[RFC 4/4] ethdev: omit MAC address restore if not required

[Dariusz Sosnowski <dsosnowski@nvidia.com>]

This patch adds a new device flag - RTE_ETH_DEV_MAC_ADDR_FORCE_RESTORE.
If device driver sets this flag, then it requires that ethdev library
forcefully reapplies configured MAC addresses,
after the port is started.
As a result, unnecessary work can be removed from rte_eth_dev_start()
for drivers which apply all available configuration in dev_start()
(such drivers do not the set the flag).

If RFC is approved, then the next version of this patch
should set the new flag for all drivers to maintain the same behavior,
until drivers adjust and it can be safely cleared.

Signed-off-by: Dariusz Sosnowski <dsosnowski@nvidia.com>
---
 lib/ethdev/rte_ethdev.c | 3 ++-
 lib/ethdev/rte_ethdev.h | 6 ++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
index a08922a78a..e4bb40cad8 100644
--- a/lib/ethdev/rte_ethdev.c
+++ b/lib/ethdev/rte_ethdev.c
@@ -1723,7 +1723,8 @@ eth_dev_config_restore(struct rte_eth_dev *dev,
 {
 	int ret;
 
-	if (!(*dev_info->dev_flags & RTE_ETH_DEV_NOLIVE_MAC_ADDR))
+	if ((*dev_info->dev_flags & RTE_ETH_DEV_MAC_ADDR_FORCE_RESTORE) &&
+	    !(*dev_info->dev_flags & RTE_ETH_DEV_NOLIVE_MAC_ADDR))
 		eth_dev_mac_restore(dev, dev_info);
 
 	if (*dev_info->dev_flags & RTE_ETH_DEV_PROMISC_FORCE_RESTORE) {
diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h
index 73405dd17d..deab07fbc0 100644
--- a/lib/ethdev/rte_ethdev.h
+++ b/lib/ethdev/rte_ethdev.h
@@ -2132,6 +2132,12 @@ struct rte_eth_dev_owner {
  * after driver's dev_start() callback is called.
  */
 #define RTE_ETH_DEV_ALLMULTI_FORCE_RESTORE RTE_BIT32(8)
+/**
+ * If this flag is set, then device driver requires that
+ * ethdev library forcefully reapplies active MAC addresses,
+ * after driver's dev_start() callback is called.
+ */
+#define RTE_ETH_DEV_MAC_ADDR_FORCE_RESTORE RTE_BIT32(9)
 /**@}*/
 
 /**
-- 
2.39.5