mailbox: Use guard/scoped_guard for con_mutex

Use guard and scoped_guard for con_mutex to simplify code.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>

Author: MrVan

drivers/mailbox/mailbox.c

@@ -6,6 +6,7 @@
  * Author: Jassi Brar <jassisinghbrar@gmail.com>
  */
 
+#include <linux/cleanup.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/err.h>
@@ -370,13 +371,9 @@ static int __mbox_bind_client(struct mbox_chan *chan, struct mbox_client *cl)
  */
 int mbox_bind_client(struct mbox_chan *chan, struct mbox_client *cl)
 {
-	int ret;
-
-	mutex_lock(&con_mutex);
-	ret = __mbox_bind_client(chan, cl);
-	mutex_unlock(&con_mutex);
+	guard(mutex)(&con_mutex);
 
-	return ret;
+	return __mbox_bind_client(chan, cl);
 }
 EXPORT_SYMBOL_GPL(mbox_bind_client);
 
@@ -417,28 +414,25 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
 		return ERR_PTR(ret);
 	}
 
-	mutex_lock(&con_mutex);
+	scoped_guard(mutex, &con_mutex) {
+		chan = ERR_PTR(-EPROBE_DEFER);
+		list_for_each_entry(mbox, &mbox_cons, node)
+			if (mbox->dev->of_node == spec.np) {
+				chan = mbox->of_xlate(mbox, &spec);
+				if (!IS_ERR(chan))
+					break;
+			}
 
-	chan = ERR_PTR(-EPROBE_DEFER);
-	list_for_each_entry(mbox, &mbox_cons, node)
-		if (mbox->dev->of_node == spec.np) {
-			chan = mbox->of_xlate(mbox, &spec);
-			if (!IS_ERR(chan))
-				break;
-		}
+		of_node_put(spec.np);
 
-	of_node_put(spec.np);
+		if (IS_ERR(chan))
+			return chan;
 
-	if (IS_ERR(chan)) {
-		mutex_unlock(&con_mutex);
-		return chan;
+		ret = __mbox_bind_client(chan, cl);
+		if (ret)
+			chan = ERR_PTR(ret);
 	}
 
-	ret = __mbox_bind_client(chan, cl);
-	if (ret)
-		chan = ERR_PTR(ret);
-
-	mutex_unlock(&con_mutex);
 	return chan;
 }
 EXPORT_SYMBOL_GPL(mbox_request_channel);
@@ -547,9 +541,8 @@ int mbox_controller_register(struct mbox_controller *mbox)
 	if (!mbox->of_xlate)
 		mbox->of_xlate = of_mbox_index_xlate;
 
-	mutex_lock(&con_mutex);
-	list_add_tail(&mbox->node, &mbox_cons);
-	mutex_unlock(&con_mutex);
+	scoped_guard(mutex, &con_mutex)
+		list_add_tail(&mbox->node, &mbox_cons);
 
 	return 0;
 }
@@ -566,17 +559,15 @@ void mbox_controller_unregister(struct mbox_controller *mbox)
 	if (!mbox)
 		return;
 
-	mutex_lock(&con_mutex);
-
-	list_del(&mbox->node);
+	scoped_guard(mutex, &con_mutex) {
+		list_del(&mbox->node);
 
-	for (i = 0; i < mbox->num_chans; i++)
-		mbox_free_channel(&mbox->chans[i]);
+		for (i = 0; i < mbox->num_chans; i++)
+			mbox_free_channel(&mbox->chans[i]);
 
-	if (mbox->txdone_poll)
-		hrtimer_cancel(&mbox->poll_hrt);
-
-	mutex_unlock(&con_mutex);
+		if (mbox->txdone_poll)
+			hrtimer_cancel(&mbox->poll_hrt);
+	}
 }
 EXPORT_SYMBOL_GPL(mbox_controller_unregister);