From 909a3f0e9d8b0d8001cf6e99808f88eca8e44328 Mon Sep 17 00:00:00 2001
From: Cheng Lingfei <chenglingfei@foxmail.com>
Date: Mon, 24 Aug 2026 20:45:46 +0800
Subject: docs: cgroup-v2: fix misc.events key format description
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

In misc cgroup, misc.events does not output a simple "max" key. Instead,
each registered misc resource outputs a separate key suffixed with ".max"
(i.e., "<res>.max").
Update the documentation to clarify that the entry key is "<res>.max".

Suggested-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Cheng Lingfei <chenglingfei@foxmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
 drivers/tty/tty_mutex.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 drivers/tty/tty_mutex.c

(limited to 'drivers/tty/tty_mutex.c')

diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c
new file mode 100644
index 000000000..784e46a0a
--- /dev/null
+++ b/drivers/tty/tty_mutex.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/tty.h>
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/semaphore.h>
+#include <linux/sched.h>
+#include "tty.h"
+
+/* Legacy tty mutex glue */
+
+/*
+ * Getting the big tty mutex.
+ */
+
+void tty_lock(struct tty_struct *tty)
+{
+	tty_kref_get(tty);
+	mutex_lock(&tty->legacy_mutex);
+}
+EXPORT_SYMBOL(tty_lock);
+
+int tty_lock_interruptible(struct tty_struct *tty)
+{
+	int ret;
+
+	tty_kref_get(tty);
+	ret = mutex_lock_interruptible(&tty->legacy_mutex);
+	if (ret)
+		tty_kref_put(tty);
+	return ret;
+}
+
+void tty_unlock(struct tty_struct *tty)
+{
+	mutex_unlock(&tty->legacy_mutex);
+	tty_kref_put(tty);
+}
+EXPORT_SYMBOL(tty_unlock);
+
+void tty_lock_slave(struct tty_struct *tty)
+{
+	if (tty && tty != tty->link)
+		tty_lock(tty);
+}
+
+void tty_unlock_slave(struct tty_struct *tty)
+{
+	if (tty && tty != tty->link)
+		tty_unlock(tty);
+}
+
+void tty_set_lock_subclass(struct tty_struct *tty)
+{
+	lockdep_set_subclass(&tty->legacy_mutex, TTY_LOCK_SLAVE);
+}
-- 
cgit v1.3.1