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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Released under the GPLv2 only.
- */
- #include <linux/module.h>
- #include <linux/string.h>
- #include <linux/bitops.h>
- #include <linux/slab.h>
- #include <linux/log2.h>
- #include <linux/usb.h>
- #include <linux/wait.h>
- #include <linux/usb/hcd.h>
- #include <linux/scatterlist.h>
- #define to_urb(d) container_of(d, struct urb, kref)
- static void urb_destroy(struct kref *kref)
- {
- struct urb *urb = to_urb(kref);
- if (urb->transfer_flags & URB_FREE_BUFFER)
- kfree(urb->transfer_buffer);
- kfree(urb);
- }
- /**
- * usb_init_urb - initializes a urb so that it can be used by a USB driver
- * @urb: pointer to the urb to initialize
- *
- * Initializes a urb so that the USB subsystem can use it properly.
- *
- * If a urb is created with a call to usb_alloc_urb() it is not
- * necessary to call this function. Only use this if you allocate the
- * space for a struct urb on your own. If you call this function, be
- * careful when freeing the memory for your urb that it is no longer in
- * use by the USB core.
- *
- * Only use this function if you _really_ understand what you are doing.
- */
- void usb_init_urb(struct urb *urb)
- {
- if (urb) {
- memset(urb, 0, sizeof(*urb));
- kref_init(&urb->kref);
- INIT_LIST_HEAD(&urb->urb_list);
- INIT_LIST_HEAD(&urb->anchor_list);
- }
- }
- EXPORT_SYMBOL_GPL(usb_init_urb);
- /**
- * usb_alloc_urb - creates a new urb for a USB driver to use
- * @iso_packets: number of iso packets for this urb
- * @mem_flags: the type of memory to allocate, see kmalloc() for a list of
- * valid options for this.
- *
- * Creates an urb for the USB driver to use, initializes a few internal
- * structures, increments the usage counter, and returns a pointer to it.
- *
- * If the driver want to use this urb for interrupt, control, or bulk
- * endpoints, pass '0' as the number of iso packets.
- *
- * The driver must call usb_free_urb() when it is finished with the urb.
- *
- * Return: A pointer to the new urb, or %NULL if no memory is available.
- */
- struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags)
- {
- struct urb *urb;
- urb = kmalloc(struct_size(urb, iso_frame_desc, iso_packets),
- mem_flags);
- if (!urb)
- return NULL;
- usb_init_urb(urb);
- return urb;
- }
- EXPORT_SYMBOL_GPL(usb_alloc_urb);
- /**
- * usb_free_urb - frees the memory used by a urb when all users of it are finished
- * @urb: pointer to the urb to free, may be NULL
- *
- * Must be called when a user of a urb is finished with it. When the last user
- * of the urb calls this function, the memory of the urb is freed.
- *
- * Note: The transfer buffer associated with the urb is not freed unless the
- * URB_FREE_BUFFER transfer flag is set.
- */
- void usb_free_urb(struct urb *urb)
- {
- if (urb)
- kref_put(&urb->kref, urb_destroy);
- }
- EXPORT_SYMBOL_GPL(usb_free_urb);
- /**
- * usb_get_urb - increments the reference count of the urb
- * @urb: pointer to the urb to modify, may be NULL
- *
- * This must be called whenever a urb is transferred from a device driver to a
- * host controller driver. This allows proper reference counting to happen
- * for urbs.
- *
- * Return: A pointer to the urb with the incremented reference counter.
- */
- struct urb *usb_get_urb(struct urb *urb)
- {
- if (urb)
- kref_get(&urb->kref);
- return urb;
- }
- EXPORT_SYMBOL_GPL(usb_get_urb);
- /**
- * usb_anchor_urb - anchors an URB while it is processed
- * @urb: pointer to the urb to anchor
- * @anchor: pointer to the anchor
- *
- * This can be called to have access to URBs which are to be executed
- * without bothering to track them
- */
- void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor)
- {
- unsigned long flags;
- spin_lock_irqsave(&anchor->lock, flags);
- usb_get_urb(urb);
- list_add_tail(&urb->anchor_list, &anchor->urb_list);
- urb->anchor = anchor;
- if (unlikely(anchor->poisoned))
- atomic_inc(&urb->reject);
- spin_unlock_irqrestore(&anchor->lock, flags);
- }
- EXPORT_SYMBOL_GPL(usb_anchor_urb);
- static int usb_anchor_check_wakeup(struct usb_anchor *anchor)
- {
- return atomic_read(&anchor->suspend_wakeups) == 0 &&
- list_empty(&anchor->urb_list);
- }
- /* Callers must hold anchor->lock */
- static void __usb_unanchor_urb(struct urb *urb, struct usb_anchor *anchor)
- {
- urb->anchor = NULL;
- list_del(&urb->anchor_list);
- usb_put_urb(urb);
- if (usb_anchor_check_wakeup(anchor))
- wake_up(&anchor->wait);
- }
- /**
- * usb_unanchor_urb - unanchors an URB
- * @urb: pointer to the urb to anchor
- *
- * Call this to stop the system keeping track of this URB
- */
- void usb_unanchor_urb(struct urb *urb)
- {
- unsigned long flags;
- struct usb_anchor *anchor;
- if (!urb)
- return;
- anchor = urb->anchor;
- if (!anchor)
- return;
- spin_lock_irqsave(&anchor->lock, flags);
- /*
- * At this point, we could be competing with another thread which
- * has the same intention. To protect the urb from being unanchored
- * twice, only the winner of the race gets the job.
