Commit e52ed2dd authored by Jiri Slaby (SUSE)'s avatar Jiri Slaby (SUSE) Committed by Greg Kroah-Hartman
Browse files

tty: serial_core: use more guard(mutex) 



Simplify 4 more functions using guard(mutex): uart_get_info(),
console_store(), serial_core_add_one_port(), and
serial_core_register_port(). Especially console_store() is now much less
convoluted. In the others, we save some goto-s and even local variables
are dropped in some.

Signed-off-by: default avatarJiri Slaby (SUSE) <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20241211074933.92973-2-jirislaby@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent bc9c7e56

drivers/tty/serial/serial_core.c

+31 −52
Original line number Diff line number Diff line
@@ -790,7 +790,6 @@ static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo) 
{

	struct uart_state *state = container_of(port, struct uart_state, port);

	struct uart_port *uport;

	int ret = -ENODEV;



	/* Initialize structure in case we error out later to prevent any stack info leakage. */

	*retinfo = (struct serial_struct){};
@@ -799,10 +798,10 @@ static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo) 
	 * Ensure the state we copy is consistent and no hardware changes

	 * occur as we go

	 */

	mutex_lock(&port->mutex);

	guard(mutex)(&port->mutex);

	uport = uart_port_check(state);

	if (!uport)

		goto out;

		return -ENODEV;



	retinfo->type	    = uport->type;

	retinfo->line	    = uport->line;
@@ -823,10 +822,7 @@ static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo) 
	retinfo->iomem_reg_shift = uport->regshift;

	retinfo->iomem_base      = (void *)(unsigned long)uport->mapbase;



	ret = 0;

out:

	mutex_unlock(&port->mutex);

	return ret;

	return 0;

}



static int uart_get_info_user(struct tty_struct *tty,
@@ -3061,26 +3057,25 @@ static ssize_t console_store(struct device *dev, 
	if (ret)

		return ret;



	mutex_lock(&port->mutex);

	guard(mutex)(&port->mutex);

	uport = uart_port_check(state);

	if (uport) {

	if (!uport)

		return -ENXIO;



	oldconsole = uart_console_registered(uport);

	if (oldconsole && !newconsole) {

		ret = unregister_console(uport->cons);

		if (ret < 0)

			return ret;

	} else if (!oldconsole && newconsole) {

			if (uart_console(uport)) {

		if (!uart_console(uport))

			return -ENOENT;



		uport->console_reinit = 1;

		register_console(uport->cons);

			} else {

				ret = -ENOENT;

			}

		}

	} else {

		ret = -ENXIO;

	}

	mutex_unlock(&port->mutex);



	return ret < 0 ? ret : count;

	return count;

}



static DEVICE_ATTR_RO(uartclk);
@@ -3136,7 +3131,6 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u 
{

	struct uart_state *state;

	struct tty_port *port;

	int ret = 0;

	struct device *tty_dev;

	int num_groups;
@@ -3146,11 +3140,9 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u 
	state = drv->state + uport->line;

	port = &state->port;



	mutex_lock(&port->mutex);

	if (state->uart_port) {

		ret = -EINVAL;

		goto out;

	}

	guard(mutex)(&port->mutex);

	if (state->uart_port)

		return -EINVAL;



	/* Link the port to the driver state table and vice versa */

	atomic_set(&state->refcount, 1);
@@ -3170,10 +3162,8 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u 
	uport->minor = drv->tty_driver->minor_start + uport->line;

	uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,

				drv->tty_driver->name_base + uport->line);

	if (!uport->name) {

		ret = -ENOMEM;

		goto out;

	}

	if (!uport->name)

		return -ENOMEM;



	if (uport->cons && uport->dev)

		of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
@@ -3189,10 +3179,9 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u 


	uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),

				    GFP_KERNEL);

	if (!uport->tty_groups) {

		ret = -ENOMEM;

		goto out;

	}

	if (!uport->tty_groups)

		return -ENOMEM;



	uport->tty_groups[0] = &tty_dev_attr_group;

	if (uport->attr_group)

		uport->tty_groups[1] = uport->attr_group;
@@ -3215,10 +3204,7 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u 
		       uport->line);

	}



 out:

	mutex_unlock(&port->mutex);



	return ret;

	return 0;

}



/**
@@ -3384,7 +3370,7 @@ int serial_core_register_port(struct uart_driver *drv, struct uart_port *port) 
	struct serial_ctrl_device *ctrl_dev, *new_ctrl_dev = NULL;

	int ret;



	mutex_lock(&port_mutex);

	guard(mutex)(&port_mutex);



	/*

	 * Prevent serial_port_runtime_resume() from trying to use the port
@@ -3396,10 +3382,8 @@ int serial_core_register_port(struct uart_driver *drv, struct uart_port *port) 
	ctrl_dev = serial_core_ctrl_find(drv, port->dev, port->ctrl_id);

	if (!ctrl_dev) {

		new_ctrl_dev = serial_core_ctrl_device_add(port);

		if (IS_ERR(new_ctrl_dev)) {

			ret = PTR_ERR(new_ctrl_dev);

			goto err_unlock;

		}

		if (IS_ERR(new_ctrl_dev))

			return PTR_ERR(new_ctrl_dev);

		ctrl_dev = new_ctrl_dev;

	}
@@ -3420,8 +3404,6 @@ int serial_core_register_port(struct uart_driver *drv, struct uart_port *port) 
	if (ret)

		goto err_unregister_port_dev;



	mutex_unlock(&port_mutex);



	return 0;



err_unregister_port_dev:
@@ -3430,9 +3412,6 @@ int serial_core_register_port(struct uart_driver *drv, struct uart_port *port) 
err_unregister_ctrl_dev:

	serial_base_ctrl_device_remove(new_ctrl_dev);



err_unlock:

	mutex_unlock(&port_mutex);



	return ret;

}