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SubjectRe: [PATCH v1 1/4] resource: Use PFN_UP / PFN_DOWN in walk_system_ram_range()
On Fri 09-08-19 14:56:58, David Hildenbrand wrote:
> This makes it clearer that we will never call func() with duplicate PFNs
> in case we have multiple sub-page memory resources. All unaligned parts
> of PFNs are completely discarded.
>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Borislav Petkov <bp@suse.de>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Nadav Amit <namit@vmware.com>
> Cc: Wei Yang <richardw.yang@linux.intel.com>
> Cc: Oscar Salvador <osalvador@suse.de>
> Signed-off-by: David Hildenbrand <david@redhat.com>

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
> kernel/resource.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/resource.c b/kernel/resource.c
> index 7ea4306503c5..88ee39fa9103 100644
> --- a/kernel/resource.c
> +++ b/kernel/resource.c
> @@ -487,8 +487,8 @@ int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
> while (start < end &&
> !find_next_iomem_res(start, end, flags, IORES_DESC_NONE,
> false, &res)) {
> - pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
> - end_pfn = (res.end + 1) >> PAGE_SHIFT;
> + pfn = PFN_UP(res.start);
> + end_pfn = PFN_DOWN(res.end + 1);
> if (end_pfn > pfn)
> ret = (*func)(pfn, end_pfn - pfn, arg);
> if (ret)
> --
> 2.21.0

--
Michal Hocko
SUSE Labs

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