diff mbox series

[v4,16/33] mm/mmap: write-lock VMAs in vma_prepare before modifying them

Message ID 20230227173632.3292573-17-surenb@google.com (mailing list archive)
State New
Headers show
Series Per-VMA locks | expand

Commit Message

Suren Baghdasaryan Feb. 27, 2023, 5:36 p.m. UTC 
Write-lock all VMAs which might be affected by a merge, split, expand
or shrink operations. All these operations use vma_prepare() before
making the modifications, therefore it provides a centralized place to
perform VMA locking.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 mm/mmap.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
diff mbox series

Patch

diff --git a/mm/mmap.c b/mm/mmap.c
index 92893d86c0af..e73fbb84ce12 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -502,6 +502,16 @@  static inline void init_vma_prep(struct vma_prepare *vp,
  */
 static inline void vma_prepare(struct vma_prepare *vp)
 {
+	if (vp->vma)
+		vma_start_write(vp->vma);
+	if (vp->adj_next)
+		vma_start_write(vp->adj_next);
+	/* vp->insert is always a newly created VMA, no need for locking */
+	if (vp->remove)
+		vma_start_write(vp->remove);
+	if (vp->remove2)
+		vma_start_write(vp->remove2);
+
 	if (vp->file) {
 		uprobe_munmap(vp->vma, vp->vma->vm_start, vp->vma->vm_end);