[PATCH v2 30/44] mm: Remove unnecessary write to vma iterator in __vma_adjust()

[Liam Howlett]

From: "Liam R. Howlett" <Liam.Howlett at Oracle.com>

If the vma start address is going to change due to an insert, then it is
safe to not write the vma to the tree.  The write of the insert vma will
alter the tree as necessary.

Signed-off-by: Liam R. Howlett <Liam.Howlett at oracle.com>
---
 mm/mmap.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index a4e564163334..174cbf25251f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -781,10 +781,12 @@ int __vma_adjust(struct vma_iterator *vmi, struct vm_area_struct *vma,
 	}
 
 	if (start != vma->vm_start) {
-		if ((vma->vm_start < start) &&
-		    (!insert || (insert->vm_end != start))) {
-			vma_iter_clear(vmi, vma->vm_start, start);
-			VM_WARN_ON(insert && insert->vm_start > vma->vm_start);
+		if (vma->vm_start < start) {
+			if (!insert || (insert->vm_end != start)) {
+				vma_iter_clear(vmi, vma->vm_start, start);
+				vma_iter_set(vmi, start);
+				VM_WARN_ON(insert && insert->vm_start > vma->vm_start);
+			}
 		} else {
 			vma_changed = true;
 		}
-- 
2.35.1