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, 644 insertions, 0 deletions

diff --git a/drivers/acpi/acpi_ipmi.c b/drivers/acpi/acpi_ipmi.c
new file mode 100644
index 000000000..0555f68c2
--- /dev/null
+++ b/drivers/acpi/acpi_ipmi.c
@@ -0,0 +1,644 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  acpi_ipmi.c - ACPI IPMI opregion
+ *
+ *  Copyright (C) 2010, 2013 Intel Corporation
+ *    Author: Zhao Yakui <yakui.zhao@intel.com>
+ *            Lv Zheng <lv.zheng@intel.com>
+ */
+
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <linux/ipmi.h>
+#include <linux/spinlock.h>
+
+MODULE_AUTHOR("Zhao Yakui");
+MODULE_DESCRIPTION("ACPI IPMI Opregion driver");
+MODULE_LICENSE("GPL");
+
+#define ACPI_IPMI_OK			0
+#define ACPI_IPMI_TIMEOUT		0x10
+#define ACPI_IPMI_UNKNOWN		0x07
+/* the IPMI timeout is 5s */
+#define IPMI_TIMEOUT			(5000)
+#define ACPI_IPMI_MAX_MSG_LENGTH	64
+
+struct acpi_ipmi_device {
+	/* the device list attached to driver_data.ipmi_devices */
+	struct list_head head;
+
+	/* the IPMI request message list */
+	struct list_head tx_msg_list;
+
+	spinlock_t tx_msg_lock;
+	acpi_handle handle;
+	struct device *dev;
+	struct ipmi_user *user_interface;
+	int ipmi_ifnum; /* IPMI interface number */
+	long curr_msgid;
+	bool dead;
+	struct kref kref;
+};
+
+struct ipmi_driver_data {
+	struct list_head ipmi_devices;
+	struct ipmi_smi_watcher bmc_events;
+	const struct ipmi_user_hndl ipmi_hndlrs;
+	struct mutex ipmi_lock;
+
+	/*
+	 * NOTE: IPMI System Interface Selection
+	 * There is no system interface specified by the IPMI operation
+	 * region access.  We try to select one system interface with ACPI
+	 * handle set.  IPMI messages passed from the ACPI codes are sent
+	 * to this selected global IPMI system interface.
+	 */
+	struct acpi_ipmi_device *selected_smi;
+};
+
+struct acpi_ipmi_msg {
+	struct list_head head;
+
+	/*
+	 * General speaking the addr type should be SI_ADDR_TYPE. And
+	 * the addr channel should be BMC.
+	 * In fact it can also be IPMB type. But we will have to
+	 * parse it from the Netfn command buffer. It is so complex
+	 * that it is skipped.
+	 */
+	struct ipmi_addr addr;
+	long tx_msgid;
+
+	/* it is used to track whether the IPMI message is finished */
+	struct completion tx_complete;
+
+	struct kernel_ipmi_msg tx_message;
+	int msg_done;
+
+	/* tx/rx data . And copy it from/to ACPI object buffer */
+	u8 data[ACPI_IPMI_MAX_MSG_LENGTH];
+	u8 rx_len;
+
+	struct acpi_ipmi_device *device;
+	struct kref kref;
+};
+
+/* IPMI request/response buffer per ACPI 4.0, sec 5.5.2.4.3.2 */
+struct acpi_ipmi_buffer {
+	u8 status;
+	u8 length;
+	u8 data[ACPI_IPMI_MAX_MSG_LENGTH];
+};
+
+static void ipmi_register_bmc(int iface, struct device *dev);
+static void ipmi_bmc_gone(int iface);
+static void ipmi_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data);
+
+static struct ipmi_driver_data driver_data = {
+	.ipmi_devices = LIST_HEAD_INIT(driver_data.ipmi_devices),
+	.bmc_events = {
+		.owner = THIS_MODULE,
+		.new_smi = ipmi_register_bmc,
+		.smi_gone = ipmi_bmc_gone,
+	},
+	.ipmi_hndlrs = {
