bond: Disable TLS features indication

Bond agnostically interacts with TLS device-offload requests via the
.ndo_sk_get_lower_dev operation. Return value is true iff bond
guarantees fixed mapping between the TLS connection and a lower netdev.

Due to this nature, the bond TLS device offload features are not
explicitly controllable in the bond layer. As of today, these are
read-only values based on the evaluation of bond_sk_check().  However,
this indication might be incorrect and misleading, when the feature bits
are "fixed" by some dependency features.  For example,
NETIF_F_HW_TLS_TX/RX are forcefully cleared in case the corresponding
checksum offload is disabled. But in fact the bond ability to still
offload TLS connections to the lower device is not hurt.

This means that these bits can not be trusted, and hence better become
unused.

This patch revives some old discussion [1] and proposes a much simpler
solution: Clear the bond's TLS features bits. Everyone should stop
reading them.

[1] https://lore.kernel.org/netdev/20210526095747.22446-1-tariqt@nvidia.com/Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Gal Pressman <gal@nvidia.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20221025105300.4718-1-tariqt@nvidia.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/bonding/bond_main.c

@@ -307,7 +307,7 @@ netdev_tx_t bond_dev_queue_xmit(struct bonding *bond, struct sk_buff *skb,
 	return dev_queue_xmit(skb);
 }
 
-bool bond_sk_check(struct bonding *bond)
+static bool bond_sk_check(struct bonding *bond)
 {
 	switch (BOND_MODE(bond)) {
 	case BOND_MODE_8023AD:
@@ -1398,13 +1398,6 @@ static netdev_features_t bond_fix_features(struct net_device *dev,
 	netdev_features_t mask;
 	struct slave *slave;
 
-#if IS_ENABLED(CONFIG_TLS_DEVICE)
-	if (bond_sk_check(bond))
-		features |= BOND_TLS_FEATURES;
-	else
-		features &= ~BOND_TLS_FEATURES;
-#endif
-
 	mask = features;
 
 	features &= ~NETIF_F_ONE_FOR_ALL;
@@ -5806,10 +5799,6 @@ void bond_setup(struct net_device *bond_dev)
 	if (BOND_MODE(bond) == BOND_MODE_ACTIVEBACKUP)
 		bond_dev->features |= BOND_XFRM_FEATURES;
 #endif /* CONFIG_XFRM_OFFLOAD */
-#if IS_ENABLED(CONFIG_TLS_DEVICE)
-	if (bond_sk_check(bond))
-		bond_dev->features |= BOND_TLS_FEATURES;
-#endif
 }
 
 /* Destroy a bonding device.

drivers/net/bonding/bond_options.c

@@ -842,19 +842,6 @@ static bool bond_set_xfrm_features(struct bonding *bond)
 	return true;
 }
 
-static bool bond_set_tls_features(struct bonding *bond)
-{
-	if (!IS_ENABLED(CONFIG_TLS_DEVICE))
-		return false;
-
-	if (bond_sk_check(bond))
-		bond->dev->wanted_features |= BOND_TLS_FEATURES;
-	else
-		bond->dev->wanted_features &= ~BOND_TLS_FEATURES;
-
-	return true;
-}
-
 static int bond_option_mode_set(struct bonding *bond,
 				const struct bond_opt_value *newval)
 {
@@ -885,7 +872,6 @@ static int bond_option_mode_set(struct bonding *bond,
 		bool update = false;
 
 		update |= bond_set_xfrm_features(bond);
-		update |= bond_set_tls_features(bond);
 
 		if (update)
 			netdev_update_features(bond->dev);
@@ -1418,10 +1404,6 @@ static int bond_option_xmit_hash_policy_set(struct bonding *bond,
 		   newval->string, newval->value);
 	bond->params.xmit_policy = newval->value;
 
-	if (bond->dev->reg_state == NETREG_REGISTERED)
-		if (bond_set_tls_features(bond))
-			netdev_update_features(bond->dev);
-
 	return 0;
 }
 

include/net/bonding.h

@@ -92,8 +92,6 @@
 #define BOND_XFRM_FEATURES (NETIF_F_HW_ESP | NETIF_F_HW_ESP_TX_CSUM | \
 			    NETIF_F_GSO_ESP)
 
-#define BOND_TLS_FEATURES (NETIF_F_HW_TLS_TX | NETIF_F_HW_TLS_RX)
-
 #ifdef CONFIG_NET_POLL_CONTROLLER
 extern atomic_t netpoll_block_tx;
 
@@ -280,8 +278,6 @@ struct bond_vlan_tag {
 	unsigned short	vlan_id;
 };
 
-bool bond_sk_check(struct bonding *bond);
-
 /**
  * Returns NULL if the net_device does not belong to any of the bond's slaves
  *