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, 413 insertions, 0 deletions

diff --git a/net/smc/smc_stats.c b/net/smc/smc_stats.c
new file mode 100644
index 000000000..e80e34f7a
--- /dev/null
+++ b/net/smc/smc_stats.c
@@ -0,0 +1,413 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Shared Memory Communications over RDMA (SMC-R) and RoCE
+ *
+ * SMC statistics netlink routines
+ *
+ * Copyright IBM Corp. 2021
+ *
+ * Author(s):  Guvenc Gulce
+ */
+#include <linux/init.h>
+#include <linux/mutex.h>
+#include <linux/percpu.h>
+#include <linux/ctype.h>
+#include <linux/smc.h>
+#include <net/genetlink.h>
+#include <net/sock.h>
+#include "smc_netlink.h"
+#include "smc_stats.h"
+
+int smc_stats_init(struct net *net)
+{
+	net->smc.fback_rsn = kzalloc(sizeof(*net->smc.fback_rsn), GFP_KERNEL);
+	if (!net->smc.fback_rsn)
+		goto err_fback;
+	net->smc.smc_stats = alloc_percpu(struct smc_stats);
+	if (!net->smc.smc_stats)
+		goto err_stats;
+	mutex_init(&net->smc.mutex_fback_rsn);
+	return 0;
+
+err_stats:
+	kfree(net->smc.fback_rsn);
+err_fback:
+	return -ENOMEM;
+}
+
+void smc_stats_exit(struct net *net)
+{
+	kfree(net->smc.fback_rsn);
+	if (net->smc.smc_stats)
+		free_percpu(net->smc.smc_stats);
+}
+
+static int smc_nl_fill_stats_rmb_data(struct sk_buff *skb,
+				      struct smc_stats *stats, int tech,
+				      int type)
+{
+	struct smc_stats_rmbcnt *stats_rmb_cnt;
+	struct nlattr *attrs;
+
+	if (type == SMC_NLA_STATS_T_TX_RMB_STATS)
+		stats_rmb_cnt = &stats->smc[tech].rmb_tx;
+	else
+		stats_rmb_cnt = &stats->smc[tech].rmb_rx;
+
+	attrs = nla_nest_start(skb, type);
+	if (!attrs)
+		goto errout;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_RMB_REUSE_CNT,
+			      stats_rmb_cnt->reuse_cnt,
+			      SMC_NLA_STATS_RMB_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_RMB_SIZE_SM_PEER_CNT,
+			      stats_rmb_cnt->buf_size_small_peer_cnt,
+			      SMC_NLA_STATS_RMB_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_RMB_SIZE_SM_CNT,
+			      stats_rmb_cnt->buf_size_small_cnt,
+			      SMC_NLA_STATS_RMB_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_RMB_FULL_PEER_CNT,
+			      stats_rmb_cnt->buf_full_peer_cnt,
+			      SMC_NLA_STATS_RMB_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_RMB_FULL_CNT,
+			      stats_rmb_cnt->buf_full_cnt,
+			      SMC_NLA_STATS_RMB_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_RMB_ALLOC_CNT,
+			      stats_rmb_cnt->alloc_cnt,
+			      SMC_NLA_STATS_RMB_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_RMB_DGRADE_CNT,
+			      stats_rmb_cnt->dgrade_cnt,
+			      SMC_NLA_STATS_RMB_PAD))
+		goto errattr;
+
+	nla_nest_end(skb, attrs);
+	return 0;
+
+errattr:
+	nla_nest_cancel(skb, attrs);
+errout:
+	return -EMSGSIZE;
+}
+
+static int smc_nl_fill_stats_bufsize_data(struct sk_buff *skb,
+					  struct smc_stats *stats, int tech,
+					  int type)
+{
+	struct smc_stats_memsize *stats_pload;
