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, 541 insertions, 0 deletions

diff --git a/drivers/most/most_cdev.c b/drivers/most/most_cdev.c
new file mode 100644
index 000000000..3722f9abd
--- /dev/null
+++ b/drivers/most/most_cdev.c
@@ -0,0 +1,541 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * cdev.c - Character device component for Mostcore
+ *
+ * Copyright (C) 2013-2015 Microchip Technology Germany II GmbH & Co. KG
+ */
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/cdev.h>
+#include <linux/poll.h>
+#include <linux/kfifo.h>
+#include <linux/uaccess.h>
+#include <linux/idr.h>
+#include <linux/most.h>
+
+#define CHRDEV_REGION_SIZE 50
+
+static struct cdev_component {
+	dev_t devno;
+	struct ida minor_id;
+	unsigned int major;
+	struct class *class;
+	struct most_component cc;
+} comp;
+
+struct comp_channel {
+	wait_queue_head_t wq;
+	spinlock_t unlink;	/* synchronization lock to unlink channels */
+	struct cdev cdev;
+	struct device *dev;
+	struct mutex io_mutex;
+	struct most_interface *iface;
+	struct most_channel_config *cfg;
+	unsigned int channel_id;
+	dev_t devno;
+	size_t mbo_offs;
+	DECLARE_KFIFO_PTR(fifo, typeof(struct mbo *));
+	int access_ref;
+	struct list_head list;
+};
+
+#define to_channel(d) container_of(d, struct comp_channel, cdev)
+static LIST_HEAD(channel_list);
+static DEFINE_SPINLOCK(ch_list_lock);
+
+static inline bool ch_has_mbo(struct comp_channel *c)
+{
+	return channel_has_mbo(c->iface, c->channel_id, &comp.cc) > 0;
+}
+
+static inline struct mbo *ch_get_mbo(struct comp_channel *c, struct mbo **mbo)
+{
+	if (!kfifo_peek(&c->fifo, mbo)) {
+		*mbo = most_get_mbo(c->iface, c->channel_id, &comp.cc);
+		if (*mbo)
+			kfifo_in(&c->fifo, mbo, 1);
+	}
+	return *mbo;
+}
+
+static struct comp_channel *get_channel(struct most_interface *iface, int id)
+{
+	struct comp_channel *c, *tmp;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ch_list_lock, flags);
+	list_for_each_entry_safe(c, tmp, &channel_list, list) {
+		if ((c->iface == iface) && (c->channel_id == id)) {
+			spin_unlock_irqrestore(&ch_list_lock, flags);
+			return c;
+		}
+	}
+	spin_unlock_irqrestore(&ch_list_lock, flags);
+	return NULL;
+}
+
+static void stop_channel(struct comp_channel *c)
+{
+	struct mbo *mbo;
+
+	while (kfifo_out((struct kfifo *)&c->fifo, &mbo, 1))
+		most_put_mbo(mbo);
+	most_stop_channel(c->iface, c->channel_id, &comp.cc);
+}
+
+static void destroy_cdev(struct comp_channel *c)
+{
+	unsigned long flags;
+
+	device_destroy(comp.class, c->devno);
+	cdev_del(&c->cdev);
+	spin_lock_irqsave(&ch_list_lock, flags);
+	list_del(&c->list);
+	spin_unlock_irqrestore(&ch_list_lock, flags);
+}
+
+static void destroy_channel(struct comp_channel *c)
+{
+	ida_simple_remove(&comp.minor_id, MINOR(c->devno));
+	kfifo_free(&c->fifo);
+	kfree(c);
+}
+
+/**
+ * comp_open - implements the syscall to open the device
+ * @inode: inode pointer
+ * @filp: file pointer
+ *
+ * This stores the channel pointer in the private data field of
+ * the file structure and activates the channel within the core.
+ */
+static int comp_open(struct inode *inode, struct file *filp)
+{
+	struct comp_channel *c;
+	int ret;
+
+	c = to_channel(inode->i_cdev);
+	filp->private_data = c;
+
+	if (((c->cfg->direction == MOST_CH_RX) &&
+	     ((filp->f_flags & O_ACCMODE) != O_RDONLY)) ||
+	     ((c->cfg->direction == MOST_CH_TX) &&
+		((filp->f_flags & O_ACCMODE) != O_WRONLY))) {
+		return -EACCES;
+	}
+
+	mutex_lock(&c->io_mutex);
+	if (!c->dev) {
+		mutex_unlock(&c->io_mutex);
+		return -ENODEV;
+	}
+
+	if (c->access_ref) {
+		mutex_unlock(&c->io_mutex);
+		return -EBUSY;
+	}
+
+	c->mbo_offs = 0;
+	ret = most_start_channel(c->iface, c->channel_id, &comp.cc);
+	if (!ret)
+		c->access_ref = 1;
+	mutex_unlock(&c->io_mutex);
+	return ret;
+}
+
+/**
+ * comp_close - implements the syscall to close the device
+ * @inode: inode pointer
+ * @filp: file pointer
+ *
+ * This stops the channel within the core.
