[alsa-devel] [PATCH 1/9] ALSA: Compress - dont use lock for all ioctls

[Vinod Koul]

Some simple ioctls like timsetamp query, capabities query can be done anytime
and should not be under the stream lock. Move these to
snd_compress_simple_iotcls() which is invoked without lock held

While at it, improve readblity a bit by sprinkling some empty lines

Signed-off-by: Vinod Koul <vinod.koul at intel.com>
Cc: <stable at vger.kernel.org>
---
 sound/core/compress_offload.c |   79 ++++++++++++++++++++++++++++++-----------
 1 files changed, 58 insertions(+), 21 deletions(-)

diff --git a/sound/core/compress_offload.c b/sound/core/compress_offload.c
index 99db892..868aefd 100644
--- a/sound/core/compress_offload.c
+++ b/sound/core/compress_offload.c
@@ -729,70 +729,107 @@ static int snd_compr_partial_drain(struct snd_compr_stream *stream)
 	return retval;
 }
 
-static long snd_compr_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
+static int snd_compress_simple_ioctls(struct file *file,
+				struct snd_compr_stream *stream,
+				unsigned int cmd, unsigned long arg)
 {
-	struct snd_compr_file *data = f->private_data;
-	struct snd_compr_stream *stream;
 	int retval = -ENOTTY;
 
-	if (snd_BUG_ON(!data))
-		return -EFAULT;
-	stream = &data->stream;
-	if (snd_BUG_ON(!stream))
-		return -EFAULT;
-	mutex_lock(&stream->device->lock);
 	switch (_IOC_NR(cmd)) {
 	case _IOC_NR(SNDRV_COMPRESS_IOCTL_VERSION):
 		put_user(SNDRV_COMPRESS_VERSION,
 				(int __user *)arg) ? -EFAULT : 0;
 		break;
+
 	case _IOC_NR(SNDRV_COMPRESS_GET_CAPS):
 		retval = snd_compr_get_caps(stream, arg);
 		break;
+
 	case _IOC_NR(SNDRV_COMPRESS_GET_CODEC_CAPS):
 		retval = snd_compr_get_codec_caps(stream, arg);
 		break;
+
+	case _IOC_NR(SNDRV_COMPRESS_TSTAMP):
+		retval = snd_compr_tstamp(stream, arg);
+		break;
+
+	case _IOC_NR(SNDRV_COMPRESS_AVAIL):
+		retval = snd_compr_ioctl_avail(stream, arg);
+		break;
+
+		/* drain and partial drain need special handling
+	 * we need to drop the locks here as the streams would get blocked on the
+	 * dsp to get drained. The locking would be handled in respective
+	 * function here
+	 */
+	case _IOC_NR(SNDRV_COMPRESS_DRAIN):
+		retval = snd_compr_drain(stream);
+		break;
+
+	case _IOC_NR(SNDRV_COMPRESS_PARTIAL_DRAIN):
+		retval = snd_compr_partial_drain(stream);
+		break;
+	}
+
+	return retval;
+}
+
+static long snd_compr_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
+{
+	struct snd_compr_file *data = f->private_data;
+	struct snd_compr_stream *stream;
+	int retval = -ENOTTY;
+
+	if (snd_BUG_ON(!data))
+		return -EFAULT;
+	stream = &data->stream;
+	if (snd_BUG_ON(!stream))
+		return -EFAULT;
+
+	mutex_lock(&stream->device->lock);
+	switch (_IOC_NR(cmd)) {
 	case _IOC_NR(SNDRV_COMPRESS_SET_PARAMS):
 		retval = snd_compr_set_params(stream, arg);
 		break;
+
 	case _IOC_NR(SNDRV_COMPRESS_GET_PARAMS):
 		retval = snd_compr_get_params(stream, arg);
 		break;
+
 	case _IOC_NR(SNDRV_COMPRESS_SET_METADATA):
 		retval = snd_compr_set_metadata(stream, arg);
 		break;
+
 	case _IOC_NR(SNDRV_COMPRESS_GET_METADATA):
 		retval = snd_compr_get_metadata(stream, arg);
 		break;
-	case _IOC_NR(SNDRV_COMPRESS_TSTAMP):
-		retval = snd_compr_tstamp(stream, arg);
-		break;
-	case _IOC_NR(SNDRV_COMPRESS_AVAIL):
-		retval = snd_compr_ioctl_avail(stream, arg);
-		break;
+
 	case _IOC_NR(SNDRV_COMPRESS_PAUSE):
 		retval = snd_compr_pause(stream);
 		break;
+
 	case _IOC_NR(SNDRV_COMPRESS_RESUME):
 		retval = snd_compr_resume(stream);
 		break;
+
 	case _IOC_NR(SNDRV_COMPRESS_START):
 		retval = snd_compr_start(stream);
 		break;
+
 	case _IOC_NR(SNDRV_COMPRESS_STOP):
 		retval = snd_compr_stop(stream);
 		break;
-	case _IOC_NR(SNDRV_COMPRESS_DRAIN):
-		retval = snd_compr_drain(stream);
-		break;
-	case _IOC_NR(SNDRV_COMPRESS_PARTIAL_DRAIN):
-		retval = snd_compr_partial_drain(stream);
-		break;
+
 	case _IOC_NR(SNDRV_COMPRESS_NEXT_TRACK):
 		retval = snd_compr_next_track(stream);
 		break;
 
+	default:
+		mutex_unlock(&stream->device->lock);
+		return snd_compress_simple_ioctls(f, stream, cmd, arg);
+
 	}
+
 	mutex_unlock(&stream->device->lock);
 	return retval;
 }
-- 
1.7.0.4