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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /*
  * message.c - synchronous message handling
  *
  * Released under the GPLv2 only.
  */
 
 #include <linux/acpi.h>
 #include <linux/pci.h>  /* for scatterlist macros */
 #include <linux/usb.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
 #include <linux/timer.h>
 #include <linux/ctype.h>
 #include <linux/nls.h>
 #include <linux/device.h>
 #include <linux/scatterlist.h>
 #include <linux/usb/cdc.h>
 #include <linux/usb/quirks.h>
 #include <linux/usb/hcd.h>  /* for usbcore internals */
 #include <linux/usb/of.h>
 #include <asm/byteorder.h>
 
 #include "usb.h"
 
 static void cancel_async_set_config(struct usb_device *udev);
 
 struct api_context {
     struct completion   done;
     int         status;
 };
 
 static void usb_api_blocking_completion(struct urb *urb)
 {
     struct api_context *ctx = urb->context;
 
     ctx->status = urb->status;
     complete(&ctx->done);
 }
 
 
 /*
  * Starts urb and waits for completion or timeout. Note that this call
  * is NOT interruptible. Many device driver i/o requests should be
  * interruptible and therefore these drivers should implement their
  * own interruptible routines.
  */
 static int usb_start_wait_urb(struct urb *urb, int timeout, int *actual_length)
 {
     struct api_context ctx;
     unsigned long expire;
     int retval;
 
     init_completion(&ctx.done);
     urb->context = &ctx;
     urb->actual_length = 0;
     retval = usb_submit_urb(urb, GFP_NOIO);
     if (unlikely(retval))
         goto out;
 
     expire = timeout ? msecs_to_jiffies(timeout) : MAX_SCHEDULE_TIMEOUT;
     if (!wait_for_completion_timeout(&ctx.done, expire)) {
         usb_kill_urb(urb);
         retval = (ctx.status == -ENOENT ? -ETIMEDOUT : ctx.status);
 
         dev_dbg(&urb->dev->dev,
             "%s timed out on ep%d%s len=%u/%u\n",
             current->comm,
             usb_endpoint_num(&urb->ep->desc),
             usb_urb_dir_in(urb) ? "in" : "out",
             urb->actual_length,
             urb->transfer_buffer_length);
     } else
         retval = ctx.status;
 out:
     if (actual_length)
         *actual_length = urb->actual_length;
 
     usb_free_urb(urb);
     return retval;
 }
 
 /*-------------------------------------------------------------------*/
 /* returns status (negative) or length (positive) */
 static int usb_internal_control_msg(struct usb_device *usb_dev,
                     unsigned int pipe,
                     struct usb_ctrlrequest *cmd,
                     void *data, int len, int timeout)
 {
     struct urb *urb;
     int retv;
     int length;
 
     urb = usb_alloc_urb(0, GFP_NOIO);
     if (!urb)
         return -ENOMEM;
 
     usb_fill_control_urb(urb, usb_dev, pipe, (unsigned char *)cmd, data,
                  len, usb_api_blocking_completion, NULL);
 
     retv = usb_start_wait_urb(urb, timeout, &length);
     if (retv < 0)
         return retv;
     else
         return length;
 }
 
 /**
  * usb_control_msg - Builds a control urb, sends it off and waits for completion
  * @dev: pointer to the usb device to send the message to
  * @pipe: endpoint "pipe" to send the message to
  * @request: USB message request value
  * @requesttype: USB message request type value
  * @value: USB message value
  * @index: USB message index value
  * @data: pointer to the data to send
  * @size: length in bytes of the data to send
  * @timeout: time in msecs to wait for the message to complete before timing
  *  out (if 0 the wait is forever)
  *
  * Context: task context, might sleep.
  *
  * This function sends a simple control message to a specified endpoint and
  * waits for the message to complete, or timeout.
  *
  * Don't use this function from within an interrupt context. If you need
  * an asynchronous message, or need to send a message from within interrupt
  * context, use usb_submit_urb(). If a thread in your driver uses this call,
  * make sure your disconnect() method can wait for it to complete. Since you
  * don't have a handle on the URB used, you can't cancel the request.
  *
  * Return: If successful, the number of bytes transferred. Otherwise, a negative
  * error number.
  */
 int usb_control_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
             __u8 requesttype, __u16 value, __u16 index, void *data,
             __u16 size, int timeout)
 {
     struct usb_ctrlrequest *dr;
     int ret;
 
     dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_NOIO);
     if (!dr)
         return -ENOMEM;
 
     dr->bRequestType = requesttype;
     dr->bRequest = request;
     dr->wValue = cpu_to_le16(value);
     dr->wIndex = cpu_to_le16(index);
     dr->wLength = cpu_to_le16(size);
 
     ret = usb_internal_control_msg(dev, pipe, dr, data, size, timeout);
 
     /* Linger a bit, prior to the next control message. */
     if (dev->quirks & USB_QUIRK_DELAY_CTRL_MSG)
         msleep(200);
 
     kfree(dr);
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(usb_control_msg);
 
 /**
  * usb_control_msg_send - Builds a control "send" message, sends it off and waits for completion
  * @dev: pointer to the usb device to send the message to
  * @endpoint: endpoint to send the message to
  * @request: USB message request value
  * @requesttype: USB message request type value
  * @value: USB message value
  * @index: USB message index value
  * @driver_data: pointer to the data to send
  * @size: length in bytes of the data to send
  * @timeout: time in msecs to wait for the message to complete before timing
  *  out (if 0 the wait is forever)
  * @memflags: the flags for memory allocation for buffers
  *
  * Context: !in_interrupt ()
  *
  * This function sends a control message to a specified endpoint that is not
  * expected to fill in a response (i.e. a "send message") and waits for the
  * message to complete, or timeout.
  *
  * Do not use this function from within an interrupt context. If you need
  * an asynchronous message, or need to send a message from within interrupt
  * context, use usb_submit_urb(). If a thread in your driver uses this call,
  * make sure your disconnect() method can wait for it to complete. Since you
  * don't have a handle on the URB used, you can't cancel the request.
  *
  * The data pointer can be made to a reference on the stack, or anywhere else,
  * as it will not be modified at all.  This does not have the restriction that
  * usb_control_msg() has where the data pointer must be to dynamically allocated
  * memory (i.e. memory that can be successfully DMAed to a device).
  *
  * Return: If successful, 0 is returned, Otherwise, a negative error number.
  */
 int usb_control_msg_send(struct usb_device *dev, __u8 endpoint, __u8 request,
              __u8 requesttype, __u16 value, __u16 index,
              const void *driver_data, __u16 size, int timeout,
              gfp_t memflags)
 {
     unsigned int pipe = usb_sndctrlpipe(dev, endpoint);
     int ret;
     u8 *data = NULL;
 
     if (size) {
         data = kmemdup(driver_data, size, memflags);
         if (!data)
             return -ENOMEM;
     }
 
     ret = usb_control_msg(dev, pipe, request, requesttype, value, index,
                   data, size, timeout);
     kfree(data);
 
     if (ret < 0)
         return ret;
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(usb_control_msg_send);
 
 /**
  * usb_control_msg_recv - Builds a control "receive" message, sends it off and waits for completion
  * @dev: pointer to the usb device to send the message to
  * @endpoint: endpoint to send the message to
  * @request: USB message request value
  * @requesttype: USB message request type value
  * @value: USB message value
  * @index: USB message index value
  * @driver_data: pointer to the data to be filled in by the message
  * @size: length in bytes of the data to be received
  * @timeout: time in msecs to wait for the message to complete before timing
  *  out (if 0 the wait is forever)
  * @memflags: the flags for memory allocation for buffers
  *
  * Context: !in_interrupt ()
  *
  * This function sends a control message to a specified endpoint that is
  * expected to fill in a response (i.e. a "receive message") and waits for the
  * message to complete, or timeout.
  *
  * Do not use this function from within an interrupt context. If you need
  * an asynchronous message, or need to send a message from within interrupt
  * context, use usb_submit_urb(). If a thread in your driver uses this call,
  * make sure your disconnect() method can wait for it to complete. Since you
  * don't have a handle on the URB used, you can't cancel the request.
  *
  * The data pointer can be made to a reference on the stack, or anywhere else
  * that can be successfully written to.  This function does not have the
  * restriction that usb_control_msg() has where the data pointer must be to
  * dynamically allocated memory (i.e. memory that can be successfully DMAed to a
  * device).
  *
  * The "whole" message must be properly received from the device in order for
  * this function to be successful.  If a device returns less than the expected
  * amount of data, then the function will fail.  Do not use this for messages
  * where a variable amount of data might be returned.
  *
  * Return: If successful, 0 is returned, Otherwise, a negative error number.
  */
 int usb_control_msg_recv(struct usb_device *dev, __u8 endpoint, __u8 request,
              __u8 requesttype, __u16 value, __u16 index,
              void *driver_data, __u16 size, int timeout,
              gfp_t memflags)
 {
     unsigned int pipe = usb_rcvctrlpipe(dev, endpoint);
     int ret;
     u8 *data;
 
     if (!size || !driver_data)
         return -EINVAL;
 
     data = kmalloc(size, memflags);
     if (!data)
         return -ENOMEM;
 
     ret = usb_control_msg(dev, pipe, request, requesttype, value, index,
                   data, size, timeout);
 
     if (ret < 0)
         goto exit;
 
     if (ret == size) {
         memcpy(driver_data, data, size);
         ret = 0;
     } else {
         ret = -EREMOTEIO;
     }
 
 exit:
     kfree(data);
     return ret;
 }
 EXPORT_SYMBOL_GPL(usb_control_msg_recv);
 
 /**
  * usb_interrupt_msg - Builds an interrupt urb, sends it off and waits for completion
  * @usb_dev: pointer to the usb device to send the message to
  * @pipe: endpoint "pipe" to send the message to
  * @data: pointer to the data to send
  * @len: length in bytes of the data to send
  * @actual_length: pointer to a location to put the actual length transferred
  *  in bytes
  * @timeout: time in msecs to wait for the message to complete before
  *  timing out (if 0 the wait is forever)
  *
  * Context: task context, might sleep.
  *
  * This function sends a simple interrupt message to a specified endpoint and
  * waits for the message to complete, or timeout.
  *
  * Don't use this function from within an interrupt context. If you need
  * an asynchronous message, or need to send a message from within interrupt
  * context, use usb_submit_urb() If a thread in your driver uses this call,
  * make sure your disconnect() method can wait for it to complete. Since you
  * don't have a handle on the URB used, you can't cancel the request.
  *
  * Return:
  * If successful, 0. Otherwise a negative error number. The number of actual
  * bytes transferred will be stored in the @actual_length parameter.
  */
 int usb_interrupt_msg(struct usb_device *usb_dev, unsigned int pipe,
               void *data, int len, int *actual_length, int timeout)
 {
     return usb_bulk_msg(usb_dev, pipe, data, len, actual_length, timeout);
 }
 EXPORT_SYMBOL_GPL(usb_interrupt_msg);
 
