mm: make vm_area_dup() actually copy the old vma data

.. and re-initialize th eanon_vma_chain head.

This removes some boiler-plate from the users, and also makes it clear
why it didn't need use the 'zalloc()' version.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 7 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index 4286ad2dd1f5..b0ed8ce1b67e 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2624,11 +2624,6 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
         if (!new)
                 return -ENOMEM;
 
-        /* most fields are the same, copy all, and then fixup */
-        *new = *vma;
-
-        INIT_LIST_HEAD(&new->anon_vma_chain);
-
         if (new_below)
                 new->vm_end = addr;
         else {
@@ -3205,13 +3200,11 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
                 new_vma = vm_area_dup(vma);
                 if (!new_vma)
                         goto out;
-                *new_vma = *vma;
                 new_vma->vm_start = addr;
                 new_vma->vm_end = addr + len;
                 new_vma->vm_pgoff = pgoff;
                 if (vma_dup_policy(vma, new_vma))
                         goto out_free_vma;
-                INIT_LIST_HEAD(&new_vma->anon_vma_chain);
                 if (anon_vma_clone(new_vma, vma))
                         goto out_free_mempol;
                 if (new_vma->vm_file)