Commit 56609c05 authored by Jiri Slaby (SUSE)'s avatar Jiri Slaby (SUSE) Committed by Greg Kroah-Hartman
Browse files

serial: serial_core: use guard()s 



Having all the new guards, use them in the serial_core code. This
improves readability, makes error handling easier, and marks locked
portions of code explicit.

Signed-off-by: default avatar"Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250814072456.182853-9-jirislaby@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 793b4501

drivers/tty/serial/serial_core.c

+59 −84
Original line number Diff line number Diff line
@@ -177,15 +177,13 @@ static void uart_start(struct tty_struct *tty) 
static void

uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)

{

	unsigned long flags;

	unsigned int old;



	uart_port_lock_irqsave(port, &flags);

	guard(uart_port_lock_irqsave)(port);

	old = port->mctrl;

	port->mctrl = (old & ~clear) | set;

	if (old != port->mctrl && !(port->rs485.flags & SER_RS485_ENABLED))

		port->ops->set_mctrl(port, port->mctrl);

	uart_port_unlock_irqrestore(port, flags);

}



#define uart_set_mctrl(port, set)	uart_update_mctrl(port, set, 0)
@@ -220,7 +218,7 @@ static void uart_change_line_settings(struct tty_struct *tty, struct uart_state 
	/*

	 * Set modem status enables based on termios cflag

	 */

	uart_port_lock_irq(uport);

	guard(uart_port_lock_irq)(uport);

	if (termios->c_cflag & CRTSCTS)

		uport->status |= UPSTAT_CTS_ENABLE;

	else
@@ -241,7 +239,6 @@ static void uart_change_line_settings(struct tty_struct *tty, struct uart_state 
		else

			__uart_start(state);

	}

	uart_port_unlock_irq(uport);

}



static int uart_alloc_xmit_buf(struct tty_port *port)
@@ -711,7 +708,6 @@ static void uart_send_xchar(struct tty_struct *tty, u8 ch) 
{

	struct uart_state *state = tty->driver_data;

	struct uart_port *port;

	unsigned long flags;



	port = uart_port_ref(state);

	if (!port)
@@ -720,11 +716,10 @@ static void uart_send_xchar(struct tty_struct *tty, u8 ch) 
	if (port->ops->send_xchar)

		port->ops->send_xchar(port, ch);

	else {

		uart_port_lock_irqsave(port, &flags);

		guard(uart_port_lock_irqsave)(port);

		port->x_char = ch;

		if (ch)

			port->ops->start_tx(port);

		uart_port_unlock_irqrestore(port, flags);

	}

	uart_port_deref(port);

}
@@ -1089,7 +1084,6 @@ static int uart_tiocmget(struct tty_struct *tty) 
	struct uart_state *state = tty->driver_data;

	struct tty_port *port = &state->port;

	struct uart_port *uport;

	int result;



	guard(mutex)(&port->mutex);
@@ -1097,12 +1091,9 @@ static int uart_tiocmget(struct tty_struct *tty) 
	if (!uport || tty_io_error(tty))

		return -EIO;



	uart_port_lock_irq(uport);

	result = uport->mctrl;

	result |= uport->ops->get_mctrl(uport);

	uart_port_unlock_irq(uport);

	guard(uart_port_lock_irq)(uport);



	return result;

	return uport->mctrl | uport->ops->get_mctrl(uport);

}



static int
@@ -1226,16 +1217,15 @@ static int uart_wait_modem_status(struct uart_state *state, unsigned long arg) 
	uport = uart_port_ref(state);

	if (!uport)

		return -EIO;

	uart_port_lock_irq(uport);

	scoped_guard(uart_port_lock_irq, uport) {

		memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));

		uart_enable_ms(uport);

	uart_port_unlock_irq(uport);

	}



	add_wait_queue(&port->delta_msr_wait, &wait);

	for (;;) {

		uart_port_lock_irq(uport);

		scoped_guard(uart_port_lock_irq, uport)

			memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));

		uart_port_unlock_irq(uport);



		set_current_state(TASK_INTERRUPTIBLE);
@@ -1430,7 +1420,6 @@ static void uart_set_rs485_rx_during_tx(struct uart_port *port, 
static int uart_rs485_config(struct uart_port *port)

