On Wed, Nov 04, 2020 at 12:16:51PM +0530, Himadri Pandya wrote:
> 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 <[email protected]>
> ---
> 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;
> }
The callers of these functions are allocating temporary transfers buffer
for each request so this is a case where the new helpers may be of worth
if you fix up the callers as well (otherwise, you're adding redundant
memdup + memcpy for each call here).
>
> #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;
This is a good example of when to use the helpers. But it seems you
should remove the "r = 0" and "out" label as well, right?
Johan
