diff --git a/drivers/staging/mei/init.c b/drivers/staging/mei/init.c
index e24b6ad3d5fb47e4560fc4be6bd796a645144a9a..eab711fb5fc4e65095003726f894cc019341a009 100644
--- a/drivers/staging/mei/init.c
+++ b/drivers/staging/mei/init.c
@@ -366,7 +366,7 @@ void mei_host_start_message(struct mei_device *dev)
 	host_start_req->host_version.major_version = HBM_MAJOR_VERSION;
 	host_start_req->host_version.minor_version = HBM_MINOR_VERSION;
 	dev->recvd_msg = false;
-	if (!mei_write_message(dev, mei_hdr, (unsigned char *)host_start_req,
+	if (mei_write_message(dev, mei_hdr, (unsigned char *)host_start_req,
 				       mei_hdr->length)) {
 		dev_dbg(&dev->pdev->dev, "write send version message to FW fail.\n");
 		dev->mei_state = MEI_RESETING;
@@ -399,7 +399,7 @@ void mei_host_enum_clients_message(struct mei_device *dev)
 	host_enum_req = (struct hbm_host_enum_request *) &dev->wr_msg_buf[1];
 	memset(host_enum_req, 0, sizeof(struct hbm_host_enum_request));
 	host_enum_req->hbm_cmd = HOST_ENUM_REQ_CMD;
-	if (!mei_write_message(dev, mei_hdr, (unsigned char *)host_enum_req,
+	if (mei_write_message(dev, mei_hdr, (unsigned char *)host_enum_req,
 				mei_hdr->length)) {
 		dev->mei_state = MEI_RESETING;
 		dev_dbg(&dev->pdev->dev, "write send enumeration request message to FW fail.\n");
@@ -407,7 +407,7 @@ void mei_host_enum_clients_message(struct mei_device *dev)
 	}
 	dev->init_clients_state = MEI_ENUM_CLIENTS_MESSAGE;
 	dev->init_clients_timer = INIT_CLIENTS_TIMEOUT;
-	return ;
+	return;
 }
 
 
@@ -485,7 +485,7 @@ int mei_host_client_properties(struct mei_device *dev)
 		host_cli_req->hbm_cmd = HOST_CLIENT_PROPERTIES_REQ_CMD;
 		host_cli_req->address = b;
 
-		if (!mei_write_message(dev, mei_header,
+		if (mei_write_message(dev, mei_header,
 				(unsigned char *)host_cli_req,
 				mei_header->length)) {
 			dev->mei_state = MEI_RESETING;
@@ -608,7 +608,7 @@ void mei_host_init_iamthif(struct mei_device *dev)
 
 	dev->iamthif_msg_buf = msg_buf;
 
-	if (!mei_connect(dev, &dev->iamthif_cl)) {
+	if (mei_connect(dev, &dev->iamthif_cl)) {
 		dev_dbg(&dev->pdev->dev, "Failed to connect to AMTHI client\n");
 		dev->iamthif_cl.state = MEI_FILE_DISCONNECTED;
 		dev->iamthif_cl.host_client_id = 0;
@@ -670,14 +670,12 @@ int mei_disconnect_host_client(struct mei_device *dev, struct mei_cl *cl)
 	if (dev->mei_host_buffer_is_empty) {
 		dev->mei_host_buffer_is_empty = false;
 		if (mei_disconnect(dev, cl)) {
-			mdelay(10); /* Wait for hardware disconnection ready */
-			list_add_tail(&cb->cb_list,
-				&dev->ctrl_rd_list.mei_cb.cb_list);
-		} else {
 			rets = -ENODEV;
 			dev_dbg(&dev->pdev->dev, "failed to call mei_disconnect.\n");
 			goto free;
 		}
+		mdelay(10); /* Wait for hardware disconnection ready */
+		list_add_tail(&cb->cb_list, &dev->ctrl_rd_list.mei_cb.cb_list);
 	} else {
 		dev_dbg(&dev->pdev->dev, "add disconnect cb to control write list\n");
 		list_add_tail(&cb->cb_list,
diff --git a/drivers/staging/mei/interface.c b/drivers/staging/mei/interface.c
index 8a80e80cd7df4ea6a772f3543b251aec54d4c6ec..9a2cfafc52a644d1e5f6c6a18006389e0962e2b1 100644
--- a/drivers/staging/mei/interface.c
+++ b/drivers/staging/mei/interface.c
@@ -125,7 +125,7 @@ int mei_count_empty_write_slots(struct mei_device *dev)
  * @write_buffer: message buffer will be written
  * @write_length: message size will be written
  *
- * returns 1 if success, 0 - otherwise.
+ * This function returns -EIO if write has failed
  */
 int mei_write_message(struct mei_device *dev,
 		      struct mei_msg_hdr *header,
@@ -157,7 +157,7 @@ int mei_write_message(struct mei_device *dev,
 	dw_to_write = ((write_length + 3) / 4);
 
