diff options
Diffstat (limited to 'drivers/usb/core/urb.c')
| -rw-r--r-- | drivers/usb/core/urb.c | 1054 |
1 files changed, 1054 insertions, 0 deletions
diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c new file mode 100644 index 000000000..9f3c54032 --- /dev/null +++ b/drivers/usb/core/urb.c @@ -0,0 +1,1054 @@ +// 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/kmsan.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; + dev_WARN_ONCE(&dev->dev, (usb_pipeout(urb->pipe) != is_out), + "BOGUS control dir, pipe %x doesn't match bRequestType %x\n", + urb->pipe, setup->bRequestType); + if (le16_to_cpu(setup->wLength) != urb->transfer_buffer_length) { + dev_dbg(&dev->dev, "BOGUS control len %d doesn't match transfer length %d\n", + le16_to_cpu(setup->wLength), + urb->transfer_buffer_length); + return -EBADR; + } + } 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); + kmsan_handle_urb(urb, is_out); + + 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); + |