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, 598 insertions, 0 deletions

diff --git a/drivers/usb/gadget/function/f_loopback.c b/drivers/usb/gadget/function/f_loopback.c
new file mode 100644
index 000000000..ae41f556e
--- /dev/null
+++ b/drivers/usb/gadget/function/f_loopback.c
@@ -0,0 +1,598 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * f_loopback.c - USB peripheral loopback configuration driver
+ *
+ * Copyright (C) 2003-2008 David Brownell
+ * Copyright (C) 2008 by Nokia Corporation
+ */
+
+/* #define VERBOSE_DEBUG */
+
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/usb/composite.h>
+
+#include "g_zero.h"
+#include "u_f.h"
+
+/*
+ * LOOPBACK FUNCTION ... a testing vehicle for USB peripherals,
+ *
+ * This takes messages of various sizes written OUT to a device, and loops
+ * them back so they can be read IN from it.  It has been used by certain
+ * test applications.  It supports limited testing of data queueing logic.
+ */
+struct f_loopback {
+	struct usb_function	function;
+
+	struct usb_ep		*in_ep;
+	struct usb_ep		*out_ep;
+
+	unsigned                qlen;
+	unsigned                buflen;
+};
+
+static inline struct f_loopback *func_to_loop(struct usb_function *f)
+{
+	return container_of(f, struct f_loopback, function);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static struct usb_interface_descriptor loopback_intf = {
+	.bLength =		sizeof(loopback_intf),
+	.bDescriptorType =	USB_DT_INTERFACE,
+
+	.bNumEndpoints =	2,
+	.bInterfaceClass =	USB_CLASS_VENDOR_SPEC,
+	/* .iInterface = DYNAMIC */
+};
+
+/* full speed support: */
+
+static struct usb_endpoint_descriptor fs_loop_source_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_IN,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_endpoint_descriptor fs_loop_sink_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bEndpointAddress =	USB_DIR_OUT,
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_descriptor_header *fs_loopback_descs[] = {
+	(struct usb_descriptor_header *) &loopback_intf,
+	(struct usb_descriptor_header *) &fs_loop_sink_desc,
+	(struct usb_descriptor_header *) &fs_loop_source_desc,
+	NULL,
+};
+
+/* high speed support: */
+
+static struct usb_endpoint_descriptor hs_loop_source_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	cpu_to_le16(512),
+};
+
+static struct usb_endpoint_descriptor hs_loop_sink_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	cpu_to_le16(512),
+};
+
+static struct usb_descriptor_header *hs_loopback_descs[] = {
+	(struct usb_descriptor_header *) &loopback_intf,
+	(struct usb_descriptor_header *) &hs_loop_source_desc,
+	(struct usb_descriptor_header *) &hs_loop_sink_desc,
+	NULL,
+};
+
+/* super speed support: */
+
+static struct usb_endpoint_descriptor ss_loop_source_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	cpu_to_le16(1024),
+};
+
+static struct usb_ss_ep_comp_descriptor ss_loop_source_comp_desc = {
+	.bLength =		USB_DT_SS_EP_COMP_SIZE,
+	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
+	.bMaxBurst =		0,
+	.bmAttributes =		0,
+	.wBytesPerInterval =	0,
+};
+
+static struct usb_endpoint_descriptor ss_loop_sink_desc = {
+	.bLength =		USB_DT_ENDPOINT_SIZE,
+	.bDescriptorType =	USB_DT_ENDPOINT,
+
+	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
+	.wMaxPacketSize =	cpu_to_le16(1024),
+};
+
+static struct usb_ss_ep_comp_descriptor ss_loop_sink_comp_desc = {
+	.bLength =		USB_DT_SS_EP_COMP_SIZE,
+	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,
+	.bMaxBurst =		0,
+	.bmAttributes =		0,
+	.wBytesPerInterval =	0,
+};
+
+static struct usb_descriptor_header *ss_loopback_descs[] = {
+	(struct usb_descriptor_header *) &loopback_intf,
+	(struct usb_descriptor_header *) &ss_loop_source_desc,
+	(struct usb_descriptor_header *) &ss_loop_source_comp_desc,
+	(struct usb_descriptor_header *) &ss_loop_sink_desc,
+	(struct usb_descriptor_header *) &ss_loop_sink_comp_desc,