 	if (dw_to_write > empty_slots)
-		return 0;
+		return -EIO;
 
 	mei_reg_write(dev, H_CB_WW, *((u32 *) header));
 
@@ -177,9 +177,9 @@ int mei_write_message(struct mei_device *dev,
 	mei_hcsr_set(dev);
 	dev->me_hw_state = mei_mecsr_read(dev);
 	if ((dev->me_hw_state & ME_RDY_HRA) != ME_RDY_HRA)
-		return 0;
+		return -EIO;
 
-	return 1;
+	return 0;
 }
 
 /**
@@ -308,7 +308,7 @@ int mei_flow_ctrl_reduce(struct mei_device *dev, struct mei_cl *cl)
  * @dev: the device structure
  * @cl: private data of the file object
  *
- * returns 1 if success, 0 - otherwise.
+ * This function returns -EIO on write failure
  */
 int mei_send_flow_control(struct mei_device *dev, struct mei_cl *cl)
 {
@@ -330,14 +330,11 @@ int mei_send_flow_control(struct mei_device *dev, struct mei_cl *cl)
 	memset(mei_flow_control->reserved, 0,
 			sizeof(mei_flow_control->reserved));
 	dev_dbg(&dev->pdev->dev, "sending flow control host client = %d, ME client = %d\n",
-	    cl->host_client_id, cl->me_client_id);
-	if (!mei_write_message(dev, mei_hdr,
-				(unsigned char *) mei_flow_control,
-				sizeof(struct hbm_flow_control)))
-		return 0;
-
-	return 1;
+		cl->host_client_id, cl->me_client_id);
 
+	return mei_write_message(dev, mei_hdr,
+				(unsigned char *) mei_flow_control,
+				sizeof(struct hbm_flow_control));
 }
 
 /**
@@ -371,7 +368,7 @@ int mei_other_client_is_connecting(struct mei_device *dev,
  * @dev: the device structure
  * @cl: private data of the file object
  *
- * returns 1 if success, 0 - otherwise.
+ * This function returns -EIO on write failure
  */
 int mei_disconnect(struct mei_device *dev, struct mei_cl *cl)
 {
@@ -393,12 +390,9 @@ int mei_disconnect(struct mei_device *dev, struct mei_cl *cl)
 	mei_cli_disconnect->hbm_cmd = CLIENT_DISCONNECT_REQ_CMD;
 	mei_cli_disconnect->reserved[0] = 0;
 
-	if (!mei_write_message(dev, mei_hdr,
+	return mei_write_message(dev, mei_hdr,
 				(unsigned char *) mei_cli_disconnect,
-				sizeof(struct hbm_client_disconnect_request)))
-		return 0;
-
-	return 1;
+				sizeof(struct hbm_client_disconnect_request));
 }
 
 /**
@@ -407,7 +401,7 @@ int mei_disconnect(struct mei_device *dev, struct mei_cl *cl)
  * @dev: the device structure
  * @cl: private data of the file object
  *
- * returns 1 if success, 0 - otherwise.
+ * This function returns -EIO on write failure
  */
 int mei_connect(struct mei_device *dev, struct mei_cl *cl)
 {
@@ -428,10 +422,7 @@ int mei_connect(struct mei_device *dev, struct mei_cl *cl)
 	mei_cli_connect->hbm_cmd = CLIENT_CONNECT_REQ_CMD;
 	mei_cli_connect->reserved = 0;
 