 /**
  * usb_bulk_msg - Builds a bulk urb, sends it off and waits for completion
  * @usb_dev: pointer to the usb device to send the message to
  * @pipe: endpoint "pipe" to send the message to
  * @data: pointer to the data to send
  * @len: length in bytes of the data to send
  * @actual_length: pointer to a location to put the actual length transferred
  *  in bytes
  * @timeout: time in msecs to wait for the message to complete before
  *  timing out (if 0 the wait is forever)
  *
  * Context: task context, might sleep.
  *
  * This function sends a simple bulk message to a specified endpoint
  * and waits for the message to complete, or timeout.
  *
  * Don't use this function from within an interrupt context. If you need
  * an asynchronous message, or need to send a message from within interrupt
  * context, use usb_submit_urb() If a thread in your driver uses this call,
  * make sure your disconnect() method can wait for it to complete. Since you
  * don't have a handle on the URB used, you can't cancel the request.
  *
  * Because there is no usb_interrupt_msg() and no USBDEVFS_INTERRUPT ioctl,
  * users are forced to abuse this routine by using it to submit URBs for
  * interrupt endpoints.  We will take the liberty of creating an interrupt URB
  * (with the default interval) if the target is an interrupt endpoint.
  *
  * Return:
  * If successful, 0. Otherwise a negative error number. The number of actual
  * bytes transferred will be stored in the @actual_length parameter.
  *
  */
 int usb_bulk_msg(struct usb_device *usb_dev, unsigned int pipe,
          void *data, int len, int *actual_length, int timeout)
 {
     struct urb *urb;
     struct usb_host_endpoint *ep;
 
     ep = usb_pipe_endpoint(usb_dev, pipe);
     if (!ep || len < 0)
         return -EINVAL;
 
     urb = usb_alloc_urb(0, GFP_KERNEL);
     if (!urb)
         return -ENOMEM;
 
     if ((ep->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
             USB_ENDPOINT_XFER_INT) {
         pipe = (pipe & ~(3 << 30)) | (PIPE_INTERRUPT << 30);
         usb_fill_int_urb(urb, usb_dev, pipe, data, len,
                 usb_api_blocking_completion, NULL,
                 ep->desc.bInterval);
     } else
         usb_fill_bulk_urb(urb, usb_dev, pipe, data, len,
                 usb_api_blocking_completion, NULL);
 
     return usb_start_wait_urb(urb, timeout, actual_length);
 }
 EXPORT_SYMBOL_GPL(usb_bulk_msg);
 
 /*-------------------------------------------------------------------*/
 
 static void sg_clean(struct usb_sg_request *io)
 {
     if (io->urbs) {
         while (io->entries--)
             usb_free_urb(io->urbs[io->entries]);
         kfree(io->urbs);
         io->urbs = NULL;
     }
     io->dev = NULL;
 }
 
 static void sg_complete(struct urb *urb)
 {
     unsigned long flags;
     struct usb_sg_request *io = urb->context;
     int status = urb->status;
 
     spin_lock_irqsave(&io->lock, flags);
 
     /* In 2.5 we require hcds' endpoint queues not to progress after fault
      * reports, until the completion callback (this!) returns.  That lets
      * device driver code (like this routine) unlink queued urbs first,
      * if it needs to, since the HC won't work on them at all.  So it's
      * not possible for page N+1 to overwrite page N, and so on.
      *
      * That's only for "hard" faults; "soft" faults (unlinks) sometimes
      * complete before the HCD can get requests away from hardware,
      * though never during cleanup after a hard fault.
      */
     if (io->status
             && (io->status != -ECONNRESET
                 || status != -ECONNRESET)
             && urb->actual_length) {
         dev_err(io->dev->bus->controller,
             "dev %s ep%d%s scatterlist error %d/%d\n",
             io->dev->devpath,
             usb_endpoint_num(&urb->ep->desc),
             usb_urb_dir_in(urb) ? "in" : "out",
             status, io->status);
         /* BUG (); */
     }
 
     if (io->status == 0 && status && status != -ECONNRESET) {
         int i, found, retval;
 
         io->status = status;
 
         /* the previous urbs, and this one, completed already.
          * unlink pending urbs so they won't rx/tx bad data.
          * careful: unlink can sometimes be synchronous...
          */
         spin_unlock_irqrestore(&io->lock, flags);
         for (i = 0, found = 0; i < io->entries; i++) {
             if (!io->urbs[i])
                 continue;
             if (found) {
                 usb_block_urb(io->urbs[i]);
                 retval = usb_unlink_urb(io->urbs[i]);
                 if (retval != -EINPROGRESS &&
                     retval != -ENODEV &&
                     retval != -EBUSY &&
                     retval != -EIDRM)
                     dev_err(&io->dev->dev,
                         "%s, unlink --> %d\n",
                         __func__, retval);
             } else if (urb == io->urbs[i])
                 found = 1;
         }
         spin_lock_irqsave(&io->lock, flags);
     }
 
     /* on the last completion, signal usb_sg_wait() */
     io->bytes += urb->actual_length;
     io->count--;
     if (!io->count)
         complete(&io->complete);
 
     spin_unlock_irqrestore(&io->lock, flags);
 }
 
 
 /**
  * usb_sg_init - initializes scatterlist-based bulk/interrupt I/O request
  * @io: request block being initialized.  until usb_sg_wait() returns,
  *  treat this as a pointer to an opaque block of memory,
  * @dev: the usb device that will send or receive the data
  * @pipe: endpoint "pipe" used to transfer the data
  * @period: polling rate for interrupt endpoints, in frames or
  *  (for high speed endpoints) microframes; ignored for bulk
  * @sg: scatterlist entries
  * @nents: how many entries in the scatterlist
  * @length: how many bytes to send from the scatterlist, or zero to
  *  send every byte identified in the list.
  * @mem_flags: SLAB_* flags affecting memory allocations in this call
  *
  * This initializes a scatter/gather request, allocating resources such as
  * I/O mappings and urb memory (except maybe memory used by USB controller
  * drivers).
  *
  * The request must be issued using usb_sg_wait(), which waits for the I/O to
  * complete (or to be canceled) and then cleans up all resources allocated by
  * usb_sg_init().
  *
  * The request may be canceled with usb_sg_cancel(), either before or after
  * usb_sg_wait() is called.
  *
  * Return: Zero for success, else a negative errno value.
  */
 int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev,
         unsigned pipe, unsigned period, struct scatterlist *sg,
         int nents, size_t length, gfp_t mem_flags)
 {
     int i;
     int urb_flags;
     int use_sg;
 
     if (!io || !dev || !sg
             || usb_pipecontrol(pipe)
             || usb_pipeisoc(pipe)
             || nents <= 0)
         return -EINVAL;
 
     spin_lock_init(&io->lock);
     io->dev = dev;
     io->pipe = pipe;
 
     if (dev->bus->sg_tablesize > 0) {
         use_sg = true;
         io->entries = 1;
     } else {
         use_sg = false;
         io->entries = nents;
     }
 
     /* initialize all the urbs we'll use */
     io->urbs = kmalloc_array(io->entries, sizeof(*io->urbs), mem_flags);
     if (!io->urbs)
         goto nomem;
 
     urb_flags = URB_NO_INTERRUPT;
     if (usb_pipein(pipe))
         urb_flags |= URB_SHORT_NOT_OK;
 
     for_each_sg(sg, sg, io->entries, i) {
         struct urb *urb;
         unsigned len;
 
         urb = usb_alloc_urb(0, mem_flags);
         if (!urb) {
             io->entries = i;
             goto nomem;
         }
         io->urbs[i] = urb;
 
         urb->dev = NULL;
         urb->pipe = pipe;
         urb->interval = period;
         urb->transfer_flags = urb_flags;
         urb->complete = sg_complete;
         urb->context = io;
         urb->sg = sg;
 
         if (use_sg) {
             /* There is no single transfer buffer */
             urb->transfer_buffer = NULL;
             urb->num_sgs = nents;
 
             /* A length of zero means transfer the whole sg list */
             len = length;
             if (len == 0) {
                 struct scatterlist  *sg2;
                 int         j;
 
                 for_each_sg(sg, sg2, nents, j)
                     len += sg2->length;
             }
         } else {
             /*
              * Some systems can't use DMA; they use PIO instead.
              * For their sakes, transfer_buffer is set whenever
              * possible.
              */
             if (!PageHighMem(sg_page(sg)))
                 urb->transfer_buffer = sg_virt(sg);
             else
                 urb->transfer_buffer = NULL;
 
             len = sg->length;
             if (length) {
                 len = min_t(size_t, len, length);
                 length -= len;
                 if (length == 0)
                     io->entries = i + 1;
             }
         }
         urb->transfer_buffer_length = len;
     }
     io->urbs[--i]->transfer_flags &= ~URB_NO_INTERRUPT;
 
     /* transaction state */
     io->count = io->entries;
     io->status = 0;
     io->bytes = 0;
     init_completion(&io->complete);
     return 0;
 
 nomem:
     sg_clean(io);
     return -ENOMEM;
 }
 EXPORT_SYMBOL_GPL(usb_sg_init);
 
