// SPDX-License-Identifier: GPL-2.0+
/*****************************************************************************/

/*
 *      devio.c  --  User space communication with USB devices.
 *
 *      Copyright (C) 1999-2000  Thomas Sailer (sailer@ife.ee.ethz.ch)
 *
 *  This file implements the usbfs/x/y files, where
 *  x is the bus number and y the device number.
 *
 *  It allows user space programs/"drivers" to communicate directly
 *  with USB devices without intervening kernel driver.
 *
 *  Revision history
 *    22.12.1999   0.1   Initial release (split from proc_usb.c)
 *    04.01.2000   0.2   Turned into its own filesystem
 *    30.09.2005   0.3   Fix user-triggerable oops in async URB delivery
 *                       (CAN-2005-3055)
 */

/*****************************************************************************/

#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/sched/signal.h>
#include <linux/slab.h>
#include <linux/signal.h>
#include <linux/poll.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/usb.h>
#include <linux/usbdevice_fs.h>
#include <linux/usb/hcd.h>      /* for usbcore internals */
#include <linux/cdev.h>
#include <linux/notifier.h>
#include <linux/security.h>
#include <linux/user_namespace.h>
#include <linux/scatterlist.h>
#include <linux/uaccess.h>
#include <linux/dma-mapping.h>
#include <asm/byteorder.h>
#include <linux/moduleparam.h>

#include "usb.h"

#define USB_MAXBUS                      64
#define USB_DEVICE_MAX                  (USB_MAXBUS * 128)
#define USB_SG_SIZE                     16384 /* split-size for large txs */

/* Mutual exclusion for removal, open, and release */
DEFINE_MUTEX(usbfs_mutex);

struct usb_dev_state {
        struct list_head list;      /* state list */
        struct usb_device *dev;
        struct file *file;
        spinlock_t lock;            /* protects the async urb lists */
        struct list_head async_pending;
        struct list_head async_completed;
        struct list_head memory_list;
        wait_queue_head_t wait;     /* wake up if a request completed */
        unsigned int discsignr;
        struct pid *disc_pid;
        const struct cred *cred;
        void __user *disccontext;
        unsigned long ifclaimed;
        u32 disabled_bulk_eps;
        bool privileges_dropped;
        unsigned long interface_allowed_mask;
};

struct usb_memory {
        struct list_head memlist;
        int vma_use_count;
        int urb_use_count;
        u32 size;
        void *mem;
        dma_addr_t dma_handle;
        unsigned long vm_start;
        struct usb_dev_state *ps;
};

struct async {
        struct list_head asynclist;
        struct usb_dev_state *ps;
        struct pid *pid;
        const struct cred *cred;
        unsigned int signr;
        unsigned int ifnum;
        void __user *userbuffer;
        void __user *userurb;
        struct urb *urb;
        struct usb_memory *usbm;
        unsigned int mem_usage;
        int status;
        u8 bulk_addr;
        u8 bulk_status;
};

static bool usbfs_snoop;
module_param(usbfs_snoop, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(usbfs_snoop, "true to log all usbfs traffic");

static unsigned usbfs_snoop_max = 65536;
module_param(usbfs_snoop_max, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(usbfs_snoop_max,
                "maximum number of bytes to print while snooping");

#define snoop(dev, format, arg...)                              \
        do {                                                    \
                if (usbfs_snoop)                                \
                        dev_info(dev, format, ## arg);          \
        } while (0)

enum snoop_when {
        SUBMIT, COMPLETE
};

#define USB_DEVICE_DEV          MKDEV(USB_DEVICE_MAJOR, 0)

/* Limit on the total amount of memory we can allocate for transfers */
static u32 usbfs_memory_mb = 16;
module_param(usbfs_memory_mb, uint, 0644);
MODULE_PARM_DESC(usbfs_memory_mb,
                "maximum MB allowed for usbfs buffers (0 = no limit)");

/* Hard limit, necessary to avoid arithmetic overflow */
#define USBFS_XFER_MAX         (UINT_MAX / 2 - 1000000)

static atomic64_t usbfs_memory_usage;   /* Total memory currently allocated */

/* Check whether it's okay to allocate more memory for a transfer */
static int usbfs_increase_memory_usage(u64 amount)
{
        u64 lim;

        lim = READ_ONCE(usbfs_memory_mb);
        lim <<= 20;

        atomic64_add(amount, &usbfs_memory_usage);

        if (lim > 0 && atomic64_read(&usbfs_memory_usage) > lim) {
                atomic64_sub(amount, &usbfs_memory_usage);
                return -ENOMEM;
        }

        return 0;
}

/* Memory for a transfer is being deallocated */
static void usbfs_decrease_memory_usage(u64 amount)
{
        atomic64_sub(amount, &usbfs_memory_usage);
}

static int connected(struct usb_dev_state *ps)
{
        return (!list_empty(&ps->list) &&
                        ps->dev->state != USB_STATE_NOTATTACHED);
}

static void dec_usb_memory_use_count(struct usb_memory *usbm, int *count)
{
        struct usb_dev_state *ps = usbm->ps;
        unsigned long flags;

        spin_lock_irqsave(&ps->lock, flags);
        --*count;
        if (usbm->urb_use_count == 0 && usbm->vma_use_count == 0) {
                list_del(&usbm->memlist);
                spin_unlock_irqrestore(&ps->lock, flags);

                usb_free_coherent(ps->dev, usbm->size, usbm->mem,
                                usbm->dma_handle);
                usbfs_decrease_memory_usage(
                        usbm->size + sizeof(struct usb_memory));
                kfree(usbm);
        } else {
                spin_unlock_irqrestore(&ps->lock, flags);
        }
}

static void usbdev_vm_open(struct vm_area_struct *vma)
{
        struct usb_memory *usbm = vma->vm_private_data;
        unsigned long flags;

        spin_lock_irqsave(&usbm->ps->lock, flags);
        ++usbm->vma_use_count;
        spin_unlock_irqrestore(&usbm->ps->lock, flags);
}

static void usbdev_vm_close(struct vm_area_struct *vma)
{
        struct usb_memory *usbm = vma->vm_private_data;

        dec_usb_memory_use_count(usbm, &usbm->vma_use_count);
}

static const struct vm_operations_struct usbdev_vm_ops = {
        .open = usbdev_vm_open,
        .close = usbdev_vm_close
};

static int usbdev_mmap(struct file *file, struct vm_area_struct *vma)
{
        struct usb_memory *usbm = NULL;
        struct usb_dev_state *ps = file->private_data;
        size_t size = vma->vm_end - vma->vm_start;
        void *mem;
        unsigned long flags;
        dma_addr_t dma_handle;
        int ret;

        ret = usbfs_increase_memory_usage(size + sizeof(struct usb_memory));
        if (ret)
                goto error;

        usbm = kzalloc(sizeof(struct usb_memory), GFP_KERNEL);
        if (!usbm) {
                ret = -ENOMEM;
                goto error_decrease_mem;
        }

        mem = usb_alloc_coherent(ps->dev, size, GFP_USER | __GFP_NOWARN,
                        &dma_handle);
        if (!mem) {
                ret = -ENOMEM;
                goto error_free_usbm;
        }

        memset(mem, 0, size);

        usbm->mem = mem;
        usbm->dma_handle = dma_handle;
        usbm->size = size;
        usbm->ps = ps;
        usbm->vm_start = vma->vm_start;
        usbm->vma_use_count = 1;
        INIT_LIST_HEAD(&usbm->memlist);

        if (remap_pfn_range(vma, vma->vm_start,
                        virt_to_phys(usbm->mem) >> PAGE_SHIFT,
                        size, vma->vm_page_prot) < 0) {
                dec_usb_memory_use_count(usbm, &usbm->vma_use_count);
                return -EAGAIN;
        }

        vma->vm_flags |= VM_IO;
        vma->vm_flags |= (VM_DONTEXPAND | VM_DONTDUMP);
        vma->vm_ops = &usbdev_vm_ops;
        vma->vm_private_data = usbm;

        spin_lock_irqsave(&ps->lock, flags);
        list_add_tail(&usbm->memlist, &ps->memory_list);
        spin_unlock_irqrestore(&ps->lock, flags);

        return 0;

error_free_usbm:
        kfree(usbm);
error_decrease_mem:
        usbfs_decrease_memory_usage(size + sizeof(struct usb_memory));
error:
        return ret;
}

static ssize_t usbdev_read(struct file *file, char __user *buf, size_t nbytes,
                           loff_t *ppos)
{
        struct usb_dev_state *ps = file->private_data;
        struct usb_device *dev = ps->dev;
        ssize_t ret = 0;
        unsigned len;
        loff_t pos;
        int i;

        pos = *ppos;
        usb_lock_device(dev);
        if (!connected(ps)) {
                ret = -ENODEV;
                goto err;
        } else if (pos < 0) {
                ret = -EINVAL;
                goto err;
        }

        if (pos < sizeof(struct usb_device_descriptor)) {
                /* 18 bytes - fits on the stack */
                struct usb_device_descriptor temp_desc;

                memcpy(&temp_desc, &dev->descriptor, sizeof(dev->descriptor));
                le16_to_cpus(&temp_desc.bcdUSB);
                le16_to_cpus(&temp_desc.idVendor);
                le16_to_cpus(&temp_desc.idProduct);
                le16_to_cpus(&temp_desc.bcdDevice);

                len = sizeof(struct usb_device_descriptor) - pos;
                if (len > nbytes)
                        len = nbytes;
                if (copy_to_user(buf, ((char *)&temp_desc) + pos, len)) {
                        ret = -EFAULT;
                        goto err;
                }

                *ppos += len;
                buf += len;
                nbytes -= len;
                ret += len;
        }

        pos = sizeof(struct usb_device_descriptor);
        for (i = 0; nbytes && i < dev->descriptor.bNumConfigurations; i++) {
                struct usb_config_descriptor *config =
                        (struct usb_config_descriptor *)dev->rawdescriptors[i];
                unsigned int length = le16_to_cpu(config->wTotalLength);

                if (*ppos < pos + length) {

                        /* The descriptor may claim to be longer than it
                         * really is.  Here is the actual allocated length. */
                        unsigned alloclen =
                                le16_to_cpu(dev->config[i].desc.wTotalLength);

                        len = length - (*ppos - pos);
                        if (len > nbytes)
                                len = nbytes;

                        /* Simply don't write (skip over) unallocated parts */
                        if (alloclen > (*ppos - pos)) {
                                alloclen -= (*ppos - pos);
                                if (copy_to_user(buf,
                                    dev->rawdescriptors[i] + (*ppos - pos),
                                    min(len, alloclen))) {
                                        ret = -EFAULT;
                                        goto err;
                                }
                        }

