HID: cp2112: fix sleep-while-atomic

A recent commit fixing DMA-buffers on stack added a shared transfer
buffer protected by a spinlock. This is broken as the USB HID request
callbacks can sleep. Fix this up by replacing the spinlock with a mutex.

Fixes: 1ffb3c40ffb5 ("HID: cp2112: make transfer buffers DMA capable")
Cc: stable <stable@vger.kernel.org>	# 4.9
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

path: root/sound/usb/caiaq/midi.h

#ifndef CAIAQ_MIDI_H
#define CAIAQ_MIDI_H

int snd_usb_caiaq_midi_init(struct snd_usb_caiaqdev *cdev);
void snd_usb_caiaq_midi_handle_input(struct snd_usb_caiaqdev *cdev,
				     int port, const char *buf, int len);
void snd_usb_caiaq_midi_output_done(struct urb *urb);

#endif /* CAIAQ_MIDI_H */