ALSA: snd-usb-caiaq: Missing lock around use of buffer positions
Fix a race which causes snd_pcm_update_hw_ptr_pos() to report a bug.
Signed-off-by: Mark Hills <mark@pogo.org.uk>
Acked-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/caiaq/audio.c b/sound/usb/caiaq/audio.c
index 121af06..e76017c 100644
--- a/sound/usb/caiaq/audio.c
+++ b/sound/usb/caiaq/audio.c
@@ -269,16 +269,22 @@
{
int index = sub->number;
struct snd_usb_caiaqdev *dev = snd_pcm_substream_chip(sub);
+ snd_pcm_uframes_t ptr;
+
+ spin_lock(&dev->spinlock);
if (dev->input_panic || dev->output_panic)
- return SNDRV_PCM_POS_XRUN;
+ ptr = SNDRV_PCM_POS_XRUN;
if (sub->stream == SNDRV_PCM_STREAM_PLAYBACK)
- return bytes_to_frames(sub->runtime,
+ ptr = bytes_to_frames(sub->runtime,
dev->audio_out_buf_pos[index]);
else
- return bytes_to_frames(sub->runtime,
+ ptr = bytes_to_frames(sub->runtime,
dev->audio_in_buf_pos[index]);
+
+ spin_unlock(&dev->spinlock);
+ return ptr;
}
/* operators for both playback and capture */