                        *ppos += len;
                        buf += len;
                        nbytes -= len;
                        ret += len;
                }

                pos += length;
        }

err:
        usb_unlock_device(dev);
        return ret;
}

/*
 * async list handling
 */

static struct async *alloc_async(unsigned int numisoframes)
{
        struct async *as;

        as = kzalloc(sizeof(struct async), GFP_KERNEL);
        if (!as)
                return NULL;
        as->urb = usb_alloc_urb(numisoframes, GFP_KERNEL);
        if (!as->urb) {
                kfree(as);
                return NULL;
        }
        return as;
}

static void free_async(struct async *as)
{
        int i;

        put_pid(as->pid);
        if (as->cred)
                put_cred(as->cred);
        for (i = 0; i < as->urb->num_sgs; i++) {
                if (sg_page(&as->urb->sg[i]))
                        kfree(sg_virt(&as->urb->sg[i]));
        }

        kfree(as->urb->sg);
        if (as->usbm == NULL)
                kfree(as->urb->transfer_buffer);
        else
                dec_usb_memory_use_count(as->usbm, &as->usbm->urb_use_count);

        kfree(as->urb->setup_packet);
        usb_free_urb(as->urb);
        usbfs_decrease_memory_usage(as->mem_usage);
        kfree(as);
}

static void async_newpending(struct async *as)
{
        struct usb_dev_state *ps = as->ps;
        unsigned long flags;

        spin_lock_irqsave(&ps->lock, flags);
        list_add_tail(&as->asynclist, &ps->async_pending);
        spin_unlock_irqrestore(&ps->lock, flags);
}

static void async_removepending(struct async *as)
{
        struct usb_dev_state *ps = as->ps;
        unsigned long flags;

        spin_lock_irqsave(&ps->lock, flags);
        list_del_init(&as->asynclist);
        spin_unlock_irqrestore(&ps->lock, flags);
}

static struct async *async_getcompleted(struct usb_dev_state *ps)
{
        unsigned long flags;
        struct async *as = NULL;

        spin_lock_irqsave(&ps->lock, flags);
        if (!list_empty(&ps->async_completed)) {
                as = list_entry(ps->async_completed.next, struct async,
                                asynclist);
                list_del_init(&as->asynclist);
        }
        spin_unlock_irqrestore(&ps->lock, flags);
        return as;
}

static struct async *async_getpending(struct usb_dev_state *ps,
                                             void __user *userurb)
{
        struct async *as;

        list_for_each_entry(as, &ps->async_pending, asynclist)
                if (as->userurb == userurb) {
                        list_del_init(&as->asynclist);
                        return as;
                }

        return NULL;
}

static void snoop_urb(struct usb_device *udev,
                void __user *userurb, int pipe, unsigned length,
                int timeout_or_status, enum snoop_when when,
                unsigned char *data, unsigned data_len)
{
        static const char *types[] = {"isoc", "int", "ctrl", "bulk"};
        static const char *dirs[] = {"out", "in"};
        int ep;
        const char *t, *d;

        if (!usbfs_snoop)
                return;

        ep = usb_pipeendpoint(pipe);
        t = types[usb_pipetype(pipe)];
        d = dirs[!!usb_pipein(pipe)];

        if (userurb) {          /* Async */
                if (when == SUBMIT)
                        dev_info(&udev->dev, "userurb %pK, ep%d %s-%s, "
                                        "length %u\n",
                                        userurb, ep, t, d, length);
                else
                        dev_info(&udev->dev, "userurb %pK, ep%d %s-%s, "
                                        "actual_length %u status %d\n",
                                        userurb, ep, t, d, length,
                                        timeout_or_status);
        } else {
                if (when == SUBMIT)
                        dev_info(&udev->dev, "ep%d %s-%s, length %u, "
                                        "timeout %d\n",
                                        ep, t, d, length, timeout_or_status);
                else
                        dev_info(&udev->dev, "ep%d %s-%s, actual_length %u, "
                                        "status %d\n",
                                        ep, t, d, length, timeout_or_status);
        }

        data_len = min(data_len, usbfs_snoop_max);
        if (data && data_len > 0) {
                print_hex_dump(KERN_DEBUG, "data: ", DUMP_PREFIX_NONE, 32, 1,
                        data, data_len, 1);
        }
}

static void snoop_urb_data(struct urb *urb, unsigned len)
{
        int i, size;

        len = min(len, usbfs_snoop_max);
        if (!usbfs_snoop || len == 0)
                return;

        if (urb->num_sgs == 0) {
                print_hex_dump(KERN_DEBUG, "data: ", DUMP_PREFIX_NONE, 32, 1,
                        urb->transfer_buffer, len, 1);
                return;
        }

        for (i = 0; i < urb->num_sgs && len; i++) {
                size = (len > USB_SG_SIZE) ? USB_SG_SIZE : len;
                print_hex_dump(KERN_DEBUG, "data: ", DUMP_PREFIX_NONE, 32, 1,
                        sg_virt(&urb->sg[i]), size, 1);
                len -= size;
        }
}

static int copy_urb_data_to_user(u8 __user *userbuffer, struct urb *urb)
{
        unsigned i, len, size;

        if (urb->number_of_packets > 0)         /* Isochronous */
                len = urb->transfer_buffer_length;
        else                                    /* Non-Isoc */
                len = urb->actual_length;

        if (urb->num_sgs == 0) {
                if (copy_to_user(userbuffer, urb->transfer_buffer, len))
                        return -EFAULT;
                return 0;
        }

        for (i = 0; i < urb->num_sgs && len; i++) {
                size = (len > USB_SG_SIZE) ? USB_SG_SIZE : len;
                if (copy_to_user(userbuffer, sg_virt(&urb->sg[i]), size))
                        return -EFAULT;
                userbuffer += size;
                len -= size;
        }

        return 0;
}

#define AS_CONTINUATION 1
#define AS_UNLINK       2

static void cancel_bulk_urbs(struct usb_dev_state *ps, unsigned bulk_addr)
__releases(ps->lock)
__acquires(ps->lock)
{
        struct urb *urb;
        struct async *as;

        /* Mark all the pending URBs that match bulk_addr, up to but not
         * including the first one without AS_CONTINUATION.  If such an
         * URB is encountered then a new transfer has already started so
         * the endpoint doesn't need to be disabled; otherwise it does.
         */
        list_for_each_entry(as, &ps->async_pending, asynclist) {
                if (as->bulk_addr == bulk_addr) {
                        if (as->bulk_status != AS_CONTINUATION)
                                goto rescan;
                        as->bulk_status = AS_UNLINK;
                        as->bulk_addr = 0;
                }
        }
        ps->disabled_bulk_eps |= (1 << bulk_addr);

        /* Now carefully unlink all the marked pending URBs */
 rescan:
        list_for_each_entry(as, &ps->async_pending, asynclist) {
                if (as->bulk_status == AS_UNLINK) {
                        as->bulk_status = 0;            /* Only once */
                        urb = as->urb;
                        usb_get_urb(urb);
                        spin_unlock(&ps->lock);         /* Allow completions */
                        usb_unlink_urb(urb);
                        usb_put_urb(urb);
                        spin_lock(&ps->lock);
                        goto rescan;
                }
        }
}

static void async_completed(struct urb *urb)
{
        struct async *as = urb->context;
        struct usb_dev_state *ps = as->ps;
        struct siginfo sinfo;
        struct pid *pid = NULL;
        const struct cred *cred = NULL;
        unsigned long flags;
        int signr;

        spin_lock_irqsave(&ps->lock, flags);
        list_move_tail(&as->asynclist, &ps->async_completed);
        as->status = urb->status;
        signr = as->signr;
        if (signr) {
                clear_siginfo(&sinfo);
                sinfo.si_signo = as->signr;
                sinfo.si_errno = as->status;
                sinfo.si_code = SI_ASYNCIO;
                sinfo.si_addr = as->userurb;
                pid = get_pid(as->pid);
                cred = get_cred(as->cred);
        }
        snoop(&urb->dev->dev, "urb complete\n");
        snoop_urb(urb->dev, as->userurb, urb->pipe, urb->actual_length,
                        as->status, COMPLETE, NULL, 0);
        if ((urb->transfer_flags & URB_DIR_MASK) == URB_DIR_IN)
                snoop_urb_data(urb, urb->actual_length);

        if (as->status < 0 && as->bulk_addr && as->status != -ECONNRESET &&
                        as->status != -ENOENT)
                cancel_bulk_urbs(ps, as->bulk_addr);

        wake_up(&ps->wait);
        spin_unlock_irqrestore(&ps->lock, flags);

        if (signr) {
                kill_pid_info_as_cred(sinfo.si_signo, &sinfo, pid, cred);
                put_pid(pid);
                put_cred(cred);
        }
}

static void destroy_async(struct usb_dev_state *ps, struct list_head *list)
{
        struct urb *urb;
        struct async *as;
        unsigned long flags;

        spin_lock_irqsave(&ps->lock, flags);
        while (!list_empty(list)) {
                as = list_entry(list->next, struct async, asynclist);
                list_del_init(&as->asynclist);
                urb = as->urb;
                usb_get_urb(urb);

                /* drop the spinlock so the completion handler can run */
                spin_unlock_irqrestore(&ps->lock, flags);
                usb_kill_urb(urb);
                usb_put_urb(urb);
                spin_lock_irqsave(&ps->lock, flags);
        }
        spin_unlock_irqrestore(&ps->lock, flags);
}

static void destroy_async_on_interface(struct usb_dev_state *ps,
                                       unsigned int ifnum)
{
        struct list_head *p, *q, hitlist;
        unsigned long flags;

        INIT_LIST_HEAD(&hitlist);
        spin_lock_irqsave(&ps->lock, flags);
        list_for_each_safe(p, q, &ps->async_pending)
                if (ifnum == list_entry(p, struct async, asynclist)->ifnum)
                        list_move_tail(p, &hitlist);
        spin_unlock_irqrestore(&ps->lock, flags);
        destroy_async(ps, &hitlist);
}

static void destroy_all_async(struct usb_dev_state *ps)
{
        destroy_async(ps, &ps->async_pending);
}

/*
 * interface claims are made only at the request of user level code,
 * which can also release them (explicitly or by closing files).
 * they're also undone when devices disconnect.
 */

static int driver_probe(struct usb_interface *intf,
                        const struct usb_device_id *id)
{
        return -ENODEV;
}

static void driver_disconnect(struct usb_interface *intf)
{
        struct usb_dev_state *ps = usb_get_intfdata(intf);
        unsigned int ifnum = intf->altsetting->desc.bInterfaceNumber;

        if (!ps)
                return;

        /* NOTE:  this relies on usbcore having canceled and completed
         * all pending I/O requests; 2.6 does that.
         */

        if (likely(ifnum < 8*sizeof(ps->ifclaimed)))
                clear_bit(ifnum, &ps->ifclaimed);
        else
                dev_warn(&intf->dev, "interface number %u out of range\n",
                         ifnum);

        usb_set_intfdata(intf, NULL);

        /* force async requests to complete */
        destroy_async_on_interface(ps, ifnum);
}