{

	struct serial_rs485 *rs485 = &port->rs485;

	unsigned long flags;

	int ret;



	if (!(rs485->flags & SER_RS485_ENABLED))
@@ -1440,9 +1429,8 @@ static int uart_rs485_config(struct uart_port *port) 
	uart_set_rs485_termination(port, rs485);

	uart_set_rs485_rx_during_tx(port, rs485);



	uart_port_lock_irqsave(port, &flags);

	scoped_guard(uart_port_lock_irqsave, port)

		ret = port->rs485_config(port, NULL, rs485);

	uart_port_unlock_irqrestore(port, flags);

	if (ret) {

		memset(rs485, 0, sizeof(*rs485));

		/* unset GPIOs */
@@ -1456,12 +1444,10 @@ static int uart_rs485_config(struct uart_port *port) 
static int uart_get_rs485_config(struct uart_port *port,

			 struct serial_rs485 __user *rs485)

{

	unsigned long flags;

	struct serial_rs485 aux;



	uart_port_lock_irqsave(port, &flags);

	scoped_guard(uart_port_lock_irqsave, port)

		aux = port->rs485;

	uart_port_unlock_irqrestore(port, flags);



	if (copy_to_user(rs485, &aux, sizeof(aux)))

		return -EFAULT;
@@ -1474,7 +1460,6 @@ static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port, 
{

	struct serial_rs485 rs485;

	int ret;

	unsigned long flags;



	if (!(port->rs485_supported.flags & SER_RS485_ENABLED))

		return -ENOTTY;
@@ -1489,7 +1474,7 @@ static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port, 
	uart_set_rs485_termination(port, &rs485);

	uart_set_rs485_rx_during_tx(port, &rs485);



	uart_port_lock_irqsave(port, &flags);

	scoped_guard(uart_port_lock_irqsave, port) {

		ret = port->rs485_config(port, &tty->termios, &rs485);

		if (!ret) {

			port->rs485 = rs485;
@@ -1498,7 +1483,7 @@ static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port, 
			if (!(rs485.flags & SER_RS485_ENABLED))

				port->ops->set_mctrl(port, port->mctrl);

		}

	uart_port_unlock_irqrestore(port, flags);

	}

	if (ret) {

		/* restore old GPIO settings */

		gpiod_set_value_cansleep(port->rs485_term_gpio,
@@ -1517,15 +1502,13 @@ static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port, 
static int uart_get_iso7816_config(struct uart_port *port,

				   struct serial_iso7816 __user *iso7816)

{

	unsigned long flags;

	struct serial_iso7816 aux;



	if (!port->iso7816_config)

		return -ENOTTY;



	uart_port_lock_irqsave(port, &flags);

	scoped_guard(uart_port_lock_irqsave, port)

		aux = port->iso7816;

	uart_port_unlock_irqrestore(port, flags);



	if (copy_to_user(iso7816, &aux, sizeof(aux)))

		return -EFAULT;
@@ -1537,8 +1520,7 @@ static int uart_set_iso7816_config(struct uart_port *port, 
				   struct serial_iso7816 __user *iso7816_user)

{

	struct serial_iso7816 iso7816;

	int i, ret;

	unsigned long flags;

	int i;



	if (!port->iso7816_config)

		return -ENOTTY;
@@ -1554,11 +1536,11 @@ static int uart_set_iso7816_config(struct uart_port *port, 
		if (iso7816.reserved[i])

			return -EINVAL;



	uart_port_lock_irqsave(port, &flags);

	ret = port->iso7816_config(port, &iso7816);

	uart_port_unlock_irqrestore(port, flags);

	scoped_guard(uart_port_lock_irqsave, port) {

		int ret = port->iso7816_config(port, &iso7816);

		if (ret)

			return ret;

