[PATCH v3 1/3] iio: ssp_sensors: ssp_spi: use guard() to release mutexes

[Sanjay Chitroda <sanjayembeddedse@gmail.com>]

From: Sanjay Chitroda <sanjayembeddedse@gmail.com>

Replace explicit mutex_lock() and mutex_unlock() with the guard() macro
for cleaner and safer mutex handling.

Signed-off-by: Sanjay Chitroda <sanjayembeddedse@gmail.com>
---
 drivers/iio/common/ssp_sensors/ssp_spi.c | 54 ++++++++++--------------
 1 file changed, 22 insertions(+), 32 deletions(-)

diff --git a/drivers/iio/common/ssp_sensors/ssp_spi.c b/drivers/iio/common/ssp_sensors/ssp_spi.c
index 6c81c0385fb5..87a38002b218 100644
--- a/drivers/iio/common/ssp_sensors/ssp_spi.c
+++ b/drivers/iio/common/ssp_sensors/ssp_spi.c
@@ -2,6 +2,7 @@
 /*
  *  Copyright (C) 2014, Samsung Electronics Co. Ltd. All Rights Reserved.
  */
+#include <linux/cleanup.h>
 
 #include "ssp.h"
 
@@ -189,55 +190,49 @@ static int ssp_do_transfer(struct ssp_data *data, struct ssp_msg *msg,
 
 	msg->done = done;
 
-	mutex_lock(&data->comm_lock);
+	guard(mutex)(&data->comm_lock);
 
 	status = ssp_check_lines(data, false);
-	if (status < 0)
-		goto _error_locked;
+	if (status < 0) {
+		data->timeout_cnt++;
+		return status;
+	}
 
 	status = spi_write(data->spi, msg->buffer, SSP_HEADER_SIZE);
 	if (status < 0) {
 		gpiod_set_value_cansleep(data->ap_mcu_gpiod, 1);
 		dev_err(SSP_DEV, "%s spi_write fail\n", __func__);
-		goto _error_locked;
+		data->timeout_cnt++;
+		return status;
 	}
 
 	if (!use_no_irq) {
-		mutex_lock(&data->pending_lock);
-		list_add_tail(&msg->list, &data->pending_list);
-		mutex_unlock(&data->pending_lock);
+		scoped_guard(mutex, &data->pending_lock)
+			list_add_tail(&msg->list, &data->pending_list);
 	}
 
 	status = ssp_check_lines(data, true);
 	if (status < 0) {
 		if (!use_no_irq) {
-			mutex_lock(&data->pending_lock);
-			list_del(&msg->list);
-			mutex_unlock(&data->pending_lock);
+			scoped_guard(mutex, &data->pending_lock)
+				list_add_tail(&msg->list, &data->pending_list);
 		}
-		goto _error_locked;
+		data->timeout_cnt++;
+		return status;
 	}
 
-	mutex_unlock(&data->comm_lock);
-
 	if (!use_no_irq && done)
 		if (wait_for_completion_timeout(done,
 						msecs_to_jiffies(timeout)) ==
 		    0) {
-			mutex_lock(&data->pending_lock);
-			list_del(&msg->list);
-			mutex_unlock(&data->pending_lock);
+			scoped_guard(mutex, &data->pending_lock)
+				list_add_tail(&msg->list, &data->pending_list);
 
 			data->timeout_cnt++;
 			return -ETIMEDOUT;
 		}
 
 	return 0;
-
-_error_locked:
-	mutex_unlock(&data->comm_lock);
-	data->timeout_cnt++;
-	return status;
 }
 
 static inline int ssp_spi_sync_command(struct ssp_data *data,
@@ -360,7 +355,7 @@ int ssp_irq_msg(struct ssp_data *data)
 		 * this is a small list, a few elements - the packets can be
 		 * received with no order
 		 */
-		mutex_lock(&data->pending_lock);
+		guard(mutex)(&data->pending_lock);
 		list_for_each_entry_safe(iter, n, &data->pending_list, list) {
 			if (iter->options == msg_options) {
 				list_del(&iter->list);
@@ -376,10 +371,8 @@ int ssp_irq_msg(struct ssp_data *data)
 			 * check but let's handle this
 			 */
 			buffer = kmalloc(length, GFP_KERNEL | GFP_DMA);
-			if (!buffer) {
-				ret = -ENOMEM;
-				goto _unlock;
-			}
+			if (!buffer)
+				return -ENOMEM;
 
 			/* got dead packet so it is always an error */
 			ret = spi_read(data->spi, buffer, length);
@@ -391,7 +384,7 @@ int ssp_irq_msg(struct ssp_data *data)
 			dev_err(SSP_DEV, "No match error %x\n",
 				msg_options);
 
-			goto _unlock;
+			return ret;
 		}
 
 		if (msg_type == SSP_AP2HUB_READ)
@@ -409,15 +402,13 @@ int ssp_irq_msg(struct ssp_data *data)
 				msg->length = 1;
 
 				list_add_tail(&msg->list, &data->pending_list);
-				goto _unlock;
+				return ret;
 			}
 		}
 
 		if (msg->done)
 			if (!completion_done(msg->done))
 				complete(msg->done);
-_unlock:
-		mutex_unlock(&data->pending_lock);
 		break;
 	case SSP_HUB2AP_WRITE:
 		buffer = kzalloc(length, GFP_KERNEL | GFP_DMA);
@@ -448,7 +439,7 @@ void ssp_clean_pending_list(struct ssp_data *data)
 {
 	struct ssp_msg *msg, *n;
 
-	mutex_lock(&data->pending_lock);
+	guard(mutex)(&data->pending_lock);
 	list_for_each_entry_safe(msg, n, &data->pending_list, list) {
 		list_del(&msg->list);
 
@@ -456,7 +447,6 @@ void ssp_clean_pending_list(struct ssp_data *data)
 			if (!completion_done(msg->done))
 				complete(msg->done);
 	}
-	mutex_unlock(&data->pending_lock);
 }
 
 int ssp_command(struct ssp_data *data, char command, int arg)
-- 
2.34.1