 /**
  * usb_sg_wait - synchronously execute scatter/gather request
  * @io: request block handle, as initialized with usb_sg_init().
  *  some fields become accessible when this call returns.
  *
  * Context: task context, might sleep.
  *
  * This function blocks until the specified I/O operation completes.  It
  * leverages the grouping of the related I/O requests to get good transfer
  * rates, by queueing the requests.  At higher speeds, such queuing can
  * significantly improve USB throughput.
  *
  * There are three kinds of completion for this function.
  *
  * (1) success, where io->status is zero.  The number of io->bytes
  *     transferred is as requested.
  * (2) error, where io->status is a negative errno value.  The number
  *     of io->bytes transferred before the error is usually less
  *     than requested, and can be nonzero.
  * (3) cancellation, a type of error with status -ECONNRESET that
  *     is initiated by usb_sg_cancel().
  *
  * When this function returns, all memory allocated through usb_sg_init() or
  * this call will have been freed.  The request block parameter may still be
  * passed to usb_sg_cancel(), or it may be freed.  It could also be
  * reinitialized and then reused.
  *
  * Data Transfer Rates:
  *
  * Bulk transfers are valid for full or high speed endpoints.
  * The best full speed data rate is 19 packets of 64 bytes each
  * per frame, or 1216 bytes per millisecond.
  * The best high speed data rate is 13 packets of 512 bytes each
  * per microframe, or 52 KBytes per millisecond.
  *
  * The reason to use interrupt transfers through this API would most likely
  * be to reserve high speed bandwidth, where up to 24 KBytes per millisecond
  * could be transferred.  That capability is less useful for low or full
  * speed interrupt endpoints, which allow at most one packet per millisecond,
  * of at most 8 or 64 bytes (respectively).
  *
  * It is not necessary to call this function to reserve bandwidth for devices
  * under an xHCI host controller, as the bandwidth is reserved when the
  * configuration or interface alt setting is selected.
  */
 void usb_sg_wait(struct usb_sg_request *io)
 {
     int i;
     int entries = io->entries;
 
     /* queue the urbs.  */
     spin_lock_irq(&io->lock);
     i = 0;
     while (i < entries && !io->status) {
         int retval;
 
         io->urbs[i]->dev = io->dev;
         spin_unlock_irq(&io->lock);
 
         retval = usb_submit_urb(io->urbs[i], GFP_NOIO);
 
         switch (retval) {
             /* maybe we retrying will recover */
         case -ENXIO:    /* hc didn't queue this one */
         case -EAGAIN:
         case -ENOMEM:
             retval = 0;
             yield();
             break;
 
             /* no error? continue immediately.
              *
              * NOTE: to work better with UHCI (4K I/O buffer may
              * need 3K of TDs) it may be good to limit how many
              * URBs are queued at once; N milliseconds?
              */
         case 0:
             ++i;
             cpu_relax();
             break;
 
             /* fail any uncompleted urbs */
         default:
             io->urbs[i]->status = retval;
             dev_dbg(&io->dev->dev, "%s, submit --> %d\n",
                 __func__, retval);
             usb_sg_cancel(io);
         }
         spin_lock_irq(&io->lock);
         if (retval && (io->status == 0 || io->status == -ECONNRESET))
             io->status = retval;
     }
     io->count -= entries - i;
     if (io->count == 0)
         complete(&io->complete);
     spin_unlock_irq(&io->lock);
 
     /* OK, yes, this could be packaged as non-blocking.
      * So could the submit loop above ... but it's easier to
      * solve neither problem than to solve both!
      */
     wait_for_completion(&io->complete);
 
     sg_clean(io);
 }
 EXPORT_SYMBOL_GPL(usb_sg_wait);
 
 /**
  * usb_sg_cancel - stop scatter/gather i/o issued by usb_sg_wait()
  * @io: request block, initialized with usb_sg_init()
  *
  * This stops a request after it has been started by usb_sg_wait().
  * It can also prevents one initialized by usb_sg_init() from starting,
  * so that call just frees resources allocated to the request.
  */
 void usb_sg_cancel(struct usb_sg_request *io)
 {
     unsigned long flags;
     int i, retval;
 
     spin_lock_irqsave(&io->lock, flags);
     if (io->status || io->count == 0) {
         spin_unlock_irqrestore(&io->lock, flags);
         return;
     }
     /* shut everything down */
     io->status = -ECONNRESET;
     io->count++;        /* Keep the request alive until we're done */
     spin_unlock_irqrestore(&io->lock, flags);
 
     for (i = io->entries - 1; i >= 0; --i) {
         usb_block_urb(io->urbs[i]);
 
         retval = usb_unlink_urb(io->urbs[i]);
         if (retval != -EINPROGRESS
             && retval != -ENODEV
             && retval != -EBUSY
             && retval != -EIDRM)
             dev_warn(&io->dev->dev, "%s, unlink --> %d\n",
                  __func__, retval);
     }
 
     spin_lock_irqsave(&io->lock, flags);
     io->count--;
     if (!io->count)
         complete(&io->complete);
     spin_unlock_irqrestore(&io->lock, flags);
 }
 EXPORT_SYMBOL_GPL(usb_sg_cancel);
 
 /*-------------------------------------------------------------------*/
 
 /**
  * usb_get_descriptor - issues a generic GET_DESCRIPTOR request
  * @dev: the device whose descriptor is being retrieved
  * @type: the descriptor type (USB_DT_*)
  * @index: the number of the descriptor
  * @buf: where to put the descriptor
  * @size: how big is "buf"?
  *
  * Context: task context, might sleep.
  *
  * Gets a USB descriptor.  Convenience functions exist to simplify
  * getting some types of descriptors.  Use
  * usb_get_string() or usb_string() for USB_DT_STRING.
  * Device (USB_DT_DEVICE) and configuration descriptors (USB_DT_CONFIG)
  * are part of the device structure.
  * In addition to a number of USB-standard descriptors, some
  * devices also use class-specific or vendor-specific descriptors.
  *
  * This call is synchronous, and may not be used in an interrupt context.
  *
  * Return: The number of bytes received on success, or else the status code
  * returned by the underlying usb_control_msg() call.
  */
 int usb_get_descriptor(struct usb_device *dev, unsigned char type,
                unsigned char index, void *buf, int size)
 {
     int i;
     int result;
 
     if (size <= 0)      /* No point in asking for no data */
         return -EINVAL;
 
     memset(buf, 0, size);   /* Make sure we parse really received data */
 
     for (i = 0; i < 3; ++i) {
         /* retry on length 0 or error; some devices are flakey */
         result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
                 USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
                 (type << 8) + index, 0, buf, size,
                 USB_CTRL_GET_TIMEOUT);
         if (result <= 0 && result != -ETIMEDOUT)
             continue;
         if (result > 1 && ((u8 *)buf)[1] != type) {
             result = -ENODATA;
             continue;
         }
         break;
     }
     return result;
 }
 EXPORT_SYMBOL_GPL(usb_get_descriptor);
 
 /**
  * usb_get_string - gets a string descriptor
  * @dev: the device whose string descriptor is being retrieved
  * @langid: code for language chosen (from string descriptor zero)
  * @index: the number of the descriptor
  * @buf: where to put the string
  * @size: how big is "buf"?
  *
  * Context: task context, might sleep.
  *
  * Retrieves a string, encoded using UTF-16LE (Unicode, 16 bits per character,
  * in little-endian byte order).
  * The usb_string() function will often be a convenient way to turn
  * these strings into kernel-printable form.
  *
  * Strings may be referenced in device, configuration, interface, or other
  * descriptors, and could also be used in vendor-specific ways.
  *
  * This call is synchronous, and may not be used in an interrupt context.
  *
  * Return: The number of bytes received on success, or else the status code
  * returned by the underlying usb_control_msg() call.
  */
 static int usb_get_string(struct usb_device *dev, unsigned short langid,
               unsigned char index, void *buf, int size)
 {
     int i;
     int result;
 
     if (size <= 0)      /* No point in asking for no data */
         return -EINVAL;
 
     for (i = 0; i < 3; ++i) {
         /* retry on length 0 or stall; some devices are flakey */
         result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
             USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
             (USB_DT_STRING << 8) + index, langid, buf, size,
             USB_CTRL_GET_TIMEOUT);
         if (result == 0 || result == -EPIPE)
             continue;
         if (result > 1 && ((u8 *) buf)[1] != USB_DT_STRING) {
             result = -ENODATA;
             continue;
         }
         break;
     }
     return result;
 }
 
 static void usb_try_string_workarounds(unsigned char *buf, int *length)
 {
     int newlength, oldlength = *length;
 
     for (newlength = 2; newlength + 1 < oldlength; newlength += 2)
         if (!isprint(buf[newlength]) || buf[newlength + 1])
             break;
 
     if (newlength > 2) {
         buf[0] = newlength;
         *length = newlength;
     }
 }
 
 static int usb_string_sub(struct usb_device *dev, unsigned int langid,
               unsigned int index, unsigned char *buf)
 {
     int rc;
 
     /* Try to read the string descriptor by asking for the maximum
      * possible number of bytes */
     if (dev->quirks & USB_QUIRK_STRING_FETCH_255)
         rc = -EIO;
     else
         rc = usb_get_string(dev, langid, index, buf, 255);
 
     /* If that failed try to read the descriptor length, then
      * ask for just that many bytes */
     if (rc < 2) {
         rc = usb_get_string(dev, langid, index, buf, 2);
         if (rc == 2)
             rc = usb_get_string(dev, langid, index, buf, buf[0]);
     }
 
     if (rc >= 2) {
         if (!buf[0] && !buf[1])
             usb_try_string_workarounds(buf, &rc);
 
         /* There might be extra junk at the end of the descriptor */
         if (buf[0] < rc)
             rc = buf[0];
 
         rc = rc - (rc & 1); /* force a multiple of two */
     }
 
     if (rc < 2)
         rc = (rc < 0 ? rc : -EINVAL);
 
     return rc;
 }
 
 static int usb_get_langid(struct usb_device *dev, unsigned char *tbuf)
 {
     int err;
 
     if (dev->have_langid)
         return 0;
 
     if (dev->string_langid < 0)
         return -EPIPE;
 
     err = usb_string_sub(dev, 0, 0, tbuf);
 
     /* If the string was reported but is malformed, default to english
      * (0x0409) */
     if (err == -ENODATA || (err > 0 && err < 4)) {
         dev->string_langid = 0x0409;
         dev->have_langid = 1;
         dev_err(&dev->dev,
             "language id specifier not provided by device, defaulting to English\n");
         return 0;
     }
 
     /* In case of all other errors, we assume the device is not able to
      * deal with strings at all. Set string_langid to -1 in order to
      * prevent any string to be retrieved from the device */
     if (err < 0) {
         dev_info(&dev->dev, "string descriptor 0 read error: %d\n",
                     err);
         dev->string_langid = -1;
         return -EPIPE;
     }
 
     /* always use the first langid listed */
     dev->string_langid = tbuf[2] | (tbuf[3] << 8);
     dev->have_langid = 1;
     dev_dbg(&dev->dev, "default language 0x%04x\n",
                 dev->string_langid);
     return 0;
 }
 
