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Subject[PATCH] mm,memory_hotplug: Explicitly pass the head to isolate_huge_page
Date
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.

Signed-off-by: Oscar Salvador <osalvador@suse.de>
---
mm/memory_hotplug.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 656ff386ac15..d5f7afda67db 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -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))
--
2.13.7
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