[patch 09/20] madvise_free, thp: fix madvise_free_huge_pmd return value after splitting

[patch 09/20] madvise_free, thp: fix madvise_free_huge_pmd return value after splitting

[akpm]

From: Huang Ying <ying.huang@intel.com>
Subject: madvise_free, thp: fix madvise_free_huge_pmd return value after splitting

madvise_free_huge_pmd should return 0 if the fallback PTE operations are
required.  In madvise_free_huge_pmd, if part pages of THP are discarded,
the THP will be split and fallback PTE operations should be used if
splitting succeeds.  But the original code will make fallback PTE
operations skipped, after splitting succeeds.  Fix that via make
madvise_free_huge_pmd return 0 after splitting successfully, so that the
fallback PTE operations will be done.

Link: http://lkml.kernel.org/r/1467135452-16688-1-git-send-email-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/huge_memory.c |    7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff -puN mm/huge_memory.c~madvise_free-thp-fix-madvise_free_huge_pmd-return-value-after-splitting mm/huge_memory.c
--- a/mm/huge_memory.c~madvise_free-thp-fix-madvise_free_huge_pmd-return-value-after-splitting
+++ a/mm/huge_memory.c
@@ -1624,14 +1624,9 @@ int madvise_free_huge_pmd(struct mmu_gat
 	if (next - addr != HPAGE_PMD_SIZE) {
 		get_page(page);
 		spin_unlock(ptl);
-		if (split_huge_page(page)) {
-			put_page(page);
-			unlock_page(page);
-			goto out_unlocked;
-		}
+		split_huge_page(page);
 		put_page(page);
 		unlock_page(page);
-		ret = 1;
 		goto out_unlocked;
 	}
 
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