saa7134: Fix unlocked snd_pcm_stop() call

commit e6355ad7 upstream.

snd_pcm_stop() must be called in the PCM substream lock context.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
[wml: Backported to 3.4: Adjust filename]
Signed-off-by: Weng Meiling <wengmeiling.weng@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/media/video/saa7134/saa7134-alsa.c

@@ -172,7 +172,9 @@ static void saa7134_irq_alsa_done(struct saa7134_dev *dev,
 		dprintk("irq: overrun [full=%d/%d] - Blocks in %d\n",dev->dmasound.read_count,
 			dev->dmasound.bufsize, dev->dmasound.blocks);
 		spin_unlock(&dev->slock);
+		snd_pcm_stream_lock(dev->dmasound.substream);
 		snd_pcm_stop(dev->dmasound.substream,SNDRV_PCM_STATE_XRUN);
+		snd_pcm_stream_unlock(dev->dmasound.substream);
 		return;
 	}