mtd: mchp23k256: propagate return value of spi_sync()

The call to spi_sync() can fail.
Check the return value and propagate it.

Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/devices/mchp23k256.c

@@ -68,6 +68,7 @@ static int mchp23k256_write(struct mtd_info *mtd, loff_t to, size_t len,
 	struct spi_transfer transfer[2] = {};
 	struct spi_message message;
 	unsigned char command[MAX_CMD_SIZE];
+	int ret;
 
 	spi_message_init(&message);
 
@@ -84,12 +85,16 @@ static int mchp23k256_write(struct mtd_info *mtd, loff_t to, size_t len,
 
 	mutex_lock(&flash->lock);
 
-	spi_sync(flash->spi, &message);
+	ret = spi_sync(flash->spi, &message);
+
+	mutex_unlock(&flash->lock);
+
+	if (ret)
+		return ret;
 
 	if (retlen && message.actual_length > sizeof(command))
 		*retlen += message.actual_length - sizeof(command);
 
-	mutex_unlock(&flash->lock);
 	return 0;
 }
 
@@ -100,6 +105,7 @@ static int mchp23k256_read(struct mtd_info *mtd, loff_t from, size_t len,
 	struct spi_transfer transfer[2] = {};
 	struct spi_message message;
 	unsigned char command[MAX_CMD_SIZE];
+	int ret;
 
 	spi_message_init(&message);
 
@@ -117,12 +123,16 @@ static int mchp23k256_read(struct mtd_info *mtd, loff_t from, size_t len,
 
 	mutex_lock(&flash->lock);
 
-	spi_sync(flash->spi, &message);
+	ret = spi_sync(flash->spi, &message);
+
+	mutex_unlock(&flash->lock);
+
+	if (ret)
+		return ret;
 
 	if (retlen && message.actual_length > sizeof(command))
 		*retlen += message.actual_length - sizeof(command);
 
-	mutex_unlock(&flash->lock);
 	return 0;
 }