+		.ipmi_recv_hndl = ipmi_msg_handler,
+	},
+	.ipmi_lock = __MUTEX_INITIALIZER(driver_data.ipmi_lock)
+};
+
+static struct acpi_ipmi_device *
+ipmi_dev_alloc(int iface, struct device *dev, acpi_handle handle)
+{
+	struct acpi_ipmi_device *ipmi_device;
+	int err;
+	struct ipmi_user *user;
+
+	ipmi_device = kzalloc(sizeof(*ipmi_device), GFP_KERNEL);
+	if (!ipmi_device)
+		return NULL;
+
+	kref_init(&ipmi_device->kref);
+	INIT_LIST_HEAD(&ipmi_device->head);
+	INIT_LIST_HEAD(&ipmi_device->tx_msg_list);
+	spin_lock_init(&ipmi_device->tx_msg_lock);
+	ipmi_device->handle = handle;
+	ipmi_device->dev = get_device(dev);
+	ipmi_device->ipmi_ifnum = iface;
+
+	err = ipmi_create_user(iface, &driver_data.ipmi_hndlrs,
+			       ipmi_device, &user);
+	if (err) {
+		put_device(dev);
+		kfree(ipmi_device);
+		return NULL;
+	}
+	ipmi_device->user_interface = user;
+
+	return ipmi_device;
+}
+
+static void ipmi_dev_release(struct acpi_ipmi_device *ipmi_device)
+{
+	ipmi_destroy_user(ipmi_device->user_interface);
+	put_device(ipmi_device->dev);
+	kfree(ipmi_device);
+}
+
+static void ipmi_dev_release_kref(struct kref *kref)
+{
+	struct acpi_ipmi_device *ipmi =
+		container_of(kref, struct acpi_ipmi_device, kref);
+
+	ipmi_dev_release(ipmi);
+}
+
+static void __ipmi_dev_kill(struct acpi_ipmi_device *ipmi_device)
+{
+	list_del(&ipmi_device->head);
+	if (driver_data.selected_smi == ipmi_device)
+		driver_data.selected_smi = NULL;
+
+	/*
+	 * Always setting dead flag after deleting from the list or
+	 * list_for_each_entry() codes must get changed.
+	 */
+	ipmi_device->dead = true;
+}
+
+static struct acpi_ipmi_device *acpi_ipmi_dev_get(void)
+{
+	struct acpi_ipmi_device *ipmi_device = NULL;
+
+	mutex_lock(&driver_data.ipmi_lock);
+	if (driver_data.selected_smi) {
+		ipmi_device = driver_data.selected_smi;
+		kref_get(&ipmi_device->kref);
+	}
+	mutex_unlock(&driver_data.ipmi_lock);
+
+	return ipmi_device;
+}
+
+static void acpi_ipmi_dev_put(struct acpi_ipmi_device *ipmi_device)
+{
+	kref_put(&ipmi_device->kref, ipmi_dev_release_kref);
+}
+
+static struct acpi_ipmi_msg *ipmi_msg_alloc(void)
+{
+	struct acpi_ipmi_device *ipmi;
+	struct acpi_ipmi_msg *ipmi_msg;
+
+	ipmi = acpi_ipmi_dev_get();
+	if (!ipmi)
+		return NULL;
+
+	ipmi_msg = kzalloc(sizeof(struct acpi_ipmi_msg), GFP_KERNEL);
+	if (!ipmi_msg) {
+		acpi_ipmi_dev_put(ipmi);
+		return NULL;
+	}
+
+	kref_init(&ipmi_msg->kref);
+	init_completion(&ipmi_msg->tx_complete);
+	INIT_LIST_HEAD(&ipmi_msg->head);
+	ipmi_msg->device = ipmi;
+	ipmi_msg->msg_done = ACPI_IPMI_UNKNOWN;
+
+	return ipmi_msg;
+}
+
+static void ipmi_msg_release(struct acpi_ipmi_msg *tx_msg)
+{
+	acpi_ipmi_dev_put(tx_msg->device);
+	kfree(tx_msg);
+}
+
+static void ipmi_msg_release_kref(struct kref *kref)
+{
+	struct acpi_ipmi_msg *tx_msg =
+		container_of(kref, struct acpi_ipmi_msg, kref);
+
+	ipmi_msg_release(tx_msg);
+}
+
+static struct acpi_ipmi_msg *acpi_ipmi_msg_get(struct acpi_ipmi_msg *tx_msg)
+{
+	kref_get(&tx_msg->kref);
+
+	return tx_msg;
+}
+
+static void acpi_ipmi_msg_put(struct acpi_ipmi_msg *tx_msg)
+{