- */
- if (likely(anchor == urb->anchor))
- __usb_unanchor_urb(urb, anchor);
- spin_unlock_irqrestore(&anchor->lock, flags);
- }
- EXPORT_SYMBOL_GPL(usb_unanchor_urb);
- /*-------------------------------------------------------------------*/
- static const int pipetypes[4] = {
- PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT
- };
- /**
- * usb_pipe_type_check - sanity check of a specific pipe for a usb device
- * @dev: struct usb_device to be checked
- * @pipe: pipe to check
- *
- * This performs a light-weight sanity check for the endpoint in the
- * given usb device. It returns 0 if the pipe is valid for the specific usb
- * device, otherwise a negative error code.
- */
- int usb_pipe_type_check(struct usb_device *dev, unsigned int pipe)
- {
- const struct usb_host_endpoint *ep;
- ep = usb_pipe_endpoint(dev, pipe);
- if (!ep)
- return -EINVAL;
- if (usb_pipetype(pipe) != pipetypes[usb_endpoint_type(&ep->desc)])
- return -EINVAL;
- return 0;
- }
- EXPORT_SYMBOL_GPL(usb_pipe_type_check);
- /**
- * usb_urb_ep_type_check - sanity check of endpoint in the given urb
- * @urb: urb to be checked
- *
- * This performs a light-weight sanity check for the endpoint in the
- * given urb. It returns 0 if the urb contains a valid endpoint, otherwise
- * a negative error code.
- */
- int usb_urb_ep_type_check(const struct urb *urb)
- {
- return usb_pipe_type_check(urb->dev, urb->pipe);
- }
- EXPORT_SYMBOL_GPL(usb_urb_ep_type_check);
- /**
- * usb_submit_urb - issue an asynchronous transfer request for an endpoint
- * @urb: pointer to the urb describing the request
- * @mem_flags: the type of memory to allocate, see kmalloc() for a list
- * of valid options for this.
- *
- * This submits a transfer request, and transfers control of the URB
- * describing that request to the USB subsystem. Request completion will
- * be indicated later, asynchronously, by calling the completion handler.
- * The three types of completion are success, error, and unlink
- * (a software-induced fault, also called "request cancellation").
- *
- * URBs may be submitted in interrupt context.
- *
- * The caller must have correctly initialized the URB before submitting
- * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are
- * available to ensure that most fields are correctly initialized, for
- * the particular kind of transfer, although they will not initialize
- * any transfer flags.
- *
- * If the submission is successful, the complete() callback from the URB
- * will be called exactly once, when the USB core and Host Controller Driver
- * (HCD) are finished with the URB. When the completion function is called,
- * control of the URB is returned to the device driver which issued the
- * request. The completion handler may then immediately free or reuse that
- * URB.
- *
- * With few exceptions, USB device drivers should never access URB fields
- * provided by usbcore or the HCD until its complete() is called.
- * The exceptions relate to periodic transfer scheduling. For both
- * interrupt and isochronous urbs, as part of successful URB submission
- * urb->interval is modified to reflect the actual transfer period used
- * (normally some power of two units). And for isochronous urbs,
- * urb->start_frame is modified to reflect when the URB's transfers were
- * scheduled to start.
- *
- * Not all isochronous transfer scheduling policies will work, but most
- * host controller drivers should easily handle ISO queues going from now
- * until 10-200 msec into the future. Drivers should try to keep at
- * least one or two msec of data in the queue; many controllers require
- * that new transfers start at least 1 msec in the future when they are
- * added. If the driver is unable to keep up and the queue empties out,
- * the behavior for new submissions is governed by the URB_ISO_ASAP flag.