+	NULL,
+};
+
+/* function-specific strings: */
+
+static struct usb_string strings_loopback[] = {
+	[0].s = "loop input to output",
+	{  }			/* end of list */
+};
+
+static struct usb_gadget_strings stringtab_loop = {
+	.language	= 0x0409,	/* en-us */
+	.strings	= strings_loopback,
+};
+
+static struct usb_gadget_strings *loopback_strings[] = {
+	&stringtab_loop,
+	NULL,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int loopback_bind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct usb_composite_dev *cdev = c->cdev;
+	struct f_loopback	*loop = func_to_loop(f);
+	int			id;
+	int ret;
+
+	/* allocate interface ID(s) */
+	id = usb_interface_id(c, f);
+	if (id < 0)
+		return id;
+	loopback_intf.bInterfaceNumber = id;
+
+	id = usb_string_id(cdev);
+	if (id < 0)
+		return id;
+	strings_loopback[0].id = id;
+	loopback_intf.iInterface = id;
+
+	/* allocate endpoints */
+
+	loop->in_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_source_desc);
+	if (!loop->in_ep) {
+autoconf_fail:
+		ERROR(cdev, "%s: can't autoconfigure on %s\n",
+			f->name, cdev->gadget->name);
+		return -ENODEV;
+	}
+
+	loop->out_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_sink_desc);
+	if (!loop->out_ep)
+		goto autoconf_fail;
+
+	/* support high speed hardware */
+	hs_loop_source_desc.bEndpointAddress =
+		fs_loop_source_desc.bEndpointAddress;
+	hs_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;
+
+	/* support super speed hardware */
+	ss_loop_source_desc.bEndpointAddress =
+		fs_loop_source_desc.bEndpointAddress;
+	ss_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;
+
+	ret = usb_assign_descriptors(f, fs_loopback_descs, hs_loopback_descs,
+			ss_loopback_descs, ss_loopback_descs);
+	if (ret)
+		return ret;
+
+	DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n",
+	    (gadget_is_superspeed(c->cdev->gadget) ? "super" :
+	     (gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full")),
+			f->name, loop->in_ep->name, loop->out_ep->name);
+	return 0;
+}
+
+static void lb_free_func(struct usb_function *f)
+{
+	struct f_lb_opts *opts;
+
+	opts = container_of(f->fi, struct f_lb_opts, func_inst);
+
+	mutex_lock(&opts->lock);
+	opts->refcnt--;
+	mutex_unlock(&opts->lock);
+
+	usb_free_all_descriptors(f);
+	kfree(func_to_loop(f));
+}
+
+static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	struct f_loopback	*loop = ep->driver_data;
+	struct usb_composite_dev *cdev = loop->function.config->cdev;
+	int			status = req->status;
+
+	switch (status) {
+	case 0:				/* normal completion? */
+		if (ep == loop->out_ep) {
+			/*
+			 * We received some data from the host so let's
+			 * queue it so host can read the from our in ep
+			 */
+			struct usb_request *in_req = req->context;
+
+			in_req->zero = (req->actual < req->length);
+			in_req->length = req->actual;
+			ep = loop->in_ep;
+			req = in_req;
+		} else {
+			/*
+			 * We have just looped back a bunch of data
+			 * to host. Now let's wait for some more data.
+			 */
+			req = req->context;
+			ep = loop->out_ep;
+		}
+
+		/* queue the buffer back to host or for next bunch of data */
+		status = usb_ep_queue(ep, req, GFP_ATOMIC);
+		if (status == 0) {
+			return;
+		} else {
+			ERROR(cdev, "Unable to loop back buffer to %s: %d\n",
+			      ep->name, status);
+			goto free_req;
+		}
+
+		/* "should never get here" */
+	default:
+		ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name,
+				status, req->actual, req->length);
+		fallthrough;
+
+	/* NOTE:  since this driver doesn't maintain an explicit record
+	 * of requests it submitted (just maintains qlen count), we
+	 * rely on the hardware driver to clean up on disconnect or
+	 * endpoint disable.
+	 */
+	case -ECONNABORTED:		/* hardware forced ep reset */
+	case -ECONNRESET:		/* request dequeued */
+	case -ESHUTDOWN:		/* disconnect from host */
+free_req:
+		usb_ep_free_request(ep == loop->in_ep ?
