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, 510 insertions, 0 deletions

diff --git a/kernel/trace/rv/rv_reactors.c b/kernel/trace/rv/rv_reactors.c
new file mode 100644
index 000000000..6aae10669
--- /dev/null
+++ b/kernel/trace/rv/rv_reactors.c
@@ -0,0 +1,510 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <bristot@kernel.org>
+ *
+ * Runtime reactor interface.
+ *
+ * A runtime monitor can cause a reaction to the detection of an
+ * exception on the model's execution. By default, the monitors have
+ * tracing reactions, printing the monitor output via tracepoints.
+ * But other reactions can be added (on-demand) via this interface.
+ *
+ * == Registering reactors ==
+ *
+ * The struct rv_reactor defines a callback function to be executed
+ * in case of a model exception happens. The callback function
+ * receives a message to be (optionally) printed before executing
+ * the reaction.
+ *
+ * A RV reactor is registered via:
+ *   int rv_register_reactor(struct rv_reactor *reactor)
+ * And unregistered via:
+ *   int rv_unregister_reactor(struct rv_reactor *reactor)
+ *
+ * These functions are exported to modules, enabling reactors to be
+ * dynamically loaded.
+ *
+ * == User interface ==
+ *
+ * The user interface resembles the kernel tracing interface and
+ * presents these files:
+ *
+ *  "available_reactors"
+ *    - List the available reactors, one per line.
+ *
+ *    For example:
+ *      # cat available_reactors
+ *      nop
+ *      panic
+ *      printk
+ *
+ *  "reacting_on"
+ *    - It is an on/off general switch for reactors, disabling
+ *    all reactions.
+ *
+ *  "monitors/MONITOR/reactors"
+ *    - List available reactors, with the select reaction for the given
+ *    MONITOR inside []. The default one is the nop (no operation)
+ *    reactor.
+ *    - Writing the name of an reactor enables it to the given
+ *    MONITOR.
+ *
+ *    For example:
+ *      # cat monitors/wip/reactors
+ *      [nop]
+ *      panic
+ *      printk
+ *      # echo panic > monitors/wip/reactors
+ *      # cat monitors/wip/reactors
+ *      nop
+ *      [panic]
+ *      printk
+ */
+
+#include <linux/slab.h>
+
+#include "rv.h"
+
+/*
+ * Interface for the reactor register.
+ */
+static LIST_HEAD(rv_reactors_list);
+
+static struct rv_reactor_def *get_reactor_rdef_by_name(char *name)
+{
+	struct rv_reactor_def *r;
+
+	list_for_each_entry(r, &rv_reactors_list, list) {
+		if (strcmp(name, r->reactor->name) == 0)
+			return r;
+	}
+	return NULL;
+}
+
+/*
+ * Available reactors seq functions.
+ */
+static int reactors_show(struct seq_file *m, void *p)
+{
+	struct rv_reactor_def *rea_def = p;
+
+	seq_printf(m, "%s\n", rea_def->reactor->name);
+	return 0;
+}
+
+static void reactors_stop(struct seq_file *m, void *p)
+{
+	mutex_unlock(&rv_interface_lock);
+}
+
+static void *reactors_start(struct seq_file *m, loff_t *pos)
+{
+	mutex_lock(&rv_interface_lock);
+	return seq_list_start(&rv_reactors_list, *pos);
+}
+
+static void *reactors_next(struct seq_file *m, void *p, loff_t *pos)
+{
+	return seq_list_next(p, &rv_reactors_list, pos);
+}
+
+/*
+ * available_reactors seq definition.
+ */
+static const struct seq_operations available_reactors_seq_ops = {
+	.start	= reactors_start,
+	.next	= reactors_next,
+	.stop	= reactors_stop,
+	.show	= reactors_show
+};
+
+/*
+ * available_reactors interface.
+ */
+static int available_reactors_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &available_reactors_seq_ops);
+};
+
+static const struct file_operations available_reactors_ops = {
+	.open    = available_reactors_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = seq_release
+};
+
+/*
+ * Monitor's reactor file.
+ */
+static int monitor_reactor_show(struct seq_file *m, void *p)
+{
+	struct rv_monitor_def *mdef = m->private;
+	struct rv_reactor_def *rdef = p;
+
+	if (mdef->rdef == rdef)
+		seq_printf(m, "[%s]\n", rdef->reactor->name);
+	else
+		seq_printf(m, "%s\n", rdef->reactor->name);
+	return 0;
+}
+
+/*
+ * available_reactors seq definition.
