rpmsg updates for v4.17

This transitions the rpmsg_trysend() code paths of SMD and GLINK to use
 non-sleeping locks, it reverts the overly optimistic handling of
 discovered SMD channels and fixes an issue in SMD where incoming
 messages races with the probing of a client driver.
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Merge tag 'rpmsg-v4.17' of git://github.com/andersson/remoteproc

Pull rpmsg updates from Bjorn Andersson:

 - transition the rpmsg_trysend() code paths of SMD and GLINK to use
   non-sleeping locks

 - revert the overly optimistic handling of discovered SMD channels

 - fix an issue in SMD where incoming messages race with the probing of
   a client driver

* tag 'rpmsg-v4.17' of git://github.com/andersson/remoteproc:
  rpmsg: smd: Use announce_create to process any receive work
  rpmsg: Only invoke announce_create for rpdev with endpoints
  rpmsg: smd: Fix container_of macros
  Revert "rpmsg: smd: Create device for all channels"
  rpmsg: glink: Use spinlock in tx path
  rpmsg: smd: Use spinlock in tx path
  rpmsg: smd: use put_device() if device_register fail
  rpmsg: glink: use put_device() if device_register fail

drivers/rpmsg/qcom_glink_native.c

@@ -113,7 +113,7 @@ struct qcom_glink {
 	spinlock_t rx_lock;
 	struct list_head rx_queue;
 
-	struct mutex tx_lock;
+	spinlock_t tx_lock;
 
 	spinlock_t idr_lock;
 	struct idr lcids;
@@ -288,15 +288,14 @@ static int qcom_glink_tx(struct qcom_glink *glink,
 			 const void *data, size_t dlen, bool wait)
 {
 	unsigned int tlen = hlen + dlen;
-	int ret;
+	unsigned long flags;
+	int ret = 0;
 
 	/* Reject packets that are too big */
 	if (tlen >= glink->tx_pipe->length)
 		return -EINVAL;
 
-	ret = mutex_lock_interruptible(&glink->tx_lock);
-	if (ret)
-		return ret;
+	spin_lock_irqsave(&glink->tx_lock, flags);
 
 	while (qcom_glink_tx_avail(glink) < tlen) {
 		if (!wait) {
@@ -304,7 +303,12 @@ static int qcom_glink_tx(struct qcom_glink *glink,
 			goto out;
 		}
 
+		/* Wait without holding the tx_lock */
+		spin_unlock_irqrestore(&glink->tx_lock, flags);
+
 		usleep_range(10000, 15000);
+
+		spin_lock_irqsave(&glink->tx_lock, flags);
 	}
 
 	qcom_glink_tx_write(glink, hdr, hlen, data, dlen);
@@ -313,7 +317,7 @@ static int qcom_glink_tx(struct qcom_glink *glink,
 	mbox_client_txdone(glink->mbox_chan, 0);
 
 out:
-	mutex_unlock(&glink->tx_lock);
+	spin_unlock_irqrestore(&glink->tx_lock, flags);
 
 	return ret;
 }
@@ -1567,7 +1571,7 @@ struct qcom_glink *qcom_glink_native_probe(struct device *dev,
 	glink->features = features;
 	glink->intentless = intentless;
 
-	mutex_init(&glink->tx_lock);
+	spin_lock_init(&glink->tx_lock);
 	spin_lock_init(&glink->rx_lock);
 	INIT_LIST_HEAD(&glink->rx_queue);
 	INIT_WORK(&glink->rx_work, qcom_glink_work);

drivers/rpmsg/qcom_glink_smem.c

@@ -217,6 +217,7 @@ struct qcom_glink *qcom_glink_smem_register(struct device *parent,
 	ret = device_register(dev);
 	if (ret) {
 		pr_err("failed to register glink edge\n");
+		put_device(dev);
 		return ERR_PTR(ret);
 	}
 
@@ -299,7 +300,7 @@ struct qcom_glink *qcom_glink_smem_register(struct device *parent,
 	return glink;
 
 err_put_dev:
-	put_device(dev);
+	device_unregister(dev);
 
 	return ERR_PTR(ret);
 }

drivers/rpmsg/qcom_smd.c

@@ -167,9 +167,9 @@ struct qcom_smd_endpoint {
 	struct qcom_smd_channel *qsch;
 };
 
-#define to_smd_device(_rpdev)	container_of(_rpdev, struct qcom_smd_device, rpdev)
+#define to_smd_device(r)	container_of(r, struct qcom_smd_device, rpdev)
 #define to_smd_edge(d)		container_of(d, struct qcom_smd_edge, dev)
-#define to_smd_endpoint(ept)	container_of(ept, struct qcom_smd_endpoint, ept)
+#define to_smd_endpoint(e)	container_of(e, struct qcom_smd_endpoint, ept)
 
 /**
  * struct qcom_smd_channel - smd channel struct
@@ -205,7 +205,7 @@ struct qcom_smd_channel {
 	struct smd_channel_info_pair *info;
 	struct smd_channel_info_word_pair *info_word;
 