/* The following routines are merely placeholders.  There is no way
 * to inform a user task about suspend or resumes.
 */
static int driver_suspend(struct usb_interface *intf, pm_message_t msg)
{
        return 0;
}

static int driver_resume(struct usb_interface *intf)
{
        return 0;
}

struct usb_driver usbfs_driver = {
        .name =         "usbfs",
        .probe =        driver_probe,
        .disconnect =   driver_disconnect,
        .suspend =      driver_suspend,
        .resume =       driver_resume,
};

static int claimintf(struct usb_dev_state *ps, unsigned int ifnum)
{
        struct usb_device *dev = ps->dev;
        struct usb_interface *intf;
        int err;

        if (ifnum >= 8*sizeof(ps->ifclaimed))
                return -EINVAL;
        /* already claimed */
        if (test_bit(ifnum, &ps->ifclaimed))
                return 0;

        if (ps->privileges_dropped &&
                        !test_bit(ifnum, &ps->interface_allowed_mask))
                return -EACCES;

        intf = usb_ifnum_to_if(dev, ifnum);
        if (!intf)
                err = -ENOENT;
        else
                err = usb_driver_claim_interface(&usbfs_driver, intf, ps);
        if (err == 0)
                set_bit(ifnum, &ps->ifclaimed);
        return err;
}

static int releaseintf(struct usb_dev_state *ps, unsigned int ifnum)
{
        struct usb_device *dev;
        struct usb_interface *intf;
        int err;

        err = -EINVAL;
        if (ifnum >= 8*sizeof(ps->ifclaimed))
                return err;
        dev = ps->dev;
        intf = usb_ifnum_to_if(dev, ifnum);
        if (!intf)
                err = -ENOENT;
        else if (test_and_clear_bit(ifnum, &ps->ifclaimed)) {
                usb_driver_release_interface(&usbfs_driver, intf);
                err = 0;
        }
        return err;
}

static int checkintf(struct usb_dev_state *ps, unsigned int ifnum)
{
        if (ps->dev->state != USB_STATE_CONFIGURED)
                return -EHOSTUNREACH;
        if (ifnum >= 8*sizeof(ps->ifclaimed))
                return -EINVAL;
        if (test_bit(ifnum, &ps->ifclaimed))
                return 0;
        /* if not yet claimed, claim it for the driver */
        dev_warn(&ps->dev->dev, "usbfs: process %d (%s) did not claim "
                 "interface %u before use\n", task_pid_nr(current),
                 current->comm, ifnum);
        return claimintf(ps, ifnum);
}

static int findintfep(struct usb_device *dev, unsigned int ep)
{
        unsigned int i, j, e;
        struct usb_interface *intf;
        struct usb_host_interface *alts;
        struct usb_endpoint_descriptor *endpt;

        if (ep & ~(USB_DIR_IN|0xf))
                return -EINVAL;
        if (!dev->actconfig)
                return -ESRCH;
        for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
                intf = dev->actconfig->interface[i];
                for (j = 0; j < intf->num_altsetting; j++) {
                        alts = &intf->altsetting[j];
                        for (e = 0; e < alts->desc.bNumEndpoints; e++) {
                                endpt = &alts->endpoint[e].desc;
                                if (endpt->bEndpointAddress == ep)
                                        return alts->desc.bInterfaceNumber;
                        }
                }
        }
        return -ENOENT;
}

static int check_ctrlrecip(struct usb_dev_state *ps, unsigned int requesttype,
                           unsigned int request, unsigned int index)
{
        int ret = 0;
        struct usb_host_interface *alt_setting;

        if (ps->dev->state != USB_STATE_UNAUTHENTICATED
         && ps->dev->state != USB_STATE_ADDRESS
         && ps->dev->state != USB_STATE_CONFIGURED)
                return -EHOSTUNREACH;
        if (USB_TYPE_VENDOR == (USB_TYPE_MASK & requesttype))
                return 0;

        /*
         * check for the special corner case 'get_device_id' in the printer
         * class specification, which we always want to allow as it is used
         * to query things like ink level, etc.
         */
        if (requesttype == 0xa1 && request == 0) {
                alt_setting = usb_find_alt_setting(ps->dev->actconfig,
                                                   index >> 8, index & 0xff);
                if (alt_setting
                 && alt_setting->desc.bInterfaceClass == USB_CLASS_PRINTER)
                        return 0;
        }

        index &= 0xff;
        switch (requesttype & USB_RECIP_MASK) {
        case USB_RECIP_ENDPOINT:
                if ((index & ~USB_DIR_IN) == 0)
                        return 0;
                ret = findintfep(ps->dev, index);
                if (ret < 0) {
                        /*
                         * Some not fully compliant Win apps seem to get
                         * index wrong and have the endpoint number here
                         * rather than the endpoint address (with the
                         * correct direction). Win does let this through,
                         * so we'll not reject it here but leave it to
                         * the device to not break KVM. But we warn.
                         */
                        ret = findintfep(ps->dev, index ^ 0x80);
                        if (ret >= 0)
                                dev_info(&ps->dev->dev,
                                        "%s: process %i (%s) requesting ep %02x but needs %02x\n",
                                        __func__, task_pid_nr(current),
                                        current->comm, index, index ^ 0x80);
                }
                if (ret >= 0)
                        ret = checkintf(ps, ret);
                break;

        case USB_RECIP_INTERFACE:
                ret = checkintf(ps, index);
                break;
        }
        return ret;
}

static struct usb_host_endpoint *ep_to_host_endpoint(struct usb_device *dev,
                                                     unsigned char ep)
{
        if (ep & USB_ENDPOINT_DIR_MASK)
                return dev->ep_in[ep & USB_ENDPOINT_NUMBER_MASK];
        else
                return dev->ep_out[ep & USB_ENDPOINT_NUMBER_MASK];
}

static int parse_usbdevfs_streams(struct usb_dev_state *ps,
                                  struct usbdevfs_streams __user *streams,
                                  unsigned int *num_streams_ret,
                                  unsigned int *num_eps_ret,
                                  struct usb_host_endpoint ***eps_ret,
                                  struct usb_interface **intf_ret)
{
        unsigned int i, num_streams, num_eps;
        struct usb_host_endpoint **eps;
        struct usb_interface *intf = NULL;
        unsigned char ep;
        int ifnum, ret;

        if (get_user(num_streams, &streams->num_streams) ||
            get_user(num_eps, &streams->num_eps))
                return -EFAULT;

        if (num_eps < 1 || num_eps > USB_MAXENDPOINTS)
                return -EINVAL;

        /* The XHCI controller allows max 2 ^ 16 streams */
        if (num_streams_ret && (num_streams < 2 || num_streams > 65536))
                return -EINVAL;

        eps = kmalloc_array(num_eps, sizeof(*eps), GFP_KERNEL);
        if (!eps)
                return -ENOMEM;

        for (i = 0; i < num_eps; i++) {
                if (get_user(ep, &streams->eps[i])) {
                        ret = -EFAULT;
                        goto error;
                }
                eps[i] = ep_to_host_endpoint(ps->dev, ep);
                if (!eps[i]) {
                        ret = -EINVAL;
                        goto error;
                }

                /* usb_alloc/free_streams operate on an usb_interface */
                ifnum = findintfep(ps->dev, ep);
                if (ifnum < 0) {
                        ret = ifnum;
                        goto error;
                }

                if (i == 0) {
                        ret = checkintf(ps, ifnum);
                        if (ret < 0)
                                goto error;
                        intf = usb_ifnum_to_if(ps->dev, ifnum);
                } else {
                        /* Verify all eps belong to the same interface */
                        if (ifnum != intf->altsetting->desc.bInterfaceNumber) {
                                ret = -EINVAL;
                                goto error;
                        }
                }
        }

        if (num_streams_ret)
                *num_streams_ret = num_streams;
        *num_eps_ret = num_eps;
        *eps_ret = eps;
        *intf_ret = intf;

        return 0;

error:
        kfree(eps);
        return ret;
}

static int match_devt(struct device *dev, void *data)
{
        return dev->devt == (dev_t) (unsigned long) data;
}

static struct usb_device *usbdev_lookup_by_devt(dev_t devt)
{
        struct device *dev;

        dev = bus_find_device(&usb_bus_type, NULL,
                              (void *) (unsigned long) devt, match_devt);
        if (!dev)
                return NULL;
        return to_usb_device(dev);
}

/*
 * file operations
 */
static int usbdev_open(struct inode *inode, struct file *file)
{
        struct usb_device *dev = NULL;
        struct usb_dev_state *ps;
        int ret;

        ret = -ENOMEM;
        ps = kzalloc(sizeof(struct usb_dev_state), GFP_KERNEL);
        if (!ps)
                goto out_free_ps;

        ret = -ENODEV;

        /* Protect against simultaneous removal or release */
        mutex_lock(&usbfs_mutex);

        /* usbdev device-node */
        if (imajor(inode) == USB_DEVICE_MAJOR)
                dev = usbdev_lookup_by_devt(inode->i_rdev);

        mutex_unlock(&usbfs_mutex);

        if (!dev)
                goto out_free_ps;

        usb_lock_device(dev);
        if (dev->state == USB_STATE_NOTATTACHED)
                goto out_unlock_device;

        ret = usb_autoresume_device(dev);
        if (ret)
                goto out_unlock_device;

        ps->dev = dev;
        ps->file = file;
        ps->interface_allowed_mask = 0xFFFFFFFF; /* 32 bits */
        spin_lock_init(&ps->lock);
        INIT_LIST_HEAD(&ps->list);
        INIT_LIST_HEAD(&ps->async_pending);
        INIT_LIST_HEAD(&ps->async_completed);
        INIT_LIST_HEAD(&ps->memory_list);
        init_waitqueue_head(&ps->wait);
        ps->disc_pid = get_pid(task_pid(current));
        ps->cred = get_current_cred();
        smp_wmb();
        list_add_tail(&ps->list, &dev->filelist);
        file->private_data = ps;
        usb_unlock_device(dev);
        snoop(&dev->dev, "opened by process %d: %s\n", task_pid_nr(current),
                        current->comm);
        return ret;

 out_unlock_device:
        usb_unlock_device(dev);
        usb_put_dev(dev);
 out_free_ps:
        kfree(ps);
        return ret;
}

static int usbdev_release(struct inode *inode, struct file *file)
{
        struct usb_dev_state *ps = file->private_data;
        struct usb_device *dev = ps->dev;
        unsigned int ifnum;
        struct async *as;

        usb_lock_device(dev);
        usb_hub_release_all_ports(dev, ps);

        list_del_init(&ps->list);

        for (ifnum = 0; ps->ifclaimed && ifnum < 8*sizeof(ps->ifclaimed);
                        ifnum++) {
                if (test_bit(ifnum, &ps->ifclaimed))
                        releaseintf(ps, ifnum);
        }
        destroy_all_async(ps);
        usb_autosuspend_device(dev);
        usb_unlock_device(dev);
        usb_put_dev(dev);
        put_pid(ps->disc_pid);
        put_cred(ps->cred);

        as = async_getcompleted(ps);
        while (as) {
                free_async(as);
                as = async_getcompleted(ps);
        }

        kfree(ps);
        return 0;
}

static int proc_control(struct usb_dev_state *ps, void __user *arg)
{
        struct usb_device *dev = ps->dev;
        struct usbdevfs_ctrltransfer ctrl;
        unsigned int tmo;
        unsigned char *tbuf;
        unsigned wLength;
        int i, pipe, ret;

