[PATCH] mm/rmap: Correct some obsolete comments of anon_vma

[Miaohe Lin <linmiaohe@huawei.com>]

The commit 2b575eb64f7a ("mm: convert anon_vma->lock to a mutex") changed
spinlock used to serialize access to vma list to mutex. And further, the
commit 5a505085f043 ("mm/rmap: Convert the struct anon_vma::mutex to an
rwsem") converted the mutex to an rwsem for solving scalability problem. So
replace spinlock with rwsem to make comment uptodate.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
 mm/rmap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index e26ae119a131..f6f43620cd97 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -168,7 +168,7 @@ static void anon_vma_chain_link(struct vm_area_struct *vma,
  *
  * Anon-vma allocations are very subtle, because we may have
  * optimistically looked up an anon_vma in page_lock_anon_vma_read()
- * and that may actually touch the spinlock even in the newly
+ * and that may actually touch the rwsem even in the newly
  * allocated vma (it depends on RCU to make sure that the
  * anon_vma isn't actually destroyed).
  *
@@ -359,7 +359,7 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma)
 		goto out_error_free_anon_vma;
 
 	/*
-	 * The root anon_vma's spinlock is the lock actually used when we
+	 * The root anon_vma's rwsem is the lock actually used when we
 	 * lock any of the anon_vmas in this anon_vma tree.
 	 */
 	anon_vma->root = pvma->anon_vma->root;
-- 
2.19.1