1 // SPDX-License-Identifier: GPL-2.0
3 * Released under the GPLv2 only.
6 #include <linux/module.h>
7 #include <linux/string.h>
8 #include <linux/bitops.h>
9 #include <linux/slab.h>
10 #include <linux/log2.h>
11 #include <linux/usb.h>
12 #include <linux/wait.h>
13 #include <linux/usb/hcd.h>
14 #include <linux/scatterlist.h>
16 #define to_urb(d) container_of(d, struct urb, kref)
19 static void urb_destroy(struct kref
*kref
)
21 struct urb
*urb
= to_urb(kref
);
23 if (urb
->transfer_flags
& URB_FREE_BUFFER
)
24 kfree(urb
->transfer_buffer
);
30 * usb_init_urb - initializes a urb so that it can be used by a USB driver
31 * @urb: pointer to the urb to initialize
33 * Initializes a urb so that the USB subsystem can use it properly.
35 * If a urb is created with a call to usb_alloc_urb() it is not
36 * necessary to call this function. Only use this if you allocate the
37 * space for a struct urb on your own. If you call this function, be
38 * careful when freeing the memory for your urb that it is no longer in
39 * use by the USB core.
41 * Only use this function if you _really_ understand what you are doing.
43 void usb_init_urb(struct urb
*urb
)
46 memset(urb
, 0, sizeof(*urb
));
47 kref_init(&urb
->kref
);
48 INIT_LIST_HEAD(&urb
->urb_list
);
49 INIT_LIST_HEAD(&urb
->anchor_list
);
52 EXPORT_SYMBOL_GPL(usb_init_urb
);
55 * usb_alloc_urb - creates a new urb for a USB driver to use
56 * @iso_packets: number of iso packets for this urb
57 * @mem_flags: the type of memory to allocate, see kmalloc() for a list of
58 * valid options for this.
60 * Creates an urb for the USB driver to use, initializes a few internal
61 * structures, increments the usage counter, and returns a pointer to it.
63 * If the driver want to use this urb for interrupt, control, or bulk
64 * endpoints, pass '0' as the number of iso packets.
66 * The driver must call usb_free_urb() when it is finished with the urb.
68 * Return: A pointer to the new urb, or %NULL if no memory is available.
70 struct urb
*usb_alloc_urb(int iso_packets
, gfp_t mem_flags
)
74 urb
= kmalloc(struct_size(urb
, iso_frame_desc
, iso_packets
),
81 EXPORT_SYMBOL_GPL(usb_alloc_urb
);
84 * usb_free_urb - frees the memory used by a urb when all users of it are finished
85 * @urb: pointer to the urb to free, may be NULL
87 * Must be called when a user of a urb is finished with it. When the last user
88 * of the urb calls this function, the memory of the urb is freed.
90 * Note: The transfer buffer associated with the urb is not freed unless the
91 * URB_FREE_BUFFER transfer flag is set.
93 void usb_free_urb(struct urb
*urb
)
96 kref_put(&urb
->kref
, urb_destroy
);
98 EXPORT_SYMBOL_GPL(usb_free_urb
);
101 * usb_get_urb - increments the reference count of the urb
102 * @urb: pointer to the urb to modify, may be NULL
104 * This must be called whenever a urb is transferred from a device driver to a
105 * host controller driver. This allows proper reference counting to happen
108 * Return: A pointer to the urb with the incremented reference counter.
110 struct urb
*usb_get_urb(struct urb
*urb
)
113 kref_get(&urb
->kref
);
116 EXPORT_SYMBOL_GPL(usb_get_urb
);
119 * usb_anchor_urb - anchors an URB while it is processed
120 * @urb: pointer to the urb to anchor
121 * @anchor: pointer to the anchor
123 * This can be called to have access to URBs which are to be executed
124 * without bothering to track them
126 void usb_anchor_urb(struct urb
*urb
, struct usb_anchor
*anchor
)
130 spin_lock_irqsave(&anchor
->lock
, flags
);
132 list_add_tail(&urb
->anchor_list
, &anchor
->urb_list
);
133 urb
->anchor
= anchor
;
135 if (unlikely(anchor
->poisoned
))
136 atomic_inc(&urb
->reject
);
138 spin_unlock_irqrestore(&anchor
->lock
, flags
);
140 EXPORT_SYMBOL_GPL(usb_anchor_urb
);
142 static int usb_anchor_check_wakeup(struct usb_anchor
*anchor
)
144 return atomic_read(&anchor
->suspend_wakeups
) == 0 &&
145 list_empty(&anchor
->urb_list
);
148 /* Callers must hold anchor->lock */
149 static void __usb_unanchor_urb(struct urb
*urb
, struct usb_anchor
*anchor
)
152 list_del(&urb
->anchor_list
);
154 if (usb_anchor_check_wakeup(anchor
))
155 wake_up(&anchor
->wait
);
159 * usb_unanchor_urb - unanchors an URB
160 * @urb: pointer to the urb to anchor
162 * Call this to stop the system keeping track of this URB
164 void usb_unanchor_urb(struct urb
*urb
)
167 struct usb_anchor
*anchor
;
172 anchor
= urb
->anchor
;
176 spin_lock_irqsave(&anchor
->lock
, flags
);
178 * At this point, we could be competing with another thread which
179 * has the same intention. To protect the urb from being unanchored
180 * twice, only the winner of the race gets the job.
