[merged mm-stable] mm-tweak-__vma_enter_locked.patch removed from -mm tree

[merged mm-stable] mm-tweak-__vma_enter_locked.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm: tweak __vma_enter_locked()
has been removed from the -mm tree.  Its filename was
     mm-tweak-__vma_enter_locked.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: mm: tweak __vma_enter_locked()
Date: Wed, 19 Nov 2025 04:26:35 +0000

Move the commentary on how __vma_enter_locked() behaves from the body of
__vma_start_write() to the head of __vma_enter_locked() and merge it with
the existing documentation.  Also add a call to
mmap_assert_write_locked().

Link: https://lkml.kernel.org/r/20251119042639.3937024-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mmap_lock.c |   13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

--- a/mm/mmap_lock.c~mm-tweak-__vma_enter_locked
+++ a/mm/mmap_lock.c
@@ -46,9 +46,9 @@ EXPORT_SYMBOL(__mmap_lock_do_trace_relea
 #ifdef CONFIG_MMU
 #ifdef CONFIG_PER_VMA_LOCK
 /*
- * Return value: 0 if vma detached,
- * 1 if vma attached with no readers,
- * -EINTR if signal received,
+ * __vma_enter_locked() returns 0 immediately if the vma is not
+ * attached, otherwise it waits for any current readers to finish and
+ * returns 1.  Returns -EINTR if a signal is received while waiting.
  */
 static inline int __vma_enter_locked(struct vm_area_struct *vma,
 		bool detaching, int state)
@@ -56,6 +56,8 @@ static inline int __vma_enter_locked(str
 	int err;
 	unsigned int tgt_refcnt = VMA_LOCK_OFFSET;
 
+	mmap_assert_write_locked(vma->vm_mm);
+
 	/* Additional refcnt if the vma is attached. */
 	if (!detaching)
 		tgt_refcnt++;
@@ -91,11 +93,6 @@ int __vma_start_write(struct vm_area_str
 {
 	int locked;
 
-	/*
-	 * __vma_enter_locked() returns false immediately if the vma is not
-	 * attached, otherwise it waits until refcnt is indicating that vma
-	 * is attached with no readers.
-	 */
 	locked = __vma_enter_locked(vma, false, state);
 	if (locked < 0)
 		return locked;
_

Patches currently in -mm which might be from willy@infradead.org are