- * If the flag is set, or if the queue is idle, then the URB is always
- * assigned to the first available (and not yet expired) slot in the
- * endpoint's schedule. If the flag is not set and the queue is active
- * then the URB is always assigned to the next slot in the schedule
- * following the end of the endpoint's previous URB, even if that slot is
- * in the past. When a packet is assigned in this way to a slot that has
- * already expired, the packet is not transmitted and the corresponding
- * usb_iso_packet_descriptor's status field will return -EXDEV. If this
- * would happen to all the packets in the URB, submission fails with a
- * -EXDEV error code.
- *
- * For control endpoints, the synchronous usb_control_msg() call is
- * often used (in non-interrupt context) instead of this call.
- * That is often used through convenience wrappers, for the requests
- * that are standardized in the USB 2.0 specification. For bulk
- * endpoints, a synchronous usb_bulk_msg() call is available.
- *
- * Return:
- * 0 on successful submissions. A negative error number otherwise.
- *
- * Request Queuing:
- *
- * URBs may be submitted to endpoints before previous ones complete, to
- * minimize the impact of interrupt latencies and system overhead on data
- * throughput. With that queuing policy, an endpoint's queue would never
- * be empty. This is required for continuous isochronous data streams,
- * and may also be required for some kinds of interrupt transfers. Such
- * queuing also maximizes bandwidth utilization by letting USB controllers
- * start work on later requests before driver software has finished the
- * completion processing for earlier (successful) requests.
- *
- * As of Linux 2.6, all USB endpoint transfer queues support depths greater
- * than one. This was previously a HCD-specific behavior, except for ISO
- * transfers. Non-isochronous endpoint queues are inactive during cleanup
- * after faults (transfer errors or cancellation).
- *
- * Reserved Bandwidth Transfers:
- *
- * Periodic transfers (interrupt or isochronous) are performed repeatedly,
- * using the interval specified in the urb. Submitting the first urb to
- * the endpoint reserves the bandwidth necessary to make those transfers.
- * If the USB subsystem can't allocate sufficient bandwidth to perform
- * the periodic request, submitting such a periodic request should fail.
- *
- * For devices under xHCI, the bandwidth is reserved at configuration time, or
- * when the alt setting is selected. If there is not enough bus bandwidth, the
- * configuration/alt setting request will fail. Therefore, submissions to
- * periodic endpoints on devices under xHCI should never fail due to bandwidth
- * constraints.
- *
- * Device drivers must explicitly request that repetition, by ensuring that
- * some URB is always on the endpoint's queue (except possibly for short
- * periods during completion callbacks). When there is no longer an urb
- * queued, the endpoint's bandwidth reservation is canceled. This means
- * drivers can use their completion handlers to ensure they keep bandwidth
- * they need, by reinitializing and resubmitting the just-completed urb
- * until the driver longer needs that periodic bandwidth.
- *
- * Memory Flags:
- *
- * The general rules for how to decide which mem_flags to use
- * are the same as for kmalloc. There are four
- * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and
- * GFP_ATOMIC.
- *
- * GFP_NOFS is not ever used, as it has not been implemented yet.
- *
- * GFP_ATOMIC is used when
- * (a) you are inside a completion handler, an interrupt, bottom half,
- * tasklet or timer, or
- * (b) you are holding a spinlock or rwlock (does not apply to
- * semaphores), or
- * (c) current->state != TASK_RUNNING, this is the case only after
- * you've changed it.
- *
- * GFP_NOIO is used in the block io path and error handling of storage
- * devices.
- *
- * All other situations use GFP_KERNEL.
- *
- * Some more specific rules for mem_flags can be inferred, such as
- * (1) start_xmit, timeout, and receive methods of network drivers must
- * use GFP_ATOMIC (they are called with a spinlock held);
- * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also
- * called with a spinlock held);
- * (3) If you use a kernel thread with a network driver you must use
- * GFP_NOIO, unless (b) or (c) apply;
- * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)
- * apply or your are in a storage driver's block io path;
- * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and
- * (6) changing firmware on a running storage or net device uses
- * GFP_NOIO, unless b) or c) apply
- *
- */
- int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
- {
- int xfertype, max;
- struct usb_device *dev;
- struct usb_host_endpoint *ep;
- int is_out;
- unsigned int allowed;
- if (!urb || !urb->complete)
- return -EINVAL;
- if (urb->hcpriv) {
- WARN_ONCE(1, "URB %pK submitted while active\n", urb);
- return -EBUSY;
- }
- dev = urb->dev;
- if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED))
- return -ENODEV;
- /* For now, get the endpoint from the pipe. Eventually drivers
- * will be required to set urb->ep directly and we will eliminate
- * urb->pipe.