+ */
+static const struct seq_operations monitor_reactors_seq_ops = {
+	.start	= reactors_start,
+	.next	= reactors_next,
+	.stop	= reactors_stop,
+	.show	= monitor_reactor_show
+};
+
+static void monitor_swap_reactors(struct rv_monitor_def *mdef, struct rv_reactor_def *rdef,
+				    bool reacting)
+{
+	bool monitor_enabled;
+
+	/* nothing to do */
+	if (mdef->rdef == rdef)
+		return;
+
+	monitor_enabled = mdef->monitor->enabled;
+	if (monitor_enabled)
+		rv_disable_monitor(mdef);
+
+	/* swap reactor's usage */
+	mdef->rdef->counter--;
+	rdef->counter++;
+
+	mdef->rdef = rdef;
+	mdef->reacting = reacting;
+	mdef->monitor->react = rdef->reactor->react;
+
+	if (monitor_enabled)
+		rv_enable_monitor(mdef);
+}
+
+static ssize_t
+monitor_reactors_write(struct file *file, const char __user *user_buf,
+		      size_t count, loff_t *ppos)
+{
+	char buff[MAX_RV_REACTOR_NAME_SIZE + 2];
+	struct rv_monitor_def *mdef;
+	struct rv_reactor_def *rdef;
+	struct seq_file *seq_f;
+	int retval = -EINVAL;
+	bool enable;
+	char *ptr;
+	int len;
+
+	if (count < 1 || count > MAX_RV_REACTOR_NAME_SIZE + 1)
+		return -EINVAL;
+
+	memset(buff, 0, sizeof(buff));
+
+	retval = simple_write_to_buffer(buff, sizeof(buff) - 1, ppos, user_buf, count);
+	if (retval < 0)
+		return -EFAULT;
+
+	ptr = strim(buff);
+
+	len = strlen(ptr);
+	if (!len)
+		return count;
+
+	/*
+	 * See monitor_reactors_open()
+	 */
+	seq_f = file->private_data;
+	mdef = seq_f->private;
+
+	mutex_lock(&rv_interface_lock);
+
+	retval = -EINVAL;
+
+	list_for_each_entry(rdef, &rv_reactors_list, list) {
+		if (strcmp(ptr, rdef->reactor->name) != 0)
+			continue;
+
+		if (rdef == get_reactor_rdef_by_name("nop"))
+			enable = false;
+		else
+			enable = true;
+
+		monitor_swap_reactors(mdef, rdef, enable);
+
+		retval = count;
+		break;
+	}
+
+	mutex_unlock(&rv_interface_lock);
+
+	return retval;
+}
+
+/*
+ * available_reactors interface.
+ */
+static int monitor_reactors_open(struct inode *inode, struct file *file)
+{
+	struct rv_monitor_def *mdef = inode->i_private;
+	struct seq_file *seq_f;
+	int ret;
+
+	ret = seq_open(file, &monitor_reactors_seq_ops);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * seq_open stores the seq_file on the file->private data.
+	 */
+	seq_f = file->private_data;
+
+	/*
+	 * Copy the create file "private" data to the seq_file private data.
+	 */
+	seq_f->private = mdef;
+
+	return 0;
+};
+
+static const struct file_operations monitor_reactors_ops = {
+	.open    = monitor_reactors_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = seq_release,
+	.write = monitor_reactors_write
+};
+
+static int __rv_register_reactor(struct rv_reactor *reactor)
+{
+	struct rv_reactor_def *r;
+
+	list_for_each_entry(r, &rv_reactors_list, list) {
+		if (strcmp(reactor->name, r->reactor->name) == 0) {
+			pr_info("Reactor %s is already registered\n", reactor->name);
+			return -EINVAL;
+		}
+	}
+
+	r = kzalloc(sizeof(struct rv_reactor_def), GFP_KERNEL);
+	if (!r)
+		return -ENOMEM;
+
+	r->reactor = reactor;
+	r->counter = 0;
+
+	list_add_tail(&r->list, &rv_reactors_list);
+
+	return 0;
+}
+
+/**
+ * rv_register_reactor - register a rv reactor.
+ * @reactor:	The rv_reactor to be registered.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int rv_register_reactor(struct rv_reactor *reactor)
+{
+	int retval = 0;
+
+	if (strlen(reactor->name) >= MAX_RV_REACTOR_NAME_SIZE) {
+		pr_info("Reactor %s has a name longer than %d\n",
+			reactor->name, MAX_RV_MONITOR_NAME_SIZE);
+		return -EINVAL;
+	}
+
+	mutex_lock(&rv_interface_lock);
+	retval = __rv_register_reactor(reactor);
+	mutex_unlock(&rv_interface_lock);
+	return retval;
+}
+
+/**
+ * rv_unregister_reactor - unregister a rv reactor.