182 if (likely(anchor
== urb
->anchor
))
183 __usb_unanchor_urb(urb
, anchor
);
184 spin_unlock_irqrestore(&anchor
->lock
, flags
);
186 EXPORT_SYMBOL_GPL(usb_unanchor_urb
);
188 /*-------------------------------------------------------------------*/
190 static const int pipetypes
[4] = {
191 PIPE_CONTROL
, PIPE_ISOCHRONOUS
, PIPE_BULK
, PIPE_INTERRUPT
195 * usb_pipe_type_check - sanity check of a specific pipe for a usb device
196 * @dev: struct usb_device to be checked
197 * @pipe: pipe to check
199 * This performs a light-weight sanity check for the endpoint in the
200 * given usb device. It returns 0 if the pipe is valid for the specific usb
201 * device, otherwise a negative error code.
203 int usb_pipe_type_check(struct usb_device
*dev
, unsigned int pipe
)
205 const struct usb_host_endpoint
*ep
;
207 ep
= usb_pipe_endpoint(dev
, pipe
);
210 if (usb_pipetype(pipe
) != pipetypes
[usb_endpoint_type(&ep
->desc
)])
214 EXPORT_SYMBOL_GPL(usb_pipe_type_check
);
217 * usb_urb_ep_type_check - sanity check of endpoint in the given urb
218 * @urb: urb to be checked
220 * This performs a light-weight sanity check for the endpoint in the
221 * given urb. It returns 0 if the urb contains a valid endpoint, otherwise
222 * a negative error code.
224 int usb_urb_ep_type_check(const struct urb
*urb
)
226 return usb_pipe_type_check(urb
->dev
, urb
->pipe
);
228 EXPORT_SYMBOL_GPL(usb_urb_ep_type_check
);
231 * usb_submit_urb - issue an asynchronous transfer request for an endpoint
232 * @urb: pointer to the urb describing the request
233 * @mem_flags: the type of memory to allocate, see kmalloc() for a list
234 * of valid options for this.
236 * This submits a transfer request, and transfers control of the URB
237 * describing that request to the USB subsystem. Request completion will
238 * be indicated later, asynchronously, by calling the completion handler.
239 * The three types of completion are success, error, and unlink
240 * (a software-induced fault, also called "request cancellation").
242 * URBs may be submitted in interrupt context.
244 * The caller must have correctly initialized the URB before submitting
245 * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are
246 * available to ensure that most fields are correctly initialized, for
247 * the particular kind of transfer, although they will not initialize
248 * any transfer flags.
250 * If the submission is successful, the complete() callback from the URB
251 * will be called exactly once, when the USB core and Host Controller Driver
252 * (HCD) are finished with the URB. When the completion function is called,
253 * control of the URB is returned to the device driver which issued the
254 * request. The completion handler may then immediately free or reuse that
257 * With few exceptions, USB device drivers should never access URB fields
258 * provided by usbcore or the HCD until its complete() is called.
259 * The exceptions relate to periodic transfer scheduling. For both
260 * interrupt and isochronous urbs, as part of successful URB submission
261 * urb->interval is modified to reflect the actual transfer period used
262 * (normally some power of two units). And for isochronous urbs,
263 * urb->start_frame is modified to reflect when the URB's transfers were
264 * scheduled to start.
