[PATCH 21/22] Input: rotary_encoder - use guard notation when acquiring mutex

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

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@gmail.com>
---
 drivers/input/misc/rotary_encoder.c | 23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/drivers/input/misc/rotary_encoder.c b/drivers/input/misc/rotary_encoder.c
index 6628fe540834..52761da9f999 100644
--- a/drivers/input/misc/rotary_encoder.c
+++ b/drivers/input/misc/rotary_encoder.c
@@ -113,7 +113,7 @@ static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
 	struct rotary_encoder *encoder = dev_id;
 	unsigned int state;
 
-	mutex_lock(&encoder->access_mutex);
+	guard(mutex)(&encoder->access_mutex);
 
 	state = rotary_encoder_get_state(encoder);
 
@@ -136,8 +136,6 @@ static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
 		break;
 	}
 
-	mutex_unlock(&encoder->access_mutex);
-
 	return IRQ_HANDLED;
 }
 
@@ -146,7 +144,7 @@ static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id)
 	struct rotary_encoder *encoder = dev_id;
 	unsigned int state;
 
-	mutex_lock(&encoder->access_mutex);
+	guard(mutex)(&encoder->access_mutex);
 
 	state = rotary_encoder_get_state(encoder);
 
@@ -159,8 +157,6 @@ static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id)
 		}
 	}
 
-	mutex_unlock(&encoder->access_mutex);
-
 	return IRQ_HANDLED;
 }
 
@@ -169,22 +165,19 @@ static irqreturn_t rotary_encoder_quarter_period_irq(int irq, void *dev_id)
 	struct rotary_encoder *encoder = dev_id;
 	unsigned int state;
 
-	mutex_lock(&encoder->access_mutex);
+	guard(mutex)(&encoder->access_mutex);
 
 	state = rotary_encoder_get_state(encoder);
 
-	if ((encoder->last_stable + 1) % 4 == state)
+	if ((encoder->last_stable + 1) % 4 == state) {
 		encoder->dir = 1;
-	else if (encoder->last_stable == (state + 1) % 4)
+		rotary_encoder_report_event(encoder);
+	} else if (encoder->last_stable == (state + 1) % 4) {
 		encoder->dir = -1;
-	else
-		goto out;
-
-	rotary_encoder_report_event(encoder);
+		rotary_encoder_report_event(encoder);
+	}
 
-out:
 	encoder->last_stable = state;
-	mutex_unlock(&encoder->access_mutex);
 
 	return IRQ_HANDLED;
 }
-- 
2.46.0.469.g59c65b2a67-goog