        if (copy_from_user(&ctrl, arg, sizeof(ctrl)))
                return -EFAULT;
        ret = check_ctrlrecip(ps, ctrl.bRequestType, ctrl.bRequest,
                              ctrl.wIndex);
        if (ret)
                return ret;
        wLength = ctrl.wLength;         /* To suppress 64k PAGE_SIZE warning */
        if (wLength > PAGE_SIZE)
                return -EINVAL;
        ret = usbfs_increase_memory_usage(PAGE_SIZE + sizeof(struct urb) +
                        sizeof(struct usb_ctrlrequest));
        if (ret)
                return ret;
        tbuf = (unsigned char *)__get_free_page(GFP_KERNEL);
        if (!tbuf) {
                ret = -ENOMEM;
                goto done;
        }
        tmo = ctrl.timeout;
        snoop(&dev->dev, "control urb: bRequestType=%02x "
                "bRequest=%02x wValue=%04x "
                "wIndex=%04x wLength=%04x\n",
                ctrl.bRequestType, ctrl.bRequest, ctrl.wValue,
                ctrl.wIndex, ctrl.wLength);
        if (ctrl.bRequestType & 0x80) {
                if (ctrl.wLength && !access_ok(VERIFY_WRITE, ctrl.data,
                                               ctrl.wLength)) {
                        ret = -EINVAL;
                        goto done;
                }
                pipe = usb_rcvctrlpipe(dev, 0);
                snoop_urb(dev, NULL, pipe, ctrl.wLength, tmo, SUBMIT, NULL, 0);

                usb_unlock_device(dev);
                i = usb_control_msg(dev, pipe, ctrl.bRequest,
                                    ctrl.bRequestType, ctrl.wValue, ctrl.wIndex,
                                    tbuf, ctrl.wLength, tmo);
                usb_lock_device(dev);
                snoop_urb(dev, NULL, pipe, max(i, 0), min(i, 0), COMPLETE,
                          tbuf, max(i, 0));
                if ((i > 0) && ctrl.wLength) {
                        if (copy_to_user(ctrl.data, tbuf, i)) {
                                ret = -EFAULT;
                                goto done;
                        }
                }
        } else {
                if (ctrl.wLength) {
                        if (copy_from_user(tbuf, ctrl.data, ctrl.wLength)) {
                                ret = -EFAULT;
                                goto done;
                        }
                }
                pipe = usb_sndctrlpipe(dev, 0);
                snoop_urb(dev, NULL, pipe, ctrl.wLength, tmo, SUBMIT,
                        tbuf, ctrl.wLength);

                usb_unlock_device(dev);
                i = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), ctrl.bRequest,
                                    ctrl.bRequestType, ctrl.wValue, ctrl.wIndex,
                                    tbuf, ctrl.wLength, tmo);
                usb_lock_device(dev);
                snoop_urb(dev, NULL, pipe, max(i, 0), min(i, 0), COMPLETE, NULL, 0);
        }
        if (i < 0 && i != -EPIPE) {
                dev_printk(KERN_DEBUG, &dev->dev, "usbfs: USBDEVFS_CONTROL "
                           "failed cmd %s rqt %u rq %u len %u ret %d\n",
                           current->comm, ctrl.bRequestType, ctrl.bRequest,
                           ctrl.wLength, i);
        }
        ret = i;
 done:
        free_page((unsigned long) tbuf);
        usbfs_decrease_memory_usage(PAGE_SIZE + sizeof(struct urb) +
                        sizeof(struct usb_ctrlrequest));
        return ret;
}

static int proc_bulk(struct usb_dev_state *ps, void __user *arg)
{
        struct usb_device *dev = ps->dev;
        struct usbdevfs_bulktransfer bulk;
        unsigned int tmo, len1, pipe;
        int len2;
        unsigned char *tbuf;
        int i, ret;

        if (copy_from_user(&bulk, arg, sizeof(bulk)))
                return -EFAULT;
        ret = findintfep(ps->dev, bulk.ep);
        if (ret < 0)
                return ret;
        ret = checkintf(ps, ret);
        if (ret)
                return ret;
        if (bulk.ep & USB_DIR_IN)
                pipe = usb_rcvbulkpipe(dev, bulk.ep & 0x7f);
        else
                pipe = usb_sndbulkpipe(dev, bulk.ep & 0x7f);
        if (!usb_maxpacket(dev, pipe, !(bulk.ep & USB_DIR_IN)))
                return -EINVAL;
        len1 = bulk.len;
        if (len1 >= (INT_MAX - sizeof(struct urb)))
                return -EINVAL;
        ret = usbfs_increase_memory_usage(len1 + sizeof(struct urb));
        if (ret)
                return ret;
        tbuf = kmalloc(len1, GFP_KERNEL);
        if (!tbuf) {
                ret = -ENOMEM;
                goto done;
        }
        tmo = bulk.timeout;
        if (bulk.ep & 0x80) {
                if (len1 && !access_ok(VERIFY_WRITE, bulk.data, len1)) {
                        ret = -EINVAL;
                        goto done;
                }
                snoop_urb(dev, NULL, pipe, len1, tmo, SUBMIT, NULL, 0);

                usb_unlock_device(dev);
                i = usb_bulk_msg(dev, pipe, tbuf, len1, &len2, tmo);
                usb_lock_device(dev);
                snoop_urb(dev, NULL, pipe, len2, i, COMPLETE, tbuf, len2);

                if (!i && len2) {
                        if (copy_to_user(bulk.data, tbuf, len2)) {
                                ret = -EFAULT;
                                goto done;
                        }
                }
        } else {
                if (len1) {
                        if (copy_from_user(tbuf, bulk.data, len1)) {
                                ret = -EFAULT;
                                goto done;
                        }
                }
                snoop_urb(dev, NULL, pipe, len1, tmo, SUBMIT, tbuf, len1);

                usb_unlock_device(dev);
                i = usb_bulk_msg(dev, pipe, tbuf, len1, &len2, tmo);
                usb_lock_device(dev);
                snoop_urb(dev, NULL, pipe, len2, i, COMPLETE, NULL, 0);
        }
        ret = (i < 0 ? i : len2);
 done:
        kfree(tbuf);
        usbfs_decrease_memory_usage(len1 + sizeof(struct urb));
        return ret;
}

static void check_reset_of_active_ep(struct usb_device *udev,
                unsigned int epnum, char *ioctl_name)
{
        struct usb_host_endpoint **eps;
        struct usb_host_endpoint *ep;

        eps = (epnum & USB_DIR_IN) ? udev->ep_in : udev->ep_out;
        ep = eps[epnum & 0x0f];
        if (ep && !list_empty(&ep->urb_list))
                dev_warn(&udev->dev, "Process %d (%s) called USBDEVFS_%s for active endpoint 0x%02x\n",
                                task_pid_nr(current), current->comm,
                                ioctl_name, epnum);
}

static int proc_resetep(struct usb_dev_state *ps, void __user *arg)
{
        unsigned int ep;
        int ret;

        if (get_user(ep, (unsigned int __user *)arg))
                return -EFAULT;
        ret = findintfep(ps->dev, ep);
        if (ret < 0)
                return ret;
        ret = checkintf(ps, ret);
        if (ret)
                return ret;
        check_reset_of_active_ep(ps->dev, ep, "RESETEP");
        usb_reset_endpoint(ps->dev, ep);
        return 0;
}

static int proc_clearhalt(struct usb_dev_state *ps, void __user *arg)
{
        unsigned int ep;
        int pipe;
        int ret;

        if (get_user(ep, (unsigned int __user *)arg))
                return -EFAULT;
        ret = findintfep(ps->dev, ep);
        if (ret < 0)
                return ret;
        ret = checkintf(ps, ret);
        if (ret)
                return ret;
        check_reset_of_active_ep(ps->dev, ep, "CLEAR_HALT");
        if (ep & USB_DIR_IN)
                pipe = usb_rcvbulkpipe(ps->dev, ep & 0x7f);
        else
                pipe = usb_sndbulkpipe(ps->dev, ep & 0x7f);

        return usb_clear_halt(ps->dev, pipe);
}

static int proc_getdriver(struct usb_dev_state *ps, void __user *arg)
{
        struct usbdevfs_getdriver gd;
        struct usb_interface *intf;
        int ret;

        if (copy_from_user(&gd, arg, sizeof(gd)))
                return -EFAULT;
        intf = usb_ifnum_to_if(ps->dev, gd.interface);
        if (!intf || !intf->dev.driver)
                ret = -ENODATA;
        else {
                strlcpy(gd.driver, intf->dev.driver->name,
                                sizeof(gd.driver));
                ret = (copy_to_user(arg, &gd, sizeof(gd)) ? -EFAULT : 0);
        }
        return ret;
}

static int proc_connectinfo(struct usb_dev_state *ps, void __user *arg)
{
        struct usbdevfs_connectinfo ci;

        memset(&ci, 0, sizeof(ci));
        ci.devnum = ps->dev->devnum;
        ci.slow = ps->dev->speed == USB_SPEED_LOW;

        if (copy_to_user(arg, &ci, sizeof(ci)))
                return -EFAULT;
        return 0;
}

static int proc_resetdevice(struct usb_dev_state *ps)
{
        struct usb_host_config *actconfig = ps->dev->actconfig;
        struct usb_interface *interface;
        int i, number;

        /* Don't allow a device reset if the process has dropped the
         * privilege to do such things and any of the interfaces are
         * currently claimed.
         */
        if (ps->privileges_dropped && actconfig) {
                for (i = 0; i < actconfig->desc.bNumInterfaces; ++i) {
                        interface = actconfig->interface[i];
                        number = interface->cur_altsetting->desc.bInterfaceNumber;
                        if (usb_interface_claimed(interface) &&
                                        !test_bit(number, &ps->ifclaimed)) {
                                dev_warn(&ps->dev->dev,
                                        "usbfs: interface %d claimed by %s while '%s' resets device\n",
                                        number, interface->dev.driver->name, current->comm);
                                return -EACCES;
                        }
                }
        }

        return usb_reset_device(ps->dev);
}

static int proc_setintf(struct usb_dev_state *ps, void __user *arg)
{
        struct usbdevfs_setinterface setintf;
        int ret;

        if (copy_from_user(&setintf, arg, sizeof(setintf)))
                return -EFAULT;
        ret = checkintf(ps, setintf.interface);
        if (ret)
                return ret;

        destroy_async_on_interface(ps, setintf.interface);

        return usb_set_interface(ps->dev, setintf.interface,
                        setintf.altsetting);
}

static int proc_setconfig(struct usb_dev_state *ps, void __user *arg)
{
        int u;
        int status = 0;
        struct usb_host_config *actconfig;

        if (get_user(u, (int __user *)arg))
                return -EFAULT;

        actconfig = ps->dev->actconfig;

        /* Don't touch the device if any interfaces are claimed.
         * It could interfere with other drivers' operations, and if
         * an interface is claimed by usbfs it could easily deadlock.
         */
        if (actconfig) {
                int i;

                for (i = 0; i < actconfig->desc.bNumInterfaces; ++i) {
                        if (usb_interface_claimed(actconfig->interface[i])) {
                                dev_warn(&ps->dev->dev,
                                        "usbfs: interface %d claimed by %s "
                                        "while '%s' sets config #%d\n",
                                        actconfig->interface[i]
                                                ->cur_altsetting
                                                ->desc.bInterfaceNumber,
                                        actconfig->interface[i]
                                                ->dev.driver->name,
                                        current->comm, u);
                                status = -EBUSY;
                                break;
                        }
                }
        }

