acct: use VMA iterator instead of linked list

The VMA iterator is faster than the linked list.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Liam R. Howlett <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Reviewed-by: Davidlohr Bueso <[email protected]>
Tested-by: Yu Zhao <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: David Howells <[email protected]>
Cc: SeongJae Park <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 5 insertions, 6 deletions

diff --git a/kernel/acct.c b/kernel/acct.c
index 13706356ec54..62200d799b9b 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -555,15 +555,14 @@ void acct_collect(long exitcode, int group_dead)
 	unsigned long vsize = 0;
 
 	if (group_dead && current->mm) {
+		struct mm_struct *mm = current->mm;
+		VMA_ITERATOR(vmi, mm, 0);
 		struct vm_area_struct *vma;
 
-		mmap_read_lock(current->mm);
-		vma = current->mm->mmap;
-		while (vma) {
+		mmap_read_lock(mm);
+		for_each_vma(vmi, vma)
 			vsize += vma->vm_end - vma->vm_start;
-			vma = vma->vm_next;
-		}
-		mmap_read_unlock(current->mm);
+		mmap_read_unlock(mm);
 	}
 
 	spin_lock_irq(&current->sighand->siglock);