-	if (!mei_write_message(dev, mei_hdr,
+	return mei_write_message(dev, mei_hdr,
 				(unsigned char *) mei_cli_connect,
-				sizeof(struct hbm_client_connect_request)))
-		return 0;
-
-	return 1;
+				sizeof(struct hbm_client_connect_request));
 }
diff --git a/drivers/staging/mei/interrupt.c b/drivers/staging/mei/interrupt.c
index a34e2f3a0706af6a71b2c90ee68cd01b8ada111f..2007d2447b1c83b42a7d6be2d812b4d78d473d3b 100644
--- a/drivers/staging/mei/interrupt.c
+++ b/drivers/staging/mei/interrupt.c
@@ -263,26 +263,25 @@ static int mei_irq_thread_read_client_message(struct mei_io_list *complete_list,
 static int _mei_irq_thread_iamthif_read(struct mei_device *dev, s32 *slots)
 {
 
-	if (((*slots) * sizeof(u32)) >= (sizeof(struct mei_msg_hdr)
+	if (((*slots) * sizeof(u32)) < (sizeof(struct mei_msg_hdr)
 			+ sizeof(struct hbm_flow_control))) {
-		*slots -= (sizeof(struct mei_msg_hdr) +
-				sizeof(struct hbm_flow_control) + 3) / 4;
-		if (!mei_send_flow_control(dev, &dev->iamthif_cl)) {
-			dev_dbg(&dev->pdev->dev, "iamthif flow control failed\n");
-		} else {
-			dev_dbg(&dev->pdev->dev, "iamthif flow control success\n");
-			dev->iamthif_state = MEI_IAMTHIF_READING;
-			dev->iamthif_flow_control_pending = false;
-			dev->iamthif_msg_buf_index = 0;
-			dev->iamthif_msg_buf_size = 0;
-			dev->iamthif_stall_timer = IAMTHIF_STALL_TIMER;
-			dev->mei_host_buffer_is_empty =
-					mei_host_buffer_is_empty(dev);
-		}
-		return 0;
-	} else {
 		return -EMSGSIZE;
 	}
+	*slots -= (sizeof(struct mei_msg_hdr) +
+				sizeof(struct hbm_flow_control) + 3) / 4;
+	if (mei_send_flow_control(dev, &dev->iamthif_cl)) {
+		dev_dbg(&dev->pdev->dev, "iamthif flow control failed\n");
+		return -EIO;
+	}
+
+	dev_dbg(&dev->pdev->dev, "iamthif flow control success\n");
+	dev->iamthif_state = MEI_IAMTHIF_READING;
+	dev->iamthif_flow_control_pending = false;
+	dev->iamthif_msg_buf_index = 0;
+	dev->iamthif_msg_buf_size = 0;
+	dev->iamthif_stall_timer = IAMTHIF_STALL_TIMER;
+	dev->mei_host_buffer_is_empty = mei_host_buffer_is_empty(dev);
+	return 0;
 }
 
 /**
@@ -306,7 +305,7 @@ static int _mei_irq_thread_close(struct mei_device *dev, s32 *slots,
 		*slots -= (sizeof(struct mei_msg_hdr) +
 			sizeof(struct hbm_client_disconnect_request) + 3) / 4;
 
