// 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) {
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? */
if (urb->interval <= 0)
return -EINVAL;
/* 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_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;
}
/* 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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