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, 576 insertions, 0 deletions

diff --git a/kernel/umh.c b/kernel/umh.c
new file mode 100644
index 000000000..fbf872c62
--- /dev/null
+++ b/kernel/umh.c
@@ -0,0 +1,576 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * umh - the kernel usermode helper
+ */
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/sched/task.h>
+#include <linux/binfmts.h>
+#include <linux/syscalls.h>
+#include <linux/unistd.h>
+#include <linux/kmod.h>
+#include <linux/slab.h>
+#include <linux/completion.h>
+#include <linux/cred.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/fs_struct.h>
+#include <linux/workqueue.h>
+#include <linux/security.h>
+#include <linux/mount.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/resource.h>
+#include <linux/notifier.h>
+#include <linux/suspend.h>
+#include <linux/rwsem.h>
+#include <linux/ptrace.h>
+#include <linux/async.h>
+#include <linux/uaccess.h>
+#include <linux/initrd.h>
+#include <linux/freezer.h>
+
+#include <trace/events/module.h>
+
+#define CAP_BSET	(void *)1
+#define CAP_PI		(void *)2
+
+static kernel_cap_t usermodehelper_bset = CAP_FULL_SET;
+static kernel_cap_t usermodehelper_inheritable = CAP_FULL_SET;
+static DEFINE_SPINLOCK(umh_sysctl_lock);
+static DECLARE_RWSEM(umhelper_sem);
+
+static void call_usermodehelper_freeinfo(struct subprocess_info *info)
+{
+	if (info->cleanup)
+		(*info->cleanup)(info);
+	kfree(info);
+}
+
+static void umh_complete(struct subprocess_info *sub_info)
+{
+	struct completion *comp = xchg(&sub_info->complete, NULL);
+	/*
+	 * See call_usermodehelper_exec(). If xchg() returns NULL
+	 * we own sub_info, the UMH_KILLABLE caller has gone away
+	 * or the caller used UMH_NO_WAIT.
+	 */
+	if (comp)
+		complete(comp);
+	else
+		call_usermodehelper_freeinfo(sub_info);
+}
+
+/*
+ * This is the task which runs the usermode application
+ */
+static int call_usermodehelper_exec_async(void *data)
+{
+	struct subprocess_info *sub_info = data;
+	struct cred *new;
+	int retval;
+
+	spin_lock_irq(&current->sighand->siglock);
+	flush_signal_handlers(current, 1);
+	spin_unlock_irq(&current->sighand->siglock);
+
+	/*
+	 * Initial kernel threads share ther FS with init, in order to
+	 * get the init root directory. But we've now created a new
+	 * thread that is going to execve a user process and has its own
+	 * 'struct fs_struct'. Reset umask to the default.
+	 */
+	current->fs->umask = 0022;
+
+	/*
+	 * Our parent (unbound workqueue) runs with elevated scheduling
+	 * priority. Avoid propagating that into the userspace child.
+	 */
+	set_user_nice(current, 0);
+
+	retval = -ENOMEM;
+	new = prepare_kernel_cred(current);
+	if (!new)
+		goto out;
+
+	spin_lock(&umh_sysctl_lock);
+	new->cap_bset = cap_intersect(usermodehelper_bset, new->cap_bset);
+	new->cap_inheritable = cap_intersect(usermodehelper_inheritable,
+					     new->cap_inheritable);
+	spin_unlock(&umh_sysctl_lock);
+
+	if (sub_info->init) {
+		retval = sub_info->init(sub_info, new);
+		if (retval) {
+			abort_creds(new);
+			goto out;
+		}
+	}
+
+	commit_creds(new);
+
+	wait_for_initramfs();
+	retval = kernel_execve(sub_info->path,
+			       (const char *const *)sub_info->argv,
+			       (const char *const *)sub_info->envp);
+out:
+	sub_info->retval = retval;
+	/*
+	 * call_usermodehelper_exec_sync() will call umh_complete
+	 * if UHM_WAIT_PROC.