+				    loop->out_ep : loop->in_ep,
+				    req->context);
+		free_ep_req(ep, req);
+		return;
+	}
+}
+
+static void disable_loopback(struct f_loopback *loop)
+{
+	struct usb_composite_dev	*cdev;
+
+	cdev = loop->function.config->cdev;
+	disable_endpoints(cdev, loop->in_ep, loop->out_ep, NULL, NULL);
+	VDBG(cdev, "%s disabled\n", loop->function.name);
+}
+
+static inline struct usb_request *lb_alloc_ep_req(struct usb_ep *ep, int len)
+{
+	return alloc_ep_req(ep, len);
+}
+
+static int alloc_requests(struct usb_composite_dev *cdev,
+			  struct f_loopback *loop)
+{
+	struct usb_request *in_req, *out_req;
+	int i;
+	int result = 0;
+
+	/*
+	 * allocate a bunch of read buffers and queue them all at once.
+	 * we buffer at most 'qlen' transfers; We allocate buffers only
+	 * for out transfer and reuse them in IN transfers to implement
+	 * our loopback functionality
+	 */
+	for (i = 0; i < loop->qlen && result == 0; i++) {
+		result = -ENOMEM;
+
+		in_req = usb_ep_alloc_request(loop->in_ep, GFP_ATOMIC);
+		if (!in_req)
+			goto fail;
+
+		out_req = lb_alloc_ep_req(loop->out_ep, loop->buflen);
+		if (!out_req)
+			goto fail_in;
+
+		in_req->complete = loopback_complete;
+		out_req->complete = loopback_complete;
+
+		in_req->buf = out_req->buf;
+		/* length will be set in complete routine */
+		in_req->context = out_req;
+		out_req->context = in_req;
+
+		result = usb_ep_queue(loop->out_ep, out_req, GFP_ATOMIC);
+		if (result) {
+			ERROR(cdev, "%s queue req --> %d\n",
+					loop->out_ep->name, result);
+			goto fail_out;
+		}
+	}
+
+	return 0;
+
+fail_out:
+	free_ep_req(loop->out_ep, out_req);
+fail_in:
+	usb_ep_free_request(loop->in_ep, in_req);
+fail:
+	return result;
+}
+
+static int enable_endpoint(struct usb_composite_dev *cdev,
+			   struct f_loopback *loop, struct usb_ep *ep)
+{
+	int					result;
+
+	result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
+	if (result)
+		goto out;
+
+	result = usb_ep_enable(ep);
+	if (result < 0)
+		goto out;
+	ep->driver_data = loop;
+	result = 0;
+
+out:
+	return result;
+}
+
+static int
+enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
+{
+	int					result = 0;
+
+	result = enable_endpoint(cdev, loop, loop->in_ep);
+	if (result)
+		goto out;
+
+	result = enable_endpoint(cdev, loop, loop->out_ep);
+	if (result)
+		goto disable_in;
+
+	result = alloc_requests(cdev, loop);
+	if (result)
+		goto disable_out;
+
+	DBG(cdev, "%s enabled\n", loop->function.name);
+	return 0;
+
+disable_out:
+	usb_ep_disable(loop->out_ep);
+disable_in:
+	usb_ep_disable(loop->in_ep);
+out:
+	return result;
+}
+
+static int loopback_set_alt(struct usb_function *f,
+		unsigned intf, unsigned alt)
+{
+	struct f_loopback	*loop = func_to_loop(f);
+	struct usb_composite_dev *cdev = f->config->cdev;
+
+	/* we know alt is zero */
+	disable_loopback(loop);
+	return enable_loopback(cdev, loop);
+}
+
+static void loopback_disable(struct usb_function *f)
+{
+	struct f_loopback	*loop = func_to_loop(f);
+
+	disable_loopback(loop);
+}
+
+static struct usb_function *loopback_alloc(struct usb_function_instance *fi)
+{
+	struct f_loopback	*loop;
+	struct f_lb_opts	*lb_opts;
+
+	loop = kzalloc(sizeof *loop, GFP_KERNEL);
+	if (!loop)
+		return ERR_PTR(-ENOMEM);
+
+	lb_opts = container_of(fi, struct f_lb_opts, func_inst);
+
+	mutex_lock(&lb_opts->lock);
+	lb_opts->refcnt++;
+	mutex_unlock(&lb_opts->lock);
+
+	loop->buflen = lb_opts->bulk_buflen;
