mm: make the vma list be doubly linked
It's a really simple list, and several of the users want to go backwards
in it to find the previous vma. So rather than have to look up the
previous entry with 'find_vma_prev()' or something similar, just make it
doubly linked instead.
Tested-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/nommu.c b/mm/nommu.c
index efa9a38..88ff091 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -604,7 +604,7 @@
*/
static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
{
- struct vm_area_struct *pvma, **pp;
+ struct vm_area_struct *pvma, **pp, *next;
struct address_space *mapping;
struct rb_node **p, *parent;
@@ -664,8 +664,11 @@
break;
}
- vma->vm_next = *pp;
+ next = *pp;
*pp = vma;
+ vma->vm_next = next;
+ if (next)
+ next->vm_prev = vma;
}
/*