 /**
  * usb_string - returns UTF-8 version of a string descriptor
  * @dev: the device whose string descriptor is being retrieved
  * @index: the number of the descriptor
  * @buf: where to put the string
  * @size: how big is "buf"?
  *
  * Context: task context, might sleep.
  *
  * This converts the UTF-16LE encoded strings returned by devices, from
  * usb_get_string_descriptor(), to null-terminated UTF-8 encoded ones
  * that are more usable in most kernel contexts.  Note that this function
  * chooses strings in the first language supported by the device.
  *
  * This call is synchronous, and may not be used in an interrupt context.
  *
  * Return: length of the string (>= 0) or usb_control_msg status (< 0).
  */
 int usb_string(struct usb_device *dev, int index, char *buf, size_t size)
 {
     unsigned char *tbuf;
     int err;
 
     if (dev->state == USB_STATE_SUSPENDED)
         return -EHOSTUNREACH;
     if (size <= 0 || !buf)
         return -EINVAL;
     buf[0] = 0;
     if (index <= 0 || index >= 256)
         return -EINVAL;
     tbuf = kmalloc(256, GFP_NOIO);
     if (!tbuf)
         return -ENOMEM;
 
     err = usb_get_langid(dev, tbuf);
     if (err < 0)
         goto errout;
 
     err = usb_string_sub(dev, dev->string_langid, index, tbuf);
     if (err < 0)
         goto errout;
 
     size--;     /* leave room for trailing NULL char in output buffer */
     err = utf16s_to_utf8s((wchar_t *) &tbuf[2], (err - 2) / 2,
             UTF16_LITTLE_ENDIAN, buf, size);
     buf[err] = 0;
 
     if (tbuf[1] != USB_DT_STRING)
         dev_dbg(&dev->dev,
             "wrong descriptor type %02x for string %d (\"%s\")\n",
             tbuf[1], index, buf);
 
  errout:
     kfree(tbuf);
     return err;
 }
 EXPORT_SYMBOL_GPL(usb_string);
 
 /* one UTF-8-encoded 16-bit character has at most three bytes */
 #define MAX_USB_STRING_SIZE (127 * 3 + 1)
 
 /**
  * usb_cache_string - read a string descriptor and cache it for later use
  * @udev: the device whose string descriptor is being read
  * @index: the descriptor index
  *
  * Return: A pointer to a kmalloc'ed buffer containing the descriptor string,
  * or %NULL if the index is 0 or the string could not be read.
  */
 char *usb_cache_string(struct usb_device *udev, int index)
 {
     char *buf;
     char *smallbuf = NULL;
     int len;
 
     if (index <= 0)
         return NULL;
 
     buf = kmalloc(MAX_USB_STRING_SIZE, GFP_NOIO);
     if (buf) {
         len = usb_string(udev, index, buf, MAX_USB_STRING_SIZE);
         if (len > 0) {
             smallbuf = kmalloc(++len, GFP_NOIO);
             if (!smallbuf)
                 return buf;
             memcpy(smallbuf, buf, len);
         }
         kfree(buf);
     }
     return smallbuf;
 }
 
 /*
  * usb_get_device_descriptor - (re)reads the device descriptor (usbcore)
  * @dev: the device whose device descriptor is being updated
  * @size: how much of the descriptor to read
  *
  * Context: task context, might sleep.
  *
  * Updates the copy of the device descriptor stored in the device structure,
  * which dedicates space for this purpose.
  *
  * Not exported, only for use by the core.  If drivers really want to read
  * the device descriptor directly, they can call usb_get_descriptor() with
  * type = USB_DT_DEVICE and index = 0.
  *
  * This call is synchronous, and may not be used in an interrupt context.
  *
  * Return: The number of bytes received on success, or else the status code
  * returned by the underlying usb_control_msg() call.
  */
 int usb_get_device_descriptor(struct usb_device *dev, unsigned int size)
 {
     struct usb_device_descriptor *desc;
     int ret;
 
     if (size > sizeof(*desc))
         return -EINVAL;
     desc = kmalloc(sizeof(*desc), GFP_NOIO);
     if (!desc)
         return -ENOMEM;
 
     ret = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, size);
     if (ret >= 0)
         memcpy(&dev->descriptor, desc, size);
     kfree(desc);
     return ret;
 }
 
 /*
  * usb_set_isoch_delay - informs the device of the packet transmit delay
  * @dev: the device whose delay is to be informed
  * Context: task context, might sleep
  *
  * Since this is an optional request, we don't bother if it fails.
  */
 int usb_set_isoch_delay(struct usb_device *dev)
 {
     /* skip hub devices */
     if (dev->descriptor.bDeviceClass == USB_CLASS_HUB)
         return 0;
 
     /* skip non-SS/non-SSP devices */
     if (dev->speed < USB_SPEED_SUPER)
         return 0;
 
     return usb_control_msg_send(dev, 0,
             USB_REQ_SET_ISOCH_DELAY,
             USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
             dev->hub_delay, 0, NULL, 0,
             USB_CTRL_SET_TIMEOUT,
             GFP_NOIO);
 }
 
 /**
  * usb_get_status - issues a GET_STATUS call
  * @dev: the device whose status is being checked
  * @recip: USB_RECIP_*; for device, interface, or endpoint
  * @type: USB_STATUS_TYPE_*; for standard or PTM status types
  * @target: zero (for device), else interface or endpoint number
  * @data: pointer to two bytes of bitmap data
  *
  * Context: task context, might sleep.
  *
  * Returns device, interface, or endpoint status.  Normally only of
  * interest to see if the device is self powered, or has enabled the
  * remote wakeup facility; or whether a bulk or interrupt endpoint
  * is halted ("stalled").
  *
  * Bits in these status bitmaps are set using the SET_FEATURE request,
  * and cleared using the CLEAR_FEATURE request.  The usb_clear_halt()
  * function should be used to clear halt ("stall") status.
  *
  * This call is synchronous, and may not be used in an interrupt context.
  *
  * Returns 0 and the status value in *@data (in host byte order) on success,
  * or else the status code from the underlying usb_control_msg() call.
  */
 int usb_get_status(struct usb_device *dev, int recip, int type, int target,
         void *data)
 {
     int ret;
     void *status;
     int length;
 
     switch (type) {
     case USB_STATUS_TYPE_STANDARD:
         length = 2;
         break;
     case USB_STATUS_TYPE_PTM:
         if (recip != USB_RECIP_DEVICE)
             return -EINVAL;
 
         length = 4;
         break;
     default:
         return -EINVAL;
     }
 
     status =  kmalloc(length, GFP_KERNEL);
     if (!status)
         return -ENOMEM;
 
     ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
         USB_REQ_GET_STATUS, USB_DIR_IN | recip, USB_STATUS_TYPE_STANDARD,
         target, status, length, USB_CTRL_GET_TIMEOUT);
 
     switch (ret) {
     case 4:
         if (type != USB_STATUS_TYPE_PTM) {
             ret = -EIO;
             break;
         }
 
         *(u32 *) data = le32_to_cpu(*(__le32 *) status);
         ret = 0;
         break;
     case 2:
         if (type != USB_STATUS_TYPE_STANDARD) {
             ret = -EIO;
             break;
         }
 
         *(u16 *) data = le16_to_cpu(*(__le16 *) status);
         ret = 0;
         break;
     default:
         ret = -EIO;
     }
 
     kfree(status);
     return ret;
 }
 EXPORT_SYMBOL_GPL(usb_get_status);
 
 /**
  * usb_clear_halt - tells device to clear endpoint halt/stall condition
  * @dev: device whose endpoint is halted
  * @pipe: endpoint "pipe" being cleared
  *
  * Context: task context, might sleep.
  *
  * This is used to clear halt conditions for bulk and interrupt endpoints,
  * as reported by URB completion status.  Endpoints that are halted are
  * sometimes referred to as being "stalled".  Such endpoints are unable
  * to transmit or receive data until the halt status is cleared.  Any URBs
  * queued for such an endpoint should normally be unlinked by the driver
  * before clearing the halt condition, as described in sections 5.7.5
  * and 5.8.5 of the USB 2.0 spec.
  *
  * Note that control and isochronous endpoints don't halt, although control
  * endpoints report "protocol stall" (for unsupported requests) using the
  * same status code used to report a true stall.
  *
  * This call is synchronous, and may not be used in an interrupt context.
  *
  * Return: Zero on success, or else the status code returned by the
  * underlying usb_control_msg() call.
  */
 int usb_clear_halt(struct usb_device *dev, int pipe)
 {
     int result;
     int endp = usb_pipeendpoint(pipe);
 
     if (usb_pipein(pipe))
         endp |= USB_DIR_IN;
 
     /* we don't care if it wasn't halted first. in fact some devices
      * (like some ibmcam model 1 units) seem to expect hosts to make
      * this request for iso endpoints, which can't halt!
      */
     result = usb_control_msg_send(dev, 0,
                       USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT,
                       USB_ENDPOINT_HALT, endp, NULL, 0,
                       USB_CTRL_SET_TIMEOUT, GFP_NOIO);
 
     /* don't un-halt or force to DATA0 except on success */
     if (result)
         return result;
 
     /* NOTE:  seems like Microsoft and Apple don't bother verifying
      * the clear "took", so some devices could lock up if you check...
      * such as the Hagiwara FlashGate DUAL.  So we won't bother.
      *
      * NOTE:  make sure the logic here doesn't diverge much from
      * the copy in usb-storage, for as long as we need two copies.
      */
 
     usb_reset_endpoint(dev, endp);
 
     return 0;
 }
 EXPORT_SYMBOL_GPL(usb_clear_halt);
 
 static int create_intf_ep_devs(struct usb_interface *intf)
 {
     struct usb_device *udev = interface_to_usbdev(intf);
     struct usb_host_interface *alt = intf->cur_altsetting;
     int i;
 
     if (intf->ep_devs_created || intf->unregistering)
         return 0;
 
     for (i = 0; i < alt->desc.bNumEndpoints; ++i)
         (void) usb_create_ep_devs(&intf->dev, &alt->endpoint[i], udev);
     intf->ep_devs_created = 1;
     return 0;
 }
 
 static void remove_intf_ep_devs(struct usb_interface *intf)
 {
     struct usb_host_interface *alt = intf->cur_altsetting;
     int i;
 
     if (!intf->ep_devs_created)
         return;
 
     for (i = 0; i < alt->desc.bNumEndpoints; ++i)
         usb_remove_ep_devs(&alt->endpoint[i]);
     intf->ep_devs_created = 0;
 }
 
