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, 645 insertions, 0 deletions

diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
new file mode 100644
index 000000000..900a64ad2
--- /dev/null
+++ b/drivers/usb/usb-skeleton.c
@@ -0,0 +1,645 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * USB Skeleton driver - 2.2
+ *
+ * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
+ *
+ * This driver is based on the 2.6.3 version of drivers/usb/usb-skeleton.c
+ * but has been rewritten to be easier to read and use.
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/kref.h>
+#include <linux/uaccess.h>
+#include <linux/usb.h>
+#include <linux/mutex.h>
+
+
+/* Define these values to match your devices */
+#define USB_SKEL_VENDOR_ID	0xfff0
+#define USB_SKEL_PRODUCT_ID	0xfff0
+
+/* table of devices that work with this driver */
+static const struct usb_device_id skel_table[] = {
+	{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
+	{ }					/* Terminating entry */
+};
+MODULE_DEVICE_TABLE(usb, skel_table);
+
+
+/* Get a minor range for your devices from the usb maintainer */
+#define USB_SKEL_MINOR_BASE	192
+
+/* our private defines. if this grows any larger, use your own .h file */
+#define MAX_TRANSFER		(PAGE_SIZE - 512)
+/*
+ * MAX_TRANSFER is chosen so that the VM is not stressed by
+ * allocations > PAGE_SIZE and the number of packets in a page
+ * is an integer 512 is the largest possible packet on EHCI
+ */
+#define WRITES_IN_FLIGHT	8
+/* arbitrarily chosen */
+
+/* Structure to hold all of our device specific stuff */
+struct usb_skel {
+	struct usb_device	*udev;			/* the usb device for this device */
+	struct usb_interface	*interface;		/* the interface for this device */
+	struct semaphore	limit_sem;		/* limiting the number of writes in progress */
+	struct usb_anchor	submitted;		/* in case we need to retract our submissions */
+	struct urb		*bulk_in_urb;		/* the urb to read data with */
+	unsigned char           *bulk_in_buffer;	/* the buffer to receive data */
+	size_t			bulk_in_size;		/* the size of the receive buffer */
+	size_t			bulk_in_filled;		/* number of bytes in the buffer */
+	size_t			bulk_in_copied;		/* already copied to user space */
+	__u8			bulk_in_endpointAddr;	/* the address of the bulk in endpoint */
+	__u8			bulk_out_endpointAddr;	/* the address of the bulk out endpoint */
+	int			errors;			/* the last request tanked */
+	bool			ongoing_read;		/* a read is going on */
+	spinlock_t		err_lock;		/* lock for errors */
+	struct kref		kref;
+	struct mutex		io_mutex;		/* synchronize I/O with disconnect */
+	unsigned long		disconnected:1;
+	wait_queue_head_t	bulk_in_wait;		/* to wait for an ongoing read */
+};
+#define to_skel_dev(d) container_of(d, struct usb_skel, kref)
+
+static struct usb_driver skel_driver;
+static void skel_draw_down(struct usb_skel *dev);
+
+static void skel_delete(struct kref *kref)
+{
+	struct usb_skel *dev = to_skel_dev(kref);
+
+	usb_free_urb(dev->bulk_in_urb);
+	usb_put_intf(dev->interface);
+	usb_put_dev(dev->udev);
+	kfree(dev->bulk_in_buffer);
+	kfree(dev);
+}
+
+static int skel_open(struct inode *inode, struct file *file)
+{
+	struct usb_skel *dev;
+	struct usb_interface *interface;
+	int subminor;
+	int retval = 0;
+
+	subminor = iminor(inode);