+	kref_put(&tx_msg->kref, ipmi_msg_release_kref);
+}
+
+#define IPMI_OP_RGN_NETFN(offset)	((offset >> 8) & 0xff)
+#define IPMI_OP_RGN_CMD(offset)		(offset & 0xff)
+static int acpi_format_ipmi_request(struct acpi_ipmi_msg *tx_msg,
+				    acpi_physical_address address,
+				    acpi_integer *value)
+{
+	struct kernel_ipmi_msg *msg;
+	struct acpi_ipmi_buffer *buffer;
+	struct acpi_ipmi_device *device;
+	unsigned long flags;
+
+	msg = &tx_msg->tx_message;
+
+	/*
+	 * IPMI network function and command are encoded in the address
+	 * within the IPMI OpRegion; see ACPI 4.0, sec 5.5.2.4.3.
+	 */
+	msg->netfn = IPMI_OP_RGN_NETFN(address);
+	msg->cmd = IPMI_OP_RGN_CMD(address);
+	msg->data = tx_msg->data;
+
+	/*
+	 * value is the parameter passed by the IPMI opregion space handler.
+	 * It points to the IPMI request message buffer
+	 */
+	buffer = (struct acpi_ipmi_buffer *)value;
+
+	/* copy the tx message data */
+	if (buffer->length > ACPI_IPMI_MAX_MSG_LENGTH) {
+		dev_WARN_ONCE(tx_msg->device->dev, true,
+			      "Unexpected request (msg len %d).\n",
+			      buffer->length);
+		return -EINVAL;
+	}
+	msg->data_len = buffer->length;
+	memcpy(tx_msg->data, buffer->data, msg->data_len);
+
+	/*
+	 * now the default type is SYSTEM_INTERFACE and channel type is BMC.
+	 * If the netfn is APP_REQUEST and the cmd is SEND_MESSAGE,
+	 * the addr type should be changed to IPMB. Then we will have to parse
+	 * the IPMI request message buffer to get the IPMB address.
+	 * If so, please fix me.
+	 */
+	tx_msg->addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
+	tx_msg->addr.channel = IPMI_BMC_CHANNEL;
+	tx_msg->addr.data[0] = 0;
+
+	/* Get the msgid */
+	device = tx_msg->device;
+
+	spin_lock_irqsave(&device->tx_msg_lock, flags);
+	device->curr_msgid++;
+	tx_msg->tx_msgid = device->curr_msgid;
+	spin_unlock_irqrestore(&device->tx_msg_lock, flags);
+
+	return 0;
+}
+
+static void acpi_format_ipmi_response(struct acpi_ipmi_msg *msg,
+				      acpi_integer *value)
+{
+	struct acpi_ipmi_buffer *buffer;
+
+	/*
+	 * value is also used as output parameter. It represents the response
+	 * IPMI message returned by IPMI command.
+	 */
+	buffer = (struct acpi_ipmi_buffer *)value;
+
+	/*
+	 * If the flag of msg_done is not set, it means that the IPMI command is
+	 * not executed correctly.
+	 */
+	buffer->status = msg->msg_done;
+	if (msg->msg_done != ACPI_IPMI_OK)
+		return;
+
+	/*
+	 * If the IPMI response message is obtained correctly, the status code
+	 * will be ACPI_IPMI_OK
+	 */
+	buffer->length = msg->rx_len;
+	memcpy(buffer->data, msg->data, msg->rx_len);
+}
+
+static void ipmi_flush_tx_msg(struct acpi_ipmi_device *ipmi)
+{
+	struct acpi_ipmi_msg *tx_msg;
+	unsigned long flags;
+
+	/*
+	 * NOTE: On-going ipmi_recv_msg
+	 * ipmi_msg_handler() may still be invoked by ipmi_si after
+	 * flushing.  But it is safe to do a fast flushing on module_exit()
+	 * without waiting for all ipmi_recv_msg(s) to complete from
+	 * ipmi_msg_handler() as it is ensured by ipmi_si that all
+	 * ipmi_recv_msg(s) are freed after invoking ipmi_destroy_user().
