net/netvsc: split send buffers from Tx descriptors

[ upstream commit cc02518 ]

The VMBus has reserved transmit area (per device) and transmit
descriptors (per queue). The previous code was always having a 1:1
mapping between send buffers and descriptors.
This can lead to one queue starving another and also buffer bloat.

Change to working more like FreeBSD where there is a pool of transmit
descriptors per queue. If send buffer is not available then no
aggregation happens but the queue can still drain.

Fixes: 4e9c73e ("net/netvsc: add Hyper-V network device")

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

drivers/net/netvsc/hn_ethdev.c

@@ -240,6 +240,9 @@ static void hn_dev_info_get(struct rte_eth_dev *dev,
 	dev_info->max_rx_queues = hv->max_queues;
 	dev_info->max_tx_queues = hv->max_queues;
 
+	dev_info->tx_desc_lim.nb_min = 1;
+	dev_info->tx_desc_lim.nb_max = 4096;
+
 	if (rte_eal_process_type() != RTE_PROC_PRIMARY)
 		return;
 
@@ -776,7 +779,7 @@ eth_hn_dev_init(struct rte_eth_dev *eth_dev)
 	if  (err)
 		goto failed;
 
-	err = hn_tx_pool_init(eth_dev);
+	err = hn_chim_init(eth_dev);
 	if (err)
 		goto failed;
 
@@ -812,7 +815,7 @@ eth_hn_dev_init(struct rte_eth_dev *eth_dev)
 failed:
 	PMD_INIT_LOG(NOTICE, "device init failed");
 
-	hn_tx_pool_uninit(eth_dev);
+	hn_chim_uninit(eth_dev);
 	hn_detach(hv);
 	return err;
 }
@@ -835,7 +838,7 @@ eth_hn_dev_uninit(struct rte_eth_dev *eth_dev)
 	eth_dev->rx_pkt_burst = NULL;
 
 	hn_detach(hv);
-	hn_tx_pool_uninit(eth_dev);
+	hn_chim_uninit(eth_dev);
 	rte_vmbus_chan_close(hv->primary->chan);
 	rte_free(hv->primary);
 	rte_eth_dev_owner_delete(hv->owner.id);