From: David Hildenbrand <david@xxxxxxxxxx> Subject: mm/memory_hotplug.c: use PFN_UP / PFN_DOWN in walk_system_ram_range() Patch series "mm/memory_hotplug: online_pages() cleanups", v2. Some cleanups (+ one fix for a special case) in the context of online_pages(). This patch (of 5): 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. Link: http://lkml.kernel.org/r/20190814154109.3448-2-david@xxxxxxxxxx Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Reviewed-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxx> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: Nadav Amit <namit@xxxxxxxxxx> Cc: Oscar Salvador <osalvador@xxxxxxx> Cc: Arun KS <arunks@xxxxxxxxxxxxxx> Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/resource.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/kernel/resource.c~resource-use-pfn_up-pfn_down-in-walk_system_ram_range +++ a/kernel/resource.c @@ -487,8 +487,8 @@ int walk_system_ram_range(unsigned long 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) _