- */
- ep = usb_pipe_endpoint(dev, urb->pipe);
- if (!ep)
- return -ENOENT;
- urb->ep = ep;
- urb->status = -EINPROGRESS;
- urb->actual_length = 0;
- /* Lots of sanity checks, so HCDs can rely on clean data
- * and don't need to duplicate tests
- */
- xfertype = usb_endpoint_type(&ep->desc);
- if (xfertype == USB_ENDPOINT_XFER_CONTROL) {
- struct usb_ctrlrequest *setup =
- (struct usb_ctrlrequest *) urb->setup_packet;
- if (!setup)
- return -ENOEXEC;
- is_out = !(setup->bRequestType & USB_DIR_IN) ||
- !setup->wLength;
- } else {
- is_out = usb_endpoint_dir_out(&ep->desc);
- }
- /* Clear the internal flags and cache the direction for later use */
- urb->transfer_flags &= ~(URB_DIR_MASK | URB_DMA_MAP_SINGLE |
- URB_DMA_MAP_PAGE | URB_DMA_MAP_SG | URB_MAP_LOCAL |
- URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL |
- URB_DMA_SG_COMBINED);
- urb->transfer_flags |= (is_out ? URB_DIR_OUT : URB_DIR_IN);
- if (xfertype != USB_ENDPOINT_XFER_CONTROL &&
- dev->state < USB_STATE_CONFIGURED)
- return -ENODEV;
- max = usb_endpoint_maxp(&ep->desc);
- if (max <= 0) {
- dev_dbg(&dev->dev,
- "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
- usb_endpoint_num(&ep->desc), is_out ? "out" : "in",
- __func__, max);
- return -EMSGSIZE;
- }
- /* periodic transfers limit size per frame/uframe,
- * but drivers only control those sizes for ISO.
- * while we're checking, initialize return status.
- */
- if (xfertype == USB_ENDPOINT_XFER_ISOC) {
- int n, len;
- /* SuperSpeed isoc endpoints have up to 16 bursts of up to
- * 3 packets each
- */
- if (dev->speed >= USB_SPEED_SUPER) {
- int burst = 1 + ep->ss_ep_comp.bMaxBurst;
- int mult = USB_SS_MULT(ep->ss_ep_comp.bmAttributes);
- max *= burst;
- max *= mult;
- }
- if (dev->speed == USB_SPEED_SUPER_PLUS &&
- USB_SS_SSP_ISOC_COMP(ep->ss_ep_comp.bmAttributes)) {
- struct usb_ssp_isoc_ep_comp_descriptor *isoc_ep_comp;
- isoc_ep_comp = &ep->ssp_isoc_ep_comp;
- max = le32_to_cpu(isoc_ep_comp->dwBytesPerInterval);
- }
- /* "high bandwidth" mode, 1-3 packets/uframe? */
- if (dev->speed == USB_SPEED_HIGH)
- max *= usb_endpoint_maxp_mult(&ep->desc);
- if (urb->number_of_packets <= 0)
- return -EINVAL;
- for (n = 0; n < urb->number_of_packets; n++) {
- len = urb->iso_frame_desc[n].length;
- if (len < 0 || len > max)
- return -EMSGSIZE;
- urb->iso_frame_desc[n].status = -EXDEV;
- urb->iso_frame_desc[n].actual_length = 0;
- }
- } else if (urb->num_sgs && !urb->dev->bus->no_sg_constraint &&
- dev->speed != USB_SPEED_WIRELESS) {
- struct scatterlist *sg;
- int i;
- for_each_sg(urb->sg, sg, urb->num_sgs - 1, i)
- if (sg->length % max)
- return -EINVAL;
- }
- /* the I/O buffer must be mapped/unmapped, except when length=0 */
- if (urb->transfer_buffer_length > INT_MAX)
- return -EMSGSIZE;
- /*
- * stuff that drivers shouldn't do, but which shouldn't
- * cause problems in HCDs if they get it wrong.
- */
- /* Check that the pipe's type matches the endpoint's type */
- if (usb_pipe_type_check(urb->dev, urb->pipe))
- dev_WARN(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n",
- usb_pipetype(urb->pipe), pipetypes[xfertype]);
- /* Check against a simple/standard policy */
- allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT | URB_DIR_MASK |
- URB_FREE_BUFFER);
- switch (xfertype) {
- case USB_ENDPOINT_XFER_BULK:
- case USB_ENDPOINT_XFER_INT:
- if (is_out)
- allowed |= URB_ZERO_PACKET;
- fallthrough;
- default: /* all non-iso endpoints */
- if (!is_out)
- allowed |= URB_SHORT_NOT_OK;
- break;
- case USB_ENDPOINT_XFER_ISOC:
- allowed |= URB_ISO_ASAP;
- break;
- }
- allowed &= urb->transfer_flags;
- /* warn if submitter gave bogus flags */
- if (allowed != urb->transfer_flags)
- dev_WARN(&dev->dev, "BOGUS urb flags, %x --> %x\n",
- urb->transfer_flags, allowed);
- /*
- * Force periodic transfer intervals to be legal values that are
- * a power of two (so HCDs don't need to).