 /**
  * usb_disable_endpoint -- Disable an endpoint by address
  * @dev: the device whose endpoint is being disabled
  * @epaddr: the endpoint's address.  Endpoint number for output,
  *  endpoint number + USB_DIR_IN for input
  * @reset_hardware: flag to erase any endpoint state stored in the
  *  controller hardware
  *
  * Disables the endpoint for URB submission and nukes all pending URBs.
  * If @reset_hardware is set then also deallocates hcd/hardware state
  * for the endpoint.
  */
 void usb_disable_endpoint(struct usb_device *dev, unsigned int epaddr,
         bool reset_hardware)
 {
     unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK;
     struct usb_host_endpoint *ep;
 
     if (!dev)
         return;
 
     if (usb_endpoint_out(epaddr)) {
         ep = dev->ep_out[epnum];
         if (reset_hardware && epnum != 0)
             dev->ep_out[epnum] = NULL;
     } else {
         ep = dev->ep_in[epnum];
         if (reset_hardware && epnum != 0)
             dev->ep_in[epnum] = NULL;
     }
     if (ep) {
         ep->enabled = 0;
         usb_hcd_flush_endpoint(dev, ep);
         if (reset_hardware)
             usb_hcd_disable_endpoint(dev, ep);
     }
 }
 
 /**
  * usb_reset_endpoint - Reset an endpoint's state.
  * @dev: the device whose endpoint is to be reset
  * @epaddr: the endpoint's address.  Endpoint number for output,
  *  endpoint number + USB_DIR_IN for input
  *
  * Resets any host-side endpoint state such as the toggle bit,
  * sequence number or current window.
  */
 void usb_reset_endpoint(struct usb_device *dev, unsigned int epaddr)
 {
     unsigned int epnum = epaddr & USB_ENDPOINT_NUMBER_MASK;
     struct usb_host_endpoint *ep;
 
     if (usb_endpoint_out(epaddr))
         ep = dev->ep_out[epnum];
     else
         ep = dev->ep_in[epnum];
     if (ep)
         usb_hcd_reset_endpoint(dev, ep);
 }
 EXPORT_SYMBOL_GPL(usb_reset_endpoint);
 
 
 /**
  * usb_disable_interface -- Disable all endpoints for an interface
  * @dev: the device whose interface is being disabled
  * @intf: pointer to the interface descriptor
  * @reset_hardware: flag to erase any endpoint state stored in the
  *  controller hardware
  *
  * Disables all the endpoints for the interface's current altsetting.
  */
 void usb_disable_interface(struct usb_device *dev, struct usb_interface *intf,
         bool reset_hardware)
 {
     struct usb_host_interface *alt = intf->cur_altsetting;
     int i;
 
     for (i = 0; i < alt->desc.bNumEndpoints; ++i) {
         usb_disable_endpoint(dev,
                 alt->endpoint[i].desc.bEndpointAddress,
                 reset_hardware);
     }
 }
 
 /*
  * usb_disable_device_endpoints -- Disable all endpoints for a device
  * @dev: the device whose endpoints are being disabled
  * @skip_ep0: 0 to disable endpoint 0, 1 to skip it.
  */
 static void usb_disable_device_endpoints(struct usb_device *dev, int skip_ep0)
 {
     struct usb_hcd *hcd = bus_to_hcd(dev->bus);
     int i;
 
     if (hcd->driver->check_bandwidth) {
         /* First pass: Cancel URBs, leave endpoint pointers intact. */
         for (i = skip_ep0; i < 16; ++i) {
             usb_disable_endpoint(dev, i, false);
             usb_disable_endpoint(dev, i + USB_DIR_IN, false);
         }
         /* Remove endpoints from the host controller internal state */
         mutex_lock(hcd->bandwidth_mutex);
         usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
         mutex_unlock(hcd->bandwidth_mutex);
     }
     /* Second pass: remove endpoint pointers */
     for (i = skip_ep0; i < 16; ++i) {
         usb_disable_endpoint(dev, i, true);
         usb_disable_endpoint(dev, i + USB_DIR_IN, true);
     }
 }
 
 /**
  * usb_disable_device - Disable all the endpoints for a USB device
  * @dev: the device whose endpoints are being disabled
  * @skip_ep0: 0 to disable endpoint 0, 1 to skip it.
  *
  * Disables all the device's endpoints, potentially including endpoint 0.
  * Deallocates hcd/hardware state for the endpoints (nuking all or most
  * pending urbs) and usbcore state for the interfaces, so that usbcore
  * must usb_set_configuration() before any interfaces could be used.
  */
 void usb_disable_device(struct usb_device *dev, int skip_ep0)
 {
     int i;
 
     /* getting rid of interfaces will disconnect
      * any drivers bound to them (a key side effect)
      */
     if (dev->actconfig) {
         /*
          * FIXME: In order to avoid self-deadlock involving the
          * bandwidth_mutex, we have to mark all the interfaces
          * before unregistering any of them.
          */
         for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++)
             dev->actconfig->interface[i]->unregistering = 1;
 
         for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
             struct usb_interface    *interface;
 
             /* remove this interface if it has been registered */
             interface = dev->actconfig->interface[i];
             if (!device_is_registered(&interface->dev))
                 continue;
             dev_dbg(&dev->dev, "unregistering interface %s\n",
                 dev_name(&interface->dev));
             remove_intf_ep_devs(interface);
             device_del(&interface->dev);
         }
 
         /* Now that the interfaces are unbound, nobody should
          * try to access them.
          */
         for (i = 0; i < dev->actconfig->desc.bNumInterfaces; i++) {
             put_device(&dev->actconfig->interface[i]->dev);
             dev->actconfig->interface[i] = NULL;
         }
 
         usb_disable_usb2_hardware_lpm(dev);
         usb_unlocked_disable_lpm(dev);
         usb_disable_ltm(dev);
 
         dev->actconfig = NULL;
         if (dev->state == USB_STATE_CONFIGURED)
             usb_set_device_state(dev, USB_STATE_ADDRESS);
     }
 
     dev_dbg(&dev->dev, "%s nuking %s URBs\n", __func__,
         skip_ep0 ? "non-ep0" : "all");
 
     usb_disable_device_endpoints(dev, skip_ep0);
 }
 
 /**
  * usb_enable_endpoint - Enable an endpoint for USB communications
  * @dev: the device whose interface is being enabled
  * @ep: the endpoint
  * @reset_ep: flag to reset the endpoint state
  *
  * Resets the endpoint state if asked, and sets dev->ep_{in,out} pointers.
  * For control endpoints, both the input and output sides are handled.
  */
 void usb_enable_endpoint(struct usb_device *dev, struct usb_host_endpoint *ep,
         bool reset_ep)
 {
     int epnum = usb_endpoint_num(&ep->desc);
     int is_out = usb_endpoint_dir_out(&ep->desc);
     int is_control = usb_endpoint_xfer_control(&ep->desc);
 
     if (reset_ep)
         usb_hcd_reset_endpoint(dev, ep);
     if (is_out || is_control)
         dev->ep_out[epnum] = ep;
     if (!is_out || is_control)
         dev->ep_in[epnum] = ep;
     ep->enabled = 1;
 }
 
 /**
  * usb_enable_interface - Enable all the endpoints for an interface
  * @dev: the device whose interface is being enabled
  * @intf: pointer to the interface descriptor
  * @reset_eps: flag to reset the endpoints' state
  *
  * Enables all the endpoints for the interface's current altsetting.
  */
 void usb_enable_interface(struct usb_device *dev,
         struct usb_interface *intf, bool reset_eps)
 {
     struct usb_host_interface *alt = intf->cur_altsetting;
     int i;
 
     for (i = 0; i < alt->desc.bNumEndpoints; ++i)
         usb_enable_endpoint(dev, &alt->endpoint[i], reset_eps);
 }
 
 /**
  * usb_set_interface - Makes a particular alternate setting be current
  * @dev: the device whose interface is being updated
  * @interface: the interface being updated
  * @alternate: the setting being chosen.
  *
  * Context: task context, might sleep.
  *
  * This is used to enable data transfers on interfaces that may not
  * be enabled by default.  Not all devices support such configurability.
  * Only the driver bound to an interface may change its setting.
  *
  * Within any given configuration, each interface may have several
  * alternative settings.  These are often used to control levels of
  * bandwidth consumption.  For example, the default setting for a high
  * speed interrupt endpoint may not send more than 64 bytes per microframe,
  * while interrupt transfers of up to 3KBytes per microframe are legal.
  * Also, isochronous endpoints may never be part of an
  * interface's default setting.  To access such bandwidth, alternate
  * interface settings must be made current.
  *
  * Note that in the Linux USB subsystem, bandwidth associated with
  * an endpoint in a given alternate setting is not reserved until an URB
  * is submitted that needs that bandwidth.  Some other operating systems
  * allocate bandwidth early, when a configuration is chosen.
  *
  * xHCI reserves bandwidth and configures the alternate setting in
  * usb_hcd_alloc_bandwidth(). If it fails the original interface altsetting
  * may be disabled. Drivers cannot rely on any particular alternate
  * setting being in effect after a failure.
  *
  * This call is synchronous, and may not be used in an interrupt context.
  * Also, drivers must not change altsettings while urbs are scheduled for
  * endpoints in that interface; all such urbs must first be completed
  * (perhaps forced by unlinking).
  *
  * Return: Zero on success, or else the status code returned by the
  * underlying usb_control_msg() call.
  */
 int usb_set_interface(struct usb_device *dev, int interface, int alternate)
 {
     struct usb_interface *iface;
     struct usb_host_interface *alt;
     struct usb_hcd *hcd = bus_to_hcd(dev->bus);
     int i, ret, manual = 0;
     unsigned int epaddr;
     unsigned int pipe;
 
     if (dev->state == USB_STATE_SUSPENDED)
         return -EHOSTUNREACH;
 
     iface = usb_ifnum_to_if(dev, interface);
     if (!iface) {
         dev_dbg(&dev->dev, "selecting invalid interface %d\n",
             interface);
         return -EINVAL;
     }
     if (iface->unregistering)
         return -ENODEV;
 
     alt = usb_altnum_to_altsetting(iface, alternate);
     if (!alt) {
         dev_warn(&dev->dev, "selecting invalid altsetting %d\n",
              alternate);
         return -EINVAL;
     }
     /*
      * usb3 hosts configure the interface in usb_hcd_alloc_bandwidth,
      * including freeing dropped endpoint ring buffers.
      * Make sure the interface endpoints are flushed before that
      */
     usb_disable_interface(dev, iface, false);
 