+	struct nlattr *attrs;
+
+	if (type == SMC_NLA_STATS_T_TXPLOAD_SIZE)
+		stats_pload = &stats->smc[tech].tx_pd;
+	else if (type == SMC_NLA_STATS_T_RXPLOAD_SIZE)
+		stats_pload = &stats->smc[tech].rx_pd;
+	else if (type == SMC_NLA_STATS_T_TX_RMB_SIZE)
+		stats_pload = &stats->smc[tech].tx_rmbsize;
+	else if (type == SMC_NLA_STATS_T_RX_RMB_SIZE)
+		stats_pload = &stats->smc[tech].rx_rmbsize;
+	else
+		goto errout;
+
+	attrs = nla_nest_start(skb, type);
+	if (!attrs)
+		goto errout;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_PLOAD_8K,
+			      stats_pload->buf[SMC_BUF_8K],
+			      SMC_NLA_STATS_PLOAD_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_PLOAD_16K,
+			      stats_pload->buf[SMC_BUF_16K],
+			      SMC_NLA_STATS_PLOAD_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_PLOAD_32K,
+			      stats_pload->buf[SMC_BUF_32K],
+			      SMC_NLA_STATS_PLOAD_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_PLOAD_64K,
+			      stats_pload->buf[SMC_BUF_64K],
+			      SMC_NLA_STATS_PLOAD_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_PLOAD_128K,
+			      stats_pload->buf[SMC_BUF_128K],
+			      SMC_NLA_STATS_PLOAD_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_PLOAD_256K,
+			      stats_pload->buf[SMC_BUF_256K],
+			      SMC_NLA_STATS_PLOAD_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_PLOAD_512K,
+			      stats_pload->buf[SMC_BUF_512K],
+			      SMC_NLA_STATS_PLOAD_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_PLOAD_1024K,
+			      stats_pload->buf[SMC_BUF_1024K],
+			      SMC_NLA_STATS_PLOAD_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_PLOAD_G_1024K,
+			      stats_pload->buf[SMC_BUF_G_1024K],
+			      SMC_NLA_STATS_PLOAD_PAD))
+		goto errattr;
+
+	nla_nest_end(skb, attrs);
+	return 0;
+
+errattr:
+	nla_nest_cancel(skb, attrs);
+errout:
+	return -EMSGSIZE;
+}
+
+static int smc_nl_fill_stats_tech_data(struct sk_buff *skb,
+				       struct smc_stats *stats, int tech)
+{
+	struct smc_stats_tech *smc_tech;
+	struct nlattr *attrs;
+
+	smc_tech = &stats->smc[tech];
+	if (tech == SMC_TYPE_D)
+		attrs = nla_nest_start(skb, SMC_NLA_STATS_SMCD_TECH);
+	else
+		attrs = nla_nest_start(skb, SMC_NLA_STATS_SMCR_TECH);
+
+	if (!attrs)
+		goto errout;
+	if (smc_nl_fill_stats_rmb_data(skb, stats, tech,
+				       SMC_NLA_STATS_T_TX_RMB_STATS))
+		goto errattr;
+	if (smc_nl_fill_stats_rmb_data(skb, stats, tech,
+				       SMC_NLA_STATS_T_RX_RMB_STATS))
+		goto errattr;
+	if (smc_nl_fill_stats_bufsize_data(skb, stats, tech,
+					   SMC_NLA_STATS_T_TXPLOAD_SIZE))
+		goto errattr;
+	if (smc_nl_fill_stats_bufsize_data(skb, stats, tech,
+					   SMC_NLA_STATS_T_RXPLOAD_SIZE))
+		goto errattr;
+	if (smc_nl_fill_stats_bufsize_data(skb, stats, tech,
+					   SMC_NLA_STATS_T_TX_RMB_SIZE))
+		goto errattr;
+	if (smc_nl_fill_stats_bufsize_data(skb, stats, tech,
