Merge branch 'netdev_features-start-cleaning-netdev_features_t-up'

Alexander Lobakin says:

====================
netdev_features: start cleaning netdev_features_t up

NETDEV_FEATURE_COUNT is currently 64, which means we can't add any new
features as netdev_features_t is u64.
As per several discussions, instead of converting netdev_features_t to
a bitmap, which would mean A LOT of changes, we can try cleaning up
netdev feature bits.
There's a bunch of bits which don't really mean features, rather device
attributes/properties that can't be changed via Ethtool in any of the
drivers. Such attributes can be moved to netdev private flags without
losing any functionality.

Start converting some read-only netdev features to private flags from
the ones that are most obvious, like lockless Tx, inability to change
network namespace etc. I was able to reduce NETDEV_FEATURE_COUNT from
64 to 60, which mean 4 free slots for new features. There are obviously
more read-only features to convert, such as highDMA, "challenged VLAN",
HSR (4 bits) - this will be done in subsequent series.

Please note that currently netdev features are not uAPI/ABI by any means.
Ethtool passes their names and bits to the userspace separately and there
are no hardcoded names/bits in the userspace, so that new Ethtool could
work on older kernels and vice versa.
This, however, isn't true for Ethtools < 3.4. I haven't changed the bit
positions of the already existing features and instead replaced the freed
bits with stubs. But it's anyway theoretically possible that Ethtools
older than 2011 will break. I hope no currently supported distros supply
such an ancient version.
Shell scripts also most likely won't break since the removed bits were
always read-only, meaning nobody would try touching them from a script.
====================

Link: https://patch.msgid.link/20240829123340.789395-1-aleksander.lobakin@intel.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: Paolo Abeni

Documentation/networking/net_cachelines/net_device.rst

@@ -7,6 +7,8 @@ net_device struct fast path usage breakdown
 
 Type                                Name                    fastpath_tx_access  fastpath_rx_access  Comments
 ..struct                            ..net_device                                                    
+unsigned_long:32                    priv_flags              read_mostly         -                   __dev_queue_xmit(tx)
+unsigned_long:1                     lltx                    read_mostly         -                   HARD_TX_LOCK,HARD_TX_TRYLOCK,HARD_TX_UNLOCK(tx)
 char                                name[16]                -                   -                   
 struct_netdev_name_node*            name_node                                                       
 struct_dev_ifalias*                 ifalias                                                         
@@ -23,7 +25,6 @@ struct_list_head                    ptype_specific
 struct                              adj_list                                                        
 unsigned_int                        flags                   read_mostly         read_mostly         __dev_queue_xmit,__dev_xmit_skb,ip6_output,__ip6_finish_output(tx);ip6_rcv_core(rx)
 xdp_features_t                      xdp_features                                                    
-unsigned_long_long                  priv_flags              read_mostly         -                   __dev_queue_xmit(tx)
 struct_net_device_ops*              netdev_ops              read_mostly         -                   netdev_core_pick_tx,netdev_start_xmit(tx)
 struct_xdp_metadata_ops*            xdp_metadata_ops                                                
 int                                 ifindex                 -                   read_mostly         ip6_rcv_core
@@ -163,6 +164,10 @@ struct_lock_class_key*              qdisc_tx_busylock
 bool                                proto_down                                                      
 unsigned:1                          wol_enabled                                                     
 unsigned:1                          threaded                -                   -                   napi_poll(napi_enable,dev_set_threaded)
+unsigned_long:1                     see_all_hwtstamp_requests                                       
+unsigned_long:1                     change_proto_down                                               
+unsigned_long:1                     netns_local                                                     
+unsigned_long:1                     fcoe_mtu                                                        
 struct_list_head                    net_notifier_list                                               
 struct_macsec_ops*                  macsec_ops                                                      
 struct_udp_tunnel_nic_info*         udp_tunnel_nic_info                                             

Documentation/networking/netdev-features.rst

@@ -139,21 +139,6 @@ chained skbs (skb->next/prev list).
 Features contained in NETIF_F_SOFT_FEATURES are features of networking
 stack. Driver should not change behaviour based on them.
 
- * LLTX driver (deprecated for hardware drivers)
-
-NETIF_F_LLTX is meant to be used by drivers that don't need locking at all,
-e.g. software tunnels.
-
-This is also used in a few legacy drivers that implement their
-own locking, don't use it for new (hardware) drivers.
-
- * netns-local device
-
-NETIF_F_NETNS_LOCAL is set for devices that are not allowed to move between
-network namespaces (e.g. loopback).
-
-Don't use it in drivers.
-
  * VLAN challenged
 
 NETIF_F_VLAN_CHALLENGED should be set for devices which can't cope with VLAN

Documentation/networking/netdevices.rst

@@ -258,11 +258,11 @@ ndo_get_stats:
 ndo_start_xmit:
 	Synchronization: __netif_tx_lock spinlock.
 
-	When the driver sets NETIF_F_LLTX in dev->features this will be
+	When the driver sets dev->lltx this will be
 	called without holding netif_tx_lock. In this case the driver
 	has to lock by itself when needed.
 	The locking there should also properly protect against
-	set_rx_mode. WARNING: use of NETIF_F_LLTX is deprecated.
+	set_rx_mode. WARNING: use of dev->lltx is deprecated.
 	Don't use it for new drivers.
 
