sound: usx2y: move to use usb_control_msg_send()

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@perex.cz>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20200914153756.3412156-7-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

sound/usb/usx2y/us122l.c

@@ -82,38 +82,11 @@ 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',
+	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;