[PATCHv9 12/32] thp: prepare change_huge_pmd() for file thp

[Kirill A. Shutemov]

change_huge_pmd() has assert which is not relvant for file page.
For shared mapping it's perfectly fine to have page table entry
writable, without explicit mkwrite.

Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
---
 mm/huge_memory.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 32974dee4250..cc13e262dbe1 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1794,7 +1794,8 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t 
*pmd,
                                entry = pmd_mkwrite(entry);
                        ret = HPAGE_PMD_NR;
                        set_pmd_at(mm, addr, pmd, entry);
-                       BUG_ON(!preserve_write && pmd_write(entry));
+                       BUG_ON(vma_is_anonymous(vma) && !preserve_write &&
+                                       pmd_write(entry));
                }
                spin_unlock(ptl);
        }
-- 
2.8.1