[PATCHv3 18/29] thp: run vma_adjust_trans_huge() outside i_mmap_rwsem

[Kirill A. Shutemov]

vma_addjust_trans_huge() splits pmd if it's crossing VMA boundary.
During split we munlock the huge page which requires rmap walk.
rmap wants to take the lock on its own.

Let's move vma_adjust_trans_huge() outside i_mmap_rwsem to fix this.

Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
---
 mm/mmap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index af6722385edf..2cb88eb252b8 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -677,6 +677,8 @@ again:                      remove_next = 1 + (end > 
next->vm_end);
                }
        }
 
+       vma_adjust_trans_huge(vma, start, end, adjust_next);
+
        if (file) {
                mapping = file->f_mapping;
                root = &mapping->i_mmap;
@@ -697,8 +699,6 @@ again:                      remove_next = 1 + (end > 
next->vm_end);
                }
        }
 
-       vma_adjust_trans_huge(vma, start, end, adjust_next);
-
        anon_vma = vma->anon_vma;
        if (!anon_vma && adjust_next)
                anon_vma = next->anon_vma;
-- 
2.7.0