05 ` Dan Williams
2020-02-07 11:13 ` Wei Yang
2020-02-07 12:14 ` Wei Yang
2020-02-07 16:44 ` Dan Williams
2020-02-07 10:51 ` Wei Yang
2020-02-07 11:26 ` Wei Yang
2020-02-09 13:50 ` Baoquan He
2020-02-09 14:14 ` David Hildenbrand
2020-02-10 0:36 ` Wei Yang
2020-02-07 4:11 ` Baoquan He
2020-02-07 10:53 ` Wei Yang [this message]
2020-02-06 23:16 ` [PATCH 3/3] mm/sparsemem: avoid memmap overwrite for non-SPARSEMEM_VMEMMAP Wei Yang
2020-02-07 2:06 ` Dan Williams
2020-02-07 3:50 ` Baoquan He
2020-02-07 11:02 ` Wei Yang
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