[RFC PATCH 10/28] mm/mmap: mark VMAs as locked in vma_adjust

[Suren Baghdasaryan]

vma_adjust modifies a VMA and possibly its neighbors. Mark them as locked
before making the modifications.

Signed-off-by: Suren Baghdasaryan <surenb at google.com>
---
 mm/mmap.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index f89c9b058105..ed58cf0689b2 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -710,6 +710,10 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
 	long adjust_next = 0;
 	int remove_next = 0;
 
+	vma_mark_locked(vma);
+	if (next)
+		vma_mark_locked(next);
+
 	if (next && !insert) {
 		struct vm_area_struct *exporter = NULL, *importer = NULL;
 
@@ -754,8 +758,11 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
 			 * If next doesn't have anon_vma, import from vma after
 			 * next, if the vma overlaps with it.
 			 */
-			if (remove_next == 2 && !next->anon_vma)
+			if (remove_next == 2 && !next->anon_vma) {
 				exporter = next->vm_next;
+				if (exporter)
+					vma_mark_locked(exporter);
+			}
 
 		} else if (end > next->vm_start) {
 			/*
@@ -931,6 +938,8 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
 			 * "vma->vm_next" gap must be updated.
 			 */
 			next = vma->vm_next;
+			if (next)
+				vma_mark_locked(next);
 		} else {
 			/*
 			 * For the scope of the comment "next" and
-- 
2.37.2.672.g94769d06f0-goog