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, 592 insertions, 0 deletions

diff --git a/drivers/md/dm-switch.c b/drivers/md/dm-switch.c
new file mode 100644
index 000000000..534dc2ca8
--- /dev/null
+++ b/drivers/md/dm-switch.c
@@ -0,0 +1,592 @@
+/*
+ * Copyright (C) 2010-2012 by Dell Inc.  All rights reserved.
+ * Copyright (C) 2011-2013 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ *
+ * dm-switch is a device-mapper target that maps IO to underlying block
+ * devices efficiently when there are a large number of fixed-sized
+ * address regions but there is no simple pattern to allow for a compact
+ * mapping representation such as dm-stripe.
+ */
+
+#include <linux/device-mapper.h>
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/vmalloc.h>
+
+#define DM_MSG_PREFIX "switch"
+
+/*
+ * One region_table_slot_t holds <region_entries_per_slot> region table
+ * entries each of which is <region_table_entry_bits> in size.
+ */
+typedef unsigned long region_table_slot_t;
+
+/*
+ * A device with the offset to its start sector.
+ */
+struct switch_path {
+	struct dm_dev *dmdev;
+	sector_t start;
+};
+
+/*
+ * Context block for a dm switch device.
+ */
+struct switch_ctx {
+	struct dm_target *ti;
+
+	unsigned nr_paths;		/* Number of paths in path_list. */
+
+	unsigned region_size;		/* Region size in 512-byte sectors */
+	unsigned long nr_regions;	/* Number of regions making up the device */
+	signed char region_size_bits;	/* log2 of region_size or -1 */
+
+	unsigned char region_table_entry_bits;	/* Number of bits in one region table entry */
+	unsigned char region_entries_per_slot;	/* Number of entries in one region table slot */
+	signed char region_entries_per_slot_bits;	/* log2 of region_entries_per_slot or -1 */
+
+	region_table_slot_t *region_table;	/* Region table */
+
+	/*
+	 * Array of dm devices to switch between.
+	 */
+	struct switch_path path_list[];
+};
+
+static struct switch_ctx *alloc_switch_ctx(struct dm_target *ti, unsigned nr_paths,
+					   unsigned region_size)
+{
+	struct switch_ctx *sctx;
+
+	sctx = kzalloc(struct_size(sctx, path_list, nr_paths), GFP_KERNEL);
+	if (!sctx)
+		return NULL;
+
+	sctx->ti = ti;
+	sctx->region_size = region_size;
+
+	ti->private = sctx;
+
+	return sctx;
+}
+
+static int alloc_region_table(struct dm_target *ti, unsigned nr_paths)
+{
+	struct switch_ctx *sctx = ti->private;
+	sector_t nr_regions = ti->len;
+	sector_t nr_slots;
+
+	if (!(sctx->region_size & (sctx->region_size - 1)))
+		sctx->region_size_bits = __ffs(sctx->region_size);
+	else
+		sctx->region_size_bits = -1;
+
+	sctx->region_table_entry_bits = 1;
+	while (sctx->region_table_entry_bits < sizeof(region_table_slot_t) * 8 &&
+	       (region_table_slot_t)1 << sctx->region_table_entry_bits < nr_paths)
+		sctx->region_table_entry_bits++;
+
+	sctx->region_entries_per_slot = (sizeof(region_table_slot_t) * 8) / sctx->region_table_entry_bits;
+	if (!(sctx->region_entries_per_slot & (sctx->region_entries_per_slot - 1)))
+		sctx->region_entries_per_slot_bits = __ffs(sctx->region_entries_per_slot);
+	else
+		sctx->region_entries_per_slot_bits = -1;
+
+	if (sector_div(nr_regions, sctx->region_size))
+		nr_regions++;
+
+	if (nr_regions >= ULONG_MAX) {
+		ti->error = "Region table too large";
+		return -EINVAL;
+	}
+	sctx->nr_regions = nr_regions;
+
+	nr_slots = nr_regions;
+	if (sector_div(nr_slots, sctx->region_entries_per_slot))
+		nr_slots++;
+
+	if (nr_slots > ULONG_MAX / sizeof(region_table_slot_t)) {
+		ti->error = "Region table too large";
+		return -EINVAL;
+	}
+
+	sctx->region_table = vmalloc(array_size(nr_slots,
+						sizeof(region_table_slot_t)));
+	if (!sctx->region_table) {
+		ti->error = "Cannot allocate region table";
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void switch_get_position(struct switch_ctx *sctx, unsigned long region_nr,
+				unsigned long *region_index, unsigned *bit)
+{
+	if (sctx->region_entries_per_slot_bits >= 0) {
+		*region_index = region_nr >> sctx->region_entries_per_slot_bits;
+		*bit = region_nr & (sctx->region_entries_per_slot - 1);
+	} else {
+		*region_index = region_nr / sctx->region_entries_per_slot;
+		*bit = region_nr % sctx->region_entries_per_slot;
+	}
+
+	*bit *= sctx->region_table_entry_bits;
+}
+
+static unsigned switch_region_table_read(struct switch_ctx *sctx, unsigned long region_nr)
+{
+	unsigned long region_index;
+	unsigned bit;
+
+	switch_get_position(sctx, region_nr, &region_index, &bit);
+
+	return (READ_ONCE(sctx->region_table[region_index]) >> bit) &
+		((1 << sctx->region_table_entry_bits) - 1);
+}
+
+/*
+ * Find which path to use at given offset.