-		if (!mei_disconnect(dev, cl)) {
+		if (mei_disconnect(dev, cl)) {
 			cl->status = 0;
 			cb_pos->information = 0;
 			list_move_tail(&cb_pos->cb_list,
@@ -838,24 +837,21 @@ static int _mei_irq_thread_read(struct mei_device *dev,	s32 *slots,
 {
 	if ((*slots * sizeof(u32)) >= (sizeof(struct mei_msg_hdr) +
 			sizeof(struct hbm_flow_control))) {
-		*slots -= (sizeof(struct mei_msg_hdr) +
-			sizeof(struct hbm_flow_control) + 3) / 4;
-		if (!mei_send_flow_control(dev, cl)) {
-			cl->status = -ENODEV;
-			cb_pos->information = 0;
-			list_move_tail(&cb_pos->cb_list,
-					&cmpl_list->mei_cb.cb_list);
-			return -ENODEV;
-		} else {
-			list_move_tail(&cb_pos->cb_list,
-					&dev->read_list.mei_cb.cb_list);
-		}
-	} else {
 		/* return the cancel routine */
 		list_del(&cb_pos->cb_list);
 		return -EBADMSG;
 	}
 
+	*slots -= (sizeof(struct mei_msg_hdr) +
+			sizeof(struct hbm_flow_control) + 3) / 4;
+	if (mei_send_flow_control(dev, cl)) {
+		cl->status = -ENODEV;
+		cb_pos->information = 0;
+		list_move_tail(&cb_pos->cb_list, &cmpl_list->mei_cb.cb_list);
+		return -ENODEV;
+	}
+	list_move_tail(&cb_pos->cb_list, &dev->read_list.mei_cb.cb_list);
+
 	return 0;
 }
 
@@ -881,7 +877,7 @@ static int _mei_irq_thread_ioctl(struct mei_device *dev, s32 *slots,
 		cl->state = MEI_FILE_CONNECTING;
 		*slots -= (sizeof(struct mei_msg_hdr) +
 			sizeof(struct hbm_client_connect_request) + 3) / 4;
-		if (!mei_connect(dev, cl)) {
+		if (mei_connect(dev, cl)) {
 			cl->status = -ENODEV;
 			cb_pos->information = 0;
 			list_del(&cb_pos->cb_list);
@@ -938,7 +934,7 @@ static int _mei_irq_thread_cmpl(struct mei_device *dev,	s32 *slots,
 				mei_hdr->length);
 		*slots -= (sizeof(struct mei_msg_hdr) +
 				mei_hdr->length + 3) / 4;
-		if (!mei_write_message(dev, mei_hdr,
+		if (mei_write_message(dev, mei_hdr,
 				(unsigned char *)
 				(cb_pos->request_buffer.data +
 				cb_pos->information),
@@ -967,7 +963,7 @@ static int _mei_irq_thread_cmpl(struct mei_device *dev,	s32 *slots,
 
 		(*slots) -= (sizeof(struct mei_msg_hdr) +
 				mei_hdr->length + 3) / 4;
-		if (!mei_write_message(dev, mei_hdr,
+		if (mei_write_message(dev, mei_hdr,
 					(unsigned char *)
 					(cb_pos->request_buffer.data +
 					cb_pos->information),
@@ -1028,7 +1024,7 @@ static int _mei_irq_thread_cmpl_iamthif(struct mei_device *dev, s32 *slots,
 		*slots -= (sizeof(struct mei_msg_hdr) +
 				mei_hdr->length + 3) / 4;
 
-		if (!mei_write_message(dev, mei_hdr,
+		if (mei_write_message(dev, mei_hdr,
 					(dev->iamthif_msg_buf +
 					dev->iamthif_msg_buf_index),
 					mei_hdr->length)) {
@@ -1063,7 +1059,7 @@ static int _mei_irq_thread_cmpl_iamthif(struct mei_device *dev, s32 *slots,
 		*slots -= (sizeof(struct mei_msg_hdr) +
 				mei_hdr->length + 3) / 4;
 