+ */
+static int comp_close(struct inode *inode, struct file *filp)
+{
+	struct comp_channel *c = to_channel(inode->i_cdev);
+
+	mutex_lock(&c->io_mutex);
+	spin_lock(&c->unlink);
+	c->access_ref = 0;
+	spin_unlock(&c->unlink);
+	if (c->dev) {
+		stop_channel(c);
+		mutex_unlock(&c->io_mutex);
+	} else {
+		mutex_unlock(&c->io_mutex);
+		destroy_channel(c);
+	}
+	return 0;
+}
+
+/**
+ * comp_write - implements the syscall to write to the device
+ * @filp: file pointer
+ * @buf: pointer to user buffer
+ * @count: number of bytes to write
+ * @offset: offset from where to start writing
+ */
+static ssize_t comp_write(struct file *filp, const char __user *buf,
+			  size_t count, loff_t *offset)
+{
+	int ret;
+	size_t to_copy, left;
+	struct mbo *mbo = NULL;
+	struct comp_channel *c = filp->private_data;
+
+	mutex_lock(&c->io_mutex);
+	while (c->dev && !ch_get_mbo(c, &mbo)) {
+		mutex_unlock(&c->io_mutex);
+
+		if ((filp->f_flags & O_NONBLOCK))
+			return -EAGAIN;
+		if (wait_event_interruptible(c->wq, ch_has_mbo(c) || !c->dev))
+			return -ERESTARTSYS;
+		mutex_lock(&c->io_mutex);
+	}
+
+	if (unlikely(!c->dev)) {
+		ret = -ENODEV;
+		goto unlock;
+	}
+
+	to_copy = min(count, c->cfg->buffer_size - c->mbo_offs);
+	left = copy_from_user(mbo->virt_address + c->mbo_offs, buf, to_copy);
+	if (left == to_copy) {
+		ret = -EFAULT;
+		goto unlock;
+	}
+
+	c->mbo_offs += to_copy - left;
+	if (c->mbo_offs >= c->cfg->buffer_size ||
+	    c->cfg->data_type == MOST_CH_CONTROL ||
+	    c->cfg->data_type == MOST_CH_ASYNC) {
+		kfifo_skip(&c->fifo);
+		mbo->buffer_length = c->mbo_offs;
+		c->mbo_offs = 0;
+		most_submit_mbo(mbo);
+	}
+
+	ret = to_copy - left;
+unlock:
+	mutex_unlock(&c->io_mutex);
+	return ret;
+}
+
+/**
+ * comp_read - implements the syscall to read from the device
+ * @filp: file pointer
+ * @buf: pointer to user buffer
+ * @count: number of bytes to read
+ * @offset: offset from where to start reading
+ */
+static ssize_t
+comp_read(struct file *filp, char __user *buf, size_t count, loff_t *offset)
+{
+	size_t to_copy, not_copied, copied;
+	struct mbo *mbo = NULL;
+	struct comp_channel *c = filp->private_data;
+
+	mutex_lock(&c->io_mutex);
+	while (c->dev && !kfifo_peek(&c->fifo, &mbo)) {
+		mutex_unlock(&c->io_mutex);
+		if (filp->f_flags & O_NONBLOCK)
+			return -EAGAIN;
+		if (wait_event_interruptible(c->wq,
+					     (!kfifo_is_empty(&c->fifo) ||
+					      (!c->dev))))
+			return -ERESTARTSYS;
+		mutex_lock(&c->io_mutex);
+	}
+
+	/* make sure we don't submit to gone devices */
+	if (unlikely(!c->dev)) {
+		mutex_unlock(&c->io_mutex);
+		return -ENODEV;
+	}
+
+	to_copy = min_t(size_t,
+			count,
+			mbo->processed_length - c->mbo_offs);
+
+	not_copied = copy_to_user(buf,
+				  mbo->virt_address + c->mbo_offs,
+				  to_copy);
+
+	copied = to_copy - not_copied;
+
+	c->mbo_offs += copied;
+	if (c->mbo_offs >= mbo->processed_length) {
+		kfifo_skip(&c->fifo);
+		most_put_mbo(mbo);
+		c->mbo_offs = 0;
+	}
+	mutex_unlock(&c->io_mutex);
+	return copied;
+}
+
+static __poll_t comp_poll(struct file *filp, poll_table *wait)