- *
- * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC
- * supports different values... this uses EHCI/UHCI defaults (and
- * EHCI can use smaller non-default values).
- */
- switch (xfertype) {
- case USB_ENDPOINT_XFER_ISOC:
- case USB_ENDPOINT_XFER_INT:
- /* too small? */
- switch (dev->speed) {
- case USB_SPEED_WIRELESS:
- if ((urb->interval < 6)
- && (xfertype == USB_ENDPOINT_XFER_INT))
- return -EINVAL;
- fallthrough;
- default:
- if (urb->interval <= 0)
- return -EINVAL;
- break;
- }
- /* too big? */
- switch (dev->speed) {
- case USB_SPEED_SUPER_PLUS:
- case USB_SPEED_SUPER: /* units are 125us */
- /* Handle up to 2^(16-1) microframes */
- if (urb->interval > (1 << 15))
- return -EINVAL;
- max = 1 << 15;
- break;
- case USB_SPEED_WIRELESS:
- if (urb->interval > 16)
- return -EINVAL;
- break;
- case USB_SPEED_HIGH: /* units are microframes */
- /* NOTE usb handles 2^15 */
- if (urb->interval > (1024 * 8))
- urb->interval = 1024 * 8;
- max = 1024 * 8;
- break;
- case USB_SPEED_FULL: /* units are frames/msec */
- case USB_SPEED_LOW:
- if (xfertype == USB_ENDPOINT_XFER_INT) {
- if (urb->interval > 255)
- return -EINVAL;
- /* NOTE ohci only handles up to 32 */
- max = 128;
- } else {
- if (urb->interval > 1024)
- urb->interval = 1024;
- /* NOTE usb and ohci handle up to 2^15 */
- max = 1024;
- }
- break;
- default:
- return -EINVAL;
- }
- if (dev->speed != USB_SPEED_WIRELESS) {
- /* Round down to a power of 2, no more than max */
- urb->interval = min(max, 1 << ilog2(urb->interval));
- }
- }
- return usb_hcd_submit_urb(urb, mem_flags);
- }
- EXPORT_SYMBOL_GPL(usb_submit_urb);
- /*-------------------------------------------------------------------*/
- /**
- * usb_unlink_urb - abort/cancel a transfer request for an endpoint
- * @urb: pointer to urb describing a previously submitted request,
- * may be NULL
- *
- * This routine cancels an in-progress request. URBs complete only once
- * per submission, and may be canceled only once per submission.
- * Successful cancellation means termination of @urb will be expedited
- * and the completion handler will be called with a status code
- * indicating that the request has been canceled (rather than any other
- * code).
- *
- * Drivers should not call this routine or related routines, such as
- * usb_kill_urb() or usb_unlink_anchored_urbs(), after their disconnect
- * method has returned. The disconnect function should synchronize with
- * a driver's I/O routines to insure that all URB-related activity has
- * completed before it returns.
- *
- * This request is asynchronous, however the HCD might call the ->complete()
- * callback during unlink. Therefore when drivers call usb_unlink_urb(), they
- * must not hold any locks that may be taken by the completion function.
- * Success is indicated by returning -EINPROGRESS, at which time the URB will
- * probably not yet have been given back to the device driver. When it is
- * eventually called, the completion function will see @urb->status ==
- * -ECONNRESET.
- * Failure is indicated by usb_unlink_urb() returning any other value.
- * Unlinking will fail when @urb is not currently "linked" (i.e., it was
- * never submitted, or it was unlinked before, or the hardware is already
- * finished with it), even if the completion handler has not yet run.
- *
- * The URB must not be deallocated while this routine is running. In
- * particular, when a driver calls this routine, it must insure that the
- * completion handler cannot deallocate the URB.
- *
- * Return: -EINPROGRESS on success. See description for other values on
- * failure.
- *
- * Unlinking and Endpoint Queues:
- *
- * [The behaviors and guarantees described below do not apply to virtual
- * root hubs but only to endpoint queues for physical USB devices.]
