sound: line6: move to use usb_control_msg_send() and usb_control_msg_recv()

The usb_control_msg_send() and usb_control_msg_recv() calls can return
an error if a "short" write/read happens, and they can handle data off
of the stack, so move the driver over to using those calls instead,
saving some logic when dynamically allocating memory.

Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Vasily Khoruzhick <anarsoul@gmail.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20200914153756.3412156-9-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 27 insertions, 42 deletions

diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c
index 60674ce4879b..601292c51491 100644
--- a/sound/usb/line6/driver.c
+++ b/sound/usb/line6/driver.c
@@ -337,23 +337,18 @@ int line6_read_data(struct usb_line6 *line6, unsigned address, void *data,
 {
 	struct usb_device *usbdev = line6->usbdev;
 	int ret;
-	unsigned char *len;
+	u8 len;
 	unsigned count;
 
 	if (address > 0xffff || datalen > 0xff)
 		return -EINVAL;
 
-	len = kmalloc(1, GFP_KERNEL);
-	if (!len)
-		return -ENOMEM;
-
 	/* query the serial number: */
-	ret = usb_control_msg(usbdev, usb_sndctrlpipe(usbdev, 0), 0x67,
-			      USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
-			      (datalen << 8) | 0x21, address,
-			      NULL, 0, LINE6_TIMEOUT * HZ);
-
-	if (ret < 0) {
+	ret = usb_control_msg_send(usbdev, 0, 0x67,
+				   USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
+				   (datalen << 8) | 0x21, address, NULL, 0,
+				   LINE6_TIMEOUT * HZ);
+	if (ret) {
 		dev_err(line6->ifcdev, "read request failed (error %d)\n", ret);
 		goto exit;
 	}
@@ -362,45 +357,41 @@ int line6_read_data(struct usb_line6 *line6, unsigned address, void *data,
 	for (count = 0; count < LINE6_READ_WRITE_MAX_RETRIES; count++) {
 		mdelay(LINE6_READ_WRITE_STATUS_DELAY);
 
-		ret = usb_control_msg(usbdev, usb_rcvctrlpipe(usbdev, 0), 0x67,
-				      USB_TYPE_VENDOR | USB_RECIP_DEVICE |
-				      USB_DIR_IN,
-				      0x0012, 0x0000, len, 1,
-				      LINE6_TIMEOUT * HZ);
-		if (ret < 0) {
+		ret = usb_control_msg_recv(usbdev, 0, 0x67,
+					   USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+					   0x0012, 0x0000, &len, 1,
+					   LINE6_TIMEOUT * HZ);
+		if (ret) {
 			dev_err(line6->ifcdev,
 				"receive length failed (error %d)\n", ret);
 			goto exit;
 		}
 
-		if (*len != 0xff)
+		if (len != 0xff)
 			break;
 	}
 
 	ret = -EIO;
-	if (*len == 0xff) {
+	if (len == 0xff) {
 		dev_err(line6->ifcdev, "read failed after %d retries\n",
 			count);
 		goto exit;
-	} else if (*len != datalen) {
+	} else if (len != datalen) {
 		/* should be equal or something went wrong */
 		dev_err(line6->ifcdev,
 			"length mismatch (expected %d, got %d)\n",
-			(int)datalen, (int)*len);
+			(int)datalen, len);
 		goto exit;
 	}
 
 	/* receive the result: */
-	ret = usb_control_msg(usbdev, usb_rcvctrlpipe(usbdev, 0), 0x67,
-			      USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
-			      0x0013, 0x0000, data, datalen,
-			      LINE6_TIMEOUT * HZ);
-
-	if (ret < 0)
+	ret = usb_control_msg_recv(usbdev, 0, 0x67,
+				   USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+				   0x0013, 0x0000, data, datalen, LINE6_TIMEOUT * HZ);
+	if (ret)
 		dev_err(line6->ifcdev, "read failed (error %d)\n", ret);
 
 exit:
-	kfree(len);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(line6_read_data);
@@ -423,12 +414,10 @@ int line6_write_data(struct usb_line6 *line6, unsigned address, void *data,
 	if (!status)
 		return -ENOMEM;
 
-	ret = usb_control_msg(usbdev, usb_sndctrlpipe(usbdev, 0), 0x67,
-			      USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
-			      0x0022, address, data, datalen,
-			      LINE6_TIMEOUT * HZ);
-
-	if (ret < 0) {
+	ret = usb_control_msg_send(usbdev, 0, 0x67,
+				   USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
+				   0x0022, address, data, datalen, LINE6_TIMEOUT * HZ);
+	if (ret) {
 		dev_err(line6->ifcdev,
 			"write request failed (error %d)\n", ret);
 		goto exit;
@@ -437,14 +426,10 @@ int line6_write_data(struct usb_line6 *line6, unsigned address, void *data,
 	for (count = 0; count < LINE6_READ_WRITE_MAX_RETRIES; count++) {
 		mdelay(LINE6_READ_WRITE_STATUS_DELAY);
 
-		ret = usb_control_msg(usbdev, usb_rcvctrlpipe(usbdev, 0),
-				      0x67,
-				      USB_TYPE_VENDOR | USB_RECIP_DEVICE |
-				      USB_DIR_IN,
-				      0x0012, 0x0000,
-				      status, 1, LINE6_TIMEOUT * HZ);
-
-		if (ret < 0) {
+		ret = usb_control_msg_recv(usbdev, 0, 0x67,
+					   USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+					   0x0012, 0x0000, status, 1, LINE6_TIMEOUT * HZ);
+		if (ret) {
 			dev_err(line6->ifcdev,
 				"receiving status failed (error %d)\n", ret);
 			goto exit;