266 * Not all isochronous transfer scheduling policies will work, but most
267 * host controller drivers should easily handle ISO queues going from now
268 * until 10-200 msec into the future. Drivers should try to keep at
269 * least one or two msec of data in the queue; many controllers require
270 * that new transfers start at least 1 msec in the future when they are
271 * added. If the driver is unable to keep up and the queue empties out,
272 * the behavior for new submissions is governed by the URB_ISO_ASAP flag.
273 * If the flag is set, or if the queue is idle, then the URB is always
274 * assigned to the first available (and not yet expired) slot in the
275 * endpoint's schedule. If the flag is not set and the queue is active
276 * then the URB is always assigned to the next slot in the schedule
277 * following the end of the endpoint's previous URB, even if that slot is
278 * in the past. When a packet is assigned in this way to a slot that has
279 * already expired, the packet is not transmitted and the corresponding
280 * usb_iso_packet_descriptor's status field will return -EXDEV. If this
281 * would happen to all the packets in the URB, submission fails with a
284 * For control endpoints, the synchronous usb_control_msg() call is
285 * often used (in non-interrupt context) instead of this call.
286 * That is often used through convenience wrappers, for the requests
287 * that are standardized in the USB 2.0 specification. For bulk
288 * endpoints, a synchronous usb_bulk_msg() call is available.
291 * 0 on successful submissions. A negative error number otherwise.
295 * URBs may be submitted to endpoints before previous ones complete, to
296 * minimize the impact of interrupt latencies and system overhead on data
297 * throughput. With that queuing policy, an endpoint's queue would never
298 * be empty. This is required for continuous isochronous data streams,
299 * and may also be required for some kinds of interrupt transfers. Such
300 * queuing also maximizes bandwidth utilization by letting USB controllers
301 * start work on later requests before driver software has finished the
302 * completion processing for earlier (successful) requests.
304 * As of Linux 2.6, all USB endpoint transfer queues support depths greater
305 * than one. This was previously a HCD-specific behavior, except for ISO
306 * transfers. Non-isochronous endpoint queues are inactive during cleanup
307 * after faults (transfer errors or cancellation).
309 * Reserved Bandwidth Transfers:
311 * Periodic transfers (interrupt or isochronous) are performed repeatedly,
312 * using the interval specified in the urb. Submitting the first urb to
313 * the endpoint reserves the bandwidth necessary to make those transfers.
314 * If the USB subsystem can't allocate sufficient bandwidth to perform
315 * the periodic request, submitting such a periodic request should fail.
317 * For devices under xHCI, the bandwidth is reserved at configuration time, or
318 * when the alt setting is selected. If there is not enough bus bandwidth, the
319 * configuration/alt setting request will fail. Therefore, submissions to
320 * periodic endpoints on devices under xHCI should never fail due to bandwidth
323 * Device drivers must explicitly request that repetition, by ensuring that
324 * some URB is always on the endpoint's queue (except possibly for short
325 * periods during completion callbacks). When there is no longer an urb
326 * queued, the endpoint's bandwidth reservation is canceled. This means
327 * drivers can use their completion handlers to ensure they keep bandwidth
328 * they need, by reinitializing and resubmitting the just-completed urb
329 * until the driver longer needs that periodic bandwidth.
333 * The general rules for how to decide which mem_flags to use
334 * are the same as for kmalloc. There are four
335 * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and
338 * GFP_NOFS is not ever used, as it has not been implemented yet.
340 * GFP_ATOMIC is used when
341 * (a) you are inside a completion handler, an interrupt, bottom half,
342 * tasklet or timer, or
343 * (b) you are holding a spinlock or rwlock (does not apply to
345 * (c) current->state != TASK_RUNNING, this is the case only after
348 * GFP_NOIO is used in the block io path and error handling of storage
351 * All other situations use GFP_KERNEL.
