From: John Ogness Date: Mon, 11 Dec 2023 09:19:18 +0000 Subject: [PATCH 08/46] serial: core: Provide low-level functions to lock port Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.9/older/patches-6.9-rt5.tar.xz It will be necessary at times for the uart nbcon console drivers to acquire the port lock directly (without the additional nbcon functionality of the port lock wrappers). These are special cases such as the implementation of the device_lock()/device_unlock() callbacks or for internal port lock wrapper synchronization. Provide low-level variants __uart_port_lock_irqsave() and __uart_port_unlock_irqrestore() for this purpose. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Acked-by: Greg Kroah-Hartman Signed-off-by: Sebastian Andrzej Siewior --- include/linux/serial_core.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -591,6 +591,24 @@ struct uart_port { void *private_data; /* generic platform data pointer */ }; +/* + * Only for console->device_lock()/_unlock() callbacks and internal + * port lock wrapper synchronization. + */ +static inline void __uart_port_lock_irqsave(struct uart_port *up, unsigned long *flags) +{ + spin_lock_irqsave(&up->lock, *flags); +} + +/* + * Only for console->device_lock()/_unlock() callbacks and internal + * port lock wrapper synchronization. + */ +static inline void __uart_port_unlock_irqrestore(struct uart_port *up, unsigned long flags) +{ + spin_unlock_irqrestore(&up->lock, flags); +} + /** * uart_port_lock - Lock the UART port * @up: Pointer to UART port structure