rmap: fix compound check logic in page_remove_file_rmap

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")
Link: http://lkml.kernel.org/r/1470838217-5889-1-git-send-email-steve.capper@arm.com
Signed-off-by: Steve Capper <steve.capper@arm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Huang Shijie <shijie.huang@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/rmap.c b/mm/rmap.c
index d4f5606..1ef3640 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1304,7 +1304,7 @@ 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. */