+
+	interface = usb_find_interface(&skel_driver, subminor);
+	if (!interface) {
+		pr_err("%s - error, can't find device for minor %d\n",
+			__func__, subminor);
+		retval = -ENODEV;
+		goto exit;
+	}
+
+	dev = usb_get_intfdata(interface);
+	if (!dev) {
+		retval = -ENODEV;
+		goto exit;
+	}
+
+	retval = usb_autopm_get_interface(interface);
+	if (retval)
+		goto exit;
+
+	/* increment our usage count for the device */
+	kref_get(&dev->kref);
+
+	/* save our object in the file's private structure */
+	file->private_data = dev;
+
+exit:
+	return retval;
+}
+
+static int skel_release(struct inode *inode, struct file *file)
+{
+	struct usb_skel *dev;
+
+	dev = file->private_data;
+	if (dev == NULL)
+		return -ENODEV;
+
+	/* allow the device to be autosuspended */
+	usb_autopm_put_interface(dev->interface);
+
+	/* decrement the count on our device */
+	kref_put(&dev->kref, skel_delete);
+	return 0;
+}
+
+static int skel_flush(struct file *file, fl_owner_t id)
+{
+	struct usb_skel *dev;
+	int res;
+
+	dev = file->private_data;
+	if (dev == NULL)
+		return -ENODEV;
+
+	/* wait for io to stop */
+	mutex_lock(&dev->io_mutex);
+	skel_draw_down(dev);
+
+	/* read out errors, leave subsequent opens a clean slate */
+	spin_lock_irq(&dev->err_lock);
+	res = dev->errors ? (dev->errors == -EPIPE ? -EPIPE : -EIO) : 0;
+	dev->errors = 0;
+	spin_unlock_irq(&dev->err_lock);
+
+	mutex_unlock(&dev->io_mutex);
+
+	return res;
+}
+
+static void skel_read_bulk_callback(struct urb *urb)
+{
+	struct usb_skel *dev;
+	unsigned long flags;
+
+	dev = urb->context;
+
+	spin_lock_irqsave(&dev->err_lock, flags);
+	/* sync/async unlink faults aren't errors */
+	if (urb->status) {
+		if (!(urb->status == -ENOENT ||
+		    urb->status == -ECONNRESET ||
+		    urb->status == -ESHUTDOWN))
+			dev_err(&dev->interface->dev,
+				"%s - nonzero write bulk status received: %d\n",
+				__func__, urb->status);
+
+		dev->errors = urb->status;
+	} else {
+		dev->bulk_in_filled = urb->actual_length;
+	}
+	dev->ongoing_read = 0;
+	spin_unlock_irqrestore(&dev->err_lock, flags);
+
+	wake_up_interruptible(&dev->bulk_in_wait);
+}
+
+static int skel_do_read_io(struct usb_skel *dev, size_t count)
+{
+	int rv;
+
+	/* prepare a read */
+	usb_fill_bulk_urb(dev->bulk_in_urb,
+			dev->udev,
+			usb_rcvbulkpipe(dev->udev,
+				dev->bulk_in_endpointAddr),
+			dev->bulk_in_buffer,
+			min(dev->bulk_in_size, count),
+			skel_read_bulk_callback,
+			dev);
+	/* tell everybody to leave the URB alone */
+	spin_lock_irq(&dev->err_lock);
+	dev->ongoing_read = 1;
+	spin_unlock_irq(&dev->err_lock);
+
+	/* submit bulk in urb, which means no data to deliver */
+	dev->bulk_in_filled = 0;
+	dev->bulk_in_copied = 0;
+
+	/* do it */
+	rv = usb_submit_urb(dev->bulk_in_urb, GFP_KERNEL);
+	if (rv < 0) {
+		dev_err(&dev->interface->dev,
+			"%s - failed submitting read urb, error %d\n",
+			__func__, rv);
+		rv = (rv == -ENOMEM) ? rv : -EIO;
+		spin_lock_irq(&dev->err_lock);
+		dev->ongoing_read = 0;
+		spin_unlock_irq(&dev->err_lock);
+	}
+
+	return rv;
+}
+
+static ssize_t skel_read(struct file *file, char *buffer, size_t count,
+			 loff_t *ppos)
+{
+	struct usb_skel *dev;
+	int rv;
+	bool ongoing_io;
+
+	dev = file->private_data;
+
+	if (!count)
+		return 0;
+
