[PATCH v10 52/69] mm/khugepaged: stop using vma linked list

[Liam Howlett]

From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>

Use vma iterator & find_vma() instead of vma linked list.

Link: https://lkml.kernel.org/r/20220504011345.662299-37-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: SeongJae Park <sj@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
 mm/huge_memory.c |  4 ++--
 mm/khugepaged.c  | 11 ++++++++---
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f7248002dad9..f44ffd3bbfae 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2266,11 +2266,11 @@ void vma_adjust_trans_huge(struct vm_area_struct *vma,
 	split_huge_pmd_if_needed(vma, end);
 
 	/*
-	 * If we're also updating the vma->vm_next->vm_start,
+	 * If we're also updating the next vma vm_start,
 	 * check if we need to split it.
 	 */
 	if (adjust_next > 0) {
-		struct vm_area_struct *next = vma->vm_next;
+		struct vm_area_struct *next = find_vma(vma->vm_mm, vma->vm_end);
 		unsigned long nstart = next->vm_start;
 		nstart += adjust_next;
 		split_huge_pmd_if_needed(next, nstart);
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 8dbd68c414d9..637bfecd6bf5 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -2092,10 +2092,12 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
 	__releases(&khugepaged_mm_lock)
 	__acquires(&khugepaged_mm_lock)
 {
+	struct vma_iterator vmi;
 	struct mm_slot *mm_slot;
 	struct mm_struct *mm;
 	struct vm_area_struct *vma;
 	int progress = 0;
+	unsigned long address;
 
 	VM_BUG_ON(!pages);
 	lockdep_assert_held(&khugepaged_mm_lock);
@@ -2119,11 +2121,14 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
 	vma = NULL;
 	if (unlikely(!mmap_read_trylock(mm)))
 		goto breakouterloop_mmap_lock;
-	if (likely(!khugepaged_test_exit(mm)))
-		vma = find_vma(mm, khugepaged_scan.address);
 
 	progress++;
-	for (; vma; vma = vma->vm_next) {
+	if (unlikely(khugepaged_test_exit(mm)))
+		goto breakouterloop;
+
+	address = khugepaged_scan.address;
+	vma_iter_init(&vmi, mm, address);
+	for_each_vma(vmi, vma) {
 		unsigned long hstart, hend;
 
 		cond_resched();
-- 
2.35.1