Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 409 insertions, 0 deletions

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
new file mode 100644
index 000000000..046b5f7d8
--- /dev/null
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
@@ -0,0 +1,409 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2013-2018, The Linux Foundation. All rights reserved.
+ *
+ * RMNET Data virtual network driver
+ */
+
+#include <linux/etherdevice.h>
+#include <linux/ethtool.h>
+#include <linux/if_arp.h>
+#include <net/pkt_sched.h>
+#include "rmnet_config.h"
+#include "rmnet_handlers.h"
+#include "rmnet_private.h"
+#include "rmnet_map.h"
+#include "rmnet_vnd.h"
+
+/* RX/TX Fixup */
+
+void rmnet_vnd_rx_fixup(struct sk_buff *skb, struct net_device *dev)
+{
+	struct rmnet_priv *priv = netdev_priv(dev);
+	struct rmnet_pcpu_stats *pcpu_ptr;
+
+	pcpu_ptr = this_cpu_ptr(priv->pcpu_stats);
+
+	u64_stats_update_begin(&pcpu_ptr->syncp);
+	pcpu_ptr->stats.rx_pkts++;
+	pcpu_ptr->stats.rx_bytes += skb->len;
+	u64_stats_update_end(&pcpu_ptr->syncp);
+}
+
+void rmnet_vnd_tx_fixup_len(unsigned int len, struct net_device *dev)
+{
+	struct rmnet_priv *priv = netdev_priv(dev);
+	struct rmnet_pcpu_stats *pcpu_ptr;
+
+	pcpu_ptr = this_cpu_ptr(priv->pcpu_stats);
+
+	u64_stats_update_begin(&pcpu_ptr->syncp);
+	pcpu_ptr->stats.tx_pkts++;
+	pcpu_ptr->stats.tx_bytes += len;
+	u64_stats_update_end(&pcpu_ptr->syncp);
+}
+
+void rmnet_vnd_tx_fixup(struct sk_buff *skb, struct net_device *dev)
+{
+	rmnet_vnd_tx_fixup_len(skb->len, dev);
+}
+
+/* Network Device Operations */
+
+static netdev_tx_t rmnet_vnd_start_xmit(struct sk_buff *skb,
+					struct net_device *dev)
+{
+	struct rmnet_priv *priv;
+
+	priv = netdev_priv(dev);
+	if (priv->real_dev) {
+		rmnet_egress_handler(skb);
+	} else {
+		this_cpu_inc(priv->pcpu_stats->stats.tx_drops);
+		kfree_skb(skb);
+	}
+	return NETDEV_TX_OK;
+}
+
+static int rmnet_vnd_headroom(struct rmnet_port *port)
+{
+	u32 headroom;
+
+	headroom = sizeof(struct rmnet_map_header);
+
+	if (port->data_format & RMNET_FLAGS_EGRESS_MAP_CKSUMV4)
+		headroom += sizeof(struct rmnet_map_ul_csum_header);
+
+	return headroom;
+}
+
+static int rmnet_vnd_change_mtu(struct net_device *rmnet_dev, int new_mtu)
+{
+	struct rmnet_priv *priv = netdev_priv(rmnet_dev);
+	struct rmnet_port *port;
+	u32 headroom;
+
+	port = rmnet_get_port_rtnl(priv->real_dev);
+
+	headroom = rmnet_vnd_headroom(port);
+
+	if (new_mtu < 0 || new_mtu > RMNET_MAX_PACKET_SIZE ||
+	    new_mtu > (priv->real_dev->mtu - headroom))
+		return -EINVAL;
+
+	rmnet_dev->mtu = new_mtu;
+	return 0;
+}
+
+static int rmnet_vnd_get_iflink(const struct net_device *dev)
+{
+	struct rmnet_priv *priv = netdev_priv(dev);
+
+	return priv->real_dev->ifindex;
