[PATCH v3 3/3] ethdev: Reject conflicting TX offloads configuration

[Morten Brørup]

When an ethdev port is configured for fast mbuf release, the driver can
use a TX burst function relying on the fast mbuf release preconditions.
Thus, also configuring this port or a queue on the port for transmitting
segmented packets is prohibited.
Checks for these conflicting configurations have been added to the ethdev
library, so the drivers don't have to implement them.

Signed-off-by: Morten Brørup <mb at smartsharesystems.com>
Acked-by: Bruce Richardson <bruce.richardson at intel.com>
Acked-by: Andrew Rybchenko <andrew.rybchenko at oktetlabs.ru>
Acked-by: Konstantin Ananyev <konstantin.ananyev at huawei.com>
---
v3:
* Shorten the added log messages. (Stephen Hemminger, Ivan Malov)
---
 lib/ethdev/rte_ethdev.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
index dd7c00bc94..00afda873f 100644
--- a/lib/ethdev/rte_ethdev.c
+++ b/lib/ethdev/rte_ethdev.c
@@ -1531,6 +1531,18 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q,
 		goto rollback;
 	}
 
+	/* MBUF_FAST_FREE preconditions conflict with MULTI_SEGS support. */
+	if ((dev_conf->txmode.offloads & RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE) &&
+	    (dev_conf->txmode.offloads & RTE_ETH_TX_OFFLOAD_MULTI_SEGS)) {
+		RTE_ETHDEV_LOG_LINE(ERR,
+			"id=%d offload clash, %s vs %s",
+			port_id,
+			rte_eth_dev_tx_offload_name(RTE_ETH_TX_OFFLOAD_MULTI_SEGS),
+			rte_eth_dev_tx_offload_name(RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE));
+		ret = -EINVAL;
+		goto rollback;
+	}
+
 	dev->data->dev_conf.rx_adv_conf.rss_conf.rss_hf =
 		rte_eth_rss_hf_refine(dev_conf->rx_adv_conf.rss_conf.rss_hf);
 
@@ -2709,6 +2721,31 @@ rte_eth_tx_queue_setup(uint16_t port_id, uint16_t tx_queue_id,
 		return -EINVAL;
 	}
 
+	/*
+	 * If the driver uses a Tx function with MBUF_FAST_FREE preconditions,
+	 * per-queue MULTI_SEGS support is not possible.
+	 */
+	if ((dev->data->dev_conf.txmode.offloads & RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE) &&
+			(local_conf.offloads & RTE_ETH_TX_OFFLOAD_MULTI_SEGS)) {
+		RTE_ETHDEV_LOG_LINE(ERR,
+			"id=%d txq=%d offload clash, per-queue %s vs per-port %s",
+			port_id, tx_queue_id,
+			rte_eth_dev_tx_offload_name(RTE_ETH_TX_OFFLOAD_MULTI_SEGS),
+			rte_eth_dev_tx_offload_name(RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE));
+		return -EINVAL;
+	}
+	/*
+	 * If the driver uses a Tx function with MULTI_SEGS support,
+	 * runtime support for per-queue MBUF_FAST_FREE optimization depends on the driver.
+	 */
+	if ((dev->data->dev_conf.txmode.offloads & RTE_ETH_TX_OFFLOAD_MULTI_SEGS) &&
+			(local_conf.offloads & RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE))
+		RTE_ETHDEV_LOG_LINE(DEBUG,
+			"id=%d txq=%d potential offload clash, per-queue %s vs per-port %s: PMD to decide",
+			port_id, tx_queue_id,
+			rte_eth_dev_tx_offload_name(RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE),
+			rte_eth_dev_tx_offload_name(RTE_ETH_TX_OFFLOAD_MULTI_SEGS));
+
 	rte_ethdev_trace_txq_setup(port_id, tx_queue_id, nb_tx_desc, tx_conf);
 	return eth_err(port_id, dev->dev_ops->tx_queue_setup(dev,
 		       tx_queue_id, nb_tx_desc, socket_id, &local_conf));
-- 
2.43.0