[PATCH 6.12 18/77] serial: sc16is7xx: use guards for simple mutex locks

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hugo Villeneuve <hvilleneuve@dimonoff.com>

[ Upstream commit 0f4f88bfd7e7bf3f3293045fffdc63586b0a889f ]

Guards can help to make the code more readable, so use them wherever they
do so.

In sc16is7xx_port_irq(), labels and 'rc' locals are eliminated completely.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://patch.msgid.link/20251027142957.1032073-6-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 246ac114f485 ("serial: sc16is7xx: enable THRI before filling TX FIFO")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/serial/sc16is7xx.c |   23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -11,6 +11,7 @@
 #define DEFAULT_SYMBOL_NAMESPACE "SERIAL_NXP_SC16IS7XX"
 
 #include <linux/bits.h>
+#include <linux/cleanup.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/device.h>
@@ -779,18 +780,15 @@ static void sc16is7xx_update_mlines(stru
 
 static bool sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
 {
-	bool rc = true;
 	unsigned int iir, rxlen;
 	struct uart_port *port = &s->p[portno].port;
 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
 
-	mutex_lock(&one->lock);
+	guard(mutex)(&one->lock);
 
 	iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG);
-	if (iir & SC16IS7XX_IIR_NO_INT_BIT) {
-		rc = false;
-		goto out_port_irq;
-	}
+	if (iir & SC16IS7XX_IIR_NO_INT_BIT)
+		return false;
 
 	iir &= SC16IS7XX_IIR_ID_MASK;
 
@@ -830,10 +828,7 @@ static bool sc16is7xx_port_irq(struct sc
 		break;
 	}
 
-out_port_irq:
-	mutex_unlock(&one->lock);
-
-	return rc;
+	return true;
 }
 
 static irqreturn_t sc16is7xx_irq(int irq, void *dev_id)
@@ -863,9 +858,8 @@ static void sc16is7xx_tx_proc(struct kth
 	    (port->rs485.delay_rts_before_send > 0))
 		msleep(port->rs485.delay_rts_before_send);
 
-	mutex_lock(&one->lock);
+	guard(mutex)(&one->lock);
 	sc16is7xx_handle_tx(port);
-	mutex_unlock(&one->lock);
 }
 
 static void sc16is7xx_reconf_rs485(struct uart_port *port)
@@ -932,9 +926,8 @@ static void sc16is7xx_ms_proc(struct kth
 	struct sc16is7xx_port *s = dev_get_drvdata(one->port.dev);
 
 	if (one->port.state) {
-		mutex_lock(&one->lock);
-		sc16is7xx_update_mlines(one);
-		mutex_unlock(&one->lock);
+		scoped_guard(mutex, &one->lock)
+			sc16is7xx_update_mlines(one);
 
 		kthread_queue_delayed_work(&s->kworker, &one->ms_work, HZ);
 	}