USB: serial: kl5kusb105: use usb_control_msg_recv() and usb_control_msg_send()

The wrappers usb_control_msg_send/recv eliminate the need of manually
allocating DMA buffers for USB messages. They also treat short reads as
an error. Hence use the wrappers and remove DMA allocations.

Note that short reads are now logged as -EREMOTEIO instead of the amount
of data read.

Signed-off-by: Himadri Pandya <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ johan: amend commit message ]
Signed-off-by: Johan Hovold <[email protected]>

Author: himadrics

drivers/usb/serial/kl5kusb105.c

@@ -124,16 +124,18 @@ static int klsi_105_chg_port_settings(struct usb_serial_port *port,
 {
 	int rc;
 
-	rc = usb_control_msg(port->serial->dev,
-			usb_sndctrlpipe(port->serial->dev, 0),
-			KL5KUSB105A_SIO_SET_DATA,
-			USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_INTERFACE,
-			0, /* value */
-			0, /* index */
-			settings,
-			sizeof(struct klsi_105_port_settings),
-			KLSI_TIMEOUT);
-	if (rc < 0)
+	rc = usb_control_msg_send(port->serial->dev,
+				  0,
+				  KL5KUSB105A_SIO_SET_DATA,
+				  USB_TYPE_VENDOR | USB_DIR_OUT |
+				  USB_RECIP_INTERFACE,
+				  0, /* value */
+				  0, /* index */
+				  settings,
+				  sizeof(struct klsi_105_port_settings),
+				  KLSI_TIMEOUT,
+				  GFP_KERNEL);
+	if (rc)
 		dev_err(&port->dev,
 			"Change port settings failed (error = %d)\n", rc);
 
@@ -167,28 +169,21 @@ static int klsi_105_get_line_state(struct usb_serial_port *port,
 				   unsigned long *line_state_p)
 {
 	int rc;
-	u8 *status_buf;
+	u8 status_buf[KLSI_STATUSBUF_LEN];
 	__u16 status;
 
-	status_buf = kmalloc(KLSI_STATUSBUF_LEN, GFP_KERNEL);
-	if (!status_buf)
-		return -ENOMEM;
-
 	status_buf[0] = 0xff;
 	status_buf[1] = 0xff;
-	rc = usb_control_msg(port->serial->dev,
-			     usb_rcvctrlpipe(port->serial->dev, 0),
-			     KL5KUSB105A_SIO_POLL,
-			     USB_TYPE_VENDOR | USB_DIR_IN,
-			     0, /* value */
-			     0, /* index */
-			     status_buf, KLSI_STATUSBUF_LEN,
-			     10000
-			     );
-	if (rc != KLSI_STATUSBUF_LEN) {
+	rc = usb_control_msg_recv(port->serial->dev, 0,
+				  KL5KUSB105A_SIO_POLL,
+				  USB_TYPE_VENDOR | USB_DIR_IN,
+				  0, /* value */
+				  0, /* index */
+				  status_buf, KLSI_STATUSBUF_LEN,
+				  10000,
+				  GFP_KERNEL);
+	if (rc) {
 		dev_err(&port->dev, "reading line status failed: %d\n", rc);
-		if (rc >= 0)
-			rc = -EIO;
 	} else {
 		status = get_unaligned_le16(status_buf);
 
@@ -198,7 +193,6 @@ static int klsi_105_get_line_state(struct usb_serial_port *port,
 		*line_state_p = klsi_105_status2linestate(status);
 	}
 
-	kfree(status_buf);
 	return rc;
 }
 
@@ -245,7 +239,7 @@ static int  klsi_105_open(struct tty_struct *tty, struct usb_serial_port *port)
 	int retval = 0;
 	int rc;
 	unsigned long line_state;
-	struct klsi_105_port_settings *cfg;
+	struct klsi_105_port_settings cfg;
 	unsigned long flags;
 
 	/* Do a defined restart:
@@ -255,27 +249,22 @@ static int  klsi_105_open(struct tty_struct *tty, struct usb_serial_port *port)
 	 * Then read the modem line control and store values in
 	 * priv->line_state.
 	 */
-	cfg = kmalloc(sizeof(*cfg), GFP_KERNEL);
-	if (!cfg)
-		return -ENOMEM;
 
-	cfg->pktlen   = 5;
-	cfg->baudrate = kl5kusb105a_sio_b9600;
-	cfg->databits = kl5kusb105a_dtb_8;
-	cfg->unknown1 = 0;
-	cfg->unknown2 = 1;
-	klsi_105_chg_port_settings(port, cfg);
+	cfg.pktlen   = 5;
+	cfg.baudrate = kl5kusb105a_sio_b9600;
+	cfg.databits = kl5kusb105a_dtb_8;
+	cfg.unknown1 = 0;
+	cfg.unknown2 = 1;
+	klsi_105_chg_port_settings(port, &cfg);
 
 	spin_lock_irqsave(&priv->lock, flags);
-	priv->cfg.pktlen   = cfg->pktlen;
-	priv->cfg.baudrate = cfg->baudrate;
-	priv->cfg.databits = cfg->databits;
-	priv->cfg.unknown1 = cfg->unknown1;
-	priv->cfg.unknown2 = cfg->unknown2;
+	priv->cfg.pktlen   = cfg.pktlen;
+	priv->cfg.baudrate = cfg.baudrate;
+	priv->cfg.databits = cfg.databits;
+	priv->cfg.unknown1 = cfg.unknown1;
+	priv->cfg.unknown2 = cfg.unknown2;
 	spin_unlock_irqrestore(&priv->lock, flags);
 
-	kfree(cfg);
-
 	/* READ_ON and urb submission */
 	rc = usb_serial_generic_open(tty, port);
 	if (rc)