+}
+
+static int rmnet_vnd_init(struct net_device *dev)
+{
+	struct rmnet_priv *priv = netdev_priv(dev);
+	int err;
+
+	priv->pcpu_stats = alloc_percpu(struct rmnet_pcpu_stats);
+	if (!priv->pcpu_stats)
+		return -ENOMEM;
+
+	err = gro_cells_init(&priv->gro_cells, dev);
+	if (err) {
+		free_percpu(priv->pcpu_stats);
+		return err;
+	}
+
+	return 0;
+}
+
+static void rmnet_vnd_uninit(struct net_device *dev)
+{
+	struct rmnet_priv *priv = netdev_priv(dev);
+
+	gro_cells_destroy(&priv->gro_cells);
+	free_percpu(priv->pcpu_stats);
+}
+
+static void rmnet_get_stats64(struct net_device *dev,
+			      struct rtnl_link_stats64 *s)
+{
+	struct rmnet_priv *priv = netdev_priv(dev);
+	struct rmnet_vnd_stats total_stats = { };
+	struct rmnet_pcpu_stats *pcpu_ptr;
+	struct rmnet_vnd_stats snapshot;
+	unsigned int cpu, start;
+
+	for_each_possible_cpu(cpu) {
+		pcpu_ptr = per_cpu_ptr(priv->pcpu_stats, cpu);
+
+		do {
+			start = u64_stats_fetch_begin(&pcpu_ptr->syncp);
+			snapshot = pcpu_ptr->stats;	/* struct assignment */
+		} while (u64_stats_fetch_retry(&pcpu_ptr->syncp, start));
+
+		total_stats.rx_pkts += snapshot.rx_pkts;
+		total_stats.rx_bytes += snapshot.rx_bytes;
+		total_stats.tx_pkts += snapshot.tx_pkts;
+		total_stats.tx_bytes += snapshot.tx_bytes;
+		total_stats.tx_drops += snapshot.tx_drops;
+	}
+
+	s->rx_packets = total_stats.rx_pkts;
+	s->rx_bytes = total_stats.rx_bytes;
+	s->tx_packets = total_stats.tx_pkts;
+	s->tx_bytes = total_stats.tx_bytes;
+	s->tx_dropped = total_stats.tx_drops;
+}
+
+static const struct net_device_ops rmnet_vnd_ops = {
+	.ndo_start_xmit = rmnet_vnd_start_xmit,
+	.ndo_change_mtu = rmnet_vnd_change_mtu,
+	.ndo_get_iflink = rmnet_vnd_get_iflink,
+	.ndo_add_slave  = rmnet_add_bridge,
+	.ndo_del_slave  = rmnet_del_bridge,
+	.ndo_init       = rmnet_vnd_init,
+	.ndo_uninit     = rmnet_vnd_uninit,
+	.ndo_get_stats64 = rmnet_get_stats64,
+};
+
+static const char rmnet_gstrings_stats[][ETH_GSTRING_LEN] = {
+	"Checksum ok",
+	"Bad IPv4 header checksum",
+	"Checksum valid bit not set",
+	"Checksum validation failed",
+	"Checksum error bad buffer",
+	"Checksum error bad ip version",
+	"Checksum error bad transport",
+	"Checksum skipped on ip fragment",
+	"Checksum skipped",
+	"Checksum computed in software",
+	"Checksum computed in hardware",
+};
+
+static void rmnet_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
+{
+	switch (stringset) {
+	case ETH_SS_STATS:
+		memcpy(buf, &rmnet_gstrings_stats,
+		       sizeof(rmnet_gstrings_stats));
+		break;
+	}
+}
+
+static int rmnet_get_sset_count(struct net_device *dev, int sset)
+{
+	switch (sset) {
+	case ETH_SS_STATS:
+		return ARRAY_SIZE(rmnet_gstrings_stats);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static void rmnet_get_ethtool_stats(struct net_device *dev,
