Re: [Linux-kernel-mentees] [PATCH 1/4] net: usbnet: use usb_control_msg_recv() and usb_control_msg_send()

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Sep 23, 2020 at 02:35:16PM +0530, Himadri Pandya wrote:
> Potential incorrect use of usb_control_msg() has resulted in new wrapper
> functions to enforce its correct usage with proper error check. Hence
> use these new wrapper functions instead of calling usb_control_msg()
> directly.
> 
> Signed-off-by: Himadri Pandya <himadrispandya@gmail.com>
> ---
>  drivers/net/usb/usbnet.c | 46 ++++------------------------------------
>  1 file changed, 4 insertions(+), 42 deletions(-)
> 
> diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
> index 2b2a841cd938..a38a85bef46a 100644
> --- a/drivers/net/usb/usbnet.c
> +++ b/drivers/net/usb/usbnet.c
> @@ -1982,64 +1982,26 @@ EXPORT_SYMBOL(usbnet_link_change);
>  static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
>  			     u16 value, u16 index, void *data, u16 size)
>  {
> -	void *buf = NULL;
> -	int err = -ENOMEM;
> -
>  	netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
>  		   " value=0x%04x index=0x%04x size=%d\n",
>  		   cmd, reqtype, value, index, size);
>  
> -	if (size) {
> -		buf = kmalloc(size, GFP_KERNEL);
> -		if (!buf)
> -			goto out;
> -	}
> -
> -	err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
> -			      cmd, reqtype, value, index, buf, size,
> +	return usb_control_msg_recv(dev->udev, 0,
> +			      cmd, reqtype, value, index, data, size,
>  			      USB_CTRL_GET_TIMEOUT);
> -	if (err > 0 && err <= size) {
> -        if (data)
> -            memcpy(data, buf, err);
> -        else
> -            netdev_dbg(dev->net,
> -                "Huh? Data requested but thrown away.\n");
> -    }
> -	kfree(buf);
> -out:
> -	return err;
>  }

Now there is no real need for these wrapper functions at all, except for
the debugging which I doubt anyone needs anymore.

So how about just deleting these and calling the real function instead?

thanks,

greg k-h
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