+ * @reactor:	The rv_reactor to be unregistered.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int rv_unregister_reactor(struct rv_reactor *reactor)
+{
+	struct rv_reactor_def *ptr, *next;
+	int ret = 0;
+
+	mutex_lock(&rv_interface_lock);
+
+	list_for_each_entry_safe(ptr, next, &rv_reactors_list, list) {
+		if (strcmp(reactor->name, ptr->reactor->name) == 0) {
+
+			if (!ptr->counter) {
+				list_del(&ptr->list);
+			} else {
+				printk(KERN_WARNING
+				       "rv: the rv_reactor %s is in use by %d monitor(s)\n",
+				       ptr->reactor->name, ptr->counter);
+				printk(KERN_WARNING "rv: the rv_reactor %s cannot be removed\n",
+				       ptr->reactor->name);
+				ret = -EBUSY;
+				break;
+			}
+		}
+	}
+
+	mutex_unlock(&rv_interface_lock);
+	return ret;
+}
+
+/*
+ * reacting_on interface.
+ */
+static bool __read_mostly reacting_on;
+
+/**
+ * rv_reacting_on - checks if reacting is on
+ *
+ * Returns 1 if on, 0 otherwise.
+ */
+bool rv_reacting_on(void)
+{
+	/* Ensures that concurrent monitors read consistent reacting_on */
+	smp_rmb();
+	return READ_ONCE(reacting_on);
+}
+
+static ssize_t reacting_on_read_data(struct file *filp,
+				     char __user *user_buf,
+				     size_t count, loff_t *ppos)
+{
+	char *buff;
+
+	buff = rv_reacting_on() ? "1\n" : "0\n";
+
+	return simple_read_from_buffer(user_buf, count, ppos, buff, strlen(buff)+1);
+}
+
+static void turn_reacting_off(void)
+{
+	WRITE_ONCE(reacting_on, false);
+	/* Ensures that concurrent monitors read consistent reacting_on */
+	smp_wmb();
+}
+
+static void turn_reacting_on(void)
+{
+	WRITE_ONCE(reacting_on, true);
+	/* Ensures that concurrent monitors read consistent reacting_on */
+	smp_wmb();
+}
+
+static ssize_t reacting_on_write_data(struct file *filp, const char __user *user_buf,
+				      size_t count, loff_t *ppos)
+{
+	int retval;
+	bool val;
+
+	retval = kstrtobool_from_user(user_buf, count, &val);
+	if (retval)
+		return retval;
+
+	mutex_lock(&rv_interface_lock);
+
+	if (val)
+		turn_reacting_on();
+	else
+		turn_reacting_off();
+
+	/*
+	 * Wait for the execution of all events to finish
+	 * before returning to user-space.
+	 */
+	tracepoint_synchronize_unregister();
+
+	mutex_unlock(&rv_interface_lock);
+
+	return count;
+}
+
+static const struct file_operations reacting_on_fops = {
+	.open   = simple_open,
+	.llseek = no_llseek,
+	.write  = reacting_on_write_data,
+	.read   = reacting_on_read_data,
+};
+
+/**
+ * reactor_populate_monitor - creates per monitor reactors file
+ * @mdef:	monitor's definition.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int reactor_populate_monitor(struct rv_monitor_def *mdef)
+{
+	struct dentry *tmp;
+
+	tmp = rv_create_file("reactors", RV_MODE_WRITE, mdef->root_d, mdef, &monitor_reactors_ops);
+	if (!tmp)
+		return -ENOMEM;
+
+	/*
+	 * Configure as the rv_nop reactor.
+	 */
+	mdef->rdef = get_reactor_rdef_by_name("nop");
+	mdef->rdef->counter++;
+	mdef->reacting = false;
+
+	return 0;
+}
+
+/**
+ * reactor_cleanup_monitor - cleanup a monitor reference
+ * @mdef:       monitor's definition.
+ */
+void reactor_cleanup_monitor(struct rv_monitor_def *mdef)
+{
+	lockdep_assert_held(&rv_interface_lock);
+	mdef->rdef->counter--;
+	WARN_ON_ONCE(mdef->rdef->counter < 0);
+}
+
+/*
+ * Nop reactor register
+ */
+static void rv_nop_reaction(char *msg)
+{
+}
+
+static struct rv_reactor rv_nop = {
+	.name = "nop",
+	.description = "no-operation reactor: do nothing.",
+	.react = rv_nop_reaction
+};
+
+int init_rv_reactors(struct dentry *root_dir)
+{
+	struct dentry *available, *reacting;
+	int retval;
+
+	available = rv_create_file("available_reactors", RV_MODE_READ, root_dir, NULL,
+				   &available_reactors_ops);
+	if (!available)
+		goto out_err;
+
+	reacting = rv_create_file("reacting_on", RV_MODE_WRITE, root_dir, NULL, &reacting_on_fops);
+	if (!reacting)
+		goto rm_available;
+
+	retval = __rv_register_reactor(&rv_nop);
+	if (retval)
+		goto rm_reacting;
+
+	turn_reacting_on();
+
+	return 0;
+
+rm_reacting:
+	rv_remove(reacting);
+rm_available:
+	rv_remove(available);
+out_err:
+	return -ENOMEM;
+}