Re: [PATCH 4/4] net: rndis_host: use usb_control_msg_recv() and usb_control_msg_send()

Greg KH
2020-09-23T10:22:39Z

On Wed, Sep 23, 2020 at 02:35:19PM +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 <himadrispandya@gmail.com>
> ---
> drivers/net/usb/rndis_host.c | 44 ++++++++++++++----------------------
> 1 file changed, 17 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/net/usb/rndis_host.c b/drivers/net/usb/rndis_host.c
> index 6fa7a009a24a..30fc4a7183d3 100644
> --- a/drivers/net/usb/rndis_host.c
> +++ b/drivers/net/usb/rndis_host.c
> @@ -113,14 +113,13 @@ int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf, int buflen)
> buf->request_id = (__force __le32) xid;
> }
> master_ifnum = info->control->cur_altsetting->desc.bInterfaceNumber;
> - retval = usb_control_msg(dev->udev,
> - usb_sndctrlpipe(dev->udev, 0),
> - USB_CDC_SEND_ENCAPSULATED_COMMAND,
> - USB_TYPE_CLASS | USB_RECIP_INTERFACE,
> - 0, master_ifnum,
> - buf, le32_to_cpu(buf->msg_len),
> - RNDIS_CONTROL_TIMEOUT_MS);
> - if (unlikely(retval < 0 || xid == 0))
> + retval = usb_control_msg_send(dev->udev, 0,
> + USB_CDC_SEND_ENCAPSULATED_COMMAND,
> + USB_TYPE_CLASS | USB_RECIP_INTERFACE,
> + 0, master_ifnum, buf,
> + le32_to_cpu(buf->msg_len),
> + RNDIS_CONTROL_TIMEOUT_MS);
> + if (unlikely(xid == 0))
> return retval;
>
> /* Some devices don't respond on the control channel until
> @@ -139,14 +138,11 @@ int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf, int buflen)
> /* Poll the control channel; the request probably completed immediately */
> rsp = le32_to_cpu(buf->msg_type) | RNDIS_MSG_COMPLETION;
> for (count = 0; count < 10; count++) {
> - memset(buf, 0, CONTROL_BUFFER_SIZE);
> - retval = usb_control_msg(dev->udev,
> - usb_rcvctrlpipe(dev->udev, 0),
> - USB_CDC_GET_ENCAPSULATED_RESPONSE,
> - USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
> - 0, master_ifnum,
> - buf, buflen,
> - RNDIS_CONTROL_TIMEOUT_MS);
> + retval = usb_control_msg_recv(dev->udev, 0,
> + USB_CDC_GET_ENCAPSULATED_RESPONSE,
> + USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
> + 0, master_ifnum, buf, buflen,
> + RNDIS_CONTROL_TIMEOUT_MS);
> if (likely(retval >= 8)) {

retval here is never going to be positive, right? So I don't think this
patch is correct :(

> msg_type = le32_to_cpu(buf->msg_type);
> msg_len = le32_to_cpu(buf->msg_len);
> @@ -178,17 +174,11 @@ int rndis_command(struct usbnet *dev, struct rndis_msg_hdr *buf, int buflen)
> msg->msg_type = cpu_to_le32(RNDIS_MSG_KEEPALIVE_C);
> msg->msg_len = cpu_to_le32(sizeof *msg);
> msg->status = cpu_to_le32(RNDIS_STATUS_SUCCESS);
> - retval = usb_control_msg(dev->udev,
> - usb_sndctrlpipe(dev->udev, 0),
> - USB_CDC_SEND_ENCAPSULATED_COMMAND,
> - USB_TYPE_CLASS | USB_RECIP_INTERFACE,
> - 0, master_ifnum,
> - msg, sizeof *msg,
> - RNDIS_CONTROL_TIMEOUT_MS);
> - if (unlikely(retval < 0))
> - dev_dbg(&info->control->dev,
> - "rndis keepalive err %d\n",
> - retval);
> + retval = usb_control_msg_send(dev->udev, 0,
> + USB_CDC_SEND_ENCAPSULATED_COMMAND,
> + USB_TYPE_CLASS | USB_RECIP_INTERFACE,
> + 0, master_ifnum, msg, sizeof(*msg),
> + RNDIS_CONTROL_TIMEOUT_MS);

You lost the error message that the previous call had if something went
wrong. Don't know if it's really needed, but there's no reason to
remove it here.

thanks,

greg k-h