Subject: [RFC net-next 1/2] net: dsa: allow taggers to customise netdev features

From: DENG Qingfang <[email-masked]>
Date: Wed, 25 Aug 2021 16:38:30 +0800

Allow taggers to add netdev features, such as VLAN offload, to slave
devices, which will make it possible for taggers to handle VLAN tags
themselves.

Signed-off-by: DENG Qingfang <[email-masked]>
---
 include/net/dsa.h | 2 ++
 net/dsa/slave.c   | 3 ++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index f9a17145255a..f65442858f71 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -96,6 +96,8 @@ struct dsa_device_ops {
 	 * its RX filter.
 	 */
 	bool promisc_on_master;
+	/* Additional features to be applied to the slave. */
+	netdev_features_t features;
 };
 
 /* This structure defines the control interfaces that are overlayed by the
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 662ff531d4e2..6d6f1aebf1ca 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -1885,7 +1885,8 @@ void dsa_slave_setup_tagger(struct net_device *slave)
 
 	p->xmit = cpu_dp->tag_ops->xmit;
 
-	slave->features = master->vlan_features | NETIF_F_HW_TC;
+	slave->features = master->vlan_features | cpu_dp->tag_ops->features |
+			  NETIF_F_HW_TC;
 	slave->hw_features |= NETIF_F_HW_TC;
 	slave->features |= NETIF_F_LLTX;
 	if (slave->needed_tailroom)
-- 
2.25.1