+	 */
+	spin_lock_irqsave(&ipmi->tx_msg_lock, flags);
+	while (!list_empty(&ipmi->tx_msg_list)) {
+		tx_msg = list_first_entry(&ipmi->tx_msg_list,
+					  struct acpi_ipmi_msg,
+					  head);
+		list_del(&tx_msg->head);
+		spin_unlock_irqrestore(&ipmi->tx_msg_lock, flags);
+
+		/* wake up the sleep thread on the Tx msg */
+		complete(&tx_msg->tx_complete);
+		acpi_ipmi_msg_put(tx_msg);
+		spin_lock_irqsave(&ipmi->tx_msg_lock, flags);
+	}
+	spin_unlock_irqrestore(&ipmi->tx_msg_lock, flags);
+}
+
+static void ipmi_cancel_tx_msg(struct acpi_ipmi_device *ipmi,
+			       struct acpi_ipmi_msg *msg)
+{
+	struct acpi_ipmi_msg *tx_msg = NULL, *iter, *temp;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ipmi->tx_msg_lock, flags);
+	list_for_each_entry_safe(iter, temp, &ipmi->tx_msg_list, head) {
+		if (msg == iter) {
+			tx_msg = iter;
+			list_del(&iter->head);
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&ipmi->tx_msg_lock, flags);
+
+	if (tx_msg)
+		acpi_ipmi_msg_put(tx_msg);
+}
+
+static void ipmi_msg_handler(struct ipmi_recv_msg *msg, void *user_msg_data)
+{
+	struct acpi_ipmi_device *ipmi_device = user_msg_data;
+	struct acpi_ipmi_msg *tx_msg = NULL, *iter, *temp;
+	struct device *dev = ipmi_device->dev;
+	unsigned long flags;
+
+	if (msg->user != ipmi_device->user_interface) {
+		dev_warn(dev,
+			 "Unexpected response is returned. returned user %p, expected user %p\n",
+			 msg->user, ipmi_device->user_interface);
+		goto out_msg;
+	}
+
+	spin_lock_irqsave(&ipmi_device->tx_msg_lock, flags);
+	list_for_each_entry_safe(iter, temp, &ipmi_device->tx_msg_list, head) {
+		if (msg->msgid == iter->tx_msgid) {
+			tx_msg = iter;
+			list_del(&iter->head);
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&ipmi_device->tx_msg_lock, flags);
+
+	if (!tx_msg) {
+		dev_warn(dev,
+			 "Unexpected response (msg id %ld) is returned.\n",
+			 msg->msgid);
+		goto out_msg;
+	}
+
+	/* copy the response data to Rx_data buffer */
+	if (msg->msg.data_len > ACPI_IPMI_MAX_MSG_LENGTH) {
+		dev_WARN_ONCE(dev, true,
+			      "Unexpected response (msg len %d).\n",
+			      msg->msg.data_len);
+		goto out_comp;
+	}
+
+	/* response msg is an error msg */
+	msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
+	if (msg->recv_type == IPMI_RESPONSE_RECV_TYPE &&
+	    msg->msg.data_len == 1) {
+		if (msg->msg.data[0] == IPMI_TIMEOUT_COMPLETION_CODE) {
+			dev_dbg_once(dev, "Unexpected response (timeout).\n");
+			tx_msg->msg_done = ACPI_IPMI_TIMEOUT;
+		}
+		goto out_comp;
+	}
+
+	tx_msg->rx_len = msg->msg.data_len;
+	memcpy(tx_msg->data, msg->msg.data, tx_msg->rx_len);
+	tx_msg->msg_done = ACPI_IPMI_OK;
+
+out_comp:
+	complete(&tx_msg->tx_complete);
+	acpi_ipmi_msg_put(tx_msg);
+out_msg:
+	ipmi_free_recv_msg(msg);
+}
+
+static void ipmi_register_bmc(int iface, struct device *dev)
+{