        /* SET_CONFIGURATION is often abused as a "cheap" driver reset,
         * so avoid usb_set_configuration()'s kick to sysfs
         */
        if (status == 0) {
                if (actconfig && actconfig->desc.bConfigurationValue == u)
                        status = usb_reset_configuration(ps->dev);
                else
                        status = usb_set_configuration(ps->dev, u);
        }

        return status;
}

static struct usb_memory *
find_memory_area(struct usb_dev_state *ps, const struct usbdevfs_urb *uurb)
{
        struct usb_memory *usbm = NULL, *iter;
        unsigned long flags;
        unsigned long uurb_start = (unsigned long)uurb->buffer;

        spin_lock_irqsave(&ps->lock, flags);
        list_for_each_entry(iter, &ps->memory_list, memlist) {
                if (uurb_start >= iter->vm_start &&
                                uurb_start < iter->vm_start + iter->size) {
                        if (uurb->buffer_length > iter->vm_start + iter->size -
                                        uurb_start) {
                                usbm = ERR_PTR(-EINVAL);
                        } else {
                                usbm = iter;
                                usbm->urb_use_count++;
                        }
                        break;
                }
        }
        spin_unlock_irqrestore(&ps->lock, flags);
        return usbm;
}

static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb,
                        struct usbdevfs_iso_packet_desc __user *iso_frame_desc,
                        void __user *arg)
{
        struct usbdevfs_iso_packet_desc *isopkt = NULL;
        struct usb_host_endpoint *ep;
        struct async *as = NULL;
        struct usb_ctrlrequest *dr = NULL;
        unsigned int u, totlen, isofrmlen;
        int i, ret, num_sgs = 0, ifnum = -1;
        int number_of_packets = 0;
        unsigned int stream_id = 0;
        void *buf;
        bool is_in;
        bool allow_short = false;
        bool allow_zero = false;
        unsigned long mask =    USBDEVFS_URB_SHORT_NOT_OK |
                                USBDEVFS_URB_BULK_CONTINUATION |
                                USBDEVFS_URB_NO_FSBR |
                                USBDEVFS_URB_ZERO_PACKET |
                                USBDEVFS_URB_NO_INTERRUPT;
        /* USBDEVFS_URB_ISO_ASAP is a special case */
        if (uurb->type == USBDEVFS_URB_TYPE_ISO)
                mask |= USBDEVFS_URB_ISO_ASAP;

        if (uurb->flags & ~mask)
                        return -EINVAL;

        if ((unsigned int)uurb->buffer_length >= USBFS_XFER_MAX)
                return -EINVAL;
        if (uurb->buffer_length > 0 && !uurb->buffer)
                return -EINVAL;
        if (!(uurb->type == USBDEVFS_URB_TYPE_CONTROL &&
            (uurb->endpoint & ~USB_ENDPOINT_DIR_MASK) == 0)) {
                ifnum = findintfep(ps->dev, uurb->endpoint);
                if (ifnum < 0)
                        return ifnum;
                ret = checkintf(ps, ifnum);
                if (ret)
                        return ret;
        }
        ep = ep_to_host_endpoint(ps->dev, uurb->endpoint);
        if (!ep)
                return -ENOENT;
        is_in = (uurb->endpoint & USB_ENDPOINT_DIR_MASK) != 0;

        u = 0;
        switch (uurb->type) {
        case USBDEVFS_URB_TYPE_CONTROL:
                if (!usb_endpoint_xfer_control(&ep->desc))
                        return -EINVAL;
                /* min 8 byte setup packet */
                if (uurb->buffer_length < 8)
                        return -EINVAL;
                dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
                if (!dr)
                        return -ENOMEM;
                if (copy_from_user(dr, uurb->buffer, 8)) {
                        ret = -EFAULT;
                        goto error;
                }
                if (uurb->buffer_length < (le16_to_cpup(&dr->wLength) + 8)) {
                        ret = -EINVAL;
                        goto error;
                }
                ret = check_ctrlrecip(ps, dr->bRequestType, dr->bRequest,
                                      le16_to_cpup(&dr->wIndex));
                if (ret)
                        goto error;
                uurb->buffer_length = le16_to_cpup(&dr->wLength);
                uurb->buffer += 8;
                if ((dr->bRequestType & USB_DIR_IN) && uurb->buffer_length) {
                        is_in = 1;
                        uurb->endpoint |= USB_DIR_IN;
                } else {
                        is_in = 0;
                        uurb->endpoint &= ~USB_DIR_IN;
                }
                if (is_in)
                        allow_short = true;
                snoop(&ps->dev->dev, "control urb: bRequestType=%02x "
                        "bRequest=%02x wValue=%04x "
                        "wIndex=%04x wLength=%04x\n",
                        dr->bRequestType, dr->bRequest,
                        __le16_to_cpup(&dr->wValue),
                        __le16_to_cpup(&dr->wIndex),
                        __le16_to_cpup(&dr->wLength));
                u = sizeof(struct usb_ctrlrequest);
                break;

        case USBDEVFS_URB_TYPE_BULK:
                if (!is_in)
                        allow_zero = true;
                else
                        allow_short = true;
                switch (usb_endpoint_type(&ep->desc)) {
                case USB_ENDPOINT_XFER_CONTROL:
                case USB_ENDPOINT_XFER_ISOC:
                        return -EINVAL;
                case USB_ENDPOINT_XFER_INT:
                        /* allow single-shot interrupt transfers */
                        uurb->type = USBDEVFS_URB_TYPE_INTERRUPT;
                        goto interrupt_urb;
                }
                num_sgs = DIV_ROUND_UP(uurb->buffer_length, USB_SG_SIZE);
                if (num_sgs == 1 || num_sgs > ps->dev->bus->sg_tablesize)
                        num_sgs = 0;
                if (ep->streams)
                        stream_id = uurb->stream_id;
                break;

        case USBDEVFS_URB_TYPE_INTERRUPT:
                if (!usb_endpoint_xfer_int(&ep->desc))
                        return -EINVAL;
 interrupt_urb:
                if (!is_in)
                        allow_zero = true;
                else
                        allow_short = true;
                break;

        case USBDEVFS_URB_TYPE_ISO:
                /* arbitrary limit */
                if (uurb->number_of_packets < 1 ||
                    uurb->number_of_packets > 128)
                        return -EINVAL;
                if (!usb_endpoint_xfer_isoc(&ep->desc))
                        return -EINVAL;
                number_of_packets = uurb->number_of_packets;
                isofrmlen = sizeof(struct usbdevfs_iso_packet_desc) *
                                   number_of_packets;
                isopkt = memdup_user(iso_frame_desc, isofrmlen);
                if (IS_ERR(isopkt)) {
                        ret = PTR_ERR(isopkt);
                        isopkt = NULL;
                        goto error;
                }
                for (totlen = u = 0; u < number_of_packets; u++) {
                        /*
                         * arbitrary limit need for USB 3.0
                         * bMaxBurst (0~15 allowed, 1~16 packets)
                         * bmAttributes (bit 1:0, mult 0~2, 1~3 packets)
                         * sizemax: 1024 * 16 * 3 = 49152
                         */
                        if (isopkt[u].length > 49152) {
                                ret = -EINVAL;
                                goto error;
                        }
                        totlen += isopkt[u].length;
                }
                u *= sizeof(struct usb_iso_packet_descriptor);
                uurb->buffer_length = totlen;
                break;

        default:
                return -EINVAL;
        }

        if (uurb->buffer_length > 0 &&
                        !access_ok(is_in ? VERIFY_WRITE : VERIFY_READ,
                                uurb->buffer, uurb->buffer_length)) {
                ret = -EFAULT;
                goto error;
        }
        as = alloc_async(number_of_packets);
        if (!as) {
                ret = -ENOMEM;
                goto error;
        }

        as->usbm = find_memory_area(ps, uurb);
        if (IS_ERR(as->usbm)) {
                ret = PTR_ERR(as->usbm);
                as->usbm = NULL;
                goto error;
        }

        /* do not use SG buffers when memory mapped segments
         * are in use
         */
        if (as->usbm)
                num_sgs = 0;

        u += sizeof(struct async) + sizeof(struct urb) + uurb->buffer_length +
             num_sgs * sizeof(struct scatterlist);
        ret = usbfs_increase_memory_usage(u);
        if (ret)
                goto error;
        as->mem_usage = u;

        if (num_sgs) {
                as->urb->sg = kmalloc_array(num_sgs,
                                            sizeof(struct scatterlist),
                                            GFP_KERNEL);
                if (!as->urb->sg) {
                        ret = -ENOMEM;
                        goto error;
                }
                as->urb->num_sgs = num_sgs;
                sg_init_table(as->urb->sg, as->urb->num_sgs);

                totlen = uurb->buffer_length;
                for (i = 0; i < as->urb->num_sgs; i++) {
                        u = (totlen > USB_SG_SIZE) ? USB_SG_SIZE : totlen;
                        buf = kmalloc(u, GFP_KERNEL);
                        if (!buf) {
                                ret = -ENOMEM;
                                goto error;
                        }
                        sg_set_buf(&as->urb->sg[i], buf, u);

                        if (!is_in) {
                                if (copy_from_user(buf, uurb->buffer, u)) {
                                        ret = -EFAULT;
                                        goto error;
                                }
                                uurb->buffer += u;
                        }
                        totlen -= u;
                }
        } else if (uurb->buffer_length > 0) {
                if (as->usbm) {
                        unsigned long uurb_start = (unsigned long)uurb->buffer;

                        as->urb->transfer_buffer = as->usbm->mem +
                                        (uurb_start - as->usbm->vm_start);
                } else {
                        as->urb->transfer_buffer = kmalloc(uurb->buffer_length,
                                        GFP_KERNEL);
                        if (!as->urb->transfer_buffer) {
                                ret = -ENOMEM;
                                goto error;
                        }
                        if (!is_in) {
                                if (copy_from_user(as->urb->transfer_buffer,
                                                   uurb->buffer,
                                                   uurb->buffer_length)) {
                                        ret = -EFAULT;
                                        goto error;
                                }
                        } else if (uurb->type == USBDEVFS_URB_TYPE_ISO) {
                                /*
                                 * Isochronous input data may end up being
                                 * discontiguous if some of the packets are
                                 * short. Clear the buffer so that the gaps
                                 * don't leak kernel data to userspace.
                                 */
                                memset(as->urb->transfer_buffer, 0,
                                                uurb->buffer_length);
                        }
                }
        }
        as->urb->dev = ps->dev;
        as->urb->pipe = (uurb->type << 30) |
                        __create_pipe(ps->dev, uurb->endpoint & 0xf) |
                        (uurb->endpoint & USB_DIR_IN);

