Merge branch 'for-next' of https://git.kernel.org/pub/scm/linux/kernel/git/mm/linux.git

1 files changed, 6 insertions, 11 deletions

diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index d09d4c3fe547..f7e8d766d128 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -272,13 +272,10 @@ struct stack_map_vma_lock {
 /*
  * Acquire a stable read-side reference on the VMA covering @ip.
  *
- * With CONFIG_PER_VMA_LOCK=y this returns a VMA with its per-VMA read
- * lock held and mmap_lock dropped, so the caller may sleep.
- *
- * With CONFIG_PER_VMA_LOCK=n it returns a VMA with mmap_lock still
- * held; the caller must snapshot any fields it needs and pin vm_file
- * with get_file() before stack_map_unlock_vma() drops mmap_lock, as
- * the VMA may be split, merged, or freed after that.
+ * On NOMMU configurations, returns with the mmap_lock held.  If the MMU
+ * is enabled, the per-VMA lock will be held instead.  The lock
+ * should be released with stack_map_unlock_vma() which will release the
+ * appropriate lock.  Once the lock is released, the VMA may be freed.
  *
  * Returns NULL on failure, in which case no lock is held.
  */
@@ -288,7 +285,6 @@ stack_map_lock_vma(struct stack_map_vma_lock *lock, unsigned long ip)
 	struct mm_struct *mm = lock->mm;
 	struct vm_area_struct *vma;
 
-	/* noop under !CONFIG_PER_VMA_LOCK */
 	vma = lock_vma_under_rcu(mm, ip);
 	if (vma) {
 		lock->vma = vma;
@@ -308,21 +304,20 @@ stack_map_lock_vma(struct stack_map_vma_lock *lock, unsigned long ip)
 		return NULL;
 	}
 
-#ifdef CONFIG_PER_VMA_LOCK
+#ifdef CONFIG_MMU
 	if (!vma_start_read_locked(vma)) {
 		mmap_read_unlock(mm);
 		return NULL;
 	}
 	mmap_read_unlock(mm);
 #endif
-
 	lock->vma = vma;
 	return vma;
 }
 
 static void stack_map_unlock_vma(struct stack_map_vma_lock *lock)
 {
-#ifdef CONFIG_PER_VMA_LOCK
+#ifdef CONFIG_MMU
 	vma_end_read(lock->vma);
 #else
 	mmap_read_unlock(lock->mm);