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, 535 insertions, 0 deletions

diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
new file mode 100644
index 000000000..14b53dac1
--- /dev/null
+++ b/drivers/input/input-mt.c
@@ -0,0 +1,535 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Input Multitouch Library
+ *
+ * Copyright (c) 2008-2010 Henrik Rydberg
+ */
+
+#include <linux/input/mt.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include "input-core-private.h"
+
+#define TRKID_SGN	((TRKID_MAX + 1) >> 1)
+
+static void copy_abs(struct input_dev *dev, unsigned int dst, unsigned int src)
+{
+	if (dev->absinfo && test_bit(src, dev->absbit)) {
+		dev->absinfo[dst] = dev->absinfo[src];
+		dev->absinfo[dst].fuzz = 0;
+		__set_bit(dst, dev->absbit);
+	}
+}
+
+/**
+ * input_mt_init_slots() - initialize MT input slots
+ * @dev: input device supporting MT events and finger tracking
+ * @num_slots: number of slots used by the device
+ * @flags: mt tasks to handle in core
+ *
+ * This function allocates all necessary memory for MT slot handling
+ * in the input device, prepares the ABS_MT_SLOT and
+ * ABS_MT_TRACKING_ID events for use and sets up appropriate buffers.
+ * Depending on the flags set, it also performs pointer emulation and
+ * frame synchronization.
+ *
+ * May be called repeatedly. Returns -EINVAL if attempting to
+ * reinitialize with a different number of slots.
+ */
+int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots,
+			unsigned int flags)
+{
+	struct input_mt *mt = dev->mt;
+	int i;
+
+	if (!num_slots)
+		return 0;
+	if (mt)
+		return mt->num_slots != num_slots ? -EINVAL : 0;
+
+	mt = kzalloc(struct_size(mt, slots, num_slots), GFP_KERNEL);
+	if (!mt)
+		goto err_mem;
+
+	mt->num_slots = num_slots;
+	mt->flags = flags;
+	input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
+	input_set_abs_params(dev, ABS_MT_TRACKING_ID, 0, TRKID_MAX, 0, 0);
+
+	if (flags & (INPUT_MT_POINTER | INPUT_MT_DIRECT)) {
+		__set_bit(EV_KEY, dev->evbit);
+		__set_bit(BTN_TOUCH, dev->keybit);
+
+		copy_abs(dev, ABS_X, ABS_MT_POSITION_X);
+		copy_abs(dev, ABS_Y, ABS_MT_POSITION_Y);
+		copy_abs(dev, ABS_PRESSURE, ABS_MT_PRESSURE);
+	}
+	if (flags & INPUT_MT_POINTER) {
+		__set_bit(BTN_TOOL_FINGER, dev->keybit);
+		__set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
+		if (num_slots >= 3)
+			__set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);
+		if (num_slots >= 4)
+			__set_bit(BTN_TOOL_QUADTAP, dev->keybit);
+		if (num_slots >= 5)
+			__set_bit(BTN_TOOL_QUINTTAP, dev->keybit);
+		__set_bit(INPUT_PROP_POINTER, dev->propbit);
+	}
+	if (flags & INPUT_MT_DIRECT)
+		__set_bit(INPUT_PROP_DIRECT, dev->propbit);
+	if (flags & INPUT_MT_SEMI_MT)
+		__set_bit(INPUT_PROP_SEMI_MT, dev->propbit);
+	if (flags & INPUT_MT_TRACK) {
+		unsigned int n2 = num_slots * num_slots;
+		mt->red = kcalloc(n2, sizeof(*mt->red), GFP_KERNEL);
+		if (!mt->red)
+			goto err_mem;
+	}
+
+	/* Mark slots as 'inactive' */
+	for (i = 0; i < num_slots; i++)
+		input_mt_set_value(&mt->slots[i], ABS_MT_TRACKING_ID, -1);
+
+	/* Mark slots as 'unused' */
+	mt->frame = 1;
+
+	dev->mt = mt;
+	return 0;
+err_mem:
+	kfree(mt);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL(input_mt_init_slots);
+
+/**
+ * input_mt_destroy_slots() - frees the MT slots of the input device
+ * @dev: input device with allocated MT slots
+ *
+ * This function is only needed in error path as the input core will
+ * automatically free the MT slots when the device is destroyed.
