mm: nommu: don't scan the vma list when deleting

Since commit 297c5eee3724 ("mm: make the vma list be doubly linked") made
it a doubly linked list, we don't need to scan the list when deleting
@vma.

And the original code didn't update the prev pointer. Fix it too.

Signed-off-by: Namhyung Kim <[email protected]>
Acked-by: Greg Ungerer <[email protected]>
Cc: David Howells <[email protected]>
Cc: Paul Mundt <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/nommu.c b/mm/nommu.c
index 0b16cb4c517bfbdc9655f698e37f89d3f0bceec6..2454d39dc06878a0e460d444b49ce4b22b713c25 100644 (file)
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -746,7 +746,6 @@ static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
  */
 static void delete_vma_from_mm(struct vm_area_struct *vma)
 {
-       struct vm_area_struct **pp;
        struct address_space *mapping;
        struct mm_struct *mm = vma->vm_mm;
 
@@ -769,12 +768,14 @@ static void delete_vma_from_mm(struct vm_area_struct *vma)
 
        /* remove from the MM's tree and list */
        rb_erase(&vma->vm_rb, &mm->mm_rb);
-       for (pp = &mm->mmap; *pp; pp = &(*pp)->vm_next) {
-               if (*pp == vma) {
-                       *pp = vma->vm_next;
-                       break;
-               }
-       }
+
+       if (vma->vm_prev)
+               vma->vm_prev->vm_next = vma->vm_next;
+       else
+               mm->mmap = vma->vm_next;
+
+       if (vma->vm_next)
+               vma->vm_next->vm_prev = vma->vm_prev;
 
        vma->vm_mm = NULL;
 }