+{
+	struct comp_channel *c = filp->private_data;
+	__poll_t mask = 0;
+
+	poll_wait(filp, &c->wq, wait);
+
+	mutex_lock(&c->io_mutex);
+	if (c->cfg->direction == MOST_CH_RX) {
+		if (!c->dev || !kfifo_is_empty(&c->fifo))
+			mask |= EPOLLIN | EPOLLRDNORM;
+	} else {
+		if (!c->dev || !kfifo_is_empty(&c->fifo) || ch_has_mbo(c))
+			mask |= EPOLLOUT | EPOLLWRNORM;
+	}
+	mutex_unlock(&c->io_mutex);
+	return mask;
+}
+
+/**
+ * Initialization of struct file_operations
+ */
+static const struct file_operations channel_fops = {
+	.owner = THIS_MODULE,
+	.read = comp_read,
+	.write = comp_write,
+	.open = comp_open,
+	.release = comp_close,
+	.poll = comp_poll,
+};
+
+/**
+ * comp_disconnect_channel - disconnect a channel
+ * @iface: pointer to interface instance
+ * @channel_id: channel index
+ *
+ * This frees allocated memory and removes the cdev that represents this
+ * channel in user space.
+ */
+static int comp_disconnect_channel(struct most_interface *iface, int channel_id)
+{
+	struct comp_channel *c;
+
+	c = get_channel(iface, channel_id);
+	if (!c)
+		return -EINVAL;
+
+	mutex_lock(&c->io_mutex);
+	spin_lock(&c->unlink);
+	c->dev = NULL;
+	spin_unlock(&c->unlink);
+	destroy_cdev(c);
+	if (c->access_ref) {
+		stop_channel(c);
+		wake_up_interruptible(&c->wq);
+		mutex_unlock(&c->io_mutex);
+	} else {
+		mutex_unlock(&c->io_mutex);
+		destroy_channel(c);
+	}
+	return 0;
+}
+
+/**
+ * comp_rx_completion - completion handler for rx channels
+ * @mbo: pointer to buffer object that has completed
+ *
+ * This searches for the channel linked to this MBO and stores it in the local
+ * fifo buffer.
+ */
+static int comp_rx_completion(struct mbo *mbo)
+{
+	struct comp_channel *c;
+
+	if (!mbo)
+		return -EINVAL;
+
+	c = get_channel(mbo->ifp, mbo->hdm_channel_id);
+	if (!c)
+		return -EINVAL;
+
+	spin_lock(&c->unlink);
+	if (!c->access_ref || !c->dev) {
+		spin_unlock(&c->unlink);
+		return -ENODEV;
+	}
+	kfifo_in(&c->fifo, &mbo, 1);
+	spin_unlock(&c->unlink);
+#ifdef DEBUG_MESG
+	if (kfifo_is_full(&c->fifo))
+		dev_warn(c->dev, "Fifo is full\n");
+#endif
+	wake_up_interruptible(&c->wq);
+	return 0;
+}
+
+/**
+ * comp_tx_completion - completion handler for tx channels
+ * @iface: pointer to interface instance
+ * @channel_id: channel index/ID
+ *
+ * This wakes sleeping processes in the wait-queue.
+ */
+static int comp_tx_completion(struct most_interface *iface, int channel_id)
+{
+	struct comp_channel *c;
+
+	c = get_channel(iface, channel_id);
+	if (!c)
+		return -EINVAL;
+
+	if ((channel_id < 0) || (channel_id >= iface->num_channels)) {
+		dev_warn(c->dev, "Channel ID out of range\n");
+		return -EINVAL;
+	}
+
+	wake_up_interruptible(&c->wq);
+	return 0;
+}
+
+/**
+ * comp_probe - probe function of the driver module
+ * @iface: pointer to interface instance
+ * @channel_id: channel index/ID
+ * @cfg: pointer to actual channel configuration
+ * @name: name of the device to be created
+ *
+ * This allocates achannel object and creates the device node in /dev
+ *
+ * Returns 0 on success or error code otherwise.
