Remove the first mapping check for vma_link.  Move the mutex_lock into the
braces when vma->vm_file is true.
Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 {
        struct address_space *mapping = NULL;
 
-       if (vma->vm_file)
+       if (vma->vm_file) {
                mapping = vma->vm_file->f_mapping;
-
-       if (mapping)
                mutex_lock(&mapping->i_mmap_mutex);
+       }
 
        __vma_link(mm, vma, prev, rb_link, rb_parent);
        __vma_link_file(vma);