1 files changed, 46 insertions, 33 deletions

diff --git a/sound/virtio/virtio_pcm_msg.c b/sound/virtio/virtio_pcm_msg.c
index aca2dc1989ba..542446c4c7ba 100644
--- a/sound/virtio/virtio_pcm_msg.c
+++ b/sound/virtio/virtio_pcm_msg.c
@@ -155,7 +155,6 @@ int virtsnd_pcm_msg_alloc(struct virtio_pcm_substream *vss,
 			    sizeof(msg->xfer));
 		sg_init_one(&msg->sgs[PCM_MSG_SG_STATUS], &msg->status,
 			    sizeof(msg->status));
-		msg->length = period_bytes;
 		virtsnd_pcm_sg_from(&msg->sgs[PCM_MSG_SG_DATA], sg_num, data,
 				    period_bytes);
 
@@ -186,61 +185,75 @@ void virtsnd_pcm_msg_free(struct virtio_pcm_substream *vss)
 /**
  * virtsnd_pcm_msg_send() - Send asynchronous I/O messages.
  * @vss: VirtIO PCM substream.
+ * @offset: starting position that has been updated
+ * @bytes: number of bytes that has been updated
  *
  * All messages are organized in an ordered circular list. Each time the
  * function is called, all currently non-enqueued messages are added to the
- * virtqueue. For this, the function keeps track of two values:
- *
- *   msg_last_enqueued = index of the last enqueued message,
- *   msg_count = # of pending messages in the virtqueue.
+ * virtqueue. For this, the function uses offset and bytes to calculate the
+ * messages that need to be added.
  *
  * Context: Any context. Expects the tx/rx queue and the VirtIO substream
  *          spinlocks to be held by caller.
  * Return: 0 on success, -errno on failure.
  */
-int virtsnd_pcm_msg_send(struct virtio_pcm_substream *vss)
+int virtsnd_pcm_msg_send(struct virtio_pcm_substream *vss, unsigned long offset,
+			 unsigned long bytes)
 {
-	struct snd_pcm_runtime *runtime = vss->substream->runtime;
 	struct virtio_snd *snd = vss->snd;
 	struct virtio_device *vdev = snd->vdev;
 	struct virtqueue *vqueue = virtsnd_pcm_queue(vss)->vqueue;
-	int i;
-	int n;
+	unsigned long period_bytes = snd_pcm_lib_period_bytes(vss->substream);
+	unsigned long start, end, i;
+	unsigned int msg_count = vss->msg_count;
 	bool notify = false;
+	int rc;
 
-	i = (vss->msg_last_enqueued + 1) % runtime->periods;
-	n = runtime->periods - vss->msg_count;
+	start = offset / period_bytes;
+	end = (offset + bytes - 1) / period_bytes;
 
-	for (; n; --n, i = (i + 1) % runtime->periods) {
+	for (i = start; i <= end; i++) {
 		struct virtio_pcm_msg *msg = vss->msgs[i];
 		struct scatterlist *psgs[] = {
 			&msg->sgs[PCM_MSG_SG_XFER],
 			&msg->sgs[PCM_MSG_SG_DATA],
 			&msg->sgs[PCM_MSG_SG_STATUS]
 		};
-		int rc;
-
-		msg->xfer.stream_id = cpu_to_le32(vss->sid);
-		memset(&msg->status, 0, sizeof(msg->status));
-
-		if (vss->direction == SNDRV_PCM_STREAM_PLAYBACK)
-			rc = virtqueue_add_sgs(vqueue, psgs, 2, 1, msg,
-					       GFP_ATOMIC);
-		else
-			rc = virtqueue_add_sgs(vqueue, psgs, 1, 2, msg,
-					       GFP_ATOMIC);
-
-		if (rc) {
-			dev_err(&vdev->dev,
-				"SID %u: failed to send I/O message\n",
-				vss->sid);
-			return rc;
+		unsigned long n;
+
+		n = period_bytes - (offset % period_bytes);
+		if (n > bytes)
+			n = bytes;
+
+		msg->length += n;
+		if (msg->length == period_bytes) {
+			msg->xfer.stream_id = cpu_to_le32(vss->sid);
+			memset(&msg->status, 0, sizeof(msg->status));
+
+			if (vss->direction == SNDRV_PCM_STREAM_PLAYBACK)
+				rc = virtqueue_add_sgs(vqueue, psgs, 2, 1, msg,
+						       GFP_ATOMIC);
+			else
+				rc = virtqueue_add_sgs(vqueue, psgs, 1, 2, msg,
+						       GFP_ATOMIC);
+
+			if (rc) {
+				dev_err(&vdev->dev,
+					"SID %u: failed to send I/O message\n",
+					vss->sid);
+				return rc;
+			}
+
+			vss->msg_count++;
 		}
 
-		vss->msg_last_enqueued = i;
-		vss->msg_count++;
+		offset = 0;
+		bytes -= n;
 	}
 
+	if (msg_count == vss->msg_count)
+		return 0;
+
 	if (!(vss->features & (1U << VIRTIO_SND_PCM_F_MSG_POLLING)))
 		notify = virtqueue_kick_prepare(vqueue);
 
@@ -309,6 +322,8 @@ static void virtsnd_pcm_msg_complete(struct virtio_pcm_msg *msg,
 	if (vss->hw_ptr >= vss->buffer_bytes)
 		vss->hw_ptr -= vss->buffer_bytes;
 
+	msg->length = 0;
+
 	vss->xfer_xrun = false;
 	vss->msg_count--;
 
@@ -320,8 +335,6 @@ static void virtsnd_pcm_msg_complete(struct virtio_pcm_msg *msg,
 					le32_to_cpu(msg->status.latency_bytes));
 
 		schedule_work(&vss->elapsed_period);
-
-		virtsnd_pcm_msg_send(vss);
 	} else if (!vss->msg_count) {
 		wake_up_all(&vss->msg_empty);
 	}