From ed6232893c9dffec587a18afca04137d98328ab0 Mon Sep 17 00:00:00 2001
From: Kyle Evans <kevans@FreeBSD.org>
Date: Fri, 29 Nov 2019 03:51:01 +0000
Subject: [PATCH] snp: don't reference tp->t_mtx directly

This is the only part of snp(4) that pokes around in struct tty directly;
replace it with the tty_getlock accessor to avoid struct tty internals.
---
 sys/dev/snp/snp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/dev/snp/snp.c b/sys/dev/snp/snp.c
index dce8a9846558..64e2d0f64537 100644
--- a/sys/dev/snp/snp.c
+++ b/sys/dev/snp/snp.c
@@ -178,7 +178,7 @@ snp_read(struct cdev *dev, struct uio *uio, int flag)
 			error = EWOULDBLOCK;
 			break;
 		}
-		error = cv_wait_sig(&ss->snp_outwait, tp->t_mtx);
+		error = cv_wait_sig(&ss->snp_outwait, tty_getlock(tp));
 		if (error != 0)
 			break;
 		if (tty_gone(tp)) {