353 * Some more specific rules for mem_flags can be inferred, such as
354 * (1) start_xmit, timeout, and receive methods of network drivers must
355 * use GFP_ATOMIC (they are called with a spinlock held);
356 * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also
357 * called with a spinlock held);
358 * (3) If you use a kernel thread with a network driver you must use
359 * GFP_NOIO, unless (b) or (c) apply;
360 * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)
361 * apply or your are in a storage driver's block io path;
362 * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and
363 * (6) changing firmware on a running storage or net device uses
364 * GFP_NOIO, unless b) or c) apply
367 int usb_submit_urb(struct urb
*urb
, gfp_t mem_flags
)
370 struct usb_device
*dev
;
371 struct usb_host_endpoint
*ep
;
373 unsigned int allowed
;
375 if (!urb
|| !urb
->complete
)
378 WARN_ONCE(1, "URB %pK submitted while active\n", urb
);
383 if ((!dev
) || (dev
->state
< USB_STATE_UNAUTHENTICATED
))
386 /* For now, get the endpoint from the pipe. Eventually drivers
387 * will be required to set urb->ep directly and we will eliminate
390 ep
= usb_pipe_endpoint(dev
, urb
->pipe
);
395 urb
->status
= -EINPROGRESS
;
396 urb
->actual_length
= 0;
398 /* Lots of sanity checks, so HCDs can rely on clean data
399 * and don't need to duplicate tests
401 xfertype
= usb_endpoint_type(&ep
->desc
);
402 if (xfertype
== USB_ENDPOINT_XFER_CONTROL
) {
403 struct usb_ctrlrequest
*setup
=
404 (struct usb_ctrlrequest
*) urb
->setup_packet
;
408 is_out
= !(setup
->bRequestType
& USB_DIR_IN
) ||
411 is_out
= usb_endpoint_dir_out(&ep
->desc
);
414 /* Clear the internal flags and cache the direction for later use */
415 urb
->transfer_flags
&= ~(URB_DIR_MASK
| URB_DMA_MAP_SINGLE
|
416 URB_DMA_MAP_PAGE
| URB_DMA_MAP_SG
| URB_MAP_LOCAL
|
417 URB_SETUP_MAP_SINGLE
| URB_SETUP_MAP_LOCAL
|
418 URB_DMA_SG_COMBINED
);
419 urb
->transfer_flags
|= (is_out
? URB_DIR_OUT
: URB_DIR_IN
);
421 if (xfertype
!= USB_ENDPOINT_XFER_CONTROL
&&
422 dev
->state
< USB_STATE_CONFIGURED
)
425 max
= usb_endpoint_maxp(&ep
->desc
);
428 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
429 usb_endpoint_num(&ep
->desc
), is_out
? "out" : "in",
434 /* periodic transfers limit size per frame/uframe,
435 * but drivers only control those sizes for ISO.
436 * while we're checking, initialize return status.
438 if (xfertype
== USB_ENDPOINT_XFER_ISOC
) {
441 /* SuperSpeed isoc endpoints have up to 16 bursts of up to
444 if (dev
->speed
>= USB_SPEED_SUPER
) {
445 int burst
= 1 + ep
->ss_ep_comp
.bMaxBurst
;
446 int mult
= USB_SS_MULT(ep
->ss_ep_comp
.bmAttributes
);
451 if (dev
->speed
== USB_SPEED_SUPER_PLUS
&&
452 USB_SS_SSP_ISOC_COMP(ep
->ss_ep_comp
.bmAttributes
)) {
453 struct usb_ssp_isoc_ep_comp_descriptor
*isoc_ep_comp
;
455 isoc_ep_comp
= &ep
->ssp_isoc_ep_comp
;
456 max
= le32_to_cpu(isoc_ep_comp
->dwBytesPerInterval
);
459 /* "high bandwidth" mode, 1-3 packets/uframe? */
460 if (dev
->speed
== USB_SPEED_HIGH
)
461 max
*= usb_endpoint_maxp_mult(&ep
->desc
);
463 if (urb
->number_of_packets
<= 0)
465 for (n
= 0; n
< urb
->number_of_packets
; n
++) {
466 len
= urb
->iso_frame_desc
[n
].length
;
467 if (len
< 0 || len
> max
)
469 urb
->iso_frame_desc
[n
].status
= -EXDEV
;
470 urb
->iso_frame_desc
[n
].actual_length
= 0;
472 } else if (urb
->num_sgs
&& !urb
->dev
->bus
->no_sg_constraint
&&
473 dev
->speed
!= USB_SPEED_WIRELESS
) {
474 struct scatterlist
*sg
;
477 for_each_sg(urb
->sg
, sg
, urb
->num_sgs
- 1, i
)
478 if (sg
->length
% max
)
482 /* the I/O buffer must be mapped/unmapped, except when length=0 */
483 if (urb
->transfer_buffer_length
> INT_MAX
)
487 * stuff that drivers shouldn't do, but which shouldn't
488 * cause problems in HCDs if they get it wrong.
