[RFC 04/13] net/ring: allow lockfree transmit if ring supports it

[Stephen Hemminger <stephen@networkplumber.org>]

Need to be able have multiple threads all using same
transmit queue when using SPAN.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 drivers/net/ring/rte_eth_ring.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/net/ring/rte_eth_ring.c b/drivers/net/ring/rte_eth_ring.c
index b1085bf390..966c64d9a5 100644
--- a/drivers/net/ring/rte_eth_ring.c
+++ b/drivers/net/ring/rte_eth_ring.c
@@ -177,6 +177,19 @@ eth_tx_queue_setup(struct rte_eth_dev *dev, uint16_t tx_queue_id,
 	return 0;
 }
 
+static bool
+eth_tx_queue_lockfree(const struct pmd_internals *internals)
+{
+	unsigned int i;
+
+	for (i = 0; i < internals->max_tx_queues; i++) {
+		const struct ring_queue *r = &internals->tx_ring_queues[i];
+
+		if (r->rng->flags & RING_F_SP_ENQ)
+			return false;
+	}
+	return true;
+}
 
 static int
 eth_dev_info(struct rte_eth_dev *dev,
@@ -189,6 +202,10 @@ eth_dev_info(struct rte_eth_dev *dev,
 	dev_info->max_rx_queues = (uint16_t)internals->max_rx_queues;
 	dev_info->rx_offload_capa = RTE_ETH_RX_OFFLOAD_SCATTER;
 	dev_info->tx_offload_capa = RTE_ETH_TX_OFFLOAD_MULTI_SEGS;
+
+	if (eth_tx_queue_lockfree(internals))
+		dev_info->tx_offload_capa |= RTE_ETH_TX_OFFLOAD_MT_LOCKFREE;
+
 	dev_info->max_tx_queues = (uint16_t)internals->max_tx_queues;
 	dev_info->min_rx_bufsize = 0;
 
-- 
2.47.2