+ */
+void input_mt_destroy_slots(struct input_dev *dev)
+{
+	if (dev->mt) {
+		kfree(dev->mt->red);
+		kfree(dev->mt);
+	}
+	dev->mt = NULL;
+}
+EXPORT_SYMBOL(input_mt_destroy_slots);
+
+/**
+ * input_mt_report_slot_state() - report contact state
+ * @dev: input device with allocated MT slots
+ * @tool_type: the tool type to use in this slot
+ * @active: true if contact is active, false otherwise
+ *
+ * Reports a contact via ABS_MT_TRACKING_ID, and optionally
+ * ABS_MT_TOOL_TYPE. If active is true and the slot is currently
+ * inactive, or if the tool type is changed, a new tracking id is
+ * assigned to the slot. The tool type is only reported if the
+ * corresponding absbit field is set.
+ *
+ * Returns true if contact is active.
+ */
+bool input_mt_report_slot_state(struct input_dev *dev,
+				unsigned int tool_type, bool active)
+{
+	struct input_mt *mt = dev->mt;
+	struct input_mt_slot *slot;
+	int id;
+
+	if (!mt)
+		return false;
+
+	slot = &mt->slots[mt->slot];
+	slot->frame = mt->frame;
+
+	if (!active) {
+		input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
+		return false;
+	}
+
+	id = input_mt_get_value(slot, ABS_MT_TRACKING_ID);
+	if (id < 0)
+		id = input_mt_new_trkid(mt);
+
+	input_event(dev, EV_ABS, ABS_MT_TRACKING_ID, id);
+	input_event(dev, EV_ABS, ABS_MT_TOOL_TYPE, tool_type);
+
+	return true;
+}
+EXPORT_SYMBOL(input_mt_report_slot_state);
+
+/**
+ * input_mt_report_finger_count() - report contact count
+ * @dev: input device with allocated MT slots
+ * @count: the number of contacts
+ *
+ * Reports the contact count via BTN_TOOL_FINGER, BTN_TOOL_DOUBLETAP,
+ * BTN_TOOL_TRIPLETAP and BTN_TOOL_QUADTAP.
+ *
+ * The input core ensures only the KEY events already setup for
+ * this device will produce output.
+ */
+void input_mt_report_finger_count(struct input_dev *dev, int count)
+{
+	input_event(dev, EV_KEY, BTN_TOOL_FINGER, count == 1);
+	input_event(dev, EV_KEY, BTN_TOOL_DOUBLETAP, count == 2);
+	input_event(dev, EV_KEY, BTN_TOOL_TRIPLETAP, count == 3);
+	input_event(dev, EV_KEY, BTN_TOOL_QUADTAP, count == 4);
+	input_event(dev, EV_KEY, BTN_TOOL_QUINTTAP, count == 5);
+}
+EXPORT_SYMBOL(input_mt_report_finger_count);
+
+/**
+ * input_mt_report_pointer_emulation() - common pointer emulation
+ * @dev: input device with allocated MT slots
+ * @use_count: report number of active contacts as finger count
+ *
+ * Performs legacy pointer emulation via BTN_TOUCH, ABS_X, ABS_Y and
+ * ABS_PRESSURE. Touchpad finger count is emulated if use_count is true.
+ *
+ * The input core ensures only the KEY and ABS axes already setup for
+ * this device will produce output.
+ */
+void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
+{
+	struct input_mt *mt = dev->mt;
+	struct input_mt_slot *oldest;
+	int oldid, count, i;
+
+	if (!mt)
+		return;
+
+	oldest = NULL;
+	oldid = mt->trkid;
+	count = 0;
+
+	for (i = 0; i < mt->num_slots; ++i) {
+		struct input_mt_slot *ps = &mt->slots[i];
+		int id = input_mt_get_value(ps, ABS_MT_TRACKING_ID);
+
+		if (id < 0)
+			continue;
+		if ((id - oldid) & TRKID_SGN) {
+			oldest = ps;
+			oldid = id;
+		}
+		count++;
+	}
+
+	input_event(dev, EV_KEY, BTN_TOUCH, count > 0);
+
+	if (use_count) {
+		if (count == 0 &&
+		    !test_bit(ABS_MT_DISTANCE, dev->absbit) &&
+		    test_bit(ABS_DISTANCE, dev->absbit) &&
+		    input_abs_get_val(dev, ABS_DISTANCE) != 0) {
+			/*
+			 * Force reporting BTN_TOOL_FINGER for devices that
+			 * only report general hover (and not per-contact
+			 * distance) when contact is in proximity but not
+			 * on the surface.