+	 */
+	if (!(sub_info->wait & UMH_WAIT_PROC))
+		umh_complete(sub_info);
+	if (!retval)
+		return 0;
+	do_exit(0);
+}
+
+/* Handles UMH_WAIT_PROC.  */
+static void call_usermodehelper_exec_sync(struct subprocess_info *sub_info)
+{
+	pid_t pid;
+
+	/* If SIGCLD is ignored do_wait won't populate the status. */
+	kernel_sigaction(SIGCHLD, SIG_DFL);
+	pid = user_mode_thread(call_usermodehelper_exec_async, sub_info, SIGCHLD);
+	if (pid < 0)
+		sub_info->retval = pid;
+	else
+		kernel_wait(pid, &sub_info->retval);
+
+	/* Restore default kernel sig handler */
+	kernel_sigaction(SIGCHLD, SIG_IGN);
+	umh_complete(sub_info);
+}
+
+/*
+ * We need to create the usermodehelper kernel thread from a task that is affine
+ * to an optimized set of CPUs (or nohz housekeeping ones) such that they
+ * inherit a widest affinity irrespective of call_usermodehelper() callers with
+ * possibly reduced affinity (eg: per-cpu workqueues). We don't want
+ * usermodehelper targets to contend a busy CPU.
+ *
+ * Unbound workqueues provide such wide affinity and allow to block on
+ * UMH_WAIT_PROC requests without blocking pending request (up to some limit).
+ *
+ * Besides, workqueues provide the privilege level that caller might not have
+ * to perform the usermodehelper request.
+ *
+ */
+static void call_usermodehelper_exec_work(struct work_struct *work)
+{
+	struct subprocess_info *sub_info =
+		container_of(work, struct subprocess_info, work);
+
+	if (sub_info->wait & UMH_WAIT_PROC) {
+		call_usermodehelper_exec_sync(sub_info);
+	} else {
+		pid_t pid;
+		/*
+		 * Use CLONE_PARENT to reparent it to kthreadd; we do not
+		 * want to pollute current->children, and we need a parent
+		 * that always ignores SIGCHLD to ensure auto-reaping.
+		 */
+		pid = user_mode_thread(call_usermodehelper_exec_async, sub_info,
+				       CLONE_PARENT | SIGCHLD);
+		if (pid < 0) {
+			sub_info->retval = pid;
+			umh_complete(sub_info);
+		}
+	}
+}
+
+/*
+ * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY
+ * (used for preventing user land processes from being created after the user
+ * land has been frozen during a system-wide hibernation or suspend operation).
+ * Should always be manipulated under umhelper_sem acquired for write.
+ */
+static enum umh_disable_depth usermodehelper_disabled = UMH_DISABLED;
+
+/* Number of helpers running */
+static atomic_t running_helpers = ATOMIC_INIT(0);
+
+/*
+ * Wait queue head used by usermodehelper_disable() to wait for all running
+ * helpers to finish.
+ */
+static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq);
+
+/*
+ * Used by usermodehelper_read_lock_wait() to wait for usermodehelper_disabled
+ * to become 'false'.