491 /* Check that the pipe's type matches the endpoint's type */
492 if (usb_pipe_type_check(urb
->dev
, urb
->pipe
))
493 dev_WARN(&dev
->dev
, "BOGUS urb xfer, pipe %x != type %x\n",
494 usb_pipetype(urb
->pipe
), pipetypes
[xfertype
]);
496 /* Check against a simple/standard policy */
497 allowed
= (URB_NO_TRANSFER_DMA_MAP
| URB_NO_INTERRUPT
| URB_DIR_MASK
|
500 case USB_ENDPOINT_XFER_BULK
:
501 case USB_ENDPOINT_XFER_INT
:
503 allowed
|= URB_ZERO_PACKET
;
505 default: /* all non-iso endpoints */
507 allowed
|= URB_SHORT_NOT_OK
;
509 case USB_ENDPOINT_XFER_ISOC
:
510 allowed
|= URB_ISO_ASAP
;
513 allowed
&= urb
->transfer_flags
;
515 /* warn if submitter gave bogus flags */
516 if (allowed
!= urb
->transfer_flags
)
517 dev_WARN(&dev
->dev
, "BOGUS urb flags, %x --> %x\n",
518 urb
->transfer_flags
, allowed
);
521 * Force periodic transfer intervals to be legal values that are
522 * a power of two (so HCDs don't need to).
524 * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC
525 * supports different values... this uses EHCI/UHCI defaults (and
526 * EHCI can use smaller non-default values).
529 case USB_ENDPOINT_XFER_ISOC
:
530 case USB_ENDPOINT_XFER_INT
:
532 switch (dev
->speed
) {
533 case USB_SPEED_WIRELESS
:
534 if ((urb
->interval
< 6)
535 && (xfertype
== USB_ENDPOINT_XFER_INT
))
539 if (urb
->interval
<= 0)
544 switch (dev
->speed
) {
545 case USB_SPEED_SUPER_PLUS
:
546 case USB_SPEED_SUPER
: /* units are 125us */
547 /* Handle up to 2^(16-1) microframes */
548 if (urb
->interval
> (1 << 15))
552 case USB_SPEED_WIRELESS
:
553 if (urb
->interval
> 16)
556 case USB_SPEED_HIGH
: /* units are microframes */
557 /* NOTE usb handles 2^15 */
558 if (urb
->interval
> (1024 * 8))
559 urb
->interval
= 1024 * 8;
562 case USB_SPEED_FULL
: /* units are frames/msec */
564 if (xfertype
== USB_ENDPOINT_XFER_INT
) {
565 if (urb
->interval
> 255)
567 /* NOTE ohci only handles up to 32 */
570 if (urb
->interval
> 1024)
571 urb
->interval
= 1024;
572 /* NOTE usb and ohci handle up to 2^15 */
579 if (dev
->speed
!= USB_SPEED_WIRELESS
) {
580 /* Round down to a power of 2, no more than max */
581 urb
->interval
= min(max
, 1 << ilog2(urb
->interval
));
585 return usb_hcd_submit_urb(urb
, mem_flags
);
587 EXPORT_SYMBOL_GPL(usb_submit_urb
);
589 /*-------------------------------------------------------------------*/
592 * usb_unlink_urb - abort/cancel a transfer request for an endpoint
593 * @urb: pointer to urb describing a previously submitted request,
596 * This routine cancels an in-progress request. URBs complete only once
597 * per submission, and may be canceled only once per submission.
598 * Successful cancellation means termination of @urb will be expedited
599 * and the completion handler will be called with a status code
600 * indicating that the request has been canceled (rather than any other
603 * Drivers should not call this routine or related routines, such as
604 * usb_kill_urb() or usb_unlink_anchored_urbs(), after their disconnect
605 * method has returned. The disconnect function should synchronize with
606 * a driver's I/O routines to insure that all URB-related activity has
607 * completed before it returns.
609 * This request is asynchronous, however the HCD might call the ->complete()
610 * callback during unlink. Therefore when drivers call usb_unlink_urb(), they
611 * must not hold any locks that may be taken by the completion function.
612 * Success is indicated by returning -EINPROGRESS, at which time the URB will
613 * probably not yet have been given back to the device driver. When it is
614 * eventually called, the completion function will see @urb->status ==
616 * Failure is indicated by usb_unlink_urb() returning any other value.
617 * Unlinking will fail when @urb is not currently "linked" (i.e., it was
618 * never submitted, or it was unlinked before, or the hardware is already
619 * finished with it), even if the completion handler has not yet run.