	}



	if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))

		return -EFAULT;
@@ -1770,9 +1752,8 @@ static void uart_tty_port_shutdown(struct tty_port *port) 
	if (WARN(!uport, "detached port still initialized!\n"))

		return;



	uart_port_lock_irq(uport);

	scoped_guard(uart_port_lock_irq, uport)

		uport->ops->stop_rx(uport);

	uart_port_unlock_irq(uport);



	serial_base_port_shutdown(uport);

	uart_port_shutdown(port);
@@ -2044,9 +2025,8 @@ static void uart_line_info(struct seq_file *m, struct uart_state *state) 
		pm_state = state->pm_state;

		if (pm_state != UART_PM_STATE_ON)

			uart_change_pm(state, UART_PM_STATE_ON);

		uart_port_lock_irq(uport);

		scoped_guard(uart_port_lock_irq, uport)

			status = uport->ops->get_mctrl(uport);

		uart_port_unlock_irq(uport);

		if (pm_state != UART_PM_STATE_ON)

			uart_change_pm(state, pm_state);
@@ -2355,9 +2335,8 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport) 
	 */

	if (!console_suspend_enabled && uart_console(uport)) {

		if (uport->ops->start_rx) {

			uart_port_lock_irq(uport);

			guard(uart_port_lock_irq)(uport);

			uport->ops->stop_rx(uport);

			uart_port_unlock_irq(uport);

		}

		device_set_awake_path(uport->dev);

		return 0;
@@ -2373,7 +2352,7 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport) 
		tty_port_set_suspended(port, true);

		tty_port_set_initialized(port, false);



		uart_port_lock_irq(uport);

		scoped_guard(uart_port_lock_irq, uport) {

			ops->stop_tx(uport);

			if (!(uport->rs485.flags & SER_RS485_ENABLED))

				ops->set_mctrl(uport, 0);
@@ -2381,7 +2360,7 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport) 
			mctrl = uport->mctrl;

			uport->mctrl = 0;

			ops->stop_rx(uport);

		uart_port_unlock_irq(uport);

		}



		/*

		 * Wait for the transmitter to empty.
@@ -2450,9 +2429,8 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport) 
			uart_change_pm(state, UART_PM_STATE_ON);

		uport->ops->set_termios(uport, &termios, NULL);

		if (!console_suspend_enabled && uport->ops->start_rx) {

			uart_port_lock_irq(uport);

			guard(uart_port_lock_irq)(uport);

			uport->ops->start_rx(uport);

			uart_port_unlock_irq(uport);

		}

		if (console_suspend_enabled)

			console_resume(uport->cons);
@@ -2463,10 +2441,9 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport) 
		int ret;



		uart_change_pm(state, UART_PM_STATE_ON);

		uart_port_lock_irq(uport);

		scoped_guard(uart_port_lock_irq, uport)

			if (!(uport->rs485.flags & SER_RS485_ENABLED))

				ops->set_mctrl(uport, 0);

		uart_port_unlock_irq(uport);

		if (console_suspend_enabled || !uart_console(uport)) {

			/* Protected by port mutex for now */

			struct tty_struct *tty = port->tty;
@@ -2476,11 +2453,11 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport) 
				if (tty)

					uart_change_line_settings(tty, state, NULL);

				uart_rs485_config(uport);

				uart_port_lock_irq(uport);

				scoped_guard(uart_port_lock_irq, uport) {

					if (!(uport->rs485.flags & SER_RS485_ENABLED))

						ops->set_mctrl(uport, uport->mctrl);

					ops->start_tx(uport);

				uart_port_unlock_irq(uport);

				}

				tty_port_set_initialized(port, true);

			} else {

				/*
@@ -2574,8 +2551,6 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state, 
	}



	if (port->type != PORT_UNKNOWN) {

		unsigned long flags;



		uart_report_port(drv, port);



		/* Synchronize with possible boot console. */
@@ -2590,11 +2565,11 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state, 
		 * keep the DTR setting that is set in uart_set_options()

		 * We probably don't need a spinlock around this, but

		 */

		uart_port_lock_irqsave(port, &flags);

		scoped_guard(uart_port_lock_irqsave, port) {

			port->mctrl &= TIOCM_DTR;

			if (!(port->rs485.flags & SER_RS485_ENABLED))

				port->ops->set_mctrl(port, port->mctrl);

		uart_port_unlock_irqrestore(port, flags);

		}



		uart_rs485_config(port);