+ */
+static DECLARE_WAIT_QUEUE_HEAD(usermodehelper_disabled_waitq);
+
+/*
+ * Time to wait for running_helpers to become zero before the setting of
+ * usermodehelper_disabled in usermodehelper_disable() fails
+ */
+#define RUNNING_HELPERS_TIMEOUT	(5 * HZ)
+
+int usermodehelper_read_trylock(void)
+{
+	DEFINE_WAIT(wait);
+	int ret = 0;
+
+	down_read(&umhelper_sem);
+	for (;;) {
+		prepare_to_wait(&usermodehelper_disabled_waitq, &wait,
+				TASK_INTERRUPTIBLE);
+		if (!usermodehelper_disabled)
+			break;
+
+		if (usermodehelper_disabled == UMH_DISABLED)
+			ret = -EAGAIN;
+
+		up_read(&umhelper_sem);
+
+		if (ret)
+			break;
+
+		schedule();
+		try_to_freeze();
+
+		down_read(&umhelper_sem);
+	}
+	finish_wait(&usermodehelper_disabled_waitq, &wait);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usermodehelper_read_trylock);
+
+long usermodehelper_read_lock_wait(long timeout)
+{
+	DEFINE_WAIT(wait);
+
+	if (timeout < 0)
+		return -EINVAL;
+
+	down_read(&umhelper_sem);
+	for (;;) {
+		prepare_to_wait(&usermodehelper_disabled_waitq, &wait,
+				TASK_UNINTERRUPTIBLE);
+		if (!usermodehelper_disabled)
+			break;
+
+		up_read(&umhelper_sem);
+
+		timeout = schedule_timeout(timeout);
+		if (!timeout)
+			break;
+
+		down_read(&umhelper_sem);
+	}
+	finish_wait(&usermodehelper_disabled_waitq, &wait);
+	return timeout;
+}
+EXPORT_SYMBOL_GPL(usermodehelper_read_lock_wait);
+
+void usermodehelper_read_unlock(void)
+{
+	up_read(&umhelper_sem);
+}
+EXPORT_SYMBOL_GPL(usermodehelper_read_unlock);
+
+/**
+ * __usermodehelper_set_disable_depth - Modify usermodehelper_disabled.
+ * @depth: New value to assign to usermodehelper_disabled.
+ *
+ * Change the value of usermodehelper_disabled (under umhelper_sem locked for
+ * writing) and wakeup tasks waiting for it to change.
+ */
+void __usermodehelper_set_disable_depth(enum umh_disable_depth depth)
+{
+	down_write(&umhelper_sem);
+	usermodehelper_disabled = depth;
+	wake_up(&usermodehelper_disabled_waitq);
+	up_write(&umhelper_sem);
+}
+
+/**
+ * __usermodehelper_disable - Prevent new helpers from being started.
+ * @depth: New value to assign to usermodehelper_disabled.
+ *
+ * Set usermodehelper_disabled to @depth and wait for running helpers to exit.
+ */
+int __usermodehelper_disable(enum umh_disable_depth depth)
+{
+	long retval;
+
+	if (!depth)
+		return -EINVAL;
+
+	down_write(&umhelper_sem);
+	usermodehelper_disabled = depth;
+	up_write(&umhelper_sem);
+
+	/*
+	 * From now on call_usermodehelper_exec() won't start any new
+	 * helpers, so it is sufficient if running_helpers turns out to
+	 * be zero at one point (it may be increased later, but that
+	 * doesn't matter).
+	 */
+	retval = wait_event_timeout(running_helpers_waitq,
+					atomic_read(&running_helpers) == 0,
+					RUNNING_HELPERS_TIMEOUT);
+	if (retval)
+		return 0;
+
+	__usermodehelper_set_disable_depth(UMH_ENABLED);
+	return -EAGAIN;
+}
+
+static void helper_lock(void)
+{
+	atomic_inc(&running_helpers);
+	smp_mb__after_atomic();
+}
+
+static void helper_unlock(void)
+{
+	if (atomic_dec_and_test(&running_helpers))
+		wake_up(&running_helpers_waitq);
+}
+
+/**
+ * call_usermodehelper_setup - prepare to call a usermode helper
+ * @path: path to usermode executable
+ * @argv: arg vector for process
+ * @envp: environment for process
+ * @gfp_mask: gfp mask for memory allocation
+ * @init: an init function
+ * @cleanup: a cleanup function
+ * @data: arbitrary context sensitive data
+ *
+ * Returns either %NULL on allocation failure, or a subprocess_info
+ * structure.  This should be passed to call_usermodehelper_exec to
+ * exec the process and free the structure.