+					   SMC_NLA_STATS_T_RX_RMB_SIZE))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_T_CLNT_V1_SUCC,
+			      smc_tech->clnt_v1_succ_cnt,
+			      SMC_NLA_STATS_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_T_CLNT_V2_SUCC,
+			      smc_tech->clnt_v2_succ_cnt,
+			      SMC_NLA_STATS_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_T_SRV_V1_SUCC,
+			      smc_tech->srv_v1_succ_cnt,
+			      SMC_NLA_STATS_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_T_SRV_V2_SUCC,
+			      smc_tech->srv_v2_succ_cnt,
+			      SMC_NLA_STATS_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_T_RX_BYTES,
+			      smc_tech->rx_bytes,
+			      SMC_NLA_STATS_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_T_TX_BYTES,
+			      smc_tech->tx_bytes,
+			      SMC_NLA_STATS_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_T_RX_CNT,
+			      smc_tech->rx_cnt,
+			      SMC_NLA_STATS_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_T_TX_CNT,
+			      smc_tech->tx_cnt,
+			      SMC_NLA_STATS_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_T_SENDPAGE_CNT,
+			      smc_tech->sendpage_cnt,
+			      SMC_NLA_STATS_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_T_CORK_CNT,
+			      smc_tech->cork_cnt,
+			      SMC_NLA_STATS_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_T_NDLY_CNT,
+			      smc_tech->ndly_cnt,
+			      SMC_NLA_STATS_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_T_SPLICE_CNT,
+			      smc_tech->splice_cnt,
+			      SMC_NLA_STATS_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_T_URG_DATA_CNT,
+			      smc_tech->urg_data_cnt,
+			      SMC_NLA_STATS_PAD))
+		goto errattr;
+
+	nla_nest_end(skb, attrs);
+	return 0;
+
+errattr:
+	nla_nest_cancel(skb, attrs);
+errout:
+	return -EMSGSIZE;
+}
+
+int smc_nl_get_stats(struct sk_buff *skb,
+		     struct netlink_callback *cb)
+{
+	struct smc_nl_dmp_ctx *cb_ctx = smc_nl_dmp_ctx(cb);
+	struct net *net = sock_net(skb->sk);
+	struct smc_stats *stats;
+	struct nlattr *attrs;
+	int cpu, i, size;
+	void *nlh;
+	u64 *src;
+	u64 *sum;
+
+	if (cb_ctx->pos[0])
+		goto errmsg;
+	nlh = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
+			  &smc_gen_nl_family, NLM_F_MULTI,
+			  SMC_NETLINK_GET_STATS);
+	if (!nlh)
+		goto errmsg;
+
+	attrs = nla_nest_start(skb, SMC_GEN_STATS);
+	if (!attrs)
+		goto errnest;
+	stats = kzalloc(sizeof(*stats), GFP_KERNEL);
+	if (!stats)
+		goto erralloc;
+	size = sizeof(*stats) / sizeof(u64);
+	for_each_possible_cpu(cpu) {
+		src = (u64 *)per_cpu_ptr(net->smc.smc_stats, cpu);
+		sum = (u64 *)stats;
+		for (i = 0; i < size; i++)
+			*(sum++) += *(src++);
+	}
+	if (smc_nl_fill_stats_tech_data(skb, stats, SMC_TYPE_D))
+		goto errattr;
+	if (smc_nl_fill_stats_tech_data(skb, stats, SMC_TYPE_R))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_CLNT_HS_ERR_CNT,
+			      stats->clnt_hshake_err_cnt,