+	/* no concurrent readers */
+	rv = mutex_lock_interruptible(&dev->io_mutex);
+	if (rv < 0)
+		return rv;
+
+	if (dev->disconnected) {		/* disconnect() was called */
+		rv = -ENODEV;
+		goto exit;
+	}
+
+	/* if IO is under way, we must not touch things */
+retry:
+	spin_lock_irq(&dev->err_lock);
+	ongoing_io = dev->ongoing_read;
+	spin_unlock_irq(&dev->err_lock);
+
+	if (ongoing_io) {
+		/* nonblocking IO shall not wait */
+		if (file->f_flags & O_NONBLOCK) {
+			rv = -EAGAIN;
+			goto exit;
+		}
+		/*
+		 * IO may take forever
+		 * hence wait in an interruptible state
+		 */
+		rv = wait_event_interruptible(dev->bulk_in_wait, (!dev->ongoing_read));
+		if (rv < 0)
+			goto exit;
+	}
+
+	/* errors must be reported */
+	rv = dev->errors;
+	if (rv < 0) {
+		/* any error is reported once */
+		dev->errors = 0;
+		/* to preserve notifications about reset */
+		rv = (rv == -EPIPE) ? rv : -EIO;
+		/* report it */
+		goto exit;
+	}
+
+	/*
+	 * if the buffer is filled we may satisfy the read
+	 * else we need to start IO
+	 */
+
+	if (dev->bulk_in_filled) {
+		/* we had read data */
+		size_t available = dev->bulk_in_filled - dev->bulk_in_copied;
+		size_t chunk = min(available, count);
+
+		if (!available) {
+			/*
+			 * all data has been used
+			 * actual IO needs to be done
+			 */
+			rv = skel_do_read_io(dev, count);
+			if (rv < 0)
+				goto exit;
+			else
+				goto retry;
+		}
+		/*
+		 * data is available
+		 * chunk tells us how much shall be copied
+		 */
+
+		if (copy_to_user(buffer,
+				 dev->bulk_in_buffer + dev->bulk_in_copied,
+				 chunk))
+			rv = -EFAULT;
+		else
+			rv = chunk;
+
+		dev->bulk_in_copied += chunk;
+
+		/*
+		 * if we are asked for more than we have,
+		 * we start IO but don't wait
+		 */
+		if (available < count)
+			skel_do_read_io(dev, count - chunk);
+	} else {
+		/* no data in the buffer */
+		rv = skel_do_read_io(dev, count);
+		if (rv < 0)
+			goto exit;
+		else
+			goto retry;
+	}
+exit:
+	mutex_unlock(&dev->io_mutex);
+	return rv;
+}
+
+static void skel_write_bulk_callback(struct urb *urb)
+{
+	struct usb_skel *dev;
+	unsigned long flags;
+
+	dev = urb->context;
+
+	/* sync/async unlink faults aren't errors */
+	if (urb->status) {
+		if (!(urb->status == -ENOENT ||
+		    urb->status == -ECONNRESET ||
+		    urb->status == -ESHUTDOWN))
+			dev_err(&dev->interface->dev,
+				"%s - nonzero write bulk status received: %d\n",
+				__func__, urb->status);
+
+		spin_lock_irqsave(&dev->err_lock, flags);
+		dev->errors = urb->status;
+		spin_unlock_irqrestore(&dev->err_lock, flags);
+	}
+
+	/* free up our allocated buffer */
+	usb_free_coherent(urb->dev, urb->transfer_buffer_length,
+			  urb->transfer_buffer, urb->transfer_dma);
+	up(&dev->limit_sem);
+}
+
+static ssize_t skel_write(struct file *file, const char *user_buffer,
+			  size_t count, loff_t *ppos)
+{
+	struct usb_skel *dev;
+	int retval = 0;
+	struct urb *urb = NULL;
+	char *buf = NULL;
+	size_t writesize = min_t(size_t, count, MAX_TRANSFER);
+
+	dev = file->private_data;
+
+	/* verify that we actually have some data to write */
+	if (count == 0)
+		goto exit;
+
+	/*
+	 * limit the number of URBs in flight to stop a user from using up all
+	 * RAM
+	 */
+	if (!(file->f_flags & O_NONBLOCK)) {