-		if (!mei_write_message(dev, mei_hdr,
+		if (mei_write_message(dev, mei_hdr,
 					(dev->iamthif_msg_buf +
 					dev->iamthif_msg_buf_index),
 					mei_hdr->length)) {
diff --git a/drivers/staging/mei/iorw.c b/drivers/staging/mei/iorw.c
index a6b969471835a1174b924c1daa1e501855bd7527..121b3770ec04dc0f8dc9576e23ae08aa4b166624 100644
--- a/drivers/staging/mei/iorw.c
+++ b/drivers/staging/mei/iorw.c
@@ -162,7 +162,7 @@ int mei_ioctl_connect_client(struct file *file,
 	    && !mei_other_client_is_connecting(dev, cl)) {
 		dev_dbg(&dev->pdev->dev, "Sending Connect Message\n");
 		dev->mei_host_buffer_is_empty = false;
-		if (!mei_connect(dev, cl)) {
+		if (mei_connect(dev, cl)) {
 			dev_dbg(&dev->pdev->dev, "Sending connect message - failed\n");
 			rets = -ENODEV;
 			goto end;
@@ -434,13 +434,11 @@ int mei_start_read(struct mei_device *dev, struct mei_cl *cl)
 	cl->read_cb = cb;
 	if (dev->mei_host_buffer_is_empty) {
 		dev->mei_host_buffer_is_empty = false;
-		if (!mei_send_flow_control(dev, cl)) {
+		if (mei_send_flow_control(dev, cl)) {
 			rets = -ENODEV;
 			goto unlock;
-		} else {
-			list_add_tail(&cb->cb_list,
-				      &dev->read_list.mei_cb.cb_list);
 		}
+		list_add_tail(&cb->cb_list, &dev->read_list.mei_cb.cb_list);
 	} else {
 		list_add_tail(&cb->cb_list, &dev->ctrl_wr_list.mei_cb.cb_list);
 	}
@@ -500,7 +498,7 @@ int amthi_write(struct mei_device *dev, struct mei_cl_cb *cb)
 		mei_hdr.me_addr = dev->iamthif_cl.me_client_id;
 		mei_hdr.reserved = 0;
 		dev->iamthif_msg_buf_index += mei_hdr.length;
-		if (!mei_write_message(dev, &mei_hdr,
+		if (mei_write_message(dev, &mei_hdr,
 					(unsigned char *)(dev->iamthif_msg_buf),
 					mei_hdr.length))
 			return -ENODEV;
diff --git a/drivers/staging/mei/main.c b/drivers/staging/mei/main.c
index 64456cec2e0604a13de08d90605cc19c8d2b459a..55b390823aed46744542cf48ddce258d89b5cc97 100644
--- a/drivers/staging/mei/main.c
+++ b/drivers/staging/mei/main.c
@@ -740,7 +740,7 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
 		mei_hdr.reserved = 0;
 		dev_dbg(&dev->pdev->dev, "call mei_write_message header=%08x.\n",
 		    *((u32 *) &mei_hdr));
-		if (!mei_write_message(dev, &mei_hdr,
+		if (mei_write_message(dev, &mei_hdr,
 			(unsigned char *) (write_cb->request_buffer.data),
 			mei_hdr.length)) {
 			rets = -ENODEV;
diff --git a/drivers/staging/mei/wd.c b/drivers/staging/mei/wd.c
index f397835d7be9e09b3528821fb9cf7bda363dda4a..a6910da78a64232af3d88872310074af1f8645b1 100644
--- a/drivers/staging/mei/wd.c
+++ b/drivers/staging/mei/wd.c
@@ -74,7 +74,7 @@ bool mei_wd_host_init(struct mei_device *dev)
 
 	dev_dbg(&dev->pdev->dev, "check wd_cl\n");
 	if (MEI_FILE_CONNECTING == dev->wd_cl.state) {
-		if (!mei_connect(dev, &dev->wd_cl)) {
+		if (mei_connect(dev, &dev->wd_cl)) {
 			dev_dbg(&dev->pdev->dev, "Failed to connect to WD client\n");
 			dev->wd_cl.state = MEI_FILE_DISCONNECTED;
 			dev->wd_cl.host_client_id = 0;
@@ -119,9 +119,7 @@ int mei_wd_send(struct mei_device *dev)
 	else
 		return -EINVAL;
 
-	if (mei_write_message(dev, mei_hdr, dev->wd_data, mei_hdr->length))
-		return 0;
-	return -EIO;
+	return mei_write_message(dev, mei_hdr, dev->wd_data, mei_hdr->length);
 }
 
 /**