serial: Make uart_remove_one_port() return void

The return value is only ever used as a return value for remove callbacks
of platform drivers. This return value is ignored by the driver core.
(The only effect is an error message, but uart_remove_one_port() already
emitted one in this case.)

So the return value isn't used at all and uart_remove_one_port() can be
changed to return void without any loss. Also this better matches the
Linux device model as remove functions are not supposed to fail.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230512173810.131447-3-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/atmel_serial.c

@@ -3006,14 +3006,13 @@ static int atmel_serial_remove(struct platform_device *pdev)
 {
 	struct uart_port *port = platform_get_drvdata(pdev);
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
-	int ret = 0;
 
 	tasklet_kill(&atmel_port->tasklet_rx);
 	tasklet_kill(&atmel_port->tasklet_tx);
 
 	device_init_wakeup(&pdev->dev, 0);
 
-	ret = uart_remove_one_port(&atmel_uart, port);
+	uart_remove_one_port(&atmel_uart, port);
 
 	kfree(atmel_port->rx_ring.buf);
 
@@ -3023,7 +3022,7 @@ static int atmel_serial_remove(struct platform_device *pdev)
 
 	pdev->dev.of_node = NULL;
 
-	return ret;
+	return 0;
 }
 
 static SIMPLE_DEV_PM_OPS(atmel_serial_pm_ops, atmel_serial_suspend,

drivers/tty/serial/clps711x.c

@@ -514,7 +514,9 @@ static int uart_clps711x_remove(struct platform_device *pdev)
 {
 	struct clps711x_port *s = platform_get_drvdata(pdev);
 
-	return uart_remove_one_port(&clps711x_uart, &s->port);
+	uart_remove_one_port(&clps711x_uart, &s->port);
+
+	return 0;
 }
 
 static const struct of_device_id __maybe_unused clps711x_uart_dt_ids[] = {

drivers/tty/serial/cpm_uart/cpm_uart_core.c

@@ -1431,7 +1431,10 @@ static int cpm_uart_probe(struct platform_device *ofdev)
 static int cpm_uart_remove(struct platform_device *ofdev)
 {
 	struct uart_cpm_port *pinfo = platform_get_drvdata(ofdev);
-	return uart_remove_one_port(&cpm_reg, &pinfo->port);
+
+	uart_remove_one_port(&cpm_reg, &pinfo->port);
+
+	return 0;
 }
 
 static const struct of_device_id cpm_uart_match[] = {

drivers/tty/serial/imx.c

@@ -2467,7 +2467,9 @@ static int imx_uart_remove(struct platform_device *pdev)
 {
 	struct imx_port *sport = platform_get_drvdata(pdev);
 
-	return uart_remove_one_port(&imx_uart_uart_driver, &sport->port);
+	uart_remove_one_port(&imx_uart_uart_driver, &sport->port);
+
+	return 0;
 }
 
 static void imx_uart_restore_context(struct imx_port *sport)

drivers/tty/serial/lantiq.c

@@ -889,7 +889,9 @@ static int lqasc_remove(struct platform_device *pdev)
 {
 	struct uart_port *port = platform_get_drvdata(pdev);
 
-	return uart_remove_one_port(&lqasc_reg, port);
+	uart_remove_one_port(&lqasc_reg, port);
+
+	return 0;
 }
 
 static const struct ltq_soc_data soc_data_lantiq = {

drivers/tty/serial/serial_core.c

@@ -3154,13 +3154,12 @@ EXPORT_SYMBOL(uart_add_one_port);
  * This unhooks (and hangs up) the specified port structure from the core
  * driver. No further calls will be made to the low-level code for this port.
  */
-int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
+void uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
 {
 	struct uart_state *state = drv->state + uport->line;
 	struct tty_port *port = &state->port;
 	struct uart_port *uart_port;
 	struct tty_struct *tty;
-	int ret = 0;
 
 	mutex_lock(&port_mutex);
 
@@ -3176,7 +3175,6 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
 
 	if (!uart_port) {
 		mutex_unlock(&port->mutex);
-		ret = -EINVAL;
 		goto out;
 	}
 	uport->flags |= UPF_DEAD;
@@ -3219,8 +3217,6 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
 	mutex_unlock(&port->mutex);
 out:
 	mutex_unlock(&port_mutex);
-
-	return ret;
 }
 EXPORT_SYMBOL(uart_remove_one_port);
 

drivers/tty/serial/st-asc.c

@@ -796,7 +796,9 @@ static int asc_serial_remove(struct platform_device *pdev)
 {
 	struct uart_port *port = platform_get_drvdata(pdev);
 
-	return uart_remove_one_port(&asc_uart_driver, port);
+	uart_remove_one_port(&asc_uart_driver, port);
+
+	return 0;
 }
 
 #ifdef CONFIG_PM_SLEEP

drivers/tty/serial/uartlite.c

@@ -685,18 +685,15 @@ static int ulite_assign(struct device *dev, int id, phys_addr_t base, int irq,
  *
  * @dev: pointer to device structure
  */
-static int ulite_release(struct device *dev)
+static void ulite_release(struct device *dev)
 {
 	struct uart_port *port = dev_get_drvdata(dev);
-	int rc = 0;
 
 	if (port) {
-		rc = uart_remove_one_port(&ulite_uart_driver, port);
+		uart_remove_one_port(&ulite_uart_driver, port);
 		dev_set_drvdata(dev, NULL);
 		port->mapbase = 0;
 	}
-
-	return rc;
 }
 
 /**
@@ -900,14 +897,13 @@ static int ulite_remove(struct platform_device *pdev)
 {
 	struct uart_port *port = dev_get_drvdata(&pdev->dev);
 	struct uartlite_data *pdata = port->private_data;
-	int rc;
 
 	clk_disable_unprepare(pdata->clk);
-	rc = ulite_release(&pdev->dev);
+	ulite_release(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_set_suspended(&pdev->dev);
 	pm_runtime_dont_use_autosuspend(&pdev->dev);
-	return rc;
+	return 0;
 }
 
 /* work with hotplug and coldplug */

drivers/tty/serial/xilinx_uartps.c

@@ -1670,14 +1670,13 @@ static int cdns_uart_remove(struct platform_device *pdev)
 {
 	struct uart_port *port = platform_get_drvdata(pdev);
 	struct cdns_uart *cdns_uart_data = port->private_data;
-	int rc;
 
 	/* Remove the cdns_uart port from the serial core */
 #ifdef CONFIG_COMMON_CLK
 	clk_notifier_unregister(cdns_uart_data->uartclk,
 			&cdns_uart_data->clk_rate_change_nb);
 #endif
-	rc = uart_remove_one_port(cdns_uart_data->cdns_uart_driver, port);
+	uart_remove_one_port(cdns_uart_data->cdns_uart_driver, port);
 	port->mapbase = 0;
 	clk_disable_unprepare(cdns_uart_data->uartclk);
 	clk_disable_unprepare(cdns_uart_data->pclk);
@@ -1693,7 +1692,7 @@ static int cdns_uart_remove(struct platform_device *pdev)
 
 	if (!--instances)
 		uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
-	return rc;
+	return 0;
 }
 
 static struct platform_driver cdns_uart_platform_driver = {

include/linux/serial_core.h

@@ -853,7 +853,7 @@ void uart_console_write(struct uart_port *port, const char *s,
 int uart_register_driver(struct uart_driver *uart);
 void uart_unregister_driver(struct uart_driver *uart);
 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
-int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
+void uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
 bool uart_match_port(const struct uart_port *port1,
 		const struct uart_port *port2);