- *
- * Host Controller Drivers (HCDs) place all the URBs for a particular
- * endpoint in a queue. Normally the queue advances as the controller
- * hardware processes each request. But when an URB terminates with an
- * error its queue generally stops (see below), at least until that URB's
- * completion routine returns. It is guaranteed that a stopped queue
- * will not restart until all its unlinked URBs have been fully retired,
- * with their completion routines run, even if that's not until some time
- * after the original completion handler returns. The same behavior and
- * guarantee apply when an URB terminates because it was unlinked.
- *
- * Bulk and interrupt endpoint queues are guaranteed to stop whenever an
- * URB terminates with any sort of error, including -ECONNRESET, -ENOENT,
- * and -EREMOTEIO. Control endpoint queues behave the same way except
- * that they are not guaranteed to stop for -EREMOTEIO errors. Queues
- * for isochronous endpoints are treated differently, because they must
- * advance at fixed rates. Such queues do not stop when an URB
- * encounters an error or is unlinked. An unlinked isochronous URB may
- * leave a gap in the stream of packets; it is undefined whether such
- * gaps can be filled in.
- *
- * Note that early termination of an URB because a short packet was
- * received will generate a -EREMOTEIO error if and only if the
- * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device
- * drivers can build deep queues for large or complex bulk transfers
- * and clean them up reliably after any sort of aborted transfer by
- * unlinking all pending URBs at the first fault.
- *
- * When a control URB terminates with an error other than -EREMOTEIO, it
- * is quite likely that the status stage of the transfer will not take
- * place.
- */
- int usb_unlink_urb(struct urb *urb)
- {
- if (!urb)
- return -EINVAL;
- if (!urb->dev)
- return -ENODEV;
- if (!urb->ep)
- return -EIDRM;
- return usb_hcd_unlink_urb(urb, -ECONNRESET);
- }
- EXPORT_SYMBOL_GPL(usb_unlink_urb);
- /**
- * usb_kill_urb - cancel a transfer request and wait for it to finish
- * @urb: pointer to URB describing a previously submitted request,
- * may be NULL
- *
- * This routine cancels an in-progress request. It is guaranteed that
- * upon return all completion handlers will have finished and the URB
- * will be totally idle and available for reuse. These features make
- * this an ideal way to stop I/O in a disconnect() callback or close()
- * function. If the request has not already finished or been unlinked
- * the completion handler will see urb->status == -ENOENT.
- *
- * While the routine is running, attempts to resubmit the URB will fail
- * with error -EPERM. Thus even if the URB's completion handler always
- * tries to resubmit, it will not succeed and the URB will become idle.
- *
- * The URB must not be deallocated while this routine is running. In
- * particular, when a driver calls this routine, it must insure that the
- * completion handler cannot deallocate the URB.
- *
- * This routine may not be used in an interrupt context (such as a bottom
- * half or a completion handler), or when holding a spinlock, or in other
- * situations where the caller can't schedule().
- *
- * This routine should not be called by a driver after its disconnect
- * method has returned.
- */
- void usb_kill_urb(struct urb *urb)
- {
- might_sleep();
- if (!(urb && urb->dev && urb->ep))
- return;
- atomic_inc(&urb->reject);
- /*
- * Order the write of urb->reject above before the read
- * of urb->use_count below. Pairs with the barriers in
- * __usb_hcd_giveback_urb() and usb_hcd_submit_urb().
- */
- smp_mb__after_atomic();
- usb_hcd_unlink_urb(urb, -ENOENT);
- wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
- atomic_dec(&urb->reject);
- }
- EXPORT_SYMBOL_GPL(usb_kill_urb);
- /**
- * usb_poison_urb - reliably kill a transfer and prevent further use of an URB
- * @urb: pointer to URB describing a previously submitted request,
- * may be NULL
- *
- * This routine cancels an in-progress request. It is guaranteed that
- * upon return all completion handlers will have finished and the URB
- * will be totally idle and cannot be reused. These features make
- * this an ideal way to stop I/O in a disconnect() callback.
- * If the request has not already finished or been unlinked
- * the completion handler will see urb->status == -ENOENT.
- *
- * After and while the routine runs, attempts to resubmit the URB will fail
- * with error -EPERM. Thus even if the URB's completion handler always
- * tries to resubmit, it will not succeed and the URB will become idle.
- *
- * The URB must not be deallocated while this routine is running. In
- * particular, when a driver calls this routine, it must insure that the
- * completion handler cannot deallocate the URB.
- *
- * This routine may not be used in an interrupt context (such as a bottom
- * half or a completion handler), or when holding a spinlock, or in other
- * situations where the caller can't schedule().
- *
- * This routine should not be called by a driver after its disconnect
- * method has returned.
