[Linux-kernel-mentees] [PATCH 03/15] usb: serial: ch314: use usb_control_msg_recv() and usb_control_msg_send()

Himadri Pandya himadrispandya at gmail.com
Wed Nov 4 06:46:51 UTC 2020


The new usb_control_msg_recv() and usb_control_msg_send() nicely wraps
usb_control_msg() with proper error check. Hence use the wrappers
instead of calling usb_control_msg() directly.

Signed-off-by: Himadri Pandya <himadrispandya at gmail.com>
---
 drivers/usb/serial/ch341.c | 45 ++++++++++++--------------------------
 1 file changed, 14 insertions(+), 31 deletions(-)

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index a2e2f56c88cd..58c5d3ce4f75 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -111,10 +111,10 @@ static int ch341_control_out(struct usb_device *dev, u8 request,
 	dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x)\n", __func__,
 		request, value, index);
 
-	r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
-			    USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
-			    value, index, NULL, 0, DEFAULT_TIMEOUT);
-	if (r < 0)
+	r = usb_control_msg_send(dev, 0, request, USB_TYPE_VENDOR |
+				 USB_RECIP_DEVICE | USB_DIR_OUT, value, index,
+				 NULL, 0, DEFAULT_TIMEOUT, GFP_KERNEL);
+	if (r)
 		dev_err(&dev->dev, "failed to send control message: %d\n", r);
 
 	return r;
@@ -129,23 +129,14 @@ static int ch341_control_in(struct usb_device *dev,
 	dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x,%u)\n", __func__,
 		request, value, index, bufsize);
 
-	r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
-			    USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
-			    value, index, buf, bufsize, DEFAULT_TIMEOUT);
-	if (r < (int)bufsize) {
-		if (r >= 0) {
-			dev_err(&dev->dev,
-				"short control message received (%d < %u)\n",
-				r, bufsize);
-			r = -EIO;
-		}
-
+	r = usb_control_msg_recv(dev, 0, request, USB_TYPE_VENDOR |
+				 USB_RECIP_DEVICE | USB_DIR_IN, value, index,
+				 buf, bufsize, DEFAULT_TIMEOUT, GFP_KERNEL);
+	if (r)
 		dev_err(&dev->dev, "failed to receive control message: %d\n",
 			r);
-		return r;
-	}
 
-	return 0;
+	return r;
 }
 
 #define CH341_CLKRATE		48000000
@@ -343,22 +334,18 @@ static int ch341_detect_quirks(struct usb_serial_port *port)
 	struct usb_device *udev = port->serial->dev;
 	const unsigned int size = 2;
 	unsigned long quirks = 0;
-	char *buffer;
+	u8 buffer[2];
 	int r;
 
-	buffer = kmalloc(size, GFP_KERNEL);
-	if (!buffer)
-		return -ENOMEM;
-
 	/*
 	 * A subset of CH34x devices does not support all features. The
 	 * prescaler is limited and there is no support for sending a RS232
 	 * break condition. A read failure when trying to set up the latter is
 	 * used to detect these devices.
 	 */
-	r = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0), CH341_REQ_READ_REG,
-			    USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
-			    CH341_REG_BREAK, 0, buffer, size, DEFAULT_TIMEOUT);
+	r = usb_control_msg_recv(udev, 0, CH341_REQ_READ_REG, USB_TYPE_VENDOR |
+				 USB_RECIP_DEVICE | USB_DIR_IN, CH341_REG_BREAK,
+				 0, &buffer, size, DEFAULT_TIMEOUT, GFP_KERNEL);
 	if (r == -EPIPE) {
 		dev_info(&port->dev, "break control not supported, using simulated break\n");
 		quirks = CH341_QUIRK_LIMITED_PRESCALER | CH341_QUIRK_SIMULATE_BREAK;
@@ -366,17 +353,13 @@ static int ch341_detect_quirks(struct usb_serial_port *port)
 		goto out;
 	}
 
-	if (r != size) {
-		if (r >= 0)
-			r = -EIO;
+	if (r) {
 		dev_err(&port->dev, "failed to read break control: %d\n", r);
 		goto out;
 	}
 
 	r = 0;
 out:
-	kfree(buffer);
-
 	if (quirks) {
 		dev_dbg(&port->dev, "enabling quirk flags: 0x%02lx\n", quirks);
 		priv->quirks |= quirks;
-- 
2.17.1



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