+ */
+static unsigned switch_get_path_nr(struct switch_ctx *sctx, sector_t offset)
+{
+	unsigned path_nr;
+	sector_t p;
+
+	p = offset;
+	if (sctx->region_size_bits >= 0)
+		p >>= sctx->region_size_bits;
+	else
+		sector_div(p, sctx->region_size);
+
+	path_nr = switch_region_table_read(sctx, p);
+
+	/* This can only happen if the processor uses non-atomic stores. */
+	if (unlikely(path_nr >= sctx->nr_paths))
+		path_nr = 0;
+
+	return path_nr;
+}
+
+static void switch_region_table_write(struct switch_ctx *sctx, unsigned long region_nr,
+				      unsigned value)
+{
+	unsigned long region_index;
+	unsigned bit;
+	region_table_slot_t pte;
+
+	switch_get_position(sctx, region_nr, &region_index, &bit);
+
+	pte = sctx->region_table[region_index];
+	pte &= ~((((region_table_slot_t)1 << sctx->region_table_entry_bits) - 1) << bit);
+	pte |= (region_table_slot_t)value << bit;
+	sctx->region_table[region_index] = pte;
+}
+
+/*
+ * Fill the region table with an initial round robin pattern.
+ */
+static void initialise_region_table(struct switch_ctx *sctx)
+{
+	unsigned path_nr = 0;
+	unsigned long region_nr;
+
+	for (region_nr = 0; region_nr < sctx->nr_regions; region_nr++) {
+		switch_region_table_write(sctx, region_nr, path_nr);
+		if (++path_nr >= sctx->nr_paths)
+			path_nr = 0;
+	}
+}
+
+static int parse_path(struct dm_arg_set *as, struct dm_target *ti)
+{
+	struct switch_ctx *sctx = ti->private;
+	unsigned long long start;
+	int r;
+
+	r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table),
+			  &sctx->path_list[sctx->nr_paths].dmdev);
+	if (r) {
+		ti->error = "Device lookup failed";
+		return r;
+	}
+
+	if (kstrtoull(dm_shift_arg(as), 10, &start) || start != (sector_t)start) {
+		ti->error = "Invalid device starting offset";
+		dm_put_device(ti, sctx->path_list[sctx->nr_paths].dmdev);
+		return -EINVAL;
+	}
+
+	sctx->path_list[sctx->nr_paths].start = start;
+
+	sctx->nr_paths++;
+
+	return 0;
+}
+
+/*
+ * Destructor: Don't free the dm_target, just the ti->private data (if any).
+ */
+static void switch_dtr(struct dm_target *ti)
+{
+	struct switch_ctx *sctx = ti->private;
+
+	while (sctx->nr_paths--)
+		dm_put_device(ti, sctx->path_list[sctx->nr_paths].dmdev);
+
+	vfree(sctx->region_table);
+	kfree(sctx);
+}
+
+/*
+ * Constructor arguments:
+ *   <num_paths> <region_size> <num_optional_args> [<optional_args>...]
+ *   [<dev_path> <offset>]+
+ *
+ * Optional args are to allow for future extension: currently this
+ * parameter must be 0.