621 * The URB must not be deallocated while this routine is running. In
622 * particular, when a driver calls this routine, it must insure that the
623 * completion handler cannot deallocate the URB.
625 * Return: -EINPROGRESS on success. See description for other values on
628 * Unlinking and Endpoint Queues:
630 * [The behaviors and guarantees described below do not apply to virtual
631 * root hubs but only to endpoint queues for physical USB devices.]
633 * Host Controller Drivers (HCDs) place all the URBs for a particular
634 * endpoint in a queue. Normally the queue advances as the controller
635 * hardware processes each request. But when an URB terminates with an
636 * error its queue generally stops (see below), at least until that URB's
637 * completion routine returns. It is guaranteed that a stopped queue
638 * will not restart until all its unlinked URBs have been fully retired,
639 * with their completion routines run, even if that's not until some time
640 * after the original completion handler returns. The same behavior and
641 * guarantee apply when an URB terminates because it was unlinked.
643 * Bulk and interrupt endpoint queues are guaranteed to stop whenever an
644 * URB terminates with any sort of error, including -ECONNRESET, -ENOENT,
645 * and -EREMOTEIO. Control endpoint queues behave the same way except
646 * that they are not guaranteed to stop for -EREMOTEIO errors. Queues
647 * for isochronous endpoints are treated differently, because they must
648 * advance at fixed rates. Such queues do not stop when an URB
649 * encounters an error or is unlinked. An unlinked isochronous URB may
650 * leave a gap in the stream of packets; it is undefined whether such
651 * gaps can be filled in.
653 * Note that early termination of an URB because a short packet was
654 * received will generate a -EREMOTEIO error if and only if the
655 * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device
656 * drivers can build deep queues for large or complex bulk transfers
657 * and clean them up reliably after any sort of aborted transfer by
658 * unlinking all pending URBs at the first fault.
660 * When a control URB terminates with an error other than -EREMOTEIO, it
661 * is quite likely that the status stage of the transfer will not take
664 int usb_unlink_urb(struct urb
*urb
)
672 return usb_hcd_unlink_urb(urb
, -ECONNRESET
);
674 EXPORT_SYMBOL_GPL(usb_unlink_urb
);
677 * usb_kill_urb - cancel a transfer request and wait for it to finish
678 * @urb: pointer to URB describing a previously submitted request,
681 * This routine cancels an in-progress request. It is guaranteed that
682 * upon return all completion handlers will have finished and the URB
683 * will be totally idle and available for reuse. These features make
684 * this an ideal way to stop I/O in a disconnect() callback or close()
685 * function. If the request has not already finished or been unlinked
686 * the completion handler will see urb->status == -ENOENT.
688 * While the routine is running, attempts to resubmit the URB will fail
689 * with error -EPERM. Thus even if the URB's completion handler always
690 * tries to resubmit, it will not succeed and the URB will become idle.
692 * The URB must not be deallocated while this routine is running. In
693 * particular, when a driver calls this routine, it must insure that the
694 * completion handler cannot deallocate the URB.
696 * This routine may not be used in an interrupt context (such as a bottom
697 * half or a completion handler), or when holding a spinlock, or in other
698 * situations where the caller can't schedule().
700 * This routine should not be called by a driver after its disconnect
701 * method has returned.
703 void usb_kill_urb(struct urb
*urb
)
706 if (!(urb
&& urb
->dev
&& urb
->ep
))
708 atomic_inc(&urb
->reject
);
710 usb_hcd_unlink_urb(urb
, -ENOENT
);
711 wait_event(usb_kill_urb_queue
, atomic_read(&urb
->use_count
) == 0);
713 atomic_dec(&urb
->reject
);
715 EXPORT_SYMBOL_GPL(usb_kill_urb
);
718 * usb_poison_urb - reliably kill a transfer and prevent further use of an URB
719 * @urb: pointer to URB describing a previously submitted request,
722 * This routine cancels an in-progress request. It is guaranteed that
723 * upon return all completion handlers will have finished and the URB
724 * will be totally idle and cannot be reused. These features make
725 * this an ideal way to stop I/O in a disconnect() callback.
726 * If the request has not already finished or been unlinked
727 * the completion handler will see urb->status == -ENOENT.
729 * After and while the routine runs, attempts to resubmit the URB will fail
730 * with error -EPERM. Thus even if the URB's completion handler always
731 * tries to resubmit, it will not succeed and the URB will become idle.
