[src/trunk]: src/sys/kern Fix lock order statement. Annotate with references...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/3d0d9b45cbb4
branches:  trunk
changeset: 822412:3d0d9b45cbb4
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sat Mar 18 22:02:11 2017 +0000

description:
Fix lock order statement.  Annotate with references to examples.

diffstat:

 sys/kern/vfs_cache.c |  11 ++++++++---
 1 files changed, 8 insertions(+), 3 deletions(-)

diffs (32 lines):

diff -r afc5279a7f97 -r 3d0d9b45cbb4 sys/kern/vfs_cache.c
--- a/sys/kern/vfs_cache.c      Sat Mar 18 21:21:24 2017 +0000
+++ b/sys/kern/vfs_cache.c      Sat Mar 18 22:02:11 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_cache.c,v 1.117 2017/03/18 21:03:28 riastradh Exp $        */
+/*     $NetBSD: vfs_cache.c,v 1.118 2017/03/18 22:02:11 riastradh Exp $        */
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -58,7 +58,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_cache.c,v 1.117 2017/03/18 21:03:28 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_cache.c,v 1.118 2017/03/18 22:02:11 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ddb.h"
@@ -110,7 +110,12 @@
  * N struct namecache::nc_lock Per-entry lock.
  * V struct vnode::v_interlock Vnode interlock.
  *
- * Lock order: C -> N -> L -> V
+ * Lock order: L -> C -> N -> V
+ *
+ *     Examples:
+ *     . L->C: cache_reclaim
+ *     . C->N->V: cache_lookup
+ *     . L->N->V: cache_purge1, cache_revlookup
  *
  * All use serialized by namecache_lock:
  *