rv: Convert to use lock guard

Convert to use lock guard to tidy up the code.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/r/dbefeb868093c40d4b29fd6b57294a6aa011b719.1763370183.git.namcao@linutronix.de
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>

Author: covanam

kernel/trace/rv/rv.c

@@ -375,15 +375,13 @@ static ssize_t monitor_enable_write_data(struct file *filp, const char __user *u
 	if (retval)
 		return retval;
 
-	mutex_lock(&rv_interface_lock);
+	guard(mutex)(&rv_interface_lock);
 
 	if (val)
 		retval = rv_enable_monitor(mon);
 	else
 		retval = rv_disable_monitor(mon);
 
-	mutex_unlock(&rv_interface_lock);
-
 	return retval ? : count;
 }
 
@@ -568,7 +566,7 @@ static void disable_all_monitors(void)
 	struct rv_monitor *mon;
 	int enabled = 0;
 
-	mutex_lock(&rv_interface_lock);
+	guard(mutex)(&rv_interface_lock);
 
 	list_for_each_entry(mon, &rv_monitors_list, list)
 		enabled += __rv_disable_monitor(mon, false);
@@ -581,8 +579,6 @@ static void disable_all_monitors(void)
 		 */
 		tracepoint_synchronize_unregister();
 	}
-
-	mutex_unlock(&rv_interface_lock);
 }
 
 static int enabled_monitors_open(struct inode *inode, struct file *file)
@@ -623,7 +619,7 @@ static ssize_t enabled_monitors_write(struct file *filp, const char __user *user
 	if (!len)
 		return count;
 
-	mutex_lock(&rv_interface_lock);
+	guard(mutex)(&rv_interface_lock);
 
 	retval = -EINVAL;
 
@@ -644,13 +640,11 @@ static ssize_t enabled_monitors_write(struct file *filp, const char __user *user
 		else
 			retval = rv_disable_monitor(mon);
 
-		if (!retval)
-			retval = count;
-
-		break;
+		if (retval)
+			return retval;
+		return count;
 	}
 
-	mutex_unlock(&rv_interface_lock);
 	return retval;
 }
 
@@ -737,7 +731,7 @@ static ssize_t monitoring_on_write_data(struct file *filp, const char __user *us
 	if (retval)
 		return retval;
 
-	mutex_lock(&rv_interface_lock);
+	guard(mutex)(&rv_interface_lock);
 
 	if (val)
 		turn_monitoring_on_with_reset();
@@ -750,8 +744,6 @@ static ssize_t monitoring_on_write_data(struct file *filp, const char __user *us
 	 */
 	tracepoint_synchronize_unregister();
 
-	mutex_unlock(&rv_interface_lock);
-
 	return count;
 }
 
@@ -784,38 +776,34 @@ int rv_register_monitor(struct rv_monitor *monitor, struct rv_monitor *parent)
 		return -EINVAL;
 	}
 
-	mutex_lock(&rv_interface_lock);
+	guard(mutex)(&rv_interface_lock);
 
 	list_for_each_entry(r, &rv_monitors_list, list) {
 		if (strcmp(monitor->name, r->name) == 0) {
 			pr_info("Monitor %s is already registered\n", monitor->name);
-			retval = -EEXIST;
-			goto out_unlock;
+			return -EEXIST;
 		}
 	}
 
 	if (parent && rv_is_nested_monitor(parent)) {
 		pr_info("Parent monitor %s is already nested, cannot nest further\n",
 			parent->name);
-		retval = -EINVAL;
-		goto out_unlock;
+		return -EINVAL;
 	}
 
 	monitor->parent = parent;
 
 	retval = create_monitor_dir(monitor, parent);
 	if (retval)
-		goto out_unlock;
+		return retval;
 
 	/* keep children close to the parent for easier visualisation */
 	if (parent)
 		list_add(&monitor->list, &parent->list);
 	else
 		list_add_tail(&monitor->list, &rv_monitors_list);
 
-out_unlock:
-	mutex_unlock(&rv_interface_lock);
-	return retval;
+	return 0;
 }
 
 /**
@@ -826,13 +814,12 @@ int rv_register_monitor(struct rv_monitor *monitor, struct rv_monitor *parent)
  */
 int rv_unregister_monitor(struct rv_monitor *monitor)
 {
-	mutex_lock(&rv_interface_lock);
+	guard(mutex)(&rv_interface_lock);
 
 	rv_disable_monitor(monitor);
 	list_del(&monitor->list);
 	destroy_monitor_dir(monitor);
 
-	mutex_unlock(&rv_interface_lock);
 	return 0;
 }
 

kernel/trace/rv/rv_reactors.c

@@ -233,23 +233,18 @@ monitor_reactors_write(struct file *file, const char __user *user_buf,
 	seq_f = file->private_data;
 	mon = seq_f->private;
 
-	mutex_lock(&rv_interface_lock);
-
-	retval = -EINVAL;
+	guard(mutex)(&rv_interface_lock);
 
 	list_for_each_entry(reactor, &rv_reactors_list, list) {
 		if (strcmp(ptr, reactor->name) != 0)
 			continue;
 
 		monitor_swap_reactors(mon, reactor);
 
-		retval = count;
-		break;
+		return count;
 	}
 
-	mutex_unlock(&rv_interface_lock);
-
-	return retval;
+	return -EINVAL;
 }
 
 /*
@@ -310,18 +305,14 @@ static int __rv_register_reactor(struct rv_reactor *reactor)
  */
 int rv_register_reactor(struct rv_reactor *reactor)
 {
-	int retval = 0;
-
 	if (strlen(reactor->name) >= MAX_RV_REACTOR_NAME_SIZE) {
 		pr_info("Reactor %s has a name longer than %d\n",
 			reactor->name, MAX_RV_MONITOR_NAME_SIZE);
 		return -EINVAL;
 	}
 
-	mutex_lock(&rv_interface_lock);
-	retval = __rv_register_reactor(reactor);
-	mutex_unlock(&rv_interface_lock);
-	return retval;
+	guard(mutex)(&rv_interface_lock);
+	return __rv_register_reactor(reactor);
 }
 
 /**
@@ -332,9 +323,8 @@ int rv_register_reactor(struct rv_reactor *reactor)
  */
 int rv_unregister_reactor(struct rv_reactor *reactor)
 {
-	mutex_lock(&rv_interface_lock);
+	guard(mutex)(&rv_interface_lock);
 	list_del(&reactor->list);
-	mutex_unlock(&rv_interface_lock);
 	return 0;
 }
 
@@ -390,7 +380,7 @@ static ssize_t reacting_on_write_data(struct file *filp, const char __user *user
 	if (retval)
 		return retval;
 
-	mutex_lock(&rv_interface_lock);
+	guard(mutex)(&rv_interface_lock);
 
 	if (val)
 		turn_reacting_on();
@@ -403,8 +393,6 @@ static ssize_t reacting_on_write_data(struct file *filp, const char __user *user
 	 */
 	tracepoint_synchronize_unregister();
 
-	mutex_unlock(&rv_interface_lock);
-
 	return count;
 }