+ *
+ * The init function is used to customize the helper process prior to
+ * exec.  A non-zero return code causes the process to error out, exit,
+ * and return the failure to the calling process
+ *
+ * The cleanup function is just before the subprocess_info is about to
+ * be freed.  This can be used for freeing the argv and envp.  The
+ * Function must be runnable in either a process context or the
+ * context in which call_usermodehelper_exec is called.
+ */
+struct subprocess_info *call_usermodehelper_setup(const char *path, char **argv,
+		char **envp, gfp_t gfp_mask,
+		int (*init)(struct subprocess_info *info, struct cred *new),
+		void (*cleanup)(struct subprocess_info *info),
+		void *data)
+{
+	struct subprocess_info *sub_info;
+	sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask);
+	if (!sub_info)
+		goto out;
+
+	INIT_WORK(&sub_info->work, call_usermodehelper_exec_work);
+
+#ifdef CONFIG_STATIC_USERMODEHELPER
+	sub_info->path = CONFIG_STATIC_USERMODEHELPER_PATH;
+#else
+	sub_info->path = path;
+#endif
+	sub_info->argv = argv;
+	sub_info->envp = envp;
+
+	sub_info->cleanup = cleanup;
+	sub_info->init = init;
+	sub_info->data = data;
+  out:
+	return sub_info;
+}
+EXPORT_SYMBOL(call_usermodehelper_setup);
+
+/**
+ * call_usermodehelper_exec - start a usermode application
+ * @sub_info: information about the subprocess
+ * @wait: wait for the application to finish and return status.
+ *        when UMH_NO_WAIT don't wait at all, but you get no useful error back
+ *        when the program couldn't be exec'ed. This makes it safe to call
+ *        from interrupt context.
+ *
+ * Runs a user-space application.  The application is started
+ * asynchronously if wait is not set, and runs as a child of system workqueues.
+ * (ie. it runs with full root capabilities and optimized affinity).
+ *
+ * Note: successful return value does not guarantee the helper was called at
+ * all. You can't rely on sub_info->{init,cleanup} being called even for
+ * UMH_WAIT_* wait modes as STATIC_USERMODEHELPER_PATH="" turns all helpers
+ * into a successful no-op.
+ */
+int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
+{
+	unsigned int state = TASK_UNINTERRUPTIBLE;
+	DECLARE_COMPLETION_ONSTACK(done);
+	int retval = 0;
+
+	if (!sub_info->path) {
+		call_usermodehelper_freeinfo(sub_info);
+		return -EINVAL;
+	}
+	helper_lock();
+	if (usermodehelper_disabled) {
+		retval = -EBUSY;
+		goto out;
+	}
+
+	/*
+	 * If there is no binary for us to call, then just return and get out of
+	 * here.  This allows us to set STATIC_USERMODEHELPER_PATH to "" and
+	 * disable all call_usermodehelper() calls.
+	 */
+	if (strlen(sub_info->path) == 0)
+		goto out;
+
+	/*
+	 * Set the completion pointer only if there is a waiter.
+	 * This makes it possible to use umh_complete to free
+	 * the data structure in case of UMH_NO_WAIT.
+	 */
+	sub_info->complete = (wait == UMH_NO_WAIT) ? NULL : &done;
+	sub_info->wait = wait;
+
+	queue_work(system_unbound_wq, &sub_info->work);
+	if (wait == UMH_NO_WAIT)	/* task has freed sub_info */
+		goto unlock;
+
+	if (wait & UMH_FREEZABLE)
+		state |= TASK_FREEZABLE;
+
+	if (wait & UMH_KILLABLE) {
+		retval = wait_for_completion_state(&done, state | TASK_KILLABLE);
+		if (!retval)
+			goto wait_done;
+
+		/* umh_complete() will see NULL and free sub_info */
+		if (xchg(&sub_info->complete, NULL))
+			goto unlock;
+
+		/*
+		 * fallthrough; in case of -ERESTARTSYS now do uninterruptible
+		 * wait_for_completion_state(). Since umh_complete() shall call
+		 * complete() in a moment if xchg() above returned NULL, this
+		 * uninterruptible wait_for_completion_state() will not block
+		 * SIGKILL'ed processes for long.