        /* This tedious sequence is necessary because the URB_* flags
         * are internal to the kernel and subject to change, whereas
         * the USBDEVFS_URB_* flags are a user API and must not be changed.
         */
        u = (is_in ? URB_DIR_IN : URB_DIR_OUT);
        if (uurb->flags & USBDEVFS_URB_ISO_ASAP)
                u |= URB_ISO_ASAP;
        if (allow_short && uurb->flags & USBDEVFS_URB_SHORT_NOT_OK)
                u |= URB_SHORT_NOT_OK;
        if (allow_zero && uurb->flags & USBDEVFS_URB_ZERO_PACKET)
                u |= URB_ZERO_PACKET;
        if (uurb->flags & USBDEVFS_URB_NO_INTERRUPT)
                u |= URB_NO_INTERRUPT;
        as->urb->transfer_flags = u;

        if (!allow_short && uurb->flags & USBDEVFS_URB_SHORT_NOT_OK)
                dev_warn(&ps->dev->dev, "Requested nonsensical USBDEVFS_URB_SHORT_NOT_OK.\n");
        if (!allow_zero && uurb->flags & USBDEVFS_URB_ZERO_PACKET)
                dev_warn(&ps->dev->dev, "Requested nonsensical USBDEVFS_URB_ZERO_PACKET.\n");

        as->urb->transfer_buffer_length = uurb->buffer_length;
        as->urb->setup_packet = (unsigned char *)dr;
        dr = NULL;
        as->urb->start_frame = uurb->start_frame;
        as->urb->number_of_packets = number_of_packets;
        as->urb->stream_id = stream_id;

        if (ep->desc.bInterval) {
                if (uurb->type == USBDEVFS_URB_TYPE_ISO ||
                                ps->dev->speed == USB_SPEED_HIGH ||
                                ps->dev->speed >= USB_SPEED_SUPER)
                        as->urb->interval = 1 <<
                                        min(15, ep->desc.bInterval - 1);
                else
                        as->urb->interval = ep->desc.bInterval;
        }

        as->urb->context = as;
        as->urb->complete = async_completed;
        for (totlen = u = 0; u < number_of_packets; u++) {
                as->urb->iso_frame_desc[u].offset = totlen;
                as->urb->iso_frame_desc[u].length = isopkt[u].length;
                totlen += isopkt[u].length;
        }
        kfree(isopkt);
        isopkt = NULL;
        as->ps = ps;
        as->userurb = arg;
        if (as->usbm) {
                unsigned long uurb_start = (unsigned long)uurb->buffer;

                as->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
                as->urb->transfer_dma = as->usbm->dma_handle +
                                (uurb_start - as->usbm->vm_start);
        } else if (is_in && uurb->buffer_length > 0)
                as->userbuffer = uurb->buffer;
        as->signr = uurb->signr;
        as->ifnum = ifnum;
        as->pid = get_pid(task_pid(current));
        as->cred = get_current_cred();
        snoop_urb(ps->dev, as->userurb, as->urb->pipe,
                        as->urb->transfer_buffer_length, 0, SUBMIT,
                        NULL, 0);
        if (!is_in)
                snoop_urb_data(as->urb, as->urb->transfer_buffer_length);

        async_newpending(as);

        if (usb_endpoint_xfer_bulk(&ep->desc)) {
                spin_lock_irq(&ps->lock);

                /* Not exactly the endpoint address; the direction bit is
                 * shifted to the 0x10 position so that the value will be
                 * between 0 and 31.
                 */
                as->bulk_addr = usb_endpoint_num(&ep->desc) |
                        ((ep->desc.bEndpointAddress & USB_ENDPOINT_DIR_MASK)
                                >> 3);

                /* If this bulk URB is the start of a new transfer, re-enable
                 * the endpoint.  Otherwise mark it as a continuation URB.
                 */
                if (uurb->flags & USBDEVFS_URB_BULK_CONTINUATION)
                        as->bulk_status = AS_CONTINUATION;
                else
                        ps->disabled_bulk_eps &= ~(1 << as->bulk_addr);

                /* Don't accept continuation URBs if the endpoint is
                 * disabled because of an earlier error.
                 */
                if (ps->disabled_bulk_eps & (1 << as->bulk_addr))
                        ret = -EREMOTEIO;
                else
                        ret = usb_submit_urb(as->urb, GFP_ATOMIC);
                spin_unlock_irq(&ps->lock);
        } else {
                ret = usb_submit_urb(as->urb, GFP_KERNEL);
        }

        if (ret) {
                dev_printk(KERN_DEBUG, &ps->dev->dev,
                           "usbfs: usb_submit_urb returned %d\n", ret);
                snoop_urb(ps->dev, as->userurb, as->urb->pipe,
                                0, ret, COMPLETE, NULL, 0);
                async_removepending(as);
                goto error;
        }
        return 0;

 error:
        if (as && as->usbm)
                dec_usb_memory_use_count(as->usbm, &as->usbm->urb_use_count);
        kfree(isopkt);
        kfree(dr);
        if (as)
                free_async(as);
        return ret;
}

static int proc_submiturb(struct usb_dev_state *ps, void __user *arg)
{
        struct usbdevfs_urb uurb;

        if (copy_from_user(&uurb, arg, sizeof(uurb)))
                return -EFAULT;

        return proc_do_submiturb(ps, &uurb,
                        (((struct usbdevfs_urb __user *)arg)->iso_frame_desc),
                        arg);
}

static int proc_unlinkurb(struct usb_dev_state *ps, void __user *arg)
{
        struct urb *urb;
        struct async *as;
        unsigned long flags;

        spin_lock_irqsave(&ps->lock, flags);
        as = async_getpending(ps, arg);
        if (!as) {
                spin_unlock_irqrestore(&ps->lock, flags);
                return -EINVAL;
        }

        urb = as->urb;
        usb_get_urb(urb);
        spin_unlock_irqrestore(&ps->lock, flags);

        usb_kill_urb(urb);
        usb_put_urb(urb);

        return 0;
}

static void compute_isochronous_actual_length(struct urb *urb)
{
        unsigned int i;

        if (urb->number_of_packets > 0) {
                urb->actual_length = 0;
                for (i = 0; i < urb->number_of_packets; i++)
                        urb->actual_length +=
                                        urb->iso_frame_desc[i].actual_length;
        }
}

static int processcompl(struct async *as, void __user * __user *arg)
{
        struct urb *urb = as->urb;
        struct usbdevfs_urb __user *userurb = as->userurb;
        void __user *addr = as->userurb;
        unsigned int i;

        compute_isochronous_actual_length(urb);
        if (as->userbuffer && urb->actual_length) {
                if (copy_urb_data_to_user(as->userbuffer, urb))
                        goto err_out;
        }
        if (put_user(as->status, &userurb->status))
                goto err_out;
        if (put_user(urb->actual_length, &userurb->actual_length))
                goto err_out;
        if (put_user(urb->error_count, &userurb->error_count))
                goto err_out;

        if (usb_endpoint_xfer_isoc(&urb->ep->desc)) {
                for (i = 0; i < urb->number_of_packets; i++) {
                        if (put_user(urb->iso_frame_desc[i].actual_length,
                                     &userurb->iso_frame_desc[i].actual_length))
                                goto err_out;
                        if (put_user(urb->iso_frame_desc[i].status,
                                     &userurb->iso_frame_desc[i].status))
                                goto err_out;
                }
        }

        if (put_user(addr, (void __user * __user *)arg))
                return -EFAULT;
        return 0;

err_out:
        return -EFAULT;
}

static struct async *reap_as(struct usb_dev_state *ps)
{
        DECLARE_WAITQUEUE(wait, current);
        struct async *as = NULL;
        struct usb_device *dev = ps->dev;

        add_wait_queue(&ps->wait, &wait);
        for (;;) {
                __set_current_state(TASK_INTERRUPTIBLE);
                as = async_getcompleted(ps);
                if (as || !connected(ps))
                        break;
                if (signal_pending(current))
                        break;
                usb_unlock_device(dev);
                schedule();
                usb_lock_device(dev);
        }
        remove_wait_queue(&ps->wait, &wait);
        set_current_state(TASK_RUNNING);
        return as;
}

static int proc_reapurb(struct usb_dev_state *ps, void __user *arg)
{
        struct async *as = reap_as(ps);

        if (as) {
                int retval;

                snoop(&ps->dev->dev, "reap %pK\n", as->userurb);
                retval = processcompl(as, (void __user * __user *)arg);
                free_async(as);
                return retval;
        }
        if (signal_pending(current))
                return -EINTR;
        return -ENODEV;
}

static int proc_reapurbnonblock(struct usb_dev_state *ps, void __user *arg)
{
        int retval;
        struct async *as;

        as = async_getcompleted(ps);
        if (as) {
                snoop(&ps->dev->dev, "reap %pK\n", as->userurb);
                retval = processcompl(as, (void __user * __user *)arg);
                free_async(as);
        } else {
                retval = (connected(ps) ? -EAGAIN : -ENODEV);
        }
        return retval;
}

#ifdef CONFIG_COMPAT
static int proc_control_compat(struct usb_dev_state *ps,
                                struct usbdevfs_ctrltransfer32 __user *p32)
{
        struct usbdevfs_ctrltransfer __user *p;
        __u32 udata;
        p = compat_alloc_user_space(sizeof(*p));
        if (copy_in_user(p, p32, (sizeof(*p32) - sizeof(compat_caddr_t))) ||
            get_user(udata, &p32->data) ||
            put_user(compat_ptr(udata), &p->data))
                return -EFAULT;
        return proc_control(ps, p);
}

static int proc_bulk_compat(struct usb_dev_state *ps,
                        struct usbdevfs_bulktransfer32 __user *p32)
{
        struct usbdevfs_bulktransfer __user *p;
        compat_uint_t n;
        compat_caddr_t addr;

        p = compat_alloc_user_space(sizeof(*p));

        if (get_user(n, &p32->ep) || put_user(n, &p->ep) ||
            get_user(n, &p32->len) || put_user(n, &p->len) ||
            get_user(n, &p32->timeout) || put_user(n, &p->timeout) ||
            get_user(addr, &p32->data) || put_user(compat_ptr(addr), &p->data))
                return -EFAULT;

        return proc_bulk(ps, p);
}
static int proc_disconnectsignal_compat(struct usb_dev_state *ps, void __user *arg)
{
        struct usbdevfs_disconnectsignal32 ds;

        if (copy_from_user(&ds, arg, sizeof(ds)))
                return -EFAULT;
        ps->discsignr = ds.signr;
        ps->disccontext = compat_ptr(ds.context);
        return 0;
}

static int get_urb32(struct usbdevfs_urb *kurb,
                     struct usbdevfs_urb32 __user *uurb)
{
        struct usbdevfs_urb32 urb32;
        if (copy_from_user(&urb32, uurb, sizeof(*uurb)))
                return -EFAULT;
        kurb->type = urb32.type;
        kurb->endpoint = urb32.endpoint;
        kurb->status = urb32.status;
        kurb->flags = urb32.flags;
        kurb->buffer = compat_ptr(urb32.buffer);
        kurb->buffer_length = urb32.buffer_length;
        kurb->actual_length = urb32.actual_length;
        kurb->start_frame = urb32.start_frame;

