linux-kernel - [PATCH 5/6] Input: turbografx - use guard notation when acquiring mutex

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Message-ID: <20240904043104.1030257-6-dmitry.torokhov@gmail.com>
Date: Tue,  3 Sep 2024 21:31:02 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: linux-input@...r.kernel.org
Cc: Erick Archer <erick.archer@...look.com>,
	Christophe JAILLET <christophe.jaillet@...adoo.fr>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 5/6] Input: turbografx - use guard notation when acquiring mutex

Using guard notation makes the code more compact and error handling
more robust by ensuring that mutexes are released in all code paths
when control leaves critical section.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
---
 drivers/input/joystick/turbografx.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/drivers/input/joystick/turbografx.c b/drivers/input/joystick/turbografx.c
index eb8455c34e67..015010a928aa 100644
--- a/drivers/input/joystick/turbografx.c
+++ b/drivers/input/joystick/turbografx.c
@@ -103,33 +103,31 @@ static void tgfx_timer(struct timer_list *t)
 static int tgfx_open(struct input_dev *dev)
 {
 	struct tgfx *tgfx = input_get_drvdata(dev);
-	int err;
 
-	err = mutex_lock_interruptible(&tgfx->sem);
-	if (err)
-		return err;
+	scoped_guard(mutex_intr, &tgfx->sem) {
+		if (!tgfx->used++) {
+			parport_claim(tgfx->pd);
+			parport_write_control(tgfx->pd->port, 0x04);
+			mod_timer(&tgfx->timer, jiffies + TGFX_REFRESH_TIME);
+		}
 
-	if (!tgfx->used++) {
-		parport_claim(tgfx->pd);
-		parport_write_control(tgfx->pd->port, 0x04);
-		mod_timer(&tgfx->timer, jiffies + TGFX_REFRESH_TIME);
+		return 0;
 	}
 
-	mutex_unlock(&tgfx->sem);
-	return 0;
+	return -EINTR;
 }
 
 static void tgfx_close(struct input_dev *dev)
 {
 	struct tgfx *tgfx = input_get_drvdata(dev);
 
-	mutex_lock(&tgfx->sem);
+	guard(mutex)(&tgfx->sem);
+
 	if (!--tgfx->used) {
 		del_timer_sync(&tgfx->timer);
 		parport_write_control(tgfx->pd->port, 0x00);
 		parport_release(tgfx->pd);
 	}
-	mutex_unlock(&tgfx->sem);
 }
 
 
-- 
2.46.0.469.g59c65b2a67-goog