+			      SMC_NLA_STATS_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_STATS_SRV_HS_ERR_CNT,
+			      stats->srv_hshake_err_cnt,
+			      SMC_NLA_STATS_PAD))
+		goto errattr;
+
+	nla_nest_end(skb, attrs);
+	genlmsg_end(skb, nlh);
+	cb_ctx->pos[0] = 1;
+	kfree(stats);
+	return skb->len;
+
+errattr:
+	kfree(stats);
+erralloc:
+	nla_nest_cancel(skb, attrs);
+errnest:
+	genlmsg_cancel(skb, nlh);
+errmsg:
+	return skb->len;
+}
+
+static int smc_nl_get_fback_details(struct sk_buff *skb,
+				    struct netlink_callback *cb, int pos,
+				    bool is_srv)
+{
+	struct smc_nl_dmp_ctx *cb_ctx = smc_nl_dmp_ctx(cb);
+	struct net *net = sock_net(skb->sk);
+	int cnt_reported = cb_ctx->pos[2];
+	struct smc_stats_fback *trgt_arr;
+	struct nlattr *attrs;
+	int rc = 0;
+	void *nlh;
+
+	if (is_srv)
+		trgt_arr = &net->smc.fback_rsn->srv[0];
+	else
+		trgt_arr = &net->smc.fback_rsn->clnt[0];
+	if (!trgt_arr[pos].fback_code)
+		return -ENODATA;
+	nlh = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
+			  &smc_gen_nl_family, NLM_F_MULTI,
+			  SMC_NETLINK_GET_FBACK_STATS);
+	if (!nlh)
+		goto errmsg;
+	attrs = nla_nest_start(skb, SMC_GEN_FBACK_STATS);
+	if (!attrs)
+		goto errout;
+	if (nla_put_u8(skb, SMC_NLA_FBACK_STATS_TYPE, is_srv))
+		goto errattr;
+	if (!cnt_reported) {
+		if (nla_put_u64_64bit(skb, SMC_NLA_FBACK_STATS_SRV_CNT,
+				      net->smc.fback_rsn->srv_fback_cnt,
+				      SMC_NLA_FBACK_STATS_PAD))
+			goto errattr;
+		if (nla_put_u64_64bit(skb, SMC_NLA_FBACK_STATS_CLNT_CNT,
+				      net->smc.fback_rsn->clnt_fback_cnt,
+				      SMC_NLA_FBACK_STATS_PAD))
+			goto errattr;
+		cnt_reported = 1;
+	}
+
+	if (nla_put_u32(skb, SMC_NLA_FBACK_STATS_RSN_CODE,
+			trgt_arr[pos].fback_code))
+		goto errattr;
+	if (nla_put_u16(skb, SMC_NLA_FBACK_STATS_RSN_CNT,
+			trgt_arr[pos].count))
+		goto errattr;
+
+	cb_ctx->pos[2] = cnt_reported;
+	nla_nest_end(skb, attrs);
+	genlmsg_end(skb, nlh);
+	return rc;
+
+errattr:
+	nla_nest_cancel(skb, attrs);
+errout:
+	genlmsg_cancel(skb, nlh);
+errmsg:
+	return -EMSGSIZE;
+}
+
+int smc_nl_get_fback_stats(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct smc_nl_dmp_ctx *cb_ctx = smc_nl_dmp_ctx(cb);
+	struct net *net = sock_net(skb->sk);
+	int rc_srv = 0, rc_clnt = 0, k;
+	int skip_serv = cb_ctx->pos[1];
+	int snum = cb_ctx->pos[0];
+	bool is_srv = true;
+
+	mutex_lock(&net->smc.mutex_fback_rsn);
+	for (k = 0; k < SMC_MAX_FBACK_RSN_CNT; k++) {
+		if (k < snum)
+			continue;
+		if (!skip_serv) {
+			rc_srv = smc_nl_get_fback_details(skb, cb, k, is_srv);
+			if (rc_srv && rc_srv != -ENODATA)
+				break;
+		} else {
+			skip_serv = 0;
+		}
+		rc_clnt = smc_nl_get_fback_details(skb, cb, k, !is_srv);
+		if (rc_clnt && rc_clnt != -ENODATA) {
+			skip_serv = 1;
+			break;
+		}
+		if (rc_clnt == -ENODATA && rc_srv == -ENODATA)
+			break;
+	}
+	mutex_unlock(&net->smc.mutex_fback_rsn);
+	cb_ctx->pos[1] = skip_serv;
+	cb_ctx->pos[0] = k;
+	return skb->len;
+}