        kurb->number_of_packets = urb32.number_of_packets;
        kurb->error_count = urb32.error_count;
        kurb->signr = urb32.signr;
        kurb->usercontext = compat_ptr(urb32.usercontext);
        return 0;
}

static int proc_submiturb_compat(struct usb_dev_state *ps, void __user *arg)
{
        struct usbdevfs_urb uurb;

        if (get_urb32(&uurb, (struct usbdevfs_urb32 __user *)arg))
                return -EFAULT;

        return proc_do_submiturb(ps, &uurb,
                        ((struct usbdevfs_urb32 __user *)arg)->iso_frame_desc,
                        arg);
}

static int processcompl_compat(struct async *as, void __user * __user *arg)
{
        struct urb *urb = as->urb;
        struct usbdevfs_urb32 __user *userurb = as->userurb;
        void __user *addr = as->userurb;
        unsigned int i;

        compute_isochronous_actual_length(urb);
        if (as->userbuffer && urb->actual_length) {
                if (copy_urb_data_to_user(as->userbuffer, urb))
                        return -EFAULT;
        }
        if (put_user(as->status, &userurb->status))
                return -EFAULT;
        if (put_user(urb->actual_length, &userurb->actual_length))
                return -EFAULT;
        if (put_user(urb->error_count, &userurb->error_count))
                return -EFAULT;

        if (usb_endpoint_xfer_isoc(&urb->ep->desc)) {
                for (i = 0; i < urb->number_of_packets; i++) {
                        if (put_user(urb->iso_frame_desc[i].actual_length,
                                     &userurb->iso_frame_desc[i].actual_length))
                                return -EFAULT;
                        if (put_user(urb->iso_frame_desc[i].status,
                                     &userurb->iso_frame_desc[i].status))
                                return -EFAULT;
                }
        }

        if (put_user(ptr_to_compat(addr), (u32 __user *)arg))
                return -EFAULT;
        return 0;
}

static int proc_reapurb_compat(struct usb_dev_state *ps, void __user *arg)
{
        struct async *as = reap_as(ps);

        if (as) {
                int retval;

                snoop(&ps->dev->dev, "reap %pK\n", as->userurb);
                retval = processcompl_compat(as, (void __user * __user *)arg);
                free_async(as);
                return retval;
        }
        if (signal_pending(current))
                return -EINTR;
        return -ENODEV;
}

static int proc_reapurbnonblock_compat(struct usb_dev_state *ps, void __user *arg)
{
        int retval;
        struct async *as;

        as = async_getcompleted(ps);
        if (as) {
                snoop(&ps->dev->dev, "reap %pK\n", as->userurb);
                retval = processcompl_compat(as, (void __user * __user *)arg);
                free_async(as);
        } else {
                retval = (connected(ps) ? -EAGAIN : -ENODEV);
        }
        return retval;
}


#endif

static int proc_disconnectsignal(struct usb_dev_state *ps, void __user *arg)
{
        struct usbdevfs_disconnectsignal ds;

        if (copy_from_user(&ds, arg, sizeof(ds)))
                return -EFAULT;
        ps->discsignr = ds.signr;
        ps->disccontext = ds.context;
        return 0;
}

static int proc_claiminterface(struct usb_dev_state *ps, void __user *arg)
{
        unsigned int ifnum;

        if (get_user(ifnum, (unsigned int __user *)arg))
                return -EFAULT;
        return claimintf(ps, ifnum);
}

static int proc_releaseinterface(struct usb_dev_state *ps, void __user *arg)
{
        unsigned int ifnum;
        int ret;

        if (get_user(ifnum, (unsigned int __user *)arg))
                return -EFAULT;
        ret = releaseintf(ps, ifnum);
        if (ret < 0)
                return ret;
        destroy_async_on_interface(ps, ifnum);
        return 0;
}

static int proc_ioctl(struct usb_dev_state *ps, struct usbdevfs_ioctl *ctl)
{
        int                     size;
        void                    *buf = NULL;
        int                     retval = 0;
        struct usb_interface    *intf = NULL;
        struct usb_driver       *driver = NULL;

        if (ps->privileges_dropped)
                return -EACCES;

        /* alloc buffer */
        size = _IOC_SIZE(ctl->ioctl_code);
        if (size > 0) {
                buf = kmalloc(size, GFP_KERNEL);
                if (buf == NULL)
                        return -ENOMEM;
                if ((_IOC_DIR(ctl->ioctl_code) & _IOC_WRITE)) {
                        if (copy_from_user(buf, ctl->data, size)) {
                                kfree(buf);
                                return -EFAULT;
                        }
                } else {
                        memset(buf, 0, size);
                }
        }

        if (!connected(ps)) {
                kfree(buf);
                return -ENODEV;
        }

        if (ps->dev->state != USB_STATE_CONFIGURED)
                retval = -EHOSTUNREACH;
        else if (!(intf = usb_ifnum_to_if(ps->dev, ctl->ifno)))
                retval = -EINVAL;
        else switch (ctl->ioctl_code) {

        /* disconnect kernel driver from interface */
        case USBDEVFS_DISCONNECT:
                if (intf->dev.driver) {
                        driver = to_usb_driver(intf->dev.driver);
                        dev_dbg(&intf->dev, "disconnect by usbfs\n");
                        usb_driver_release_interface(driver, intf);
                } else
                        retval = -ENODATA;
                break;

        /* let kernel drivers try to (re)bind to the interface */
        case USBDEVFS_CONNECT:
                if (!intf->dev.driver)
                        retval = device_attach(&intf->dev);
                else
                        retval = -EBUSY;
                break;

        /* talk directly to the interface's driver */
        default:
                if (intf->dev.driver)
                        driver = to_usb_driver(intf->dev.driver);
                if (driver == NULL || driver->unlocked_ioctl == NULL) {
                        retval = -ENOTTY;
                } else {
                        retval = driver->unlocked_ioctl(intf, ctl->ioctl_code, buf);
                        if (retval == -ENOIOCTLCMD)
                                retval = -ENOTTY;
                }
        }

        /* cleanup and return */
        if (retval >= 0
                        && (_IOC_DIR(ctl->ioctl_code) & _IOC_READ) != 0
                        && size > 0
                        && copy_to_user(ctl->data, buf, size) != 0)
                retval = -EFAULT;

        kfree(buf);
        return retval;
}

static int proc_ioctl_default(struct usb_dev_state *ps, void __user *arg)
{
        struct usbdevfs_ioctl   ctrl;

        if (copy_from_user(&ctrl, arg, sizeof(ctrl)))
                return -EFAULT;
        return proc_ioctl(ps, &ctrl);
}

#ifdef CONFIG_COMPAT
static int proc_ioctl_compat(struct usb_dev_state *ps, compat_uptr_t arg)
{
        struct usbdevfs_ioctl32 ioc32;
        struct usbdevfs_ioctl ctrl;

        if (copy_from_user(&ioc32, compat_ptr(arg), sizeof(ioc32)))
                return -EFAULT;
        ctrl.ifno = ioc32.ifno;
        ctrl.ioctl_code = ioc32.ioctl_code;
        ctrl.data = compat_ptr(ioc32.data);
        return proc_ioctl(ps, &ctrl);
}
#endif

static int proc_claim_port(struct usb_dev_state *ps, void __user *arg)
{
        unsigned portnum;
        int rc;

        if (get_user(portnum, (unsigned __user *) arg))
                return -EFAULT;
        rc = usb_hub_claim_port(ps->dev, portnum, ps);
        if (rc == 0)
                snoop(&ps->dev->dev, "port %d claimed by process %d: %s\n",
                        portnum, task_pid_nr(current), current->comm);
        return rc;
}

static int proc_release_port(struct usb_dev_state *ps, void __user *arg)
{
        unsigned portnum;

        if (get_user(portnum, (unsigned __user *) arg))
                return -EFAULT;
        return usb_hub_release_port(ps->dev, portnum, ps);
}

static int proc_get_capabilities(struct usb_dev_state *ps, void __user *arg)
{
        __u32 caps;

        caps = USBDEVFS_CAP_ZERO_PACKET | USBDEVFS_CAP_NO_PACKET_SIZE_LIM |
                        USBDEVFS_CAP_REAP_AFTER_DISCONNECT | USBDEVFS_CAP_MMAP |
                        USBDEVFS_CAP_DROP_PRIVILEGES;
        if (!ps->dev->bus->no_stop_on_short)
                caps |= USBDEVFS_CAP_BULK_CONTINUATION;
        if (ps->dev->bus->sg_tablesize)
                caps |= USBDEVFS_CAP_BULK_SCATTER_GATHER;

        if (put_user(caps, (__u32 __user *)arg))
                return -EFAULT;

        return 0;
}

static int proc_disconnect_claim(struct usb_dev_state *ps, void __user *arg)
{
        struct usbdevfs_disconnect_claim dc;
        struct usb_interface *intf;

        if (copy_from_user(&dc, arg, sizeof(dc)))
                return -EFAULT;

        intf = usb_ifnum_to_if(ps->dev, dc.interface);
        if (!intf)
                return -EINVAL;

        if (intf->dev.driver) {
                struct usb_driver *driver = to_usb_driver(intf->dev.driver);

                if (ps->privileges_dropped)
                        return -EACCES;

                if ((dc.flags & USBDEVFS_DISCONNECT_CLAIM_IF_DRIVER) &&
                                strncmp(dc.driver, intf->dev.driver->name,
                                        sizeof(dc.driver)) != 0)
                        return -EBUSY;

                if ((dc.flags & USBDEVFS_DISCONNECT_CLAIM_EXCEPT_DRIVER) &&
                                strncmp(dc.driver, intf->dev.driver->name,
                                        sizeof(dc.driver)) == 0)
                        return -EBUSY;

                dev_dbg(&intf->dev, "disconnect by usbfs\n");
                usb_driver_release_interface(driver, intf);
        }

        return claimintf(ps, dc.interface);
}

static int proc_alloc_streams(struct usb_dev_state *ps, void __user *arg)
{
        unsigned num_streams, num_eps;
        struct usb_host_endpoint **eps;
        struct usb_interface *intf;
        int r;

        r = parse_usbdevfs_streams(ps, arg, &num_streams, &num_eps,
                                   &eps, &intf);
        if (r)
                return r;

        destroy_async_on_interface(ps,
                                   intf->altsetting[0].desc.bInterfaceNumber);

        r = usb_alloc_streams(intf, eps, num_eps, num_streams, GFP_KERNEL);
        kfree(eps);
        return r;
}

static int proc_free_streams(struct usb_dev_state *ps, void __user *arg)
{
        unsigned num_eps;
        struct usb_host_endpoint **eps;
        struct usb_interface *intf;
        int r;

        r = parse_usbdevfs_streams(ps, arg, NULL, &num_eps, &eps, &intf);
        if (r)
                return r;

        destroy_async_on_interface(ps,
                                   intf->altsetting[0].desc.bInterfaceNumber);

        r = usb_free_streams(intf, eps, num_eps, GFP_KERNEL);
        kfree(eps);
        return r;
}

static int proc_drop_privileges(struct usb_dev_state *ps, void __user *arg)
{
        u32 data;

        if (copy_from_user(&data, arg, sizeof(data)))
                return -EFAULT;