+		 */
+	}
+	wait_for_completion_state(&done, state);
+
+wait_done:
+	retval = sub_info->retval;
+out:
+	call_usermodehelper_freeinfo(sub_info);
+unlock:
+	helper_unlock();
+	return retval;
+}
+EXPORT_SYMBOL(call_usermodehelper_exec);
+
+/**
+ * call_usermodehelper() - prepare and start a usermode application
+ * @path: path to usermode executable
+ * @argv: arg vector for process
+ * @envp: environment for process
+ * @wait: wait for the application to finish and return status.
+ *        when UMH_NO_WAIT don't wait at all, but you get no useful error back
+ *        when the program couldn't be exec'ed. This makes it safe to call
+ *        from interrupt context.
+ *
+ * This function is the equivalent to use call_usermodehelper_setup() and
+ * call_usermodehelper_exec().
+ */
+int call_usermodehelper(const char *path, char **argv, char **envp, int wait)
+{
+	struct subprocess_info *info;
+	gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;
+
+	info = call_usermodehelper_setup(path, argv, envp, gfp_mask,
+					 NULL, NULL, NULL);
+	if (info == NULL)
+		return -ENOMEM;
+
+	return call_usermodehelper_exec(info, wait);
+}
+EXPORT_SYMBOL(call_usermodehelper);
+
+static int proc_cap_handler(struct ctl_table *table, int write,
+			 void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table t;
+	unsigned long cap_array[_KERNEL_CAPABILITY_U32S];
+	kernel_cap_t new_cap;
+	int err, i;
+
+	if (write && (!capable(CAP_SETPCAP) ||
+		      !capable(CAP_SYS_MODULE)))
+		return -EPERM;
+
+	/*
+	 * convert from the global kernel_cap_t to the ulong array to print to
+	 * userspace if this is a read.
+	 */
+	spin_lock(&umh_sysctl_lock);
+	for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++)  {
+		if (table->data == CAP_BSET)
+			cap_array[i] = usermodehelper_bset.cap[i];
+		else if (table->data == CAP_PI)
+			cap_array[i] = usermodehelper_inheritable.cap[i];
+		else
+			BUG();
+	}
+	spin_unlock(&umh_sysctl_lock);
+
+	t = *table;
+	t.data = &cap_array;
+
+	/*
+	 * actually read or write and array of ulongs from userspace.  Remember
+	 * these are least significant 32 bits first
+	 */
+	err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
+	if (err < 0)
+		return err;
+
+	/*
+	 * convert from the sysctl array of ulongs to the kernel_cap_t
+	 * internal representation
+	 */
+	for (i = 0; i < _KERNEL_CAPABILITY_U32S; i++)
+		new_cap.cap[i] = cap_array[i];
+
+	/*
+	 * Drop everything not in the new_cap (but don't add things)
+	 */
+	if (write) {
+		spin_lock(&umh_sysctl_lock);
+		if (table->data == CAP_BSET)
+			usermodehelper_bset = cap_intersect(usermodehelper_bset, new_cap);
+		if (table->data == CAP_PI)
+			usermodehelper_inheritable = cap_intersect(usermodehelper_inheritable, new_cap);
+		spin_unlock(&umh_sysctl_lock);
+	}
+
+	return 0;
+}
+
+struct ctl_table usermodehelper_table[] = {
+	{
+		.procname	= "bset",
+		.data		= CAP_BSET,
+		.maxlen		= _KERNEL_CAPABILITY_U32S * sizeof(unsigned long),
+		.mode		= 0600,
+		.proc_handler	= proc_cap_handler,
+	},
+	{
+		.procname	= "inheritable",
+		.data		= CAP_PI,
+		.maxlen		= _KERNEL_CAPABILITY_U32S * sizeof(unsigned long),
+		.mode		= 0600,
+		.proc_handler	= proc_cap_handler,
+	},
+	{ }
+};