+ */
+static int switch_ctr(struct dm_target *ti, unsigned argc, char **argv)
+{
+	static const struct dm_arg _args[] = {
+		{1, (KMALLOC_MAX_SIZE - sizeof(struct switch_ctx)) / sizeof(struct switch_path), "Invalid number of paths"},
+		{1, UINT_MAX, "Invalid region size"},
+		{0, 0, "Invalid number of optional args"},
+	};
+
+	struct switch_ctx *sctx;
+	struct dm_arg_set as;
+	unsigned nr_paths, region_size, nr_optional_args;
+	int r;
+
+	as.argc = argc;
+	as.argv = argv;
+
+	r = dm_read_arg(_args, &as, &nr_paths, &ti->error);
+	if (r)
+		return -EINVAL;
+
+	r = dm_read_arg(_args + 1, &as, &region_size, &ti->error);
+	if (r)
+		return r;
+
+	r = dm_read_arg_group(_args + 2, &as, &nr_optional_args, &ti->error);
+	if (r)
+		return r;
+	/* parse optional arguments here, if we add any */
+
+	if (as.argc != nr_paths * 2) {
+		ti->error = "Incorrect number of path arguments";
+		return -EINVAL;
+	}
+
+	sctx = alloc_switch_ctx(ti, nr_paths, region_size);
+	if (!sctx) {
+		ti->error = "Cannot allocate redirection context";
+		return -ENOMEM;
+	}
+
+	r = dm_set_target_max_io_len(ti, region_size);
+	if (r)
+		goto error;
+
+	while (as.argc) {
+		r = parse_path(&as, ti);
+		if (r)
+			goto error;
+	}
+
+	r = alloc_region_table(ti, nr_paths);
+	if (r)
+		goto error;
+
+	initialise_region_table(sctx);
+
+	/* For UNMAP, sending the request down any path is sufficient */
+	ti->num_discard_bios = 1;
+
+	return 0;
+
+error:
+	switch_dtr(ti);
+
+	return r;
+}
+
+static int switch_map(struct dm_target *ti, struct bio *bio)
+{
+	struct switch_ctx *sctx = ti->private;
+	sector_t offset = dm_target_offset(ti, bio->bi_iter.bi_sector);
+	unsigned path_nr = switch_get_path_nr(sctx, offset);
+
+	bio_set_dev(bio, sctx->path_list[path_nr].dmdev->bdev);
+	bio->bi_iter.bi_sector = sctx->path_list[path_nr].start + offset;
+
+	return DM_MAPIO_REMAPPED;
+}
+
+/*
+ * We need to parse hex numbers in the message as quickly as possible.
+ *
+ * This table-based hex parser improves performance.
+ * It improves a time to load 1000000 entries compared to the condition-based
+ * parser.
+ *		table-based parser	condition-based parser
+ * PA-RISC	0.29s			0.31s
+ * Opteron	0.0495s			0.0498s
+ */
+static const unsigned char hex_table[256] = {
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 255, 255, 255, 255, 255, 255,
+255, 10, 11, 12, 13, 14, 15, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 10, 11, 12, 13, 14, 15, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255
+};
+
+static __always_inline unsigned long parse_hex(const char **string)
+{
+	unsigned char d;
+	unsigned long r = 0;
+
+	while ((d = hex_table[(unsigned char)**string]) < 16) {
+		r = (r << 4) | d;
+		(*string)++;
+	}
+
+	return r;
+}
+
+static int process_set_region_mappings(struct switch_ctx *sctx,
+				       unsigned argc, char **argv)
+{
+	unsigned i;
+	unsigned long region_index = 0;
+
+	for (i = 1; i < argc; i++) {
+		unsigned long path_nr;
+		const char *string = argv[i];
+
+		if ((*string & 0xdf) == 'R') {
+			unsigned long cycle_length, num_write;
+
+			string++;
+			if (unlikely(*string == ',')) {
+				DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
+				return -EINVAL;
+			}
+			cycle_length = parse_hex(&string);
+			if (unlikely(*string != ',')) {
+				DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
+				return -EINVAL;
+			}
+			string++;
+			if (unlikely(!*string)) {
+				DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
+				return -EINVAL;
+			}
+			num_write = parse_hex(&string);
+			if (unlikely(*string)) {
+				DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
+				return -EINVAL;
+			}
+
+			if (unlikely(!cycle_length) || unlikely(cycle_length - 1 > region_index)) {
+				DMWARN("invalid set_region_mappings cycle length: %lu > %lu",
+				       cycle_length - 1, region_index);
+				return -EINVAL;
+			}
+			if (unlikely(region_index + num_write < region_index) ||
+			    unlikely(region_index + num_write >= sctx->nr_regions)) {
+				DMWARN("invalid set_region_mappings region number: %lu + %lu >= %lu",
+				       region_index, num_write, sctx->nr_regions);
+				return -EINVAL;
+			}
+
+			while (num_write--) {
+				region_index++;
+				path_nr = switch_region_table_read(sctx, region_index - cycle_length);
+				switch_region_table_write(sctx, region_index, path_nr);
+			}
+
+			continue;
+		}
+
+		if (*string == ':')
+			region_index++;
+		else {
+			region_index = parse_hex(&string);
+			if (unlikely(*string != ':')) {
+				DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
+				return -EINVAL;
+			}
+		}
+
+		string++;
+		if (unlikely(!*string)) {
+			DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
+			return -EINVAL;
+		}
+
+		path_nr = parse_hex(&string);
+		if (unlikely(*string)) {
+			DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
+			return -EINVAL;
+		}
+		if (unlikely(region_index >= sctx->nr_regions)) {
+			DMWARN("invalid set_region_mappings region number: %lu >= %lu", region_index, sctx->nr_regions);
+			return -EINVAL;
+		}
+		if (unlikely(path_nr >= sctx->nr_paths)) {
+			DMWARN("invalid set_region_mappings device: %lu >= %u", path_nr, sctx->nr_paths);
+			return -EINVAL;
+		}
+
+		switch_region_table_write(sctx, region_index, path_nr);
+	}
+
+	return 0;
+}
+
+/*
+ * Messages are processed one-at-a-time.