+		if (down_interruptible(&dev->limit_sem)) {
+			retval = -ERESTARTSYS;
+			goto exit;
+		}
+	} else {
+		if (down_trylock(&dev->limit_sem)) {
+			retval = -EAGAIN;
+			goto exit;
+		}
+	}
+
+	spin_lock_irq(&dev->err_lock);
+	retval = dev->errors;
+	if (retval < 0) {
+		/* any error is reported once */
+		dev->errors = 0;
+		/* to preserve notifications about reset */
+		retval = (retval == -EPIPE) ? retval : -EIO;
+	}
+	spin_unlock_irq(&dev->err_lock);
+	if (retval < 0)
+		goto error;
+
+	/* create a urb, and a buffer for it, and copy the data to the urb */
+	urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!urb) {
+		retval = -ENOMEM;
+		goto error;
+	}
+
+	buf = usb_alloc_coherent(dev->udev, writesize, GFP_KERNEL,
+				 &urb->transfer_dma);
+	if (!buf) {
+		retval = -ENOMEM;
+		goto error;
+	}
+
+	if (copy_from_user(buf, user_buffer, writesize)) {
+		retval = -EFAULT;
+		goto error;
+	}
+
+	/* this lock makes sure we don't submit URBs to gone devices */
+	mutex_lock(&dev->io_mutex);
+	if (dev->disconnected) {		/* disconnect() was called */
+		mutex_unlock(&dev->io_mutex);
+		retval = -ENODEV;
+		goto error;
+	}
+
+	/* initialize the urb properly */
+	usb_fill_bulk_urb(urb, dev->udev,
+			  usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
+			  buf, writesize, skel_write_bulk_callback, dev);
+	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+	usb_anchor_urb(urb, &dev->submitted);
+
+	/* send the data out the bulk port */
+	retval = usb_submit_urb(urb, GFP_KERNEL);
+	mutex_unlock(&dev->io_mutex);
+	if (retval) {
+		dev_err(&dev->interface->dev,
+			"%s - failed submitting write urb, error %d\n",
+			__func__, retval);
+		goto error_unanchor;
+	}
+
+	/*
+	 * release our reference to this urb, the USB core will eventually free
+	 * it entirely
+	 */
+	usb_free_urb(urb);
+
+
+	return writesize;
+
+error_unanchor:
+	usb_unanchor_urb(urb);
+error:
+	if (urb) {
+		usb_free_coherent(dev->udev, writesize, buf, urb->transfer_dma);
+		usb_free_urb(urb);
+	}
+	up(&dev->limit_sem);
+
+exit:
+	return retval;
+}
+
+static const struct file_operations skel_fops = {
+	.owner =	THIS_MODULE,
+	.read =		skel_read,
+	.write =	skel_write,
+	.open =		skel_open,
+	.release =	skel_release,
+	.flush =	skel_flush,
+	.llseek =	noop_llseek,
+};
+
+/*
+ * usb class driver info in order to get a minor number from the usb core,
+ * and to have the device registered with the driver core
+ */
+static struct usb_class_driver skel_class = {
+	.name =		"skel%d",
+	.fops =		&skel_fops,
+	.minor_base =	USB_SKEL_MINOR_BASE,
+};
+
+static int skel_probe(struct usb_interface *interface,
+		      const struct usb_device_id *id)
+{
+	struct usb_skel *dev;
+	struct usb_endpoint_descriptor *bulk_in, *bulk_out;
+	int retval;
+
+	/* allocate memory for our device state and initialize it */
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	kref_init(&dev->kref);
+	sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);
+	mutex_init(&dev->io_mutex);
+	spin_lock_init(&dev->err_lock);
+	init_usb_anchor(&dev->submitted);
+	init_waitqueue_head(&dev->bulk_in_wait);
+
+	dev->udev = usb_get_dev(interface_to_usbdev(interface));
+	dev->interface = usb_get_intf(interface);
+
+	/* set up the endpoint information */
+	/* use only the first bulk-in and bulk-out endpoints */
