[RFC 11/18] net: macsec: report real_dev features when HW offloading is enabled

[Igor Russkikh <irusskikh@marvell.com>]

From: Mark Starovoytov <mstarovoitov@marvell.com>

This patch makes real_dev_feature propagation by MACSec offloaded device.

Issue description:
real_dev features are disabled upon macsec creation.

Root cause:
Features limitation (specific to SW MACSec limitation) is being applied
to HW offloaded case as well.
This causes 'set_features' request on the real_dev with reduced feature
set due to chain propagation.

Proposed solution:
Report real_dev features when HW offloading is enabled.
NB! MACSec offloaded device does not propagate VLAN offload features at
the moment. This can potentially be added later on as a separate patch.

Note: this patch requires HW offloading to be enabled by default in order
to function properly.

Signed-off-by: Mark Starovoytov <mstarovoitov@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
---
 drivers/net/macsec.c | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index 38403037cea0..a3d96fffa84f 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -2474,6 +2474,10 @@ static int macsec_upd_offload(struct sk_buff *skb, struct genl_info *info)
 		goto rollback;
 
 	rtnl_unlock();
+	/* Force features update, since they are different for SW MACSec and
+	 * HW offloading cases.
+	 */
+	netdev_update_features(dev);
 	return 0;
 
 rollback:
@@ -3234,9 +3238,16 @@ static netdev_tx_t macsec_start_xmit(struct sk_buff *skb,
 	return ret;
 }
 
-#define MACSEC_FEATURES \
+#define SW_MACSEC_FEATURES \
 	(NETIF_F_SG | NETIF_F_HIGHDMA | NETIF_F_FRAGLIST)
 
+/* If h/w offloading is enabled, use real device features save for
+ *   VLAN_FEATURES - they require additional ops
+ *   HW_MACSEC - no reason to report it
+ */
+#define REAL_DEV_FEATURES(dev) \
+	((dev)->features & ~(NETIF_F_VLAN_FEATURES | NETIF_F_HW_MACSEC))
+
 static int macsec_dev_init(struct net_device *dev)
 {
 	struct macsec_dev *macsec = macsec_priv(dev);
@@ -3253,8 +3264,12 @@ static int macsec_dev_init(struct net_device *dev)
 		return err;
 	}
 
-	dev->features = real_dev->features & MACSEC_FEATURES;
-	dev->features |= NETIF_F_LLTX | NETIF_F_GSO_SOFTWARE;
+	if (macsec_is_offloaded(macsec)) {
+		dev->features = REAL_DEV_FEATURES(real_dev);
+	} else {
+		dev->features = real_dev->features & SW_MACSEC_FEATURES;
+		dev->features |= NETIF_F_LLTX | NETIF_F_GSO_SOFTWARE;
+	}
 
 	dev->needed_headroom = real_dev->needed_headroom +
 			       MACSEC_NEEDED_HEADROOM;
@@ -3283,7 +3298,10 @@ static netdev_features_t macsec_fix_features(struct net_device *dev,
 	struct macsec_dev *macsec = macsec_priv(dev);
 	struct net_device *real_dev = macsec->real_dev;
 
-	features &= (real_dev->features & MACSEC_FEATURES) |
+	if (macsec_is_offloaded(macsec))
+		return REAL_DEV_FEATURES(real_dev);
+
+	features &= (real_dev->features & SW_MACSEC_FEATURES) |
 		    NETIF_F_GSO_SOFTWARE | NETIF_F_SOFT_FEATURES;
 	features |= NETIF_F_LLTX;
 
-- 
2.17.1