+	loop->qlen = lb_opts->qlen;
+	if (!loop->qlen)
+		loop->qlen = 32;
+
+	loop->function.name = "loopback";
+	loop->function.bind = loopback_bind;
+	loop->function.set_alt = loopback_set_alt;
+	loop->function.disable = loopback_disable;
+	loop->function.strings = loopback_strings;
+
+	loop->function.free_func = lb_free_func;
+
+	return &loop->function;
+}
+
+static inline struct f_lb_opts *to_f_lb_opts(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct f_lb_opts,
+			    func_inst.group);
+}
+
+static void lb_attr_release(struct config_item *item)
+{
+	struct f_lb_opts *lb_opts = to_f_lb_opts(item);
+
+	usb_put_function_instance(&lb_opts->func_inst);
+}
+
+static struct configfs_item_operations lb_item_ops = {
+	.release		= lb_attr_release,
+};
+
+static ssize_t f_lb_opts_qlen_show(struct config_item *item, char *page)
+{
+	struct f_lb_opts *opts = to_f_lb_opts(item);
+	int result;
+
+	mutex_lock(&opts->lock);
+	result = sprintf(page, "%d\n", opts->qlen);
+	mutex_unlock(&opts->lock);
+
+	return result;
+}
+
+static ssize_t f_lb_opts_qlen_store(struct config_item *item,
+				    const char *page, size_t len)
+{
+	struct f_lb_opts *opts = to_f_lb_opts(item);
+	int ret;
+	u32 num;
+
+	mutex_lock(&opts->lock);
+	if (opts->refcnt) {
+		ret = -EBUSY;
+		goto end;
+	}
+
+	ret = kstrtou32(page, 0, &num);
+	if (ret)
+		goto end;
+
+	opts->qlen = num;
+	ret = len;
+end:
+	mutex_unlock(&opts->lock);
+	return ret;
+}
+
+CONFIGFS_ATTR(f_lb_opts_, qlen);
+
+static ssize_t f_lb_opts_bulk_buflen_show(struct config_item *item, char *page)
+{
+	struct f_lb_opts *opts = to_f_lb_opts(item);
+	int result;
+
+	mutex_lock(&opts->lock);
+	result = sprintf(page, "%d\n", opts->bulk_buflen);
+	mutex_unlock(&opts->lock);
+
+	return result;
+}
+
+static ssize_t f_lb_opts_bulk_buflen_store(struct config_item *item,
+				    const char *page, size_t len)
+{
+	struct f_lb_opts *opts = to_f_lb_opts(item);
+	int ret;
+	u32 num;
+
+	mutex_lock(&opts->lock);
+	if (opts->refcnt) {
+		ret = -EBUSY;
+		goto end;
+	}
+
+	ret = kstrtou32(page, 0, &num);
+	if (ret)
+		goto end;
+
+	opts->bulk_buflen = num;
+	ret = len;
+end:
+	mutex_unlock(&opts->lock);
+	return ret;
+}
+
+CONFIGFS_ATTR(f_lb_opts_, bulk_buflen);
+
+static struct configfs_attribute *lb_attrs[] = {
+	&f_lb_opts_attr_qlen,
+	&f_lb_opts_attr_bulk_buflen,
+	NULL,
+};
+
+static const struct config_item_type lb_func_type = {
+	.ct_item_ops    = &lb_item_ops,
+	.ct_attrs	= lb_attrs,
+	.ct_owner       = THIS_MODULE,
+};
+
+static void lb_free_instance(struct usb_function_instance *fi)
+{
+	struct f_lb_opts *lb_opts;
+
+	lb_opts = container_of(fi, struct f_lb_opts, func_inst);
+	kfree(lb_opts);
+}
+
+static struct usb_function_instance *loopback_alloc_instance(void)
+{
+	struct f_lb_opts *lb_opts;
+
+	lb_opts = kzalloc(sizeof(*lb_opts), GFP_KERNEL);
+	if (!lb_opts)
+		return ERR_PTR(-ENOMEM);
+	mutex_init(&lb_opts->lock);
+	lb_opts->func_inst.free_func_inst = lb_free_instance;
+	lb_opts->bulk_buflen = GZERO_BULK_BUFLEN;
+	lb_opts->qlen = GZERO_QLEN;
+
+	config_group_init_type_name(&lb_opts->func_inst.group, "",
+				    &lb_func_type);
+
+	return  &lb_opts->func_inst;
+}
+DECLARE_USB_FUNCTION(Loopback, loopback_alloc_instance, loopback_alloc);
+
+int __init lb_modinit(void)
+{
+	return usb_function_register(&Loopbackusb_func);
+}
+
+void __exit lb_modexit(void)
+{
+	usb_function_unregister(&Loopbackusb_func);
+}
+
+MODULE_LICENSE("GPL");