From 512fa9a4e0bc14978fb6a01fd8d0e2cbbe0cc985 Mon Sep 17 00:00:00 2001
From: Mateusz Guzik <mjg@FreeBSD.org>
Date: Sun, 19 Jan 2020 05:36:45 +0000
Subject: [PATCH] vfs: plug a conditional assigment of lo_name in getnewvnode

It only matters for witness. No functional changes.
---
 sys/kern/vfs_subr.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index 08b7649a2aa..9597cd99dc0 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -1669,11 +1669,15 @@ getnewvnode(const char *tag, struct mount *mp, struct vop_vector *vops,
 	 * that we can compare pointers rather than doing a strcmp().
 	 */
 	lo = &vp->v_vnlock->lock_object;
+#ifdef WITNESS
 	if (lo->lo_name != tag) {
+#endif
 		lo->lo_name = tag;
+#ifdef WITNESS
 		WITNESS_DESTROY(lo);
 		WITNESS_INIT(lo, tag);
 	}
+#endif
 	/*
 	 * By default, don't allow shared locks unless filesystems opt-in.
 	 */