     /* Make sure we have enough bandwidth for this alternate interface.
      * Remove the current alt setting and add the new alt setting.
      */
     mutex_lock(hcd->bandwidth_mutex);
     /* Disable LPM, and re-enable it once the new alt setting is installed,
      * so that the xHCI driver can recalculate the U1/U2 timeouts.
      */
     if (usb_disable_lpm(dev)) {
         dev_err(&iface->dev, "%s Failed to disable LPM\n", __func__);
         mutex_unlock(hcd->bandwidth_mutex);
         return -ENOMEM;
     }
     /* Changing alt-setting also frees any allocated streams */
     for (i = 0; i < iface->cur_altsetting->desc.bNumEndpoints; i++)
         iface->cur_altsetting->endpoint[i].streams = 0;
 
     ret = usb_hcd_alloc_bandwidth(dev, NULL, iface->cur_altsetting, alt);
     if (ret < 0) {
         dev_info(&dev->dev, "Not enough bandwidth for altsetting %d\n",
                 alternate);
         usb_enable_lpm(dev);
         mutex_unlock(hcd->bandwidth_mutex);
         return ret;
     }
 
     if (dev->quirks & USB_QUIRK_NO_SET_INTF)
         ret = -EPIPE;
     else
         ret = usb_control_msg_send(dev, 0,
                        USB_REQ_SET_INTERFACE,
                        USB_RECIP_INTERFACE, alternate,
                        interface, NULL, 0, 5000,
                        GFP_NOIO);
 
     /* 9.4.10 says devices don't need this and are free to STALL the
      * request if the interface only has one alternate setting.
      */
     if (ret == -EPIPE && iface->num_altsetting == 1) {
         dev_dbg(&dev->dev,
             "manual set_interface for iface %d, alt %d\n",
             interface, alternate);
         manual = 1;
     } else if (ret) {
         /* Re-instate the old alt setting */
         usb_hcd_alloc_bandwidth(dev, NULL, alt, iface->cur_altsetting);
         usb_enable_lpm(dev);
         mutex_unlock(hcd->bandwidth_mutex);
         return ret;
     }
     mutex_unlock(hcd->bandwidth_mutex);
 
     /* FIXME drivers shouldn't need to replicate/bugfix the logic here
      * when they implement async or easily-killable versions of this or
      * other "should-be-internal" functions (like clear_halt).
      * should hcd+usbcore postprocess control requests?
      */
 
     /* prevent submissions using previous endpoint settings */
     if (iface->cur_altsetting != alt) {
         remove_intf_ep_devs(iface);
         usb_remove_sysfs_intf_files(iface);
     }
     usb_disable_interface(dev, iface, true);
 
     iface->cur_altsetting = alt;
 
     /* Now that the interface is installed, re-enable LPM. */
     usb_unlocked_enable_lpm(dev);
 
     /* If the interface only has one altsetting and the device didn't
      * accept the request, we attempt to carry out the equivalent action
      * by manually clearing the HALT feature for each endpoint in the
      * new altsetting.
      */
     if (manual) {
         for (i = 0; i < alt->desc.bNumEndpoints; i++) {
             epaddr = alt->endpoint[i].desc.bEndpointAddress;
             pipe = __create_pipe(dev,
                     USB_ENDPOINT_NUMBER_MASK & epaddr) |
                     (usb_endpoint_out(epaddr) ?
                     USB_DIR_OUT : USB_DIR_IN);
 
             usb_clear_halt(dev, pipe);
         }
     }
 
     /* 9.1.1.5: reset toggles for all endpoints in the new altsetting
      *
      * Note:
      * Despite EP0 is always present in all interfaces/AS, the list of
      * endpoints from the descriptor does not contain EP0. Due to its
      * omnipresence one might expect EP0 being considered "affected" by
      * any SetInterface request and hence assume toggles need to be reset.
      * However, EP0 toggles are re-synced for every individual transfer
      * during the SETUP stage - hence EP0 toggles are "don't care" here.
      * (Likewise, EP0 never "halts" on well designed devices.)
      */
     usb_enable_interface(dev, iface, true);
     if (device_is_registered(&iface->dev)) {
         usb_create_sysfs_intf_files(iface);
         create_intf_ep_devs(iface);
     }
     return 0;
 }
 EXPORT_SYMBOL_GPL(usb_set_interface);
 
 /**
  * usb_reset_configuration - lightweight device reset
  * @dev: the device whose configuration is being reset
  *
  * This issues a standard SET_CONFIGURATION request to the device using
  * the current configuration.  The effect is to reset most USB-related
  * state in the device, including interface altsettings (reset to zero),
  * endpoint halts (cleared), and endpoint state (only for bulk and interrupt
  * endpoints).  Other usbcore state is unchanged, including bindings of
  * usb device drivers to interfaces.
  *
  * Because this affects multiple interfaces, avoid using this with composite
  * (multi-interface) devices.  Instead, the driver for each interface may
  * use usb_set_interface() on the interfaces it claims.  Be careful though;
  * some devices don't support the SET_INTERFACE request, and others won't
  * reset all the interface state (notably endpoint state).  Resetting the whole
  * configuration would affect other drivers' interfaces.
  *
  * The caller must own the device lock.
  *
  * Return: Zero on success, else a negative error code.
  *
  * If this routine fails the device will probably be in an unusable state
  * with endpoints disabled, and interfaces only partially enabled.
  */
 int usb_reset_configuration(struct usb_device *dev)
 {
     int         i, retval;
     struct usb_host_config  *config;
     struct usb_hcd *hcd = bus_to_hcd(dev->bus);
 
     if (dev->state == USB_STATE_SUSPENDED)
         return -EHOSTUNREACH;
 
     /* caller must have locked the device and must own
      * the usb bus readlock (so driver bindings are stable);
      * calls during probe() are fine
      */
 
     usb_disable_device_endpoints(dev, 1); /* skip ep0*/
 
     config = dev->actconfig;
     retval = 0;
     mutex_lock(hcd->bandwidth_mutex);
     /* Disable LPM, and re-enable it once the configuration is reset, so
      * that the xHCI driver can recalculate the U1/U2 timeouts.
      */
     if (usb_disable_lpm(dev)) {
         dev_err(&dev->dev, "%s Failed to disable LPM\n", __func__);
         mutex_unlock(hcd->bandwidth_mutex);
         return -ENOMEM;
     }
 
     /* xHCI adds all endpoints in usb_hcd_alloc_bandwidth */
     retval = usb_hcd_alloc_bandwidth(dev, config, NULL, NULL);
     if (retval < 0) {
         usb_enable_lpm(dev);
         mutex_unlock(hcd->bandwidth_mutex);
         return retval;
     }
     retval = usb_control_msg_send(dev, 0, USB_REQ_SET_CONFIGURATION, 0,
                       config->desc.bConfigurationValue, 0,
                       NULL, 0, USB_CTRL_SET_TIMEOUT,
                       GFP_NOIO);
     if (retval) {
         usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
         usb_enable_lpm(dev);
         mutex_unlock(hcd->bandwidth_mutex);
         return retval;
     }
     mutex_unlock(hcd->bandwidth_mutex);
 
     /* re-init hc/hcd interface/endpoint state */
     for (i = 0; i < config->desc.bNumInterfaces; i++) {
         struct usb_interface *intf = config->interface[i];
         struct usb_host_interface *alt;
 
         alt = usb_altnum_to_altsetting(intf, 0);
 
         /* No altsetting 0?  We'll assume the first altsetting.
          * We could use a GetInterface call, but if a device is
          * so non-compliant that it doesn't have altsetting 0
          * then I wouldn't trust its reply anyway.
          */
         if (!alt)
             alt = &intf->altsetting[0];
 
         if (alt != intf->cur_altsetting) {
             remove_intf_ep_devs(intf);
             usb_remove_sysfs_intf_files(intf);
         }
         intf->cur_altsetting = alt;
         usb_enable_interface(dev, intf, true);
         if (device_is_registered(&intf->dev)) {
             usb_create_sysfs_intf_files(intf);
             create_intf_ep_devs(intf);
         }
     }
     /* Now that the interfaces are installed, re-enable LPM. */
     usb_unlocked_enable_lpm(dev);
     return 0;
 }
 EXPORT_SYMBOL_GPL(usb_reset_configuration);
 
 static void usb_release_interface(struct device *dev)
 {
     struct usb_interface *intf = to_usb_interface(dev);
     struct usb_interface_cache *intfc =
             altsetting_to_usb_interface_cache(intf->altsetting);
 
     kref_put(&intfc->ref, usb_release_interface_cache);
     usb_put_dev(interface_to_usbdev(intf));
     of_node_put(dev->of_node);
     kfree(intf);
 }
 
 /*
  * usb_deauthorize_interface - deauthorize an USB interface
  *
  * @intf: USB interface structure
  */
 void usb_deauthorize_interface(struct usb_interface *intf)
 {
     struct device *dev = &intf->dev;
 
     device_lock(dev->parent);
 
     if (intf->authorized) {
         device_lock(dev);
         intf->authorized = 0;
         device_unlock(dev);
 
         usb_forced_unbind_intf(intf);
     }
 
     device_unlock(dev->parent);
 }
 
 /*
  * usb_authorize_interface - authorize an USB interface
  *
  * @intf: USB interface structure
  */
 void usb_authorize_interface(struct usb_interface *intf)
 {
     struct device *dev = &intf->dev;
 
     if (!intf->authorized) {
         device_lock(dev);
         intf->authorized = 1; /* authorize interface */
         device_unlock(dev);
     }
 }
 
 static int usb_if_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
     struct usb_device *usb_dev;
     struct usb_interface *intf;
     struct usb_host_interface *alt;
 
     intf = to_usb_interface(dev);
     usb_dev = interface_to_usbdev(intf);
     alt = intf->cur_altsetting;
 
     if (add_uevent_var(env, "INTERFACE=%d/%d/%d",
            alt->desc.bInterfaceClass,
            alt->desc.bInterfaceSubClass,
            alt->desc.bInterfaceProtocol))
         return -ENOMEM;
 
     if (add_uevent_var(env,
            "MODALIAS=usb:"
            "v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02Xin%02X",
            le16_to_cpu(usb_dev->descriptor.idVendor),
            le16_to_cpu(usb_dev->descriptor.idProduct),
            le16_to_cpu(usb_dev->descriptor.bcdDevice),
            usb_dev->descriptor.bDeviceClass,
            usb_dev->descriptor.bDeviceSubClass,
            usb_dev->descriptor.bDeviceProtocol,
            alt->desc.bInterfaceClass,
            alt->desc.bInterfaceSubClass,
            alt->desc.bInterfaceProtocol,
            alt->desc.bInterfaceNumber))
         return -ENOMEM;
 