 	Context: Process with BHs disabled or BH (timer),

Documentation/networking/switchdev.rst

@@ -137,10 +137,10 @@ would be sub-port 0 on port 1 on switch 1.
 Port Features
 ^^^^^^^^^^^^^
 
-NETIF_F_NETNS_LOCAL
+dev->netns_local
 
 If the switchdev driver (and device) only supports offloading of the default
-network namespace (netns), the driver should set this feature flag to prevent
+network namespace (netns), the driver should set this private flag to prevent
 the port netdev from being moved out of the default netns.  A netns-aware
 driver/device would not set this flag and be responsible for partitioning
 hardware to preserve netns containment.  This means hardware cannot forward

drivers/net/amt.c

@@ -3098,9 +3098,9 @@ static void amt_link_setup(struct net_device *dev)
 	dev->hard_header_len	= 0;
 	dev->addr_len		= 0;
 	dev->priv_flags		|= IFF_NO_QUEUE;
-	dev->features		|= NETIF_F_LLTX;
+	dev->lltx		= true;
+	dev->netns_local	= true;
 	dev->features		|= NETIF_F_GSO_SOFTWARE;
-	dev->features		|= NETIF_F_NETNS_LOCAL;
 	dev->hw_features	|= NETIF_F_SG | NETIF_F_HW_CSUM;
 	dev->hw_features	|= NETIF_F_FRAGLIST | NETIF_F_RXCSUM;
 	dev->hw_features	|= NETIF_F_GSO_SOFTWARE;

drivers/net/bareudp.c

@@ -553,7 +553,6 @@ static void bareudp_setup(struct net_device *dev)
 	SET_NETDEV_DEVTYPE(dev, &bareudp_type);
 	dev->features    |= NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_FRAGLIST;
 	dev->features    |= NETIF_F_RXCSUM;
-	dev->features    |= NETIF_F_LLTX;
 	dev->features    |= NETIF_F_GSO_SOFTWARE;
 	dev->hw_features |= NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_FRAGLIST;
 	dev->hw_features |= NETIF_F_RXCSUM;
@@ -566,6 +565,7 @@ static void bareudp_setup(struct net_device *dev)
 	dev->type = ARPHRD_NONE;
 	netif_keep_dst(dev);
 	dev->priv_flags |= IFF_NO_QUEUE;
+	dev->lltx = true;
 	dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
 }

drivers/net/bonding/bond_main.c

@@ -5928,7 +5928,10 @@ void bond_setup(struct net_device *bond_dev)
 #endif /* CONFIG_XFRM_OFFLOAD */
 
 	/* don't acquire bond device's netif_tx_lock when transmitting */
-	bond_dev->features |= NETIF_F_LLTX;
+	bond_dev->lltx = true;
+
+	/* Don't allow bond devices to change network namespaces. */
+	bond_dev->netns_local = true;
 
 	/* By default, we declare the bond to be fully
 	 * VLAN hardware accelerated capable. Special
@@ -5937,9 +5940,6 @@ void bond_setup(struct net_device *bond_dev)
 	 * capable
 	 */
 
-	/* Don't allow bond devices to change network namespaces. */
-	bond_dev->features |= NETIF_F_NETNS_LOCAL;
-
 	bond_dev->hw_features = BOND_VLAN_FEATURES |
 				NETIF_F_HW_VLAN_CTAG_RX |
 				NETIF_F_HW_VLAN_CTAG_FILTER |

drivers/net/dummy.c

@@ -109,9 +109,10 @@ static void dummy_setup(struct net_device *dev)
 	dev->flags |= IFF_NOARP;
 	dev->flags &= ~IFF_MULTICAST;
 	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE | IFF_NO_QUEUE;
+	dev->lltx = true;
 	dev->features	|= NETIF_F_SG | NETIF_F_FRAGLIST;
 	dev->features	|= NETIF_F_GSO_SOFTWARE;
-	dev->features	|= NETIF_F_HW_CSUM | NETIF_F_HIGHDMA | NETIF_F_LLTX;
+	dev->features	|= NETIF_F_HW_CSUM | NETIF_F_HIGHDMA;
 	dev->features	|= NETIF_F_GSO_ENCAP_ALL;
 	dev->hw_features |= dev->features;
 	dev->hw_enc_features |= dev->features;

drivers/net/ethernet/adi/adin1110.c

@@ -1599,7 +1599,7 @@ static int adin1110_probe_netdevs(struct adin1110_priv *priv)
 		netdev->netdev_ops = &adin1110_netdev_ops;
 		netdev->ethtool_ops = &adin1110_ethtool_ops;
 		netdev->priv_flags |= IFF_UNICAST_FLT;
-		netdev->features |= NETIF_F_NETNS_LOCAL;
+		netdev->netns_local = true;
 
 		port_priv->phydev = get_phy_device(priv->mii_bus, i + 1, false);
 		if (IS_ERR(port_priv->phydev)) {

drivers/net/ethernet/chelsio/cxgb/cxgb2.c

@@ -1034,7 +1034,8 @@ static int init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 		netdev->hw_features |= NETIF_F_SG | NETIF_F_IP_CSUM |
 			NETIF_F_RXCSUM;
 		netdev->features |= NETIF_F_SG | NETIF_F_IP_CSUM |
-			NETIF_F_RXCSUM | NETIF_F_LLTX | NETIF_F_HIGHDMA;
+			NETIF_F_RXCSUM | NETIF_F_HIGHDMA;
+		netdev->lltx = true;
 
 		if (vlan_tso_capable(adapter)) {
 			netdev->features |=