linux-kernel - [PATCH 2/6] Input: gamecon - use guard notation when acquiring mutex

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Message-ID: <20240904043104.1030257-3-dmitry.torokhov@gmail.com>
Date: Tue,  3 Sep 2024 21:30:59 -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 2/6] Input: gamecon - 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/gamecon.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/drivers/input/joystick/gamecon.c b/drivers/input/joystick/gamecon.c
index c38de3094553..968c0e653f2e 100644
--- a/drivers/input/joystick/gamecon.c
+++ b/drivers/input/joystick/gamecon.c
@@ -765,33 +765,31 @@ static void gc_timer(struct timer_list *t)
 static int gc_open(struct input_dev *dev)
 {
 	struct gc *gc = input_get_drvdata(dev);
-	int err;
 
-	err = mutex_lock_interruptible(&gc->mutex);
-	if (err)
-		return err;
+	scoped_guard(mutex_intr, &gc->mutex) {
+		if (!gc->used++) {
+			parport_claim(gc->pd);
+			parport_write_control(gc->pd->port, 0x04);
+			mod_timer(&gc->timer, jiffies + GC_REFRESH_TIME);
+		}
 
-	if (!gc->used++) {
-		parport_claim(gc->pd);
-		parport_write_control(gc->pd->port, 0x04);
-		mod_timer(&gc->timer, jiffies + GC_REFRESH_TIME);
+		return 0;
 	}
 
-	mutex_unlock(&gc->mutex);
-	return 0;
+	return -EINTR;
 }
 
 static void gc_close(struct input_dev *dev)
 {
 	struct gc *gc = input_get_drvdata(dev);
 
-	mutex_lock(&gc->mutex);
+	guard(mutex)(&gc->mutex);
+
 	if (!--gc->used) {
 		del_timer_sync(&gc->timer);
 		parport_write_control(gc->pd->port, 0x00);
 		parport_release(gc->pd);
 	}
-	mutex_unlock(&gc->mutex);
 }
 
 static int gc_setup_pad(struct gc *gc, int idx, int pad_type)
-- 
2.46.0.469.g59c65b2a67-goog