Re: [PATCH 06/10] sound: usx2y: move to use usb_control_msg_send()

[Takashi Iwai]

On Wed, 02 Sep 2020 13:01:08 +0200,
Greg Kroah-Hartman wrote:
> 
> The usb_control_msg_send() call can handle data on the stack, as well as
> returning an error if a "short" write happens, so move the driver over
> to using that call instead.  This ends up removing a helper function
> that is no longer needed.
> 
> Cc: Jaroslav Kysela <perex@xxxxxxxx>
> Cc: Takashi Iwai <tiwai@xxxxxxxx>
> Cc: alsa-devel@xxxxxxxxxxxxxxxx
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

Reviewed-by: Takashi Iwai <tiwai@xxxxxxx>


thanks,

Takashi

> ---
>  sound/usb/usx2y/us122l.c | 42 ++++++++--------------------------------
>  1 file changed, 8 insertions(+), 34 deletions(-)
> 
> diff --git a/sound/usb/usx2y/us122l.c b/sound/usb/usx2y/us122l.c
> index f86f7a61fb36..e5c5a0d03d8a 100644
> --- a/sound/usb/usx2y/us122l.c
> +++ b/sound/usb/usx2y/us122l.c
> @@ -82,40 +82,13 @@ static int us144_create_usbmidi(struct snd_card *card)
>  				  &US122L(card)->midi_list, &quirk);
>  }
>  
> -/*
> - * Wrapper for usb_control_msg().
> - * Allocates a temp buffer to prevent dmaing from/to the stack.
> - */
> -static int us122l_ctl_msg(struct usb_device *dev, unsigned int pipe,
> -			  __u8 request, __u8 requesttype,
> -			  __u16 value, __u16 index, void *data,
> -			  __u16 size, int timeout)
> -{
> -	int err;
> -	void *buf = NULL;
> -
> -	if (size > 0) {
> -		buf = kmemdup(data, size, GFP_KERNEL);
> -		if (!buf)
> -			return -ENOMEM;
> -	}
> -	err = usb_control_msg(dev, pipe, request, requesttype,
> -			      value, index, buf, size, timeout);
> -	if (size > 0) {
> -		memcpy(data, buf, size);
> -		kfree(buf);
> -	}
> -	return err;
> -}
> -
>  static void pt_info_set(struct usb_device *dev, u8 v)
>  {
>  	int ret;
>  
> -	ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
> -			      'I',
> -			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
> -			      v, 0, NULL, 0, 1000);
> +	ret = usb_control_msg_send(dev, 0, 'I',
> +				   USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
> +				   v, 0, NULL, 0, 1000);
>  	snd_printdd(KERN_DEBUG "%i\n", ret);
>  }
>  
> @@ -305,10 +278,11 @@ static int us122l_set_sample_rate(struct usb_device *dev, int rate)
>  	data[0] = rate;
>  	data[1] = rate >> 8;
>  	data[2] = rate >> 16;
> -	err = us122l_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
> -			     USB_TYPE_CLASS|USB_RECIP_ENDPOINT|USB_DIR_OUT,
> -			     UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep, data, 3, 1000);
> -	if (err < 0)
> +	err = usb_control_msg_send(dev, 0, UAC_SET_CUR,
> +				   USB_TYPE_CLASS|USB_RECIP_ENDPOINT|USB_DIR_OUT,
> +				   UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep, data, 3,
> +				   1000);
> +	if (err)
>  		snd_printk(KERN_ERR "%d: cannot set freq %d to ep 0x%x\n",
>  			   dev->devnum, rate, ep);
>  	return err;
> -- 
> 2.28.0
>