- */
- void usb_poison_urb(struct urb *urb)
- {
- might_sleep();
- if (!urb)
- return;
- atomic_inc(&urb->reject);
- /*
- * Order the write of urb->reject above before the read
- * of urb->use_count below. Pairs with the barriers in
- * __usb_hcd_giveback_urb() and usb_hcd_submit_urb().
- */
- smp_mb__after_atomic();
- if (!urb->dev || !urb->ep)
- return;
- usb_hcd_unlink_urb(urb, -ENOENT);
- wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
- }
- EXPORT_SYMBOL_GPL(usb_poison_urb);
- void usb_unpoison_urb(struct urb *urb)
- {
- if (!urb)
- return;
- atomic_dec(&urb->reject);
- }
- EXPORT_SYMBOL_GPL(usb_unpoison_urb);
- /**
- * usb_block_urb - reliably prevent further use of an URB
- * @urb: pointer to URB to be blocked, may be NULL
- *
- * After the routine has run, attempts to resubmit the URB will fail
- * with error -EPERM. Thus even if the URB's completion handler always
- * tries to resubmit, it will not succeed and the URB will become idle.
- *
- * The URB must not be deallocated while this routine is running. In
- * particular, when a driver calls this routine, it must insure that the
- * completion handler cannot deallocate the URB.
- */
- void usb_block_urb(struct urb *urb)
- {
- if (!urb)
- return;
- atomic_inc(&urb->reject);
- }
- EXPORT_SYMBOL_GPL(usb_block_urb);
- /**
- * usb_kill_anchored_urbs - kill all URBs associated with an anchor
- * @anchor: anchor the requests are bound to
- *
- * This kills all outstanding URBs starting from the back of the queue,
- * with guarantee that no completer callbacks will take place from the
- * anchor after this function returns.
- *
- * This routine should not be called by a driver after its disconnect
- * method has returned.
- */
- void usb_kill_anchored_urbs(struct usb_anchor *anchor)
- {
- struct urb *victim;
- int surely_empty;
- do {
- spin_lock_irq(&anchor->lock);
- while (!list_empty(&anchor->urb_list)) {
- victim = list_entry(anchor->urb_list.prev,
- struct urb, anchor_list);
- /* make sure the URB isn't freed before we kill it */
- usb_get_urb(victim);
- spin_unlock_irq(&anchor->lock);
- /* this will unanchor the URB */
- usb_kill_urb(victim);
- usb_put_urb(victim);
- spin_lock_irq(&anchor->lock);
- }
- surely_empty = usb_anchor_check_wakeup(anchor);
- spin_unlock_irq(&anchor->lock);
- cpu_relax();
- } while (!surely_empty);
- }
- EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs);
- /**
- * usb_poison_anchored_urbs - cease all traffic from an anchor
- * @anchor: anchor the requests are bound to
- *
- * this allows all outstanding URBs to be poisoned starting
- * from the back of the queue. Newly added URBs will also be
- * poisoned
- *
- * This routine should not be called by a driver after its disconnect
- * method has returned.
- */
- void usb_poison_anchored_urbs(struct usb_anchor *anchor)
- {
- struct urb *victim;
- int surely_empty;
- do {
- spin_lock_irq(&anchor->lock);
- anchor->poisoned = 1;
- while (!list_empty(&anchor->urb_list)) {
- victim = list_entry(anchor->urb_list.prev,
- struct urb, anchor_list);
- /* make sure the URB isn't freed before we kill it */
- usb_get_urb(victim);
- spin_unlock_irq(&anchor->lock);
- /* this will unanchor the URB */
- usb_poison_urb(victim);
- usb_put_urb(victim);
- spin_lock_irq(&anchor->lock);
- }
- surely_empty = usb_anchor_check_wakeup(anchor);
- spin_unlock_irq(&anchor->lock);
- cpu_relax();
- } while (!surely_empty);
- }
- EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs);
- /**
- * usb_unpoison_anchored_urbs - let an anchor be used successfully again
- * @anchor: anchor the requests are bound to
- *
- * Reverses the effect of usb_poison_anchored_urbs
- * the anchor can be used normally after it returns
- */
- void usb_unpoison_anchored_urbs(struct usb_anchor *anchor)
- {
- unsigned long flags;
- struct urb *lazarus;
- spin_lock_irqsave(&anchor->lock, flags);
- list_for_each_entry(lazarus, &anchor->urb_list, anchor_list) {
- usb_unpoison_urb(lazarus);
- }
- anchor->poisoned = 0;
- spin_unlock_irqrestore(&anchor->lock, flags);
- }
- EXPORT_SYMBOL_GPL(usb_unpoison_anchored_urbs);
- /**
- * usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse
- * @anchor: anchor the requests are bound to
- *
- * this allows all outstanding URBs to be unlinked starting
- * from the back of the queue. This function is asynchronous.