-	struct mutex tx_lock;
+	spinlock_t tx_lock;
 	wait_queue_head_t fblockread_event;
 
 	void *tx_fifo;
@@ -729,6 +729,7 @@ static int __qcom_smd_send(struct qcom_smd_channel *channel, const void *data,
 {
 	__le32 hdr[5] = { cpu_to_le32(len), };
 	int tlen = sizeof(hdr) + len;
+	unsigned long flags;
 	int ret;
 
 	/* Word aligned channels only accept word size aligned data */
@@ -739,9 +740,11 @@ static int __qcom_smd_send(struct qcom_smd_channel *channel, const void *data,
 	if (tlen >= channel->fifo_size)
 		return -EINVAL;
 
-	ret = mutex_lock_interruptible(&channel->tx_lock);
-	if (ret)
-		return ret;
+	/* Highlight the fact that if we enter the loop below we might sleep */
+	if (wait)
+		might_sleep();
+
+	spin_lock_irqsave(&channel->tx_lock, flags);
 
 	while (qcom_smd_get_tx_avail(channel) < tlen &&
 	       channel->state == SMD_CHANNEL_OPENED) {
@@ -753,7 +756,7 @@ static int __qcom_smd_send(struct qcom_smd_channel *channel, const void *data,
 		SET_TX_CHANNEL_FLAG(channel, fBLOCKREADINTR, 0);
 
 		/* Wait without holding the tx_lock */
-		mutex_unlock(&channel->tx_lock);
+		spin_unlock_irqrestore(&channel->tx_lock, flags);
 
 		ret = wait_event_interruptible(channel->fblockread_event,
 				       qcom_smd_get_tx_avail(channel) >= tlen ||
@@ -761,9 +764,7 @@ static int __qcom_smd_send(struct qcom_smd_channel *channel, const void *data,
 		if (ret)
 			return ret;
 
-		ret = mutex_lock_interruptible(&channel->tx_lock);
-		if (ret)
-			return ret;
+		spin_lock_irqsave(&channel->tx_lock, flags);
 
 		SET_TX_CHANNEL_FLAG(channel, fBLOCKREADINTR, 1);
 	}
@@ -787,7 +788,7 @@ static int __qcom_smd_send(struct qcom_smd_channel *channel, const void *data,
 	qcom_smd_signal_channel(channel);
 
 out_unlock:
-	mutex_unlock(&channel->tx_lock);
+	spin_unlock_irqrestore(&channel->tx_lock, flags);
 
 	return ret;
 }
@@ -996,8 +997,26 @@ static struct device_node *qcom_smd_match_channel(struct device_node *edge_node,
 	return NULL;
 }
 
+static int qcom_smd_announce_create(struct rpmsg_device *rpdev)
+{
+	struct qcom_smd_endpoint *qept = to_smd_endpoint(rpdev->ept);
+	struct qcom_smd_channel *channel = qept->qsch;
+	unsigned long flags;
+	bool kick_state;
+
+	spin_lock_irqsave(&channel->recv_lock, flags);
+	kick_state = qcom_smd_channel_intr(channel);
+	spin_unlock_irqrestore(&channel->recv_lock, flags);
+
+	if (kick_state)
+		schedule_work(&channel->edge->state_work);
+
+	return 0;
+}
+
 static const struct rpmsg_device_ops qcom_smd_device_ops = {
 	.create_ept = qcom_smd_create_ept,
+	.announce_create = qcom_smd_announce_create,
 };
 
 static const struct rpmsg_endpoint_ops qcom_smd_endpoint_ops = {
@@ -1090,7 +1109,7 @@ static struct qcom_smd_channel *qcom_smd_create_channel(struct qcom_smd_edge *ed
 	if (!channel->name)
 		return ERR_PTR(-ENOMEM);
 
-	mutex_init(&channel->tx_lock);
+	spin_lock_init(&channel->tx_lock);
 	spin_lock_init(&channel->recv_lock);
 	init_waitqueue_head(&channel->fblockread_event);
 	init_waitqueue_head(&channel->state_change_event);
@@ -1234,6 +1253,11 @@ static void qcom_channel_state_worker(struct work_struct *work)
 		if (channel->state != SMD_CHANNEL_CLOSED)
 			continue;
 
+		remote_state = GET_RX_CHANNEL_INFO(channel, state);
+		if (remote_state != SMD_CHANNEL_OPENING &&
+		    remote_state != SMD_CHANNEL_OPENED)
+			continue;
+
 		if (channel->registered)
 			continue;
 
@@ -1408,6 +1432,7 @@ struct qcom_smd_edge *qcom_smd_register_edge(struct device *parent,
 	ret = device_register(&edge->dev);
 	if (ret) {
 		pr_err("failed to register smd edge\n");
+		put_device(&edge->dev);
 		return ERR_PTR(ret);
 	}
 
@@ -1428,7 +1453,7 @@ struct qcom_smd_edge *qcom_smd_register_edge(struct device *parent,
 	return edge;
 
 unregister_dev:
-	put_device(&edge->dev);
+	device_unregister(&edge->dev);
 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL(qcom_smd_register_edge);

drivers/rpmsg/rpmsg_core.c

@@ -442,7 +442,7 @@ static int rpmsg_dev_probe(struct device *dev)
 		goto out;
 	}
 
-	if (rpdev->ops->announce_create)
+	if (ept && rpdev->ops->announce_create)
 		err = rpdev->ops->announce_create(rpdev);
 out:
 	return err;