     return 0;
 }
 
 struct device_type usb_if_device_type = {
     .name =     "usb_interface",
     .release =  usb_release_interface,
     .uevent =   usb_if_uevent,
 };
 
 static struct usb_interface_assoc_descriptor *find_iad(struct usb_device *dev,
                         struct usb_host_config *config,
                         u8 inum)
 {
     struct usb_interface_assoc_descriptor *retval = NULL;
     struct usb_interface_assoc_descriptor *intf_assoc;
     int first_intf;
     int last_intf;
     int i;
 
     for (i = 0; (i < USB_MAXIADS && config->intf_assoc[i]); i++) {
         intf_assoc = config->intf_assoc[i];
         if (intf_assoc->bInterfaceCount == 0)
             continue;
 
         first_intf = intf_assoc->bFirstInterface;
         last_intf = first_intf + (intf_assoc->bInterfaceCount - 1);
         if (inum >= first_intf && inum <= last_intf) {
             if (!retval)
                 retval = intf_assoc;
             else
                 dev_err(&dev->dev, "Interface #%d referenced"
                     " by multiple IADs\n", inum);
         }
     }
 
     return retval;
 }
 
 
 /*
  * Internal function to queue a device reset
  * See usb_queue_reset_device() for more details
  */
 static void __usb_queue_reset_device(struct work_struct *ws)
 {
     int rc;
     struct usb_interface *iface =
         container_of(ws, struct usb_interface, reset_ws);
     struct usb_device *udev = interface_to_usbdev(iface);
 
     rc = usb_lock_device_for_reset(udev, iface);
     if (rc >= 0) {
         usb_reset_device(udev);
         usb_unlock_device(udev);
     }
     usb_put_intf(iface);    /* Undo _get_ in usb_queue_reset_device() */
 }
 
 
 /*
  * usb_set_configuration - Makes a particular device setting be current
  * @dev: the device whose configuration is being updated
  * @configuration: the configuration being chosen.
  *
  * Context: task context, might sleep. Caller holds device lock.
  *
  * This is used to enable non-default device modes.  Not all devices
  * use this kind of configurability; many devices only have one
  * configuration.
  *
  * @configuration is the value of the configuration to be installed.
  * According to the USB spec (e.g. section 9.1.1.5), configuration values
  * must be non-zero; a value of zero indicates that the device in
  * unconfigured.  However some devices erroneously use 0 as one of their
  * configuration values.  To help manage such devices, this routine will
  * accept @configuration = -1 as indicating the device should be put in
  * an unconfigured state.
  *
  * USB device configurations may affect Linux interoperability,
  * power consumption and the functionality available.  For example,
  * the default configuration is limited to using 100mA of bus power,
  * so that when certain device functionality requires more power,
  * and the device is bus powered, that functionality should be in some
  * non-default device configuration.  Other device modes may also be
  * reflected as configuration options, such as whether two ISDN
  * channels are available independently; and choosing between open
  * standard device protocols (like CDC) or proprietary ones.
  *
  * Note that a non-authorized device (dev->authorized == 0) will only
  * be put in unconfigured mode.
  *
  * Note that USB has an additional level of device configurability,
  * associated with interfaces.  That configurability is accessed using
  * usb_set_interface().
  *
  * This call is synchronous. The calling context must be able to sleep,
  * must own the device lock, and must not hold the driver model's USB
  * bus mutex; usb interface driver probe() methods cannot use this routine.
  *
  * Returns zero on success, or else the status code returned by the
  * underlying call that failed.  On successful completion, each interface
  * in the original device configuration has been destroyed, and each one
  * in the new configuration has been probed by all relevant usb device
  * drivers currently known to the kernel.
  */
 int usb_set_configuration(struct usb_device *dev, int configuration)
 {
     int i, ret;
     struct usb_host_config *cp = NULL;
     struct usb_interface **new_interfaces = NULL;
     struct usb_hcd *hcd = bus_to_hcd(dev->bus);
     int n, nintf;
 
     if (dev->authorized == 0 || configuration == -1)
         configuration = 0;
     else {
         for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {
             if (dev->config[i].desc.bConfigurationValue ==
                     configuration) {
                 cp = &dev->config[i];
                 break;
             }
         }
     }
     if ((!cp && configuration != 0))
         return -EINVAL;
 
     /* The USB spec says configuration 0 means unconfigured.
      * But if a device includes a configuration numbered 0,
      * we will accept it as a correctly configured state.
      * Use -1 if you really want to unconfigure the device.
      */
     if (cp && configuration == 0)
         dev_warn(&dev->dev, "config 0 descriptor??\n");
 
     /* Allocate memory for new interfaces before doing anything else,
      * so that if we run out then nothing will have changed. */
     n = nintf = 0;
     if (cp) {
         nintf = cp->desc.bNumInterfaces;
         new_interfaces = kmalloc_array(nintf, sizeof(*new_interfaces),
                            GFP_NOIO);
         if (!new_interfaces)
             return -ENOMEM;
 
         for (; n < nintf; ++n) {
             new_interfaces[n] = kzalloc(
                     sizeof(struct usb_interface),
                     GFP_NOIO);
             if (!new_interfaces[n]) {
                 ret = -ENOMEM;
 free_interfaces:
                 while (--n >= 0)
                     kfree(new_interfaces[n]);
                 kfree(new_interfaces);
                 return ret;
             }
         }
 
         i = dev->bus_mA - usb_get_max_power(dev, cp);
         if (i < 0)
             dev_warn(&dev->dev, "new config #%d exceeds power "
                     "limit by %dmA\n",
                     configuration, -i);
     }
 
     /* Wake up the device so we can send it the Set-Config request */
     ret = usb_autoresume_device(dev);
     if (ret)
         goto free_interfaces;
 
     /* if it's already configured, clear out old state first.
      * getting rid of old interfaces means unbinding their drivers.
      */
     if (dev->state != USB_STATE_ADDRESS)
         usb_disable_device(dev, 1); /* Skip ep0 */
 
     /* Get rid of pending async Set-Config requests for this device */
     cancel_async_set_config(dev);
 
     /* Make sure we have bandwidth (and available HCD resources) for this
      * configuration.  Remove endpoints from the schedule if we're dropping
      * this configuration to set configuration 0.  After this point, the
      * host controller will not allow submissions to dropped endpoints.  If
      * this call fails, the device state is unchanged.
      */
     mutex_lock(hcd->bandwidth_mutex);
     /* Disable LPM, and re-enable it once the new configuration is
      * installed, so that the xHCI driver can recalculate the U1/U2
      * timeouts.
      */
     if (dev->actconfig && usb_disable_lpm(dev)) {
         dev_err(&dev->dev, "%s Failed to disable LPM\n", __func__);
         mutex_unlock(hcd->bandwidth_mutex);
         ret = -ENOMEM;
         goto free_interfaces;
     }
     ret = usb_hcd_alloc_bandwidth(dev, cp, NULL, NULL);
     if (ret < 0) {
         if (dev->actconfig)
             usb_enable_lpm(dev);
         mutex_unlock(hcd->bandwidth_mutex);
         usb_autosuspend_device(dev);
         goto free_interfaces;
     }
 
     /*
      * Initialize the new interface structures and the
      * hc/hcd/usbcore interface/endpoint state.
      */
     for (i = 0; i < nintf; ++i) {
         struct usb_interface_cache *intfc;
         struct usb_interface *intf;
         struct usb_host_interface *alt;
         u8 ifnum;
 
         cp->interface[i] = intf = new_interfaces[i];
         intfc = cp->intf_cache[i];
         intf->altsetting = intfc->altsetting;
         intf->num_altsetting = intfc->num_altsetting;
         intf->authorized = !!HCD_INTF_AUTHORIZED(hcd);
         kref_get(&intfc->ref);
 
         alt = usb_altnum_to_altsetting(intf, 0);
 
         /* No altsetting 0?  We'll assume the first altsetting.
          * We could use a GetInterface call, but if a device is
          * so non-compliant that it doesn't have altsetting 0
          * then I wouldn't trust its reply anyway.
          */
         if (!alt)
             alt = &intf->altsetting[0];
 
         ifnum = alt->desc.bInterfaceNumber;
         intf->intf_assoc = find_iad(dev, cp, ifnum);
         intf->cur_altsetting = alt;
         usb_enable_interface(dev, intf, true);
         intf->dev.parent = &dev->dev;
         if (usb_of_has_combined_node(dev)) {
             device_set_of_node_from_dev(&intf->dev, &dev->dev);
         } else {
             intf->dev.of_node = usb_of_get_interface_node(dev,
                     configuration, ifnum);
         }
         ACPI_COMPANION_SET(&intf->dev, ACPI_COMPANION(&dev->dev));
         intf->dev.driver = NULL;
         intf->dev.bus = &usb_bus_type;
         intf->dev.type = &usb_if_device_type;
         intf->dev.groups = usb_interface_groups;
         INIT_WORK(&intf->reset_ws, __usb_queue_reset_device);
         intf->minor = -1;
         device_initialize(&intf->dev);
         pm_runtime_no_callbacks(&intf->dev);
         dev_set_name(&intf->dev, "%d-%s:%d.%d", dev->bus->busnum,
                 dev->devpath, configuration, ifnum);
         usb_get_dev(dev);
     }
     kfree(new_interfaces);
 
     ret = usb_control_msg_send(dev, 0, USB_REQ_SET_CONFIGURATION, 0,
                    configuration, 0, NULL, 0,
                    USB_CTRL_SET_TIMEOUT, GFP_NOIO);
     if (ret && cp) {
         /*
          * All the old state is gone, so what else can we do?
          * The device is probably useless now anyway.
          */
         usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
         for (i = 0; i < nintf; ++i) {
             usb_disable_interface(dev, cp->interface[i], true);
             put_device(&cp->interface[i]->dev);
             cp->interface[i] = NULL;
         }
         cp = NULL;
     }
 
     dev->actconfig = cp;
     mutex_unlock(hcd->bandwidth_mutex);
 
     if (!cp) {
         usb_set_device_state(dev, USB_STATE_ADDRESS);
 