+			 */
+			count = 1;
+		}
+
+		input_mt_report_finger_count(dev, count);
+	}
+
+	if (oldest) {
+		int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);
+		int y = input_mt_get_value(oldest, ABS_MT_POSITION_Y);
+
+		input_event(dev, EV_ABS, ABS_X, x);
+		input_event(dev, EV_ABS, ABS_Y, y);
+
+		if (test_bit(ABS_MT_PRESSURE, dev->absbit)) {
+			int p = input_mt_get_value(oldest, ABS_MT_PRESSURE);
+			input_event(dev, EV_ABS, ABS_PRESSURE, p);
+		}
+	} else {
+		if (test_bit(ABS_MT_PRESSURE, dev->absbit))
+			input_event(dev, EV_ABS, ABS_PRESSURE, 0);
+	}
+}
+EXPORT_SYMBOL(input_mt_report_pointer_emulation);
+
+static void __input_mt_drop_unused(struct input_dev *dev, struct input_mt *mt)
+{
+	int i;
+
+	lockdep_assert_held(&dev->event_lock);
+
+	for (i = 0; i < mt->num_slots; i++) {
+		if (input_mt_is_active(&mt->slots[i]) &&
+		    !input_mt_is_used(mt, &mt->slots[i])) {
+			input_handle_event(dev, EV_ABS, ABS_MT_SLOT, i);
+			input_handle_event(dev, EV_ABS, ABS_MT_TRACKING_ID, -1);
+		}
+	}
+}
+
+/**
+ * input_mt_drop_unused() - Inactivate slots not seen in this frame
+ * @dev: input device with allocated MT slots
+ *
+ * Lift all slots not seen since the last call to this function.
+ */
+void input_mt_drop_unused(struct input_dev *dev)
+{
+	struct input_mt *mt = dev->mt;
+
+	if (mt) {
+		unsigned long flags;
+
+		spin_lock_irqsave(&dev->event_lock, flags);
+
+		__input_mt_drop_unused(dev, mt);
+		mt->frame++;
+
+		spin_unlock_irqrestore(&dev->event_lock, flags);
+	}
+}
+EXPORT_SYMBOL(input_mt_drop_unused);
+
+/**
+ * input_mt_release_slots() - Deactivate all slots
+ * @dev: input device with allocated MT slots
+ *
+ * Lift all active slots.
+ */
+void input_mt_release_slots(struct input_dev *dev)
+{
+	struct input_mt *mt = dev->mt;
+
+	lockdep_assert_held(&dev->event_lock);
+
+	if (mt) {
+		/* This will effectively mark all slots unused. */
+		mt->frame++;
+
+		__input_mt_drop_unused(dev, mt);
+
+		if (test_bit(ABS_PRESSURE, dev->absbit))
+			input_handle_event(dev, EV_ABS, ABS_PRESSURE, 0);
+
+		mt->frame++;
+	}
+}
+
+/**
+ * input_mt_sync_frame() - synchronize mt frame
+ * @dev: input device with allocated MT slots
+ *
+ * Close the frame and prepare the internal state for a new one.
+ * Depending on the flags, marks unused slots as inactive and performs
+ * pointer emulation.
+ */
+void input_mt_sync_frame(struct input_dev *dev)
+{
+	struct input_mt *mt = dev->mt;
+	bool use_count = false;
+
+	if (!mt)
+		return;
+
+	if (mt->flags & INPUT_MT_DROP_UNUSED) {
+		unsigned long flags;
+
+		spin_lock_irqsave(&dev->event_lock, flags);
+		__input_mt_drop_unused(dev, mt);
+		spin_unlock_irqrestore(&dev->event_lock, flags);
+	}
+
+	if ((mt->flags & INPUT_MT_POINTER) && !(mt->flags & INPUT_MT_SEMI_MT))
+		use_count = true;
+
+	input_mt_report_pointer_emulation(dev, use_count);
+
+	mt->frame++;
+}
+EXPORT_SYMBOL(input_mt_sync_frame);
+
+static int adjust_dual(int *begin, int step, int *end, int eq, int mu)
+{
+	int f, *p, s, c;
+
+	if (begin == end)
+		return 0;
+
+	f = *begin;
+	p = begin + step;
+	s = p == end ? f + 1 : *p;
+
+	for (; p != end; p += step) {
+		if (*p < f) {
+			s = f;
+			f = *p;
+		} else if (*p < s) {
+			s = *p;
+		}
+	}
+
+	c = (f + s + 1) / 2;
+	if (c == 0 || (c > mu && (!eq || mu > 0)))
+		return 0;
+	/* Improve convergence for positive matrices by penalizing overcovers */
+	if (s < 0 && mu <= 0)
+		c *= 2;
+
+	for (p = begin; p != end; p += step)
+		*p -= c;
+
+	return (c < s && s <= 0) || (f >= 0 && f < c);
+}
+
+static void find_reduced_matrix(int *w, int nr, int nc, int nrc, int mu)
+{
+	int i, k, sum;
+
+	for (k = 0; k < nrc; k++) {
+		for (i = 0; i < nr; i++)
