mei: mei_write: revamp function flow

Use goto statement for error handling instead of deeper if constructs
and rename label 'unlock_dev' to more appropriate 'err'
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/main.c

@@ -543,24 +543,24 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
 
 	if (dev->dev_state != MEI_DEV_ENABLED) {
 		rets = -ENODEV;
-		goto unlock_dev;
+		goto err;
 	}
 
 	i = mei_me_cl_by_id(dev, cl->me_client_id);
 	if (i < 0) {
 		rets = -ENODEV;
-		goto unlock_dev;
+		goto err;
 	}
 	if (length > dev->me_clients[i].props.max_msg_length || length <= 0) {
 		rets = -EMSGSIZE;
-		goto unlock_dev;
+		goto err;
 	}
 
 	if (cl->state != MEI_FILE_CONNECTED) {
 		rets = -ENODEV;
 		dev_err(&dev->pdev->dev, "host client = %d,  is not connected to ME client = %d",
 			cl->host_client_id, cl->me_client_id);
-		goto unlock_dev;
+		goto err;
 	}
 	if (cl == &dev->iamthif_cl) {
 		write_cb = find_amthi_read_list_entry(dev, file);
@@ -599,17 +599,17 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
 	if (!write_cb) {
 		dev_err(&dev->pdev->dev, "write cb allocation failed\n");
 		rets = -ENOMEM;
-		goto unlock_dev;
+		goto err;
 	}
 	rets = mei_io_cb_alloc_req_buf(write_cb, length);
 	if (rets)
-		goto unlock_dev;
+		goto err;
 
 	dev_dbg(&dev->pdev->dev, "cb request size = %zd\n", length);
 
 	rets = copy_from_user(write_cb->request_buffer.data, ubuf, length);
 	if (rets)
-		goto unlock_dev;
+		goto err;
 
 	cl->sm_state = 0;
 	if (length == 4 &&
@@ -624,7 +624,7 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
 	if (cl == &dev->iamthif_cl) {
 		rets = mei_io_cb_alloc_resp_buf(write_cb, dev->iamthif_mtu);
 		if (rets)
-			goto unlock_dev;
+			goto err;
 
 		write_cb->major_file_operations = MEI_IOCTL;
 
@@ -641,7 +641,7 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
 			if (rets) {
 				dev_err(&dev->pdev->dev, "amthi write failed with status = %d\n",
 				    rets);
-				goto unlock_dev;
+				goto err;
 			}
 		}
 		mutex_unlock(&dev->device_lock);
@@ -654,10 +654,15 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
 	    cl->host_client_id, cl->me_client_id);
 	rets = mei_flow_ctrl_creds(dev, cl);
 	if (rets < 0)
-		goto unlock_dev;
+		goto err;
+
+	if (rets == 0 || dev->mei_host_buffer_is_empty == false) {
+		write_cb->buf_idx = 0;
+		mei_hdr.msg_complete = 0;
+		cl->writing_state = MEI_WRITING;
+		goto out;
+	}
 
-	if (rets && dev->mei_host_buffer_is_empty) {
-		rets = 0;
 	dev->mei_host_buffer_is_empty = false;
 	if (length >  mei_hbuf_max_data(dev)) {
 		mei_hdr.length = mei_hbuf_max_data(dev);
@@ -672,33 +677,28 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
 	dev_dbg(&dev->pdev->dev, "call mei_write_message header=%08x.\n",
 	    *((u32 *) &mei_hdr));
 	if (mei_write_message(dev, &mei_hdr,
-			(unsigned char *) (write_cb->request_buffer.data),
-			mei_hdr.length)) {
+		write_cb->request_buffer.data, mei_hdr.length)) {
 		rets = -ENODEV;
-			goto unlock_dev;
+		goto err;
 	}
 	cl->writing_state = MEI_WRITING;
 	write_cb->buf_idx = mei_hdr.length;
+
+out:
 	if (mei_hdr.msg_complete) {
 		if (mei_flow_ctrl_reduce(dev, cl)) {
 			rets = -ENODEV;
-				goto unlock_dev;
+			goto err;
 		}
 		list_add_tail(&write_cb->list, &dev->write_waiting_list.list);
 	} else {
 		list_add_tail(&write_cb->list, &dev->write_list.list);
 	}
 
-	} else {
-
-		write_cb->buf_idx = 0;
-		cl->writing_state = MEI_WRITING;
-		list_add_tail(&write_cb->list, &dev->write_list.list);
-	}
 	mutex_unlock(&dev->device_lock);
 	return length;
 
-unlock_dev:
+err:
 	mutex_unlock(&dev->device_lock);
 	mei_io_cb_free(write_cb);
 	return rets;