+	struct acpi_ipmi_device *ipmi_device, *temp;
+	int err;
+	struct ipmi_smi_info smi_data;
+	acpi_handle handle;
+
+	err = ipmi_get_smi_info(iface, &smi_data);
+	if (err)
+		return;
+
+	if (smi_data.addr_src != SI_ACPI)
+		goto err_ref;
+	handle = smi_data.addr_info.acpi_info.acpi_handle;
+	if (!handle)
+		goto err_ref;
+
+	ipmi_device = ipmi_dev_alloc(iface, smi_data.dev, handle);
+	if (!ipmi_device) {
+		dev_warn(smi_data.dev, "Can't create IPMI user interface\n");
+		goto err_ref;
+	}
+
+	mutex_lock(&driver_data.ipmi_lock);
+	list_for_each_entry(temp, &driver_data.ipmi_devices, head) {
+		/*
+		 * if the corresponding ACPI handle is already added
+		 * to the device list, don't add it again.
+		 */
+		if (temp->handle == handle)
+			goto err_lock;
+	}
+	if (!driver_data.selected_smi)
+		driver_data.selected_smi = ipmi_device;
+	list_add_tail(&ipmi_device->head, &driver_data.ipmi_devices);
+	mutex_unlock(&driver_data.ipmi_lock);
+
+	put_device(smi_data.dev);
+	return;
+
+err_lock:
+	mutex_unlock(&driver_data.ipmi_lock);
+	ipmi_dev_release(ipmi_device);
+err_ref:
+	put_device(smi_data.dev);
+}
+
+static void ipmi_bmc_gone(int iface)
+{
+	struct acpi_ipmi_device *ipmi_device = NULL, *iter, *temp;
+
+	mutex_lock(&driver_data.ipmi_lock);
+	list_for_each_entry_safe(iter, temp,
+				 &driver_data.ipmi_devices, head) {
+		if (iter->ipmi_ifnum != iface) {
+			ipmi_device = iter;
+			__ipmi_dev_kill(iter);
+			break;
+		}
+	}
+	if (!driver_data.selected_smi)
+		driver_data.selected_smi = list_first_entry_or_null(
+					&driver_data.ipmi_devices,
+					struct acpi_ipmi_device, head);
+	mutex_unlock(&driver_data.ipmi_lock);
+
+	if (ipmi_device) {
+		ipmi_flush_tx_msg(ipmi_device);
+		acpi_ipmi_dev_put(ipmi_device);
+	}
+}
+
+/*
+ * This is the IPMI opregion space handler.
+ * @function: indicates the read/write. In fact as the IPMI message is driven
+ * by command, only write is meaningful.
+ * @address: This contains the netfn/command of IPMI request message.
+ * @bits   : not used.
+ * @value  : it is an in/out parameter. It points to the IPMI message buffer.
+ *	     Before the IPMI message is sent, it represents the actual request
+ *	     IPMI message. After the IPMI message is finished, it represents
+ *	     the response IPMI message returned by IPMI command.
+ * @handler_context: IPMI device context.
+ */
+static acpi_status
+acpi_ipmi_space_handler(u32 function, acpi_physical_address address,
+			u32 bits, acpi_integer *value,
+			void *handler_context, void *region_context)
+{
+	struct acpi_ipmi_msg *tx_msg;
+	struct acpi_ipmi_device *ipmi_device;
+	int err;
+	acpi_status status;
+	unsigned long flags;
+
+	/*
+	 * IPMI opregion message.
+	 * IPMI message is firstly written to the BMC and system software
+	 * can get the respsonse. So it is unmeaningful for the read access
+	 * of IPMI opregion.