+			adjust_dual(w + i, nr, w + i + nrc, nr <= nc, mu);
+		sum = 0;
+		for (i = 0; i < nrc; i += nr)
+			sum += adjust_dual(w + i, 1, w + i + nr, nc <= nr, mu);
+		if (!sum)
+			break;
+	}
+}
+
+static int input_mt_set_matrix(struct input_mt *mt,
+			       const struct input_mt_pos *pos, int num_pos,
+			       int mu)
+{
+	const struct input_mt_pos *p;
+	struct input_mt_slot *s;
+	int *w = mt->red;
+	int x, y;
+
+	for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
+		if (!input_mt_is_active(s))
+			continue;
+		x = input_mt_get_value(s, ABS_MT_POSITION_X);
+		y = input_mt_get_value(s, ABS_MT_POSITION_Y);
+		for (p = pos; p != pos + num_pos; p++) {
+			int dx = x - p->x, dy = y - p->y;
+			*w++ = dx * dx + dy * dy - mu;
+		}
+	}
+
+	return w - mt->red;
+}
+
+static void input_mt_set_slots(struct input_mt *mt,
+			       int *slots, int num_pos)
+{
+	struct input_mt_slot *s;
+	int *w = mt->red, j;
+
+	for (j = 0; j != num_pos; j++)
+		slots[j] = -1;
+
+	for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
+		if (!input_mt_is_active(s))
+			continue;
+
+		for (j = 0; j != num_pos; j++) {
+			if (w[j] < 0) {
+				slots[j] = s - mt->slots;
+				break;
+			}
+		}
+
+		w += num_pos;
+	}
+
+	for (s = mt->slots; s != mt->slots + mt->num_slots; s++) {
+		if (input_mt_is_active(s))
+			continue;
+
+		for (j = 0; j != num_pos; j++) {
+			if (slots[j] < 0) {
+				slots[j] = s - mt->slots;
+				break;
+			}
+		}
+	}
+}
+
+/**
+ * input_mt_assign_slots() - perform a best-match assignment
+ * @dev: input device with allocated MT slots
+ * @slots: the slot assignment to be filled
+ * @pos: the position array to match
+ * @num_pos: number of positions
+ * @dmax: maximum ABS_MT_POSITION displacement (zero for infinite)
+ *
+ * Performs a best match against the current contacts and returns
+ * the slot assignment list. New contacts are assigned to unused
+ * slots.
+ *
+ * The assignments are balanced so that all coordinate displacements are
+ * below the euclidian distance dmax. If no such assignment can be found,
+ * some contacts are assigned to unused slots.
+ *
+ * Returns zero on success, or negative error in case of failure.
+ */
+int input_mt_assign_slots(struct input_dev *dev, int *slots,
+			  const struct input_mt_pos *pos, int num_pos,
+			  int dmax)
+{
+	struct input_mt *mt = dev->mt;
+	int mu = 2 * dmax * dmax;
+	int nrc;
+
+	if (!mt || !mt->red)
+		return -ENXIO;
+	if (num_pos > mt->num_slots)
+		return -EINVAL;
+	if (num_pos < 1)
+		return 0;
+
+	nrc = input_mt_set_matrix(mt, pos, num_pos, mu);
+	find_reduced_matrix(mt->red, num_pos, nrc / num_pos, nrc, mu);
+	input_mt_set_slots(mt, slots, num_pos);
+
+	return 0;
+}
+EXPORT_SYMBOL(input_mt_assign_slots);
+
+/**
+ * input_mt_get_slot_by_key() - return slot matching key
+ * @dev: input device with allocated MT slots
+ * @key: the key of the sought slot
+ *
+ * Returns the slot of the given key, if it exists, otherwise
+ * set the key on the first unused slot and return.
+ *
+ * If no available slot can be found, -1 is returned.
+ * Note that for this function to work properly, input_mt_sync_frame() has
+ * to be called at each frame.
+ */
+int input_mt_get_slot_by_key(struct input_dev *dev, int key)
+{
+	struct input_mt *mt = dev->mt;
+	struct input_mt_slot *s;
+
+	if (!mt)
+		return -1;
+
+	for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
+		if (input_mt_is_active(s) && s->key == key)
+			return s - mt->slots;
+
+	for (s = mt->slots; s != mt->slots + mt->num_slots; s++)
+		if (!input_mt_is_active(s) && !input_mt_is_used(mt, s)) {
+			s->key = key;
+			return s - mt->slots;
+		}
+
+	return -1;
+}
+EXPORT_SYMBOL(input_mt_get_slot_by_key);