[RFC 3/4] Remove nest locking operation with mmap_sem

[Laurent Dufour]

The range locking framework doesn't yet provide nest locking
operation, so remove them assuming that the check is now good.

Signed-off-by: Laurent Dufour <lduf...@linux.vnet.ibm.com>
---
 mm/mmap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index cd8fa7e74784..4df13e633e92 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3284,7 +3284,7 @@ static void vm_lock_anon_vma(struct mm_struct *mm, struct 
anon_vma *anon_vma)
                 * The LSB of head.next can't change from under us
                 * because we hold the mm_all_locks_mutex.
                 */
-               down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_sem);
+               down_write(&anon_vma->root->rwsem);
                /*
                 * We can safely modify head.next after taking the
                 * anon_vma->root->rwsem. If some other vma in this mm shares
@@ -3314,7 +3314,7 @@ static void vm_lock_mapping(struct mm_struct *mm, struct 
address_space *mapping)
                 */
                if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
                        BUG();
-               down_write_nest_lock(&mapping->i_mmap_rwsem, &mm->mmap_sem);
+               down_write(&mapping->i_mmap_rwsem);
        }
 }
 
-- 
2.7.4