mm: thp: Return the correct value for change_huge_pmd

The wrong value is being returned by change_huge_pmd since commit
10c1045f28e8 ("mm: numa: avoid unnecessary TLB flushes when setting
NUMA hinting entries") which allows a fallthrough that tries to adjust
non-existent PTEs. This patch corrects it.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 89b9075f8c116a8e94dc6d7f1c5bc1962d9ecc39..626e93db28ba162d11e7d286985604bbc523981c 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1487,6 +1487,7 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 
        if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
                pmd_t entry;
+               ret = 1;
 
                /*
                 * Avoid trapping faults against the zero page. The read-only
@@ -1495,11 +1496,10 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
                 */
                if (prot_numa && is_huge_zero_pmd(*pmd)) {
                        spin_unlock(ptl);
-                       return 0;
+                       return ret;
                }
 
                if (!prot_numa || !pmd_protnone(*pmd)) {
-                       ret = 1;
                        entry = pmdp_get_and_clear_notify(mm, addr, pmd);
                        entry = pmd_modify(entry, newprot);
                        ret = HPAGE_PMD_NR;