USB: serial: cp210x: use usb_control_msg_recv() and usb_control_msg_send()

The new wrapper functions for usb_control_msg() can accept data from
stack and treat short reads as errors. Hence use the wrappers functions.
Please note that because of this change, cp210x_read_reg_block() will no
longer log the length of short reads.

Signed-off-by: Himadri Pandya <himadrispandya@gmail.com>
Link: https://lore.kernel.org/r/20211001065720.21330-3-himadrispandya@gmail.com
[ johan: style changes ]
Signed-off-by: Johan Hovold <johan@kernel.org>

1 files changed, 31 insertions, 78 deletions

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 66a6ac50a4cd..920b97665375 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -629,30 +629,20 @@ static int cp210x_read_reg_block(struct usb_serial_port *port, u8 req,
 {
 	struct usb_serial *serial = port->serial;
 	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
-	void *dmabuf;
 	int result;
 
-	dmabuf = kmalloc(bufsize, GFP_KERNEL);
-	if (!dmabuf)
-		return -ENOMEM;
 
-	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
-			req, REQTYPE_INTERFACE_TO_HOST, 0,
-			port_priv->bInterfaceNumber, dmabuf, bufsize,
-			USB_CTRL_GET_TIMEOUT);
-	if (result == bufsize) {
-		memcpy(buf, dmabuf, bufsize);
-		result = 0;
-	} else {
+	result = usb_control_msg_recv(serial->dev, 0, req,
+			REQTYPE_INTERFACE_TO_HOST, 0,
+			port_priv->bInterfaceNumber, buf, bufsize,
+			USB_CTRL_SET_TIMEOUT, GFP_KERNEL);
+	if (result) {
 		dev_err(&port->dev, "failed get req 0x%x size %d status: %d\n",
 				req, bufsize, result);
-		if (result >= 0)
-			result = -EIO;
+		return result;
 	}
 
-	kfree(dmabuf);
-
-	return result;
+	return 0;
 }
 
 /*
@@ -670,31 +660,19 @@ static int cp210x_read_u8_reg(struct usb_serial_port *port, u8 req, u8 *val)
 static int cp210x_read_vendor_block(struct usb_serial *serial, u8 type, u16 val,
 				    void *buf, int bufsize)
 {
-	void *dmabuf;
 	int result;
 
-	dmabuf = kmalloc(bufsize, GFP_KERNEL);
-	if (!dmabuf)
-		return -ENOMEM;
-
-	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
-				 CP210X_VENDOR_SPECIFIC, type, val,
-				 cp210x_interface_num(serial), dmabuf, bufsize,
-				 USB_CTRL_GET_TIMEOUT);
-	if (result == bufsize) {
-		memcpy(buf, dmabuf, bufsize);
-		result = 0;
-	} else {
+	result = usb_control_msg_recv(serial->dev, 0, CP210X_VENDOR_SPECIFIC,
+			type, val, cp210x_interface_num(serial), buf, bufsize,
+			USB_CTRL_GET_TIMEOUT, GFP_KERNEL);
+	if (result) {
 		dev_err(&serial->interface->dev,
 			"failed to get vendor val 0x%04x size %d: %d\n", val,
 			bufsize, result);
-		if (result >= 0)
-			result = -EIO;
+		return result;
 	}
 
-	kfree(dmabuf);
-
-	return result;
+	return 0;
 }
 
 /*
@@ -728,21 +706,13 @@ static int cp210x_write_reg_block(struct usb_serial_port *port, u8 req,
 {
 	struct usb_serial *serial = port->serial;
 	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
-	void *dmabuf;
 	int result;
 
-	dmabuf = kmemdup(buf, bufsize, GFP_KERNEL);
-	if (!dmabuf)
-		return -ENOMEM;
-
-	result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
-			req, REQTYPE_HOST_TO_INTERFACE, 0,
-			port_priv->bInterfaceNumber, dmabuf, bufsize,
-			USB_CTRL_SET_TIMEOUT);
-
-	kfree(dmabuf);
-
-	if (result < 0) {
+	result = usb_control_msg_send(serial->dev, 0, req,
+			REQTYPE_HOST_TO_INTERFACE, 0,
+			port_priv->bInterfaceNumber, buf, bufsize,
+			USB_CTRL_SET_TIMEOUT, GFP_KERNEL);
+	if (result) {
 		dev_err(&port->dev, "failed set req 0x%x size %d status: %d\n",
 				req, bufsize, result);
 		return result;
@@ -771,21 +741,12 @@ static int cp210x_write_u32_reg(struct usb_serial_port *port, u8 req, u32 val)
 static int cp210x_write_vendor_block(struct usb_serial *serial, u8 type,
 				     u16 val, void *buf, int bufsize)
 {
-	void *dmabuf;
 	int result;
 
-	dmabuf = kmemdup(buf, bufsize, GFP_KERNEL);
-	if (!dmabuf)
-		return -ENOMEM;
-
-	result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
-				 CP210X_VENDOR_SPECIFIC, type, val,
-				 cp210x_interface_num(serial), dmabuf, bufsize,
-				 USB_CTRL_SET_TIMEOUT);
-
-	kfree(dmabuf);
-
-	if (result < 0) {
+	result = usb_control_msg_send(serial->dev, 0, CP210X_VENDOR_SPECIFIC,
+			type, val, cp210x_interface_num(serial), buf, bufsize,
+			USB_CTRL_SET_TIMEOUT, GFP_KERNEL);
+	if (result) {
 		dev_err(&serial->interface->dev,
 			"failed to set vendor val 0x%04x size %d: %d\n", val,
 			bufsize, result);
@@ -950,29 +911,21 @@ static int cp210x_get_tx_queue_byte_count(struct usb_serial_port *port,
 {
 	struct usb_serial *serial = port->serial;
 	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
-	struct cp210x_comm_status *sts;
+	struct cp210x_comm_status sts;
 	int result;
 
-	sts = kmalloc(sizeof(*sts), GFP_KERNEL);
-	if (!sts)
-		return -ENOMEM;
-
-	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
-			CP210X_GET_COMM_STATUS, REQTYPE_INTERFACE_TO_HOST,
-			0, port_priv->bInterfaceNumber, sts, sizeof(*sts),
-			USB_CTRL_GET_TIMEOUT);
-	if (result == sizeof(*sts)) {
-		*count = le32_to_cpu(sts->ulAmountInOutQueue);
-		result = 0;
-	} else {
+	result = usb_control_msg_recv(serial->dev, 0, CP210X_GET_COMM_STATUS,
+			REQTYPE_INTERFACE_TO_HOST, 0,
+			port_priv->bInterfaceNumber, &sts, sizeof(sts),
+			USB_CTRL_GET_TIMEOUT, GFP_KERNEL);
+	if (result) {
 		dev_err(&port->dev, "failed to get comm status: %d\n", result);
-		if (result >= 0)
-			result = -EIO;
+		return result;
 	}
 
-	kfree(sts);
+	*count = le32_to_cpu(sts.ulAmountInOutQueue);
 
-	return result;
+	return 0;
 }
 
 static bool cp210x_tx_empty(struct usb_serial_port *port)