733 * The URB must not be deallocated while this routine is running. In
734 * particular, when a driver calls this routine, it must insure that the
735 * completion handler cannot deallocate the URB.
737 * This routine may not be used in an interrupt context (such as a bottom
738 * half or a completion handler), or when holding a spinlock, or in other
739 * situations where the caller can't schedule().
741 * This routine should not be called by a driver after its disconnect
742 * method has returned.
744 void usb_poison_urb(struct urb
*urb
)
749 atomic_inc(&urb
->reject
);
751 if (!urb
->dev
|| !urb
->ep
)
754 usb_hcd_unlink_urb(urb
, -ENOENT
);
755 wait_event(usb_kill_urb_queue
, atomic_read(&urb
->use_count
) == 0);
757 EXPORT_SYMBOL_GPL(usb_poison_urb
);
759 void usb_unpoison_urb(struct urb
*urb
)
764 atomic_dec(&urb
->reject
);
766 EXPORT_SYMBOL_GPL(usb_unpoison_urb
);
769 * usb_block_urb - reliably prevent further use of an URB
770 * @urb: pointer to URB to be blocked, may be NULL
772 * After the routine has run, attempts to resubmit the URB will fail
773 * with error -EPERM. Thus even if the URB's completion handler always
774 * tries to resubmit, it will not succeed and the URB will become idle.
776 * The URB must not be deallocated while this routine is running. In
777 * particular, when a driver calls this routine, it must insure that the
778 * completion handler cannot deallocate the URB.
780 void usb_block_urb(struct urb
*urb
)
785 atomic_inc(&urb
->reject
);
787 EXPORT_SYMBOL_GPL(usb_block_urb
);
790 * usb_kill_anchored_urbs - kill all URBs associated with an anchor
791 * @anchor: anchor the requests are bound to
793 * This kills all outstanding URBs starting from the back of the queue,
794 * with guarantee that no completer callbacks will take place from the
795 * anchor after this function returns.
797 * This routine should not be called by a driver after its disconnect
798 * method has returned.
800 void usb_kill_anchored_urbs(struct usb_anchor
*anchor
)
806 spin_lock_irq(&anchor
->lock
);
807 while (!list_empty(&anchor
->urb_list
)) {
808 victim
= list_entry(anchor
->urb_list
.prev
,
809 struct urb
, anchor_list
);
810 /* make sure the URB isn't freed before we kill it */
812 spin_unlock_irq(&anchor
->lock
);
813 /* this will unanchor the URB */
814 usb_kill_urb(victim
);
816 spin_lock_irq(&anchor
->lock
);
818 surely_empty
= usb_anchor_check_wakeup(anchor
);
820 spin_unlock_irq(&anchor
->lock
);
822 } while (!surely_empty
);
824 EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs
);
828 * usb_poison_anchored_urbs - cease all traffic from an anchor
829 * @anchor: anchor the requests are bound to
831 * this allows all outstanding URBs to be poisoned starting
832 * from the back of the queue. Newly added URBs will also be
835 * This routine should not be called by a driver after its disconnect
836 * method has returned.
838 void usb_poison_anchored_urbs(struct usb_anchor
*anchor
)
844 spin_lock_irq(&anchor
->lock
);
845 anchor
->poisoned
= 1;
846 while (!list_empty(&anchor
->urb_list
)) {
847 victim
= list_entry(anchor
->urb_list
.prev
,
848 struct urb
, anchor_list
);
849 /* make sure the URB isn't freed before we kill it */
851 spin_unlock_irq(&anchor
->lock
);
852 /* this will unanchor the URB */
853 usb_poison_urb(victim
);
855 spin_lock_irq(&anchor
->lock
);
857 surely_empty
= usb_anchor_check_wakeup(anchor
);
859 spin_unlock_irq(&anchor
->lock
);
861 } while (!surely_empty
);
863 EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs
);
866 * usb_unpoison_anchored_urbs - let an anchor be used successfully again
867 * @anchor: anchor the requests are bound to
869 * Reverses the effect of usb_poison_anchored_urbs
870 * the anchor can be used normally after it returns
872 void usb_unpoison_anchored_urbs(struct usb_anchor
*anchor
)
877 spin_lock_irqsave(&anchor
->lock
, flags
);
878 list_for_each_entry(lazarus
, &anchor
->urb_list
, anchor_list
) {
879 usb_unpoison_urb(lazarus
);
881 anchor
->poisoned
= 0;
882 spin_unlock_irqrestore(&anchor
->lock
, flags
);
884 EXPORT_SYMBOL_GPL(usb_unpoison_anchored_urbs
);
886 * usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse
887 * @anchor: anchor the requests are bound to
889 * this allows all outstanding URBs to be unlinked starting
890 * from the back of the queue. This function is asynchronous.