+	retval = usb_find_common_endpoints(interface->cur_altsetting,
+			&bulk_in, &bulk_out, NULL, NULL);
+	if (retval) {
+		dev_err(&interface->dev,
+			"Could not find both bulk-in and bulk-out endpoints\n");
+		goto error;
+	}
+
+	dev->bulk_in_size = usb_endpoint_maxp(bulk_in);
+	dev->bulk_in_endpointAddr = bulk_in->bEndpointAddress;
+	dev->bulk_in_buffer = kmalloc(dev->bulk_in_size, GFP_KERNEL);
+	if (!dev->bulk_in_buffer) {
+		retval = -ENOMEM;
+		goto error;
+	}
+	dev->bulk_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!dev->bulk_in_urb) {
+		retval = -ENOMEM;
+		goto error;
+	}
+
+	dev->bulk_out_endpointAddr = bulk_out->bEndpointAddress;
+
+	/* save our data pointer in this interface device */
+	usb_set_intfdata(interface, dev);
+
+	/* we can register the device now, as it is ready */
+	retval = usb_register_dev(interface, &skel_class);
+	if (retval) {
+		/* something prevented us from registering this driver */
+		dev_err(&interface->dev,
+			"Not able to get a minor for this device.\n");
+		usb_set_intfdata(interface, NULL);
+		goto error;
+	}
+
+	/* let the user know what node this device is now attached to */
+	dev_info(&interface->dev,
+		 "USB Skeleton device now attached to USBSkel-%d",
+		 interface->minor);
+	return 0;
+
+error:
+	/* this frees allocated memory */
+	kref_put(&dev->kref, skel_delete);
+
+	return retval;
+}
+
+static void skel_disconnect(struct usb_interface *interface)
+{
+	struct usb_skel *dev;
+	int minor = interface->minor;
+
+	dev = usb_get_intfdata(interface);
+
+	/* give back our minor */
+	usb_deregister_dev(interface, &skel_class);
+
+	/* prevent more I/O from starting */
+	mutex_lock(&dev->io_mutex);
+	dev->disconnected = 1;
+	mutex_unlock(&dev->io_mutex);
+
+	usb_kill_urb(dev->bulk_in_urb);
+	usb_kill_anchored_urbs(&dev->submitted);
+
+	/* decrement our usage count */
+	kref_put(&dev->kref, skel_delete);
+
+	dev_info(&interface->dev, "USB Skeleton #%d now disconnected", minor);
+}
+
+static void skel_draw_down(struct usb_skel *dev)
+{
+	int time;
+
+	time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
+	if (!time)
+		usb_kill_anchored_urbs(&dev->submitted);
+	usb_kill_urb(dev->bulk_in_urb);
+}
+
+static int skel_suspend(struct usb_interface *intf, pm_message_t message)
+{
+	struct usb_skel *dev = usb_get_intfdata(intf);
+
+	if (!dev)
+		return 0;
+	skel_draw_down(dev);
+	return 0;
+}
+
+static int skel_resume(struct usb_interface *intf)
+{
+	return 0;
+}
+
+static int skel_pre_reset(struct usb_interface *intf)
+{
+	struct usb_skel *dev = usb_get_intfdata(intf);
+
+	mutex_lock(&dev->io_mutex);
+	skel_draw_down(dev);
+
+	return 0;
+}
+
+static int skel_post_reset(struct usb_interface *intf)
+{
+	struct usb_skel *dev = usb_get_intfdata(intf);
+
+	/* we are sure no URBs are active - no locking needed */
+	dev->errors = -EPIPE;
+	mutex_unlock(&dev->io_mutex);
+
+	return 0;
+}
+
+static struct usb_driver skel_driver = {
+	.name =		"skeleton",
+	.probe =	skel_probe,
+	.disconnect =	skel_disconnect,
+	.suspend =	skel_suspend,
+	.resume =	skel_resume,
+	.pre_reset =	skel_pre_reset,
+	.post_reset =	skel_post_reset,
+	.id_table =	skel_table,
+	.supports_autosuspend = 1,
+};
+
+module_usb_driver(skel_driver);
+
+MODULE_LICENSE("GPL v2");