[PATCH 03/17] Input: atkbd - use guard notation when acquiring mutex

[Dmitry Torokhov]

This 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 at gmail.com>
---
 drivers/input/keyboard/atkbd.c | 37 ++++++++++++++--------------------
 1 file changed, 15 insertions(+), 22 deletions(-)

diff --git a/drivers/input/keyboard/atkbd.c b/drivers/input/keyboard/atkbd.c
index f4f2078cf501..5855d4fc6e6a 100644
--- a/drivers/input/keyboard/atkbd.c
+++ b/drivers/input/keyboard/atkbd.c
@@ -639,7 +639,7 @@ static void atkbd_event_work(struct work_struct *work)
 {
 	struct atkbd *atkbd = container_of(work, struct atkbd, event_work.work);
 
-	mutex_lock(&atkbd->mutex);
+	guard(mutex)(&atkbd->mutex);
 
 	if (!atkbd->enabled) {
 		/*
@@ -657,8 +657,6 @@ static void atkbd_event_work(struct work_struct *work)
 		if (test_and_clear_bit(ATKBD_REP_EVENT_BIT, &atkbd->event_mask))
 			atkbd_set_repeat_rate(atkbd);
 	}
-
-	mutex_unlock(&atkbd->mutex);
 }
 
 /*
@@ -1361,7 +1359,7 @@ static int atkbd_reconnect(struct serio *serio)
 {
 	struct atkbd *atkbd = atkbd_from_serio(serio);
 	struct serio_driver *drv = serio->drv;
-	int retval = -1;
+	int error;
 
 	if (!atkbd || !drv) {
 		dev_dbg(&serio->dev,
@@ -1369,16 +1367,17 @@ static int atkbd_reconnect(struct serio *serio)
 		return -1;
 	}
 
-	mutex_lock(&atkbd->mutex);
+	guard(mutex)(&atkbd->mutex);
 
 	atkbd_disable(atkbd);
 
 	if (atkbd->write) {
-		if (atkbd_probe(atkbd))
-			goto out;
+		error = atkbd_probe(atkbd);
+		if (error)
+			return error;
 
 		if (atkbd->set != atkbd_select_set(atkbd, atkbd->set, atkbd->extra))
-			goto out;
+			return -EIO;
 
 		/*
 		 * Restore LED state and repeat rate. While input core
@@ -1404,11 +1403,7 @@ static int atkbd_reconnect(struct serio *serio)
 	if (atkbd->write)
 		atkbd_activate(atkbd);
 
-	retval = 0;
-
- out:
-	mutex_unlock(&atkbd->mutex);
-	return retval;
+	return 0;
 }
 
 static const struct serio_device_id atkbd_serio_ids[] = {
@@ -1465,17 +1460,15 @@ static ssize_t atkbd_attr_set_helper(struct device *dev, const char *buf, size_t
 	struct atkbd *atkbd = atkbd_from_serio(serio);
 	int retval;
 
-	retval = mutex_lock_interruptible(&atkbd->mutex);
-	if (retval)
-		return retval;
+	scoped_guard(mutex_intr, &atkbd->mutex) {
+		atkbd_disable(atkbd);
+		retval = handler(atkbd, buf, count);
+		atkbd_enable(atkbd);
 
-	atkbd_disable(atkbd);
-	retval = handler(atkbd, buf, count);
-	atkbd_enable(atkbd);
-
-	mutex_unlock(&atkbd->mutex);
+		return retval;
+	}
 
-	return retval;
+	return -EINTR;
 }
 
 static ssize_t atkbd_show_extra(struct atkbd *atkbd, char *buf)
-- 
2.46.0.295.g3b9ea8a38a-goog