891 * The unlinking is just triggered. It may happen after this
892 * function has returned.
894 * This routine should not be called by a driver after its disconnect
895 * method has returned.
897 void usb_unlink_anchored_urbs(struct usb_anchor
*anchor
)
901 while ((victim
= usb_get_from_anchor(anchor
)) != NULL
) {
902 usb_unlink_urb(victim
);
906 EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs
);
909 * usb_anchor_suspend_wakeups
910 * @anchor: the anchor you want to suspend wakeups on
912 * Call this to stop the last urb being unanchored from waking up any
913 * usb_wait_anchor_empty_timeout waiters. This is used in the hcd urb give-
914 * back path to delay waking up until after the completion handler has run.
916 void usb_anchor_suspend_wakeups(struct usb_anchor
*anchor
)
919 atomic_inc(&anchor
->suspend_wakeups
);
921 EXPORT_SYMBOL_GPL(usb_anchor_suspend_wakeups
);
924 * usb_anchor_resume_wakeups
925 * @anchor: the anchor you want to resume wakeups on
927 * Allow usb_wait_anchor_empty_timeout waiters to be woken up again, and
928 * wake up any current waiters if the anchor is empty.
930 void usb_anchor_resume_wakeups(struct usb_anchor
*anchor
)
935 atomic_dec(&anchor
->suspend_wakeups
);
936 if (usb_anchor_check_wakeup(anchor
))
937 wake_up(&anchor
->wait
);
939 EXPORT_SYMBOL_GPL(usb_anchor_resume_wakeups
);
942 * usb_wait_anchor_empty_timeout - wait for an anchor to be unused
943 * @anchor: the anchor you want to become unused
944 * @timeout: how long you are willing to wait in milliseconds
946 * Call this is you want to be sure all an anchor's
949 * Return: Non-zero if the anchor became unused. Zero on timeout.
951 int usb_wait_anchor_empty_timeout(struct usb_anchor
*anchor
,
952 unsigned int timeout
)
954 return wait_event_timeout(anchor
->wait
,
955 usb_anchor_check_wakeup(anchor
),
956 msecs_to_jiffies(timeout
));
958 EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout
);
961 * usb_get_from_anchor - get an anchor's oldest urb
962 * @anchor: the anchor whose urb you want
964 * This will take the oldest urb from an anchor,
965 * unanchor and return it
967 * Return: The oldest urb from @anchor, or %NULL if @anchor has no
968 * urbs associated with it.
970 struct urb
*usb_get_from_anchor(struct usb_anchor
*anchor
)
975 spin_lock_irqsave(&anchor
->lock
, flags
);
976 if (!list_empty(&anchor
->urb_list
)) {
977 victim
= list_entry(anchor
->urb_list
.next
, struct urb
,
980 __usb_unanchor_urb(victim
, anchor
);
984 spin_unlock_irqrestore(&anchor
->lock
, flags
);
989 EXPORT_SYMBOL_GPL(usb_get_from_anchor
);
992 * usb_scuttle_anchored_urbs - unanchor all an anchor's urbs
993 * @anchor: the anchor whose urbs you want to unanchor
995 * use this to get rid of all an anchor's urbs
997 void usb_scuttle_anchored_urbs(struct usb_anchor
*anchor
)
1000 unsigned long flags
;
1004 spin_lock_irqsave(&anchor
->lock
, flags
);
1005 while (!list_empty(&anchor
->urb_list
)) {
1006 victim
= list_entry(anchor
->urb_list
.prev
,
1007 struct urb
, anchor_list
);
1008 __usb_unanchor_urb(victim
, anchor
);
1010 surely_empty
= usb_anchor_check_wakeup(anchor
);
1012 spin_unlock_irqrestore(&anchor
->lock
, flags
);
1014 } while (!surely_empty
);
1017 EXPORT_SYMBOL_GPL(usb_scuttle_anchored_urbs
);
1020 * usb_anchor_