[PATCH net-next 1/2] NTB: ntb_transport: Add per-payload client metadata

@@ -123,7 +123,7 @@ static void ntb_netdev_event_handler(void *data, int link_is_up)
 }
 
 static void ntb_netdev_rx_handler(struct ntb_transport_qp *qp, void *qp_data,
-				  void *data, int len)
+				  void *data, int len, unsigned int meta)
 {
 	struct ntb_netdev_queue *q = qp_data;
 	struct ntb_netdev *dev = q->ntdev;

@@ -258,7 +258,7 @@ static netdev_tx_t ntb_netdev_start_xmit(struct sk_buff *skb,
 
 	ntb_netdev_maybe_stop_tx(ndev, q, tx_stop);
 
-	rc = ntb_transport_tx_enqueue(q->qp, skb, skb->data, skb->len);
+	rc = ntb_transport_tx_enqueue(q->qp, skb, skb->data, skb->len, 0);
 	if (rc)
 		goto err;
 

@@ -167,7 +167,7 @@ struct ntb_transport_qp {
 	unsigned int tx_max_frame;
 
 	void (*rx_handler)(struct ntb_transport_qp *qp, void *qp_data,
-			   void *data, int len);
+			   void *data, int len, unsigned int meta);
 	struct list_head rx_post_q;
 	struct list_head rx_pend_q;
 	struct list_head rx_free_q;

@@ -264,6 +264,10 @@ enum {
 	LINK_DOWN_FLAG = BIT(1),
 };
 
+/* Reserve the low byte for transport flags. */
+#define DESC_META_SHIFT		8
+#define DESC_META_MASK		(~0U << DESC_META_SHIFT)
+
 struct ntb_payload_header {
 	unsigned int ver;
 	unsigned int len;

@@ -1435,6 +1439,7 @@ static void ntb_complete_rxc(struct ntb_transport_qp *qp)
 	struct ntb_queue_entry *entry;
 	void *cb_data;
 	unsigned int len;
+	unsigned int meta;
 	unsigned long irqflags;
 
 	spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);

@@ -1450,13 +1455,14 @@ static void ntb_complete_rxc(struct ntb_transport_qp *qp)
 
 		cb_data = entry->cb_data;
 		len = entry->len;
+		meta = entry->flags >> DESC_META_SHIFT;
 
 		list_move_tail(&entry->entry, &qp->rx_free_q);
 
 		spin_unlock_irqrestore(&qp->ntb_rx_q_lock, irqflags);
 
 		if (qp->rx_handler && qp->client_ready)
-			qp->rx_handler(qp, qp->cb_data, cb_data, len);
+			qp->rx_handler(qp, qp->cb_data, cb_data, len, meta);
 
 		spin_lock_irqsave(&qp->ntb_rx_q_lock, irqflags);
 	}

@@ -1647,6 +1653,7 @@ static int ntb_process_rxc(struct ntb_transport_qp *qp)
 
 	entry->rx_hdr = hdr;
 	entry->rx_index = qp->rx_index;
+	entry->flags = hdr->flags & DESC_META_MASK;
 
 	if (hdr->len > entry->len) {
 		dev_dbg(&qp->ndev->pdev->dev,

@@ -2332,6 +2339,7 @@ EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
  * @cb: per buffer pointer for callback function to use
  * @data: pointer to data buffer that will be sent
  * @len: length of the data buffer
+ * @meta: client metadata to send with the buffer
  *
  * Enqueue a new transmit buffer onto the transport queue from which a NTB
  * payload will be transmitted.  This assumes that a lock is being held to

@@ -2340,12 +2348,12 @@ EXPORT_SYMBOL_GPL(ntb_transport_rx_enqueue);
  * RETURNS: An appropriate -ERRNO error value on error, or zero for success.
  */
 int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
-			     unsigned int len)
+			     unsigned int len, unsigned int meta)
 {
 	struct ntb_queue_entry *entry;
 	int rc;
 
-	if (!qp || !len)
+	if (!qp || !len || meta > NTB_TRANSPORT_MAX_META)
 		return -EINVAL;
 
 	/* If the qp link is down already, just ignore. */

@@ -2361,7 +2369,7 @@ int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
 	entry->cb_data = cb;
 	entry->buf = data;
 	entry->len = len;
-	entry->flags = 0;
+	entry->flags = meta << DESC_META_SHIFT;
 	entry->errors = 0;
 	entry->tx_index = 0;
 

@@ -50,6 +50,8 @@
 
 struct ntb_transport_qp;
 
+#define NTB_TRANSPORT_MAX_META	0x00ffffffU
+
 struct ntb_transport_client {
 	struct device_driver driver;
 	int (*probe)(struct device *client_dev);

@@ -63,7 +65,7 @@ void ntb_transport_unregister_client_dev(char *device_name);
 
 struct ntb_queue_handlers {
 	void (*rx_handler)(struct ntb_transport_qp *qp, void *qp_data,
-			   void *data, int len);
+			   void *data, int len, unsigned int meta);
 	void (*tx_handler)(struct ntb_transport_qp *qp, void *qp_data,
 			   void *data, int len);
 	void (*event_handler)(void *data, int status);

@@ -78,7 +80,7 @@ void ntb_transport_free_queue(struct ntb_transport_qp *qp);
 int ntb_transport_rx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
 			     unsigned int len);
 int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data,
-			     unsigned int len);
+			     unsigned int len, unsigned int meta);
 void *ntb_transport_rx_remove(struct ntb_transport_qp *qp, unsigned int *len);
 void ntb_transport_link_up(struct ntb_transport_qp *qp);
 void ntb_transport_link_down(struct ntb_transport_qp *qp);