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mm,memory_hotplug: explicitly pass the head to isolate_huge_page

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isolate_huge_page() expects we pass the head of hugetlb page to it:

  bool isolate_huge_page(...)
  {
	...
	VM_BUG_ON_PAGE(!PageHead(page), page);
	...
  }

While I really cannot think of any situation where we end up with a
non-head page between hands in do_migrate_range(), let us make sure the
code is as sane as possible by explicitly passing the Head.  Since we
already got the pointer, it does not take us extra effort.

Link: http://lkml.kernel.org/r/20190208090604.975-1-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Anthony Yznaga <anthony.yznaga@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oscar Salvador
2019-03-05 15:48:53 -08:00
committed by Linus Torvalds
parent 494eec70f0
commit daf3538ad5
1 changed files with 2 additions and 2 deletions
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4
mm/memory_hotplug.c
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@@ -1378,12 +1378,12 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
if (PageHuge(page)) {
struct page *head = compound_head(page);
pfn = page_to_pfn(head) + (1<<compound_order(head)) - 1;
if (compound_order(head) > PFN_SECTION_SHIFT) {
ret = -EBUSY;
break;
}
isolate_huge_page(page, &source);
pfn = page_to_pfn(head) + (1<<compound_order(head)) - 1;
isolate_huge_page(head, &source);
continue;
} else if (PageTransHuge(page))
pfn = page_to_pfn(compound_head(page))