rpmsg: process _all_ pending messages in rpmsg_recv_done

Change virtqueue callback function rpmsg_recv_done() to process all
available messages instead of just one message.
Signed-off-by: Robert Tivy <rtivy@ti.com>
[split _recv function instead of adding indentation]
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>

drivers/rpmsg/virtio_rpmsg_bus.c

@@ -776,23 +776,13 @@ int rpmsg_send_offchannel_raw(struct rpmsg_channel *rpdev, u32 src, u32 dst,
 }
 EXPORT_SYMBOL(rpmsg_send_offchannel_raw);
 
-/* called when an rx buffer is used, and it's time to digest a message */
-static void rpmsg_recv_done(struct virtqueue *rvq)
+static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
+			     struct rpmsg_hdr *msg, unsigned int len)
 {
-	struct rpmsg_hdr *msg;
-	unsigned int len;
 	struct rpmsg_endpoint *ept;
 	struct scatterlist sg;
-	struct virtproc_info *vrp = rvq->vdev->priv;
-	struct device *dev = &rvq->vdev->dev;
 	int err;
 
-	msg = virtqueue_get_buf(rvq, &len);
-	if (!msg) {
-		dev_err(dev, "uhm, incoming signal, but no used buffer ?\n");
-		return;
-	}
-
 	dev_dbg(dev, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n",
 					msg->src, msg->dst, msg->len,
 					msg->flags, msg->reserved);
@@ -806,7 +796,7 @@ static void rpmsg_recv_done(struct virtqueue *rvq)
 	if (len > RPMSG_BUF_SIZE ||
 		msg->len > (len - sizeof(struct rpmsg_hdr))) {
 		dev_warn(dev, "inbound msg too big: (%d, %d)\n", len, msg->len);
-		return;
+		return -EINVAL;
 	}
 
 	/* use the dst addr to fetch the callback of the appropriate user */
@@ -842,11 +832,42 @@ static void rpmsg_recv_done(struct virtqueue *rvq)
 	err = virtqueue_add_buf(vrp->rvq, &sg, 0, 1, msg, GFP_KERNEL);
 	if (err < 0) {
 		dev_err(dev, "failed to add a virtqueue buffer: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+/* called when an rx buffer is used, and it's time to digest a message */
+static void rpmsg_recv_done(struct virtqueue *rvq)
+{
+	struct virtproc_info *vrp = rvq->vdev->priv;
+	struct device *dev = &rvq->vdev->dev;
+	struct rpmsg_hdr *msg;
+	unsigned int len, msgs_received = 0;
+	int err;
+
+	msg = virtqueue_get_buf(rvq, &len);
+	if (!msg) {
+		dev_err(dev, "uhm, incoming signal, but no used buffer ?\n");
 		return;
 	}
 
+	while (msg) {
+		err = rpmsg_recv_single(vrp, dev, msg, len);
+		if (err)
+			break;
+
+		msgs_received++;
+
+		msg = virtqueue_get_buf(rvq, &len);
+	};
+
+	dev_dbg(dev, "Received %u messages\n", msgs_received);
+
 	/* tell the remote processor we added another available rx buffer */
-	virtqueue_kick(vrp->rvq);
+	if (msgs_received)
+		virtqueue_kick(vrp->rvq);
 }
 
 /*