+				    struct ethtool_stats *stats, u64 *data)
+{
+	struct rmnet_priv *priv = netdev_priv(dev);
+	struct rmnet_priv_stats *st = &priv->stats;
+
+	if (!data)
+		return;
+
+	memcpy(data, st, ARRAY_SIZE(rmnet_gstrings_stats) * sizeof(u64));
+}
+
+static int rmnet_get_coalesce(struct net_device *dev,
+			      struct ethtool_coalesce *coal,
+			      struct kernel_ethtool_coalesce *kernel_coal,
+			      struct netlink_ext_ack *extack)
+{
+	struct rmnet_priv *priv = netdev_priv(dev);
+	struct rmnet_port *port;
+
+	port = rmnet_get_port_rtnl(priv->real_dev);
+
+	memset(kernel_coal, 0, sizeof(*kernel_coal));
+	kernel_coal->tx_aggr_max_bytes = port->egress_agg_params.bytes;
+	kernel_coal->tx_aggr_max_frames = port->egress_agg_params.count;
+	kernel_coal->tx_aggr_time_usecs = div_u64(port->egress_agg_params.time_nsec,
+						  NSEC_PER_USEC);
+
+	return 0;
+}
+
+static int rmnet_set_coalesce(struct net_device *dev,
+			      struct ethtool_coalesce *coal,
+			      struct kernel_ethtool_coalesce *kernel_coal,
+			      struct netlink_ext_ack *extack)
+{
+	struct rmnet_priv *priv = netdev_priv(dev);
+	struct rmnet_port *port;
+
+	port = rmnet_get_port_rtnl(priv->real_dev);
+
+	if (kernel_coal->tx_aggr_max_frames < 1 || kernel_coal->tx_aggr_max_frames > 64)
+		return -EINVAL;
+
+	if (kernel_coal->tx_aggr_max_bytes > 32768)
+		return -EINVAL;
+
+	rmnet_map_update_ul_agg_config(port, kernel_coal->tx_aggr_max_bytes,
+				       kernel_coal->tx_aggr_max_frames,
+				       kernel_coal->tx_aggr_time_usecs);
+
+	return 0;
+}
+
+static const struct ethtool_ops rmnet_ethtool_ops = {
+	.supported_coalesce_params = ETHTOOL_COALESCE_TX_AGGR,
+	.get_coalesce = rmnet_get_coalesce,
+	.set_coalesce = rmnet_set_coalesce,
+	.get_ethtool_stats = rmnet_get_ethtool_stats,
+	.get_strings = rmnet_get_strings,
+	.get_sset_count = rmnet_get_sset_count,
+};
+
+/* Called by kernel whenever a new rmnet<n> device is created. Sets MTU,
+ * flags, ARP type, needed headroom, etc...
+ */
+void rmnet_vnd_setup(struct net_device *rmnet_dev)
+{
+	rmnet_dev->netdev_ops = &rmnet_vnd_ops;
+	rmnet_dev->mtu = RMNET_DFLT_PACKET_SIZE;
+	rmnet_dev->needed_headroom = RMNET_NEEDED_HEADROOM;
+	eth_hw_addr_random(rmnet_dev);
+	rmnet_dev->tx_queue_len = RMNET_TX_QUEUE_LEN;
+
+	/* Raw IP mode */
+	rmnet_dev->header_ops = NULL;  /* No header */
+	rmnet_dev->type = ARPHRD_RAWIP;
+	rmnet_dev->hard_header_len = 0;
+	rmnet_dev->flags &= ~(IFF_BROADCAST | IFF_MULTICAST);
+
+	rmnet_dev->needs_free_netdev = true;
+	rmnet_dev->ethtool_ops = &rmnet_ethtool_ops;
+
+	rmnet_dev->features |= NETIF_F_LLTX;
+
+	/* This perm addr will be used as interface identifier by IPv6 */
+	rmnet_dev->addr_assign_type = NET_ADDR_RANDOM;