+ */
+static int comp_probe(struct most_interface *iface, int channel_id,
+		      struct most_channel_config *cfg, char *name, char *args)
+{
+	struct comp_channel *c;
+	unsigned long cl_flags;
+	int retval;
+	int current_minor;
+
+	if (!cfg || !name)
+		return -EINVAL;
+
+	c = get_channel(iface, channel_id);
+	if (c)
+		return -EEXIST;
+
+	current_minor = ida_simple_get(&comp.minor_id, 0, 0, GFP_KERNEL);
+	if (current_minor < 0)
+		return current_minor;
+
+	c = kzalloc(sizeof(*c), GFP_KERNEL);
+	if (!c) {
+		retval = -ENOMEM;
+		goto err_remove_ida;
+	}
+
+	c->devno = MKDEV(comp.major, current_minor);
+	cdev_init(&c->cdev, &channel_fops);
+	c->cdev.owner = THIS_MODULE;
+	retval = cdev_add(&c->cdev, c->devno, 1);
+	if (retval < 0)
+		goto err_free_c;
+	c->iface = iface;
+	c->cfg = cfg;
+	c->channel_id = channel_id;
+	c->access_ref = 0;
+	spin_lock_init(&c->unlink);
+	INIT_KFIFO(c->fifo);
+	retval = kfifo_alloc(&c->fifo, cfg->num_buffers, GFP_KERNEL);
+	if (retval)
+		goto err_del_cdev_and_free_channel;
+	init_waitqueue_head(&c->wq);
+	mutex_init(&c->io_mutex);
+	spin_lock_irqsave(&ch_list_lock, cl_flags);
+	list_add_tail(&c->list, &channel_list);
+	spin_unlock_irqrestore(&ch_list_lock, cl_flags);
+	c->dev = device_create(comp.class, NULL, c->devno, NULL, "%s", name);
+
+	if (IS_ERR(c->dev)) {
+		retval = PTR_ERR(c->dev);
+		goto err_free_kfifo_and_del_list;
+	}
+	kobject_uevent(&c->dev->kobj, KOBJ_ADD);
+	return 0;
+
+err_free_kfifo_and_del_list:
+	kfifo_free(&c->fifo);
+	list_del(&c->list);
+err_del_cdev_and_free_channel:
+	cdev_del(&c->cdev);
+err_free_c:
+	kfree(c);
+err_remove_ida:
+	ida_simple_remove(&comp.minor_id, current_minor);
+	return retval;
+}
+
+static struct cdev_component comp = {
+	.cc = {
+		.mod = THIS_MODULE,
+		.name = "cdev",
+		.probe_channel = comp_probe,
+		.disconnect_channel = comp_disconnect_channel,
+		.rx_completion = comp_rx_completion,
+		.tx_completion = comp_tx_completion,
+	},
+};
+
+static int __init most_cdev_init(void)
+{
+	int err;
+
+	comp.class = class_create(THIS_MODULE, "most_cdev");
+	if (IS_ERR(comp.class))
+		return PTR_ERR(comp.class);
+
+	ida_init(&comp.minor_id);
+
+	err = alloc_chrdev_region(&comp.devno, 0, CHRDEV_REGION_SIZE, "cdev");
+	if (err < 0)
+		goto dest_ida;
+	comp.major = MAJOR(comp.devno);
+	err = most_register_component(&comp.cc);
+	if (err)
+		goto free_cdev;
+	err = most_register_configfs_subsys(&comp.cc);
+	if (err)
+		goto deregister_comp;
+	return 0;
+
+deregister_comp:
+	most_deregister_component(&comp.cc);
+free_cdev:
+	unregister_chrdev_region(comp.devno, CHRDEV_REGION_SIZE);
+dest_ida:
+	ida_destroy(&comp.minor_id);
+	class_destroy(comp.class);
+	return err;
+}
+
+static void __exit most_cdev_exit(void)
+{
+	struct comp_channel *c, *tmp;
+
+	most_deregister_configfs_subsys(&comp.cc);
+	most_deregister_component(&comp.cc);
+
+	list_for_each_entry_safe(c, tmp, &channel_list, list) {
+		destroy_cdev(c);
+		destroy_channel(c);
+	}
+	unregister_chrdev_region(comp.devno, CHRDEV_REGION_SIZE);
+	ida_destroy(&comp.minor_id);
+	class_destroy(comp.class);
+}
+
+module_init(most_cdev_init);
+module_exit(most_cdev_exit);
+MODULE_AUTHOR("Christian Gromm <christian.gromm@microchip.com>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("character device component for mostcore");