[PATCH 19.11 3/4] net/ena: advertise scattered Rx capability

[Michal Krawczyk]

[ upstream commit e2a6d08bef489215ebb77b1d3033875ada757cfa ]

ENA can't be forced to always pass single descriptor for the Rx packet.
Even if the passed buffer size is big enough to hold the data, we can't
make assumption that the HW won't use extra descriptor because of
internal optimizations. This assumption may be true, but only for some
of the FW revisions, which may differ depending on the used AWS instance
type.

As the scattered Rx support on the Rx path already exists, the driver
just needs to announce DEV_RX_OFFLOAD_SCATTER capability by turning on
the rte_eth_dev_data::scattered_rx option.

Fixes: 1173fca25af9 ("ena: add polling-mode driver")
Cc: stable at dpdk.org

Signed-off-by: Michal Krawczyk <mk at semihalf.com>
Reviewed-by: Igor Chauskin <igorch at amazon.com>
Reviewed-by: Shai Brandes <shaibran at amazon.com>
---
 drivers/net/ena/ena_ethdev.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/ena/ena_ethdev.c b/drivers/net/ena/ena_ethdev.c
index 5f15d55d4..62c15f3c9 100644
--- a/drivers/net/ena/ena_ethdev.c
+++ b/drivers/net/ena/ena_ethdev.c
@@ -1937,8 +1937,14 @@ static int ena_dev_configure(struct rte_eth_dev *dev)
 
 	dev->data->dev_conf.txmode.offloads |= DEV_TX_OFFLOAD_MULTI_SEGS;
 
+	/* Scattered Rx cannot be turned off in the HW, so this capability must
+	 * be forced.
+	 */
+	dev->data->scattered_rx = 1;
+
 	adapter->tx_selected_offloads = dev->data->dev_conf.txmode.offloads;
 	adapter->rx_selected_offloads = dev->data->dev_conf.rxmode.offloads;
+
 	return 0;
 }
 
@@ -1985,6 +1991,7 @@ static uint64_t ena_get_rx_port_offloads(struct ena_adapter *adapter)
 		port_offloads |= DEV_RX_OFFLOAD_RSS_HASH;
 
 	port_offloads |= DEV_RX_OFFLOAD_JUMBO_FRAME;
+	port_offloads |= DEV_RX_OFFLOAD_SCATTER;
 
 	return port_offloads;
 }
-- 
2.25.1