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Subject[PATCH v2] rmap: Fix compound check logic in page_remove_file_rmap
Date
In page_remove_file_rmap(.) we have the following check:
VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page);

This is meant to check for either HugeTLB pages or THP when a compound
page is passed in.

Unfortunately, if one disables CONFIG_TRANSPARENT_HUGEPAGE, then
PageTransHuge(.) will always return false, provoking BUGs when one runs
the libhugetlbfs test suite.

This patch replaces PageTransHuge(), with PageHead() which will work for
both HugeTLB and THP.

Fixes: dd78fedde4b9 ("rmap: support file thp")
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steve Capper <steve.capper@arm.com>

---

v2 - switch to PageHead as suggested by Kirill.
---
mm/rmap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index 709bc83..1180340 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1303,7 +1303,7 @@ static void page_remove_file_rmap(struct page *page, bool compound)
{
int i, nr = 1;

- VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page);
+ VM_BUG_ON_PAGE(compound && !PageHead(page), page);
lock_page_memcg(page);

/* Hugepages are not counted in NR_FILE_MAPPED for now. */
--
1.8.3.1
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