         /* Leave LPM disabled while the device is unconfigured. */
         usb_autosuspend_device(dev);
         return ret;
     }
     usb_set_device_state(dev, USB_STATE_CONFIGURED);
 
     if (cp->string == NULL &&
             !(dev->quirks & USB_QUIRK_CONFIG_INTF_STRINGS))
         cp->string = usb_cache_string(dev, cp->desc.iConfiguration);
 
     /* Now that the interfaces are installed, re-enable LPM. */
     usb_unlocked_enable_lpm(dev);
     /* Enable LTM if it was turned off by usb_disable_device. */
     usb_enable_ltm(dev);
 
     /* Now that all the interfaces are set up, register them
      * to trigger binding of drivers to interfaces.  probe()
      * routines may install different altsettings and may
      * claim() any interfaces not yet bound.  Many class drivers
      * need that: CDC, audio, video, etc.
      */
     for (i = 0; i < nintf; ++i) {
         struct usb_interface *intf = cp->interface[i];
 
         if (intf->dev.of_node &&
             !of_device_is_available(intf->dev.of_node)) {
             dev_info(&dev->dev, "skipping disabled interface %d\n",
                  intf->cur_altsetting->desc.bInterfaceNumber);
             continue;
         }
 
         dev_dbg(&dev->dev,
             "adding %s (config #%d, interface %d)\n",
             dev_name(&intf->dev), configuration,
             intf->cur_altsetting->desc.bInterfaceNumber);
         device_enable_async_suspend(&intf->dev);
         ret = device_add(&intf->dev);
         if (ret != 0) {
             dev_err(&dev->dev, "device_add(%s) --> %d\n",
                 dev_name(&intf->dev), ret);
             continue;
         }
         create_intf_ep_devs(intf);
     }
 
     usb_autosuspend_device(dev);
     return 0;
 }
 EXPORT_SYMBOL_GPL(usb_set_configuration);
 
 static LIST_HEAD(set_config_list);
 static DEFINE_SPINLOCK(set_config_lock);
 
 struct set_config_request {
     struct usb_device   *udev;
     int         config;
     struct work_struct  work;
     struct list_head    node;
 };
 
 /* Worker routine for usb_driver_set_configuration() */
 static void driver_set_config_work(struct work_struct *work)
 {
     struct set_config_request *req =
         container_of(work, struct set_config_request, work);
     struct usb_device *udev = req->udev;
 
     usb_lock_device(udev);
     spin_lock(&set_config_lock);
     list_del(&req->node);
     spin_unlock(&set_config_lock);
 
     if (req->config >= -1)      /* Is req still valid? */
         usb_set_configuration(udev, req->config);
     usb_unlock_device(udev);
     usb_put_dev(udev);
     kfree(req);
 }
 
 /* Cancel pending Set-Config requests for a device whose configuration
  * was just changed
  */
 static void cancel_async_set_config(struct usb_device *udev)
 {
     struct set_config_request *req;
 
     spin_lock(&set_config_lock);
     list_for_each_entry(req, &set_config_list, node) {
         if (req->udev == udev)
             req->config = -999; /* Mark as cancelled */
     }
     spin_unlock(&set_config_lock);
 }
 
 /**
  * usb_driver_set_configuration - Provide a way for drivers to change device configurations
  * @udev: the device whose configuration is being updated
  * @config: the configuration being chosen.
  * Context: In process context, must be able to sleep
  *
  * Device interface drivers are not allowed to change device configurations.
  * This is because changing configurations will destroy the interface the
  * driver is bound to and create new ones; it would be like a floppy-disk
  * driver telling the computer to replace the floppy-disk drive with a
  * tape drive!
  *
  * Still, in certain specialized circumstances the need may arise.  This
  * routine gets around the normal restrictions by using a work thread to
  * submit the change-config request.
  *
  * Return: 0 if the request was successfully queued, error code otherwise.
  * The caller has no way to know whether the queued request will eventually
  * succeed.
  */
 int usb_driver_set_configuration(struct usb_device *udev, int config)
 {
     struct set_config_request *req;
 
     req = kmalloc(sizeof(*req), GFP_KERNEL);
     if (!req)
         return -ENOMEM;
     req->udev = udev;
     req->config = config;
     INIT_WORK(&req->work, driver_set_config_work);
 
     spin_lock(&set_config_lock);
     list_add(&req->node, &set_config_list);
     spin_unlock(&set_config_lock);
 
     usb_get_dev(udev);
     schedule_work(&req->work);
     return 0;
 }
 EXPORT_SYMBOL_GPL(usb_driver_set_configuration);
 
 /**
  * cdc_parse_cdc_header - parse the extra headers present in CDC devices
  * @hdr: the place to put the results of the parsing
  * @intf: the interface for which parsing is requested
  * @buffer: pointer to the extra headers to be parsed
  * @buflen: length of the extra headers
  *
  * This evaluates the extra headers present in CDC devices which
  * bind the interfaces for data and control and provide details
  * about the capabilities of the device.
  *
  * Return: number of descriptors parsed or -EINVAL
  * if the header is contradictory beyond salvage
  */
 
 int cdc_parse_cdc_header(struct usb_cdc_parsed_header *hdr,
                 struct usb_interface *intf,
                 u8 *buffer,
                 int buflen)
 {
     /* duplicates are ignored */
     struct usb_cdc_union_desc *union_header = NULL;
 
     /* duplicates are not tolerated */
     struct usb_cdc_header_desc *header = NULL;
     struct usb_cdc_ether_desc *ether = NULL;
     struct usb_cdc_mdlm_detail_desc *detail = NULL;
     struct usb_cdc_mdlm_desc *desc = NULL;
 
     unsigned int elength;
     int cnt = 0;
 
     memset(hdr, 0x00, sizeof(struct usb_cdc_parsed_header));
     hdr->phonet_magic_present = false;
     while (buflen > 0) {
         elength = buffer[0];
         if (!elength) {
             dev_err(&intf->dev, "skipping garbage byte\n");
             elength = 1;
             goto next_desc;
         }
         if ((buflen < elength) || (elength < 3)) {
             dev_err(&intf->dev, "invalid descriptor buffer length\n");
             break;
         }
         if (buffer[1] != USB_DT_CS_INTERFACE) {
             dev_err(&intf->dev, "skipping garbage\n");
             goto next_desc;
         }
 
         switch (buffer[2]) {
         case USB_CDC_UNION_TYPE: /* we've found it */
             if (elength < sizeof(struct usb_cdc_union_desc))
                 goto next_desc;
             if (union_header) {
                 dev_err(&intf->dev, "More than one union descriptor, skipping ...\n");
                 goto next_desc;
             }
             union_header = (struct usb_cdc_union_desc *)buffer;
             break;
         case USB_CDC_COUNTRY_TYPE:
             if (elength < sizeof(struct usb_cdc_country_functional_desc))
                 goto next_desc;
             hdr->usb_cdc_country_functional_desc =
                 (struct usb_cdc_country_functional_desc *)buffer;
             break;
         case USB_CDC_HEADER_TYPE:
             if (elength != sizeof(struct usb_cdc_header_desc))
                 goto next_desc;
             if (header)
                 return -EINVAL;
             header = (struct usb_cdc_header_desc *)buffer;
             break;
         case USB_CDC_ACM_TYPE:
             if (elength < sizeof(struct usb_cdc_acm_descriptor))
                 goto next_desc;
             hdr->usb_cdc_acm_descriptor =
                 (struct usb_cdc_acm_descriptor *)buffer;
             break;
         case USB_CDC_ETHERNET_TYPE:
             if (elength != sizeof(struct usb_cdc_ether_desc))
                 goto next_desc;
             if (ether)
                 return -EINVAL;
             ether = (struct usb_cdc_ether_desc *)buffer;
             break;
         case USB_CDC_CALL_MANAGEMENT_TYPE:
             if (elength < sizeof(struct usb_cdc_call_mgmt_descriptor))
                 goto next_desc;
             hdr->usb_cdc_call_mgmt_descriptor =
                 (struct usb_cdc_call_mgmt_descriptor *)buffer;
             break;
         case USB_CDC_DMM_TYPE:
             if (elength < sizeof(struct usb_cdc_dmm_desc))
                 goto next_desc;
             hdr->usb_cdc_dmm_desc =
                 (struct usb_cdc_dmm_desc *)buffer;
             break;
         case USB_CDC_MDLM_TYPE:
             if (elength < sizeof(struct usb_cdc_mdlm_desc))
                 goto next_desc;
             if (desc)
                 return -EINVAL;
             desc = (struct usb_cdc_mdlm_desc *)buffer;
             break;
         case USB_CDC_MDLM_DETAIL_TYPE:
             if (elength < sizeof(struct usb_cdc_mdlm_detail_desc))
                 goto next_desc;
             if (detail)
                 return -EINVAL;
             detail = (struct usb_cdc_mdlm_detail_desc *)buffer;
             break;
         case USB_CDC_NCM_TYPE:
             if (elength < sizeof(struct usb_cdc_ncm_desc))
                 goto next_desc;
             hdr->usb_cdc_ncm_desc = (struct usb_cdc_ncm_desc *)buffer;
             break;
         case USB_CDC_MBIM_TYPE:
             if (elength < sizeof(struct usb_cdc_mbim_desc))
                 goto next_desc;
 
             hdr->usb_cdc_mbim_desc = (struct usb_cdc_mbim_desc *)buffer;
             break;
         case USB_CDC_MBIM_EXTENDED_TYPE:
             if (elength < sizeof(struct usb_cdc_mbim_extended_desc))
                 break;
             hdr->usb_cdc_mbim_extended_desc =
                 (struct usb_cdc_mbim_extended_desc *)buffer;
             break;
         case CDC_PHONET_MAGIC_NUMBER:
             hdr->phonet_magic_present = true;
             break;
         default:
             /*
              * there are LOTS more CDC descriptors that
              * could legitimately be found here.
              */
             dev_dbg(&intf->dev, "Ignoring descriptor: type %02x, length %ud\n",
                     buffer[2], elength);
             goto next_desc;
         }
         cnt++;
 next_desc:
         buflen -= elength;
         buffer += elength;
     }
     hdr->usb_cdc_union_desc = union_header;
     hdr->usb_cdc_header_desc = header;
     hdr->usb_cdc_mdlm_detail_desc = detail;
     hdr->usb_cdc_mdlm_desc = desc;
     hdr->usb_cdc_ether_desc = ether;
     return cnt;
 }
 
 EXPORT_SYMBOL(cdc_parse_cdc_header);

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