[PATCH 1/2] net/i40e: preserve RSS RETA across port stop and start

[Ciara Loftus]

Currently, updating the RSS redirection table and then stopping and
starting a port loses the update. The port comes back with the default
table. The ethdev API requires RSS settings to be retained across
stop/start.

The `rss_reta_updated` flag protects a user-provided RETA from being
overwritten by the default table when the device is started. However
`i40e_dev_stop()` clears this flag, so a subsequent `i40e_dev_start()`
treats the RETA as untouched and resets it to the default.

Fix it by clearing `rss_reta_updated` in `i40e_dev_configure()` instead of
`i40e_dev_stop()`. A reconfiguration still reverts to the default table,
while a plain stop/start now preserves the RETA.

Bugzilla ID: 1127

Fixes: 36c5dc8e5d3c ("net/i40e: fix overwriting RSS RETA")
Cc: stable at dpdk.org

Signed-off-by: Ciara Loftus <ciara.loftus at intel.com>
---
 drivers/net/intel/i40e/i40e_ethdev.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/intel/i40e/i40e_ethdev.c b/drivers/net/intel/i40e/i40e_ethdev.c
index b6b2d291ee..3de3423634 100644
--- a/drivers/net/intel/i40e/i40e_ethdev.c
+++ b/drivers/net/intel/i40e/i40e_ethdev.c
@@ -1992,6 +1992,9 @@ i40e_dev_configure(struct rte_eth_dev *dev)
 	if (dev->data->dev_conf.rxmode.mq_mode & RTE_ETH_MQ_RX_RSS_FLAG)
 		dev->data->dev_conf.rxmode.offloads |= RTE_ETH_RX_OFFLOAD_RSS_HASH;
 
+	/* A new configuration reverts the RETA to the driver default. */
+	pf->adapter->rss_reta_updated = 0;
+
 	ret = i40e_dev_init_vlan(dev);
 	if (ret < 0)
 		goto err;
@@ -2676,8 +2679,6 @@ i40e_dev_stop(struct rte_eth_dev *dev)
 	hw->adapter_stopped = 1;
 	dev->data->dev_started = 0;
 
-	pf->adapter->rss_reta_updated = 0;
-
 	return 0;
 }
 
-- 
2.43.0