+	eth_random_addr(rmnet_dev->perm_addr);
+}
+
+/* Exposed API */
+
+int rmnet_vnd_newlink(u8 id, struct net_device *rmnet_dev,
+		      struct rmnet_port *port,
+		      struct net_device *real_dev,
+		      struct rmnet_endpoint *ep,
+		      struct netlink_ext_ack *extack)
+
+{
+	struct rmnet_priv *priv = netdev_priv(rmnet_dev);
+	u32 headroom;
+	int rc;
+
+	if (rmnet_get_endpoint(port, id)) {
+		NL_SET_ERR_MSG_MOD(extack, "MUX ID already exists");
+		return -EBUSY;
+	}
+
+	rmnet_dev->hw_features = NETIF_F_RXCSUM;
+	rmnet_dev->hw_features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
+	rmnet_dev->hw_features |= NETIF_F_SG;
+
+	priv->real_dev = real_dev;
+
+	headroom = rmnet_vnd_headroom(port);
+
+	if (rmnet_vnd_change_mtu(rmnet_dev, real_dev->mtu - headroom)) {
+		NL_SET_ERR_MSG_MOD(extack, "Invalid MTU on real dev");
+		return -EINVAL;
+	}
+
+	rc = register_netdevice(rmnet_dev);
+	if (!rc) {
+		ep->egress_dev = rmnet_dev;
+		ep->mux_id = id;
+		port->nr_rmnet_devs++;
+
+		rmnet_dev->rtnl_link_ops = &rmnet_link_ops;
+
+		priv->mux_id = id;
+
+		netdev_dbg(rmnet_dev, "rmnet dev created\n");
+	}
+
+	return rc;
+}
+
+int rmnet_vnd_dellink(u8 id, struct rmnet_port *port,
+		      struct rmnet_endpoint *ep)
+{
+	if (id >= RMNET_MAX_LOGICAL_EP || !ep->egress_dev)
+		return -EINVAL;
+
+	ep->egress_dev = NULL;
+	port->nr_rmnet_devs--;
+	return 0;
+}
+
+int rmnet_vnd_do_flow_control(struct net_device *rmnet_dev, int enable)
+{
+	netdev_dbg(rmnet_dev, "Setting VND TX queue state to %d\n", enable);
+	/* Although we expect similar number of enable/disable
+	 * commands, optimize for the disable. That is more
+	 * latency sensitive than enable
+	 */
+	if (unlikely(enable))
+		netif_wake_queue(rmnet_dev);
+	else
+		netif_stop_queue(rmnet_dev);
+
+	return 0;
+}
+
+int rmnet_vnd_validate_real_dev_mtu(struct net_device *real_dev)
+{
+	struct hlist_node *tmp_ep;
+	struct rmnet_endpoint *ep;
+	struct rmnet_port *port;
+	unsigned long bkt_ep;
+	u32 headroom;
+
+	port = rmnet_get_port_rtnl(real_dev);
+
+	headroom = rmnet_vnd_headroom(port);
+
+	hash_for_each_safe(port->muxed_ep, bkt_ep, tmp_ep, ep, hlnode) {
+		if (ep->egress_dev->mtu > (real_dev->mtu - headroom))
+			return -1;
+	}
+
+	return 0;
+}
+
+int rmnet_vnd_update_dev_mtu(struct rmnet_port *port,
+			     struct net_device *real_dev)
+{
+	struct hlist_node *tmp_ep;
+	struct rmnet_endpoint *ep;
+	unsigned long bkt_ep;
+	u32 headroom;
+
+	headroom = rmnet_vnd_headroom(port);
+
+	hash_for_each_safe(port->muxed_ep, bkt_ep, tmp_ep, ep, hlnode) {
+		if (ep->egress_dev->mtu <= (real_dev->mtu - headroom))
+			continue;
+
+		if (rmnet_vnd_change_mtu(ep->egress_dev,
+					 real_dev->mtu - headroom))
+			return -1;
+	}
+
+	return 0;
+}