- * The unlinking is just triggered. It may happen after this
- * function has returned.
- *
- * This routine should not be called by a driver after its disconnect
- * method has returned.
- */
- void usb_unlink_anchored_urbs(struct usb_anchor *anchor)
- {
- struct urb *victim;
- while ((victim = usb_get_from_anchor(anchor)) != NULL) {
- usb_unlink_urb(victim);
- usb_put_urb(victim);
- }
- }
- EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs);
- /**
- * usb_anchor_suspend_wakeups
- * @anchor: the anchor you want to suspend wakeups on
- *
- * Call this to stop the last urb being unanchored from waking up any
- * usb_wait_anchor_empty_timeout waiters. This is used in the hcd urb give-
- * back path to delay waking up until after the completion handler has run.
- */
- void usb_anchor_suspend_wakeups(struct usb_anchor *anchor)
- {
- if (anchor)
- atomic_inc(&anchor->suspend_wakeups);
- }
- EXPORT_SYMBOL_GPL(usb_anchor_suspend_wakeups);
- /**
- * usb_anchor_resume_wakeups
- * @anchor: the anchor you want to resume wakeups on
- *
- * Allow usb_wait_anchor_empty_timeout waiters to be woken up again, and
- * wake up any current waiters if the anchor is empty.
- */
- void usb_anchor_resume_wakeups(struct usb_anchor *anchor)
- {
- if (!anchor)
- return;
- atomic_dec(&anchor->suspend_wakeups);
- if (usb_anchor_check_wakeup(anchor))
- wake_up(&anchor->wait);
- }
- EXPORT_SYMBOL_GPL(usb_anchor_resume_wakeups);
- /**
- * usb_wait_anchor_empty_timeout - wait for an anchor to be unused
- * @anchor: the anchor you want to become unused
- * @timeout: how long you are willing to wait in milliseconds
- *
- * Call this is you want to be sure all an anchor's
- * URBs have finished
- *
- * Return: Non-zero if the anchor became unused. Zero on timeout.
- */
- int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,
- unsigned int timeout)
- {
- return wait_event_timeout(anchor->wait,
- usb_anchor_check_wakeup(anchor),
- msecs_to_jiffies(timeout));
- }
- EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout);
- /**
- * usb_get_from_anchor - get an anchor's oldest urb
- * @anchor: the anchor whose urb you want
- *
- * This will take the oldest urb from an anchor,
- * unanchor and return it
- *
- * Return: The oldest urb from @anchor, or %NULL if @anchor has no
- * urbs associated with it.
- */
- struct urb *usb_get_from_anchor(struct usb_anchor *anchor)
- {
- struct urb *victim;
- unsigned long flags;
- spin_lock_irqsave(&anchor->lock, flags);
- if (!list_empty(&anchor->urb_list)) {
- victim = list_entry(anchor->urb_list.next, struct urb,
- anchor_list);
- usb_get_urb(victim);
- __usb_unanchor_urb(victim, anchor);
- } else {
- victim = NULL;
- }
- spin_unlock_irqrestore(&anchor->lock, flags);
- return victim;
- }
- EXPORT_SYMBOL_GPL(usb_get_from_anchor);
- /**
- * usb_scuttle_anchored_urbs - unanchor all an anchor's urbs
- * @anchor: the anchor whose urbs you want to unanchor
- *
- * use this to get rid of all an anchor's urbs
- */
- void usb_scuttle_anchored_urbs(struct usb_anchor *anchor)
- {
- struct urb *victim;
- unsigned long flags;
- int surely_empty;
- do {
- spin_lock_irqsave(&anchor->lock, flags);
- while (!list_empty(&anchor->urb_list)) {
- victim = list_entry(anchor->urb_list.prev,
- struct urb, anchor_list);
- __usb_unanchor_urb(victim, anchor);
- }
- surely_empty = usb_anchor_check_wakeup(anchor);
- spin_unlock_irqrestore(&anchor->lock, flags);
- cpu_relax();
- } while (!surely_empty);
- }
- EXPORT_SYMBOL_GPL(usb_scuttle_anchored_urbs);
- /**
- * usb_anchor_empty - is an anchor empty
- * @anchor: the anchor you want to query
- *
- * Return: 1 if the anchor has no urbs associated with it.
- */
- int usb_anchor_empty(struct usb_anchor *anchor)
- {
- return list_empty(&anchor->urb_list);
- }
- EXPORT_SYMBOL_GPL(usb_anchor_empty);
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