        /* This is a one way operation. Once privileges are
         * dropped, you cannot regain them. You may however reissue
         * this ioctl to shrink the allowed interfaces mask.
         */
        ps->interface_allowed_mask &= data;
        ps->privileges_dropped = true;

        return 0;
}

/*
 * NOTE:  All requests here that have interface numbers as parameters
 * are assuming that somehow the configuration has been prevented from
 * changing.  But there's no mechanism to ensure that...
 */
static long usbdev_do_ioctl(struct file *file, unsigned int cmd,
                                void __user *p)
{
        struct usb_dev_state *ps = file->private_data;
        struct inode *inode = file_inode(file);
        struct usb_device *dev = ps->dev;
        int ret = -ENOTTY;

        if (!(file->f_mode & FMODE_WRITE))
                return -EPERM;

        usb_lock_device(dev);

        /* Reap operations are allowed even after disconnection */
        switch (cmd) {
        case USBDEVFS_REAPURB:
                snoop(&dev->dev, "%s: REAPURB\n", __func__);
                ret = proc_reapurb(ps, p);
                goto done;

        case USBDEVFS_REAPURBNDELAY:
                snoop(&dev->dev, "%s: REAPURBNDELAY\n", __func__);
                ret = proc_reapurbnonblock(ps, p);
                goto done;

#ifdef CONFIG_COMPAT
        case USBDEVFS_REAPURB32:
                snoop(&dev->dev, "%s: REAPURB32\n", __func__);
                ret = proc_reapurb_compat(ps, p);
                goto done;

        case USBDEVFS_REAPURBNDELAY32:
                snoop(&dev->dev, "%s: REAPURBNDELAY32\n", __func__);
                ret = proc_reapurbnonblock_compat(ps, p);
                goto done;
#endif
        }

        if (!connected(ps)) {
                usb_unlock_device(dev);
                return -ENODEV;
        }

        switch (cmd) {
        case USBDEVFS_CONTROL:
                snoop(&dev->dev, "%s: CONTROL\n", __func__);
                ret = proc_control(ps, p);
                if (ret >= 0)
                        inode->i_mtime = current_time(inode);
                break;

        case USBDEVFS_BULK:
                snoop(&dev->dev, "%s: BULK\n", __func__);
                ret = proc_bulk(ps, p);
                if (ret >= 0)
                        inode->i_mtime = current_time(inode);
                break;

        case USBDEVFS_RESETEP:
                snoop(&dev->dev, "%s: RESETEP\n", __func__);
                ret = proc_resetep(ps, p);
                if (ret >= 0)
                        inode->i_mtime = current_time(inode);
                break;

        case USBDEVFS_RESET:
                snoop(&dev->dev, "%s: RESET\n", __func__);
                ret = proc_resetdevice(ps);
                break;

        case USBDEVFS_CLEAR_HALT:
                snoop(&dev->dev, "%s: CLEAR_HALT\n", __func__);
                ret = proc_clearhalt(ps, p);
                if (ret >= 0)
                        inode->i_mtime = current_time(inode);
                break;

        case USBDEVFS_GETDRIVER:
                snoop(&dev->dev, "%s: GETDRIVER\n", __func__);
                ret = proc_getdriver(ps, p);
                break;

        case USBDEVFS_CONNECTINFO:
                snoop(&dev->dev, "%s: CONNECTINFO\n", __func__);
                ret = proc_connectinfo(ps, p);
                break;

        case USBDEVFS_SETINTERFACE:
                snoop(&dev->dev, "%s: SETINTERFACE\n", __func__);
                ret = proc_setintf(ps, p);
                break;

        case USBDEVFS_SETCONFIGURATION:
                snoop(&dev->dev, "%s: SETCONFIGURATION\n", __func__);
                ret = proc_setconfig(ps, p);
                break;

        case USBDEVFS_SUBMITURB:
                snoop(&dev->dev, "%s: SUBMITURB\n", __func__);
                ret = proc_submiturb(ps, p);
                if (ret >= 0)
                        inode->i_mtime = current_time(inode);
                break;

#ifdef CONFIG_COMPAT
        case USBDEVFS_CONTROL32:
                snoop(&dev->dev, "%s: CONTROL32\n", __func__);
                ret = proc_control_compat(ps, p);
                if (ret >= 0)
                        inode->i_mtime = current_time(inode);
                break;

        case USBDEVFS_BULK32:
                snoop(&dev->dev, "%s: BULK32\n", __func__);
                ret = proc_bulk_compat(ps, p);
                if (ret >= 0)
                        inode->i_mtime = current_time(inode);
                break;

        case USBDEVFS_DISCSIGNAL32:
                snoop(&dev->dev, "%s: DISCSIGNAL32\n", __func__);
                ret = proc_disconnectsignal_compat(ps, p);
                break;

        case USBDEVFS_SUBMITURB32:
                snoop(&dev->dev, "%s: SUBMITURB32\n", __func__);
                ret = proc_submiturb_compat(ps, p);
                if (ret >= 0)
                        inode->i_mtime = current_time(inode);
                break;

        case USBDEVFS_IOCTL32:
                snoop(&dev->dev, "%s: IOCTL32\n", __func__);
                ret = proc_ioctl_compat(ps, ptr_to_compat(p));
                break;
#endif

        case USBDEVFS_DISCARDURB:
                snoop(&dev->dev, "%s: DISCARDURB %pK\n", __func__, p);
                ret = proc_unlinkurb(ps, p);
                break;

        case USBDEVFS_DISCSIGNAL:
                snoop(&dev->dev, "%s: DISCSIGNAL\n", __func__);
                ret = proc_disconnectsignal(ps, p);
                break;

        case USBDEVFS_CLAIMINTERFACE:
                snoop(&dev->dev, "%s: CLAIMINTERFACE\n", __func__);
                ret = proc_claiminterface(ps, p);
                break;

        case USBDEVFS_RELEASEINTERFACE:
                snoop(&dev->dev, "%s: RELEASEINTERFACE\n", __func__);
                ret = proc_releaseinterface(ps, p);
                break;

        case USBDEVFS_IOCTL:
                snoop(&dev->dev, "%s: IOCTL\n", __func__);
                ret = proc_ioctl_default(ps, p);
                break;

        case USBDEVFS_CLAIM_PORT:
                snoop(&dev->dev, "%s: CLAIM_PORT\n", __func__);
                ret = proc_claim_port(ps, p);
                break;

        case USBDEVFS_RELEASE_PORT:
                snoop(&dev->dev, "%s: RELEASE_PORT\n", __func__);
                ret = proc_release_port(ps, p);
                break;
        case USBDEVFS_GET_CAPABILITIES:
                ret = proc_get_capabilities(ps, p);
                break;
        case USBDEVFS_DISCONNECT_CLAIM:
                ret = proc_disconnect_claim(ps, p);
                break;
        case USBDEVFS_ALLOC_STREAMS:
                ret = proc_alloc_streams(ps, p);
                break;
        case USBDEVFS_FREE_STREAMS:
                ret = proc_free_streams(ps, p);
                break;
        case USBDEVFS_DROP_PRIVILEGES:
                ret = proc_drop_privileges(ps, p);
                break;
        case USBDEVFS_GET_SPEED:
                ret = ps->dev->speed;
                break;
        }

 done:
        usb_unlock_device(dev);
        if (ret >= 0)
                inode->i_atime = current_time(inode);
        return ret;
}

static long usbdev_ioctl(struct file *file, unsigned int cmd,
                        unsigned long arg)
{
        int ret;

        ret = usbdev_do_ioctl(file, cmd, (void __user *)arg);

        return ret;
}

#ifdef CONFIG_COMPAT
static long usbdev_compat_ioctl(struct file *file, unsigned int cmd,
                        unsigned long arg)
{
        int ret;

        ret = usbdev_do_ioctl(file, cmd, compat_ptr(arg));

        return ret;
}
#endif

/* No kernel lock - fine */
static __poll_t usbdev_poll(struct file *file,
                                struct poll_table_struct *wait)
{
        struct usb_dev_state *ps = file->private_data;
        __poll_t mask = 0;

        poll_wait(file, &ps->wait, wait);
        if (file->f_mode & FMODE_WRITE && !list_empty(&ps->async_completed))
                mask |= EPOLLOUT | EPOLLWRNORM;
        if (!connected(ps))
                mask |= EPOLLHUP;
        if (list_empty(&ps->list))
                mask |= EPOLLERR;
        return mask;
}

const struct file_operations usbdev_file_operations = {
        .owner =          THIS_MODULE,
        .llseek =         no_seek_end_llseek,
        .read =           usbdev_read,
        .poll =           usbdev_poll,
        .unlocked_ioctl = usbdev_ioctl,
#ifdef CONFIG_COMPAT
        .compat_ioctl =   usbdev_compat_ioctl,
#endif
        .mmap =           usbdev_mmap,
        .open =           usbdev_open,
        .release =        usbdev_release,
};

static void usbdev_remove(struct usb_device *udev)
{
        struct usb_dev_state *ps;
        struct siginfo sinfo;

        while (!list_empty(&udev->filelist)) {
                ps = list_entry(udev->filelist.next, struct usb_dev_state, list);
                destroy_all_async(ps);
                wake_up_all(&ps->wait);
                list_del_init(&ps->list);
                if (ps->discsignr) {
                        clear_siginfo(&sinfo);
                        sinfo.si_signo = ps->discsignr;
                        sinfo.si_errno = EPIPE;
                        sinfo.si_code = SI_ASYNCIO;
                        sinfo.si_addr = ps->disccontext;
                        kill_pid_info_as_cred(ps->discsignr, &sinfo,
                                        ps->disc_pid, ps->cred);
                }
        }
}

static int usbdev_notify(struct notifier_block *self,
                               unsigned long action, void *dev)
{
        switch (action) {
        case USB_DEVICE_ADD:
                break;
        case USB_DEVICE_REMOVE:
                usbdev_remove(dev);
                break;
        }
        return NOTIFY_OK;
}

static struct notifier_block usbdev_nb = {
        .notifier_call =        usbdev_notify,
};

static struct cdev usb_device_cdev;

int __init usb_devio_init(void)
{
        int retval;

        retval = register_chrdev_region(USB_DEVICE_DEV, USB_DEVICE_MAX,
                                        "usb_device");
        if (retval) {
                printk(KERN_ERR "Unable to register minors for usb_device\n");
                goto out;
        }
        cdev_init(&usb_device_cdev, &usbdev_file_operations);
        retval = cdev_add(&usb_device_cdev, USB_DEVICE_DEV, USB_DEVICE_MAX);
        if (retval) {
                printk(KERN_ERR "Unable to get usb_device major %d\n",
                       USB_DEVICE_MAJOR);
                goto error_cdev;
        }
        usb_register_notify(&usbdev_nb);
out:
        return retval;

error_cdev:
        unregister_chrdev_region(USB_DEVICE_DEV, USB_DEVICE_MAX);
        goto out;
}

void usb_devio_cleanup(void)
{
        usb_unregister_notify(&usbdev_nb);
        cdev_del(&usb_device_cdev);
        unregister_chrdev_region(USB_DEVICE_DEV, USB_DEVICE_MAX);
}