+ *
+ * Only set_region_mappings is supported.
+ */
+static int switch_message(struct dm_target *ti, unsigned argc, char **argv,
+			  char *result, unsigned maxlen)
+{
+	static DEFINE_MUTEX(message_mutex);
+
+	struct switch_ctx *sctx = ti->private;
+	int r = -EINVAL;
+
+	mutex_lock(&message_mutex);
+
+	if (!strcasecmp(argv[0], "set_region_mappings"))
+		r = process_set_region_mappings(sctx, argc, argv);
+	else
+		DMWARN("Unrecognised message received.");
+
+	mutex_unlock(&message_mutex);
+
+	return r;
+}
+
+static void switch_status(struct dm_target *ti, status_type_t type,
+			  unsigned status_flags, char *result, unsigned maxlen)
+{
+	struct switch_ctx *sctx = ti->private;
+	unsigned sz = 0;
+	int path_nr;
+
+	switch (type) {
+	case STATUSTYPE_INFO:
+		result[0] = '\0';
+		break;
+
+	case STATUSTYPE_TABLE:
+		DMEMIT("%u %u 0", sctx->nr_paths, sctx->region_size);
+		for (path_nr = 0; path_nr < sctx->nr_paths; path_nr++)
+			DMEMIT(" %s %llu", sctx->path_list[path_nr].dmdev->name,
+			       (unsigned long long)sctx->path_list[path_nr].start);
+		break;
+
+	case STATUSTYPE_IMA:
+		result[0] = '\0';
+		break;
+	}
+}
+
+/*
+ * Switch ioctl:
+ *
+ * Passthrough all ioctls to the path for sector 0
+ */
+static int switch_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
+{
+	struct switch_ctx *sctx = ti->private;
+	unsigned path_nr;
+
+	path_nr = switch_get_path_nr(sctx, 0);
+
+	*bdev = sctx->path_list[path_nr].dmdev->bdev;
+
+	/*
+	 * Only pass ioctls through if the device sizes match exactly.
+	 */
+	if (ti->len + sctx->path_list[path_nr].start !=
+	    bdev_nr_sectors((*bdev)))
+		return 1;
+	return 0;
+}
+
+static int switch_iterate_devices(struct dm_target *ti,
+				  iterate_devices_callout_fn fn, void *data)
+{
+	struct switch_ctx *sctx = ti->private;
+	int path_nr;
+	int r;
+
+	for (path_nr = 0; path_nr < sctx->nr_paths; path_nr++) {
+		r = fn(ti, sctx->path_list[path_nr].dmdev,
+			 sctx->path_list[path_nr].start, ti->len, data);
+		if (r)
+			return r;
+	}
+
+	return 0;
+}
+
+static struct target_type switch_target = {
+	.name = "switch",
+	.version = {1, 1, 0},
+	.features = DM_TARGET_NOWAIT,
+	.module = THIS_MODULE,
+	.ctr = switch_ctr,
+	.dtr = switch_dtr,
+	.map = switch_map,
+	.message = switch_message,
+	.status = switch_status,
+	.prepare_ioctl = switch_prepare_ioctl,
+	.iterate_devices = switch_iterate_devices,
+};
+
+static int __init dm_switch_init(void)
+{
+	int r;
+
+	r = dm_register_target(&switch_target);
+	if (r < 0)
+		DMERR("dm_register_target() failed %d", r);
+
+	return r;
+}
+
+static void __exit dm_switch_exit(void)
+{
+	dm_unregister_target(&switch_target);
+}
+
+module_init(dm_switch_init);
+module_exit(dm_switch_exit);
+
+MODULE_DESCRIPTION(DM_NAME " dynamic path switching target");
+MODULE_AUTHOR("Kevin D. O'Kelley <Kevin_OKelley@dell.com>");
+MODULE_AUTHOR("Narendran Ganapathy <Narendran_Ganapathy@dell.com>");
+MODULE_AUTHOR("Jim Ramsay <Jim_Ramsay@dell.com>");
+MODULE_AUTHOR("Mikulas Patocka <mpatocka@redhat.com>");
+MODULE_LICENSE("GPL");