From bb3b2cfeb206f5b10b859e134651b54120e3f530 Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Tue, 30 Jun 2026 18:05:56 +0100 Subject: ARM: 9480/1: entry: expand comment in __switch_to As per discussion between the developers in the mail thread linked, expand the comment in __switch_to so that readers of the code understand what is going on. Suggested-by: Mark Rutland Acked-by: Mark Rutland Signed-off-by: Linus Walleij > Signed-off-by: Russell King --- 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 +#include +#include +#include +#include +#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