+	 */
+	if ((function & ACPI_IO_MASK) == ACPI_READ)
+		return AE_TYPE;
+
+	tx_msg = ipmi_msg_alloc();
+	if (!tx_msg)
+		return AE_NOT_EXIST;
+	ipmi_device = tx_msg->device;
+
+	if (acpi_format_ipmi_request(tx_msg, address, value) != 0) {
+		ipmi_msg_release(tx_msg);
+		return AE_TYPE;
+	}
+
+	acpi_ipmi_msg_get(tx_msg);
+	mutex_lock(&driver_data.ipmi_lock);
+	/* Do not add a tx_msg that can not be flushed. */
+	if (ipmi_device->dead) {
+		mutex_unlock(&driver_data.ipmi_lock);
+		ipmi_msg_release(tx_msg);
+		return AE_NOT_EXIST;
+	}
+	spin_lock_irqsave(&ipmi_device->tx_msg_lock, flags);
+	list_add_tail(&tx_msg->head, &ipmi_device->tx_msg_list);
+	spin_unlock_irqrestore(&ipmi_device->tx_msg_lock, flags);
+	mutex_unlock(&driver_data.ipmi_lock);
+
+	err = ipmi_request_settime(ipmi_device->user_interface,
+				   &tx_msg->addr,
+				   tx_msg->tx_msgid,
+				   &tx_msg->tx_message,
+				   NULL, 0, 0, IPMI_TIMEOUT);
+	if (err) {
+		status = AE_ERROR;
+		goto out_msg;
+	}
+	wait_for_completion(&tx_msg->tx_complete);
+
+	acpi_format_ipmi_response(tx_msg, value);
+	status = AE_OK;
+
+out_msg:
+	ipmi_cancel_tx_msg(ipmi_device, tx_msg);
+	acpi_ipmi_msg_put(tx_msg);
+	return status;
+}
+
+static int __init acpi_ipmi_init(void)
+{
+	int result;
+	acpi_status status;
+
+	if (acpi_disabled)
+		return 0;
+
+	status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
+						    ACPI_ADR_SPACE_IPMI,
+						    &acpi_ipmi_space_handler,
+						    NULL, NULL);
+	if (ACPI_FAILURE(status)) {
+		pr_warn("Can't register IPMI opregion space handle\n");
+		return -EINVAL;
+	}
+
+	result = ipmi_smi_watcher_register(&driver_data.bmc_events);
+	if (result) {
+		acpi_remove_address_space_handler(ACPI_ROOT_OBJECT,
+										  ACPI_ADR_SPACE_IPMI,
+										  &acpi_ipmi_space_handler);
+		pr_err("Can't register IPMI system interface watcher\n");
+	}
+
+	return result;
+}
+
+static void __exit acpi_ipmi_exit(void)
+{
+	struct acpi_ipmi_device *ipmi_device;
+
+	if (acpi_disabled)
+		return;
+
+	ipmi_smi_watcher_unregister(&driver_data.bmc_events);
+
+	/*
+	 * When one smi_watcher is unregistered, it is only deleted
+	 * from the smi_watcher list. But the smi_gone callback function
+	 * is not called. So explicitly uninstall the ACPI IPMI oregion
+	 * handler and free it.
+	 */
+	mutex_lock(&driver_data.ipmi_lock);
+	while (!list_empty(&driver_data.ipmi_devices)) {
+		ipmi_device = list_first_entry(&driver_data.ipmi_devices,
+					       struct acpi_ipmi_device,
+					       head);
+		__ipmi_dev_kill(ipmi_device);
+		mutex_unlock(&driver_data.ipmi_lock);
+
+		ipmi_flush_tx_msg(ipmi_device);
+		acpi_ipmi_dev_put(ipmi_device);
+
+		mutex_lock(&driver_data.ipmi_lock);
+	}
+	mutex_unlock(&driver_data.ipmi_lock);
+	acpi_remove_address_space_handler(ACPI_ROOT_OBJECT,
+					  ACPI_ADR_SPACE_IPMI,
+					  &acpi_ipmi_space_handler);
+}
+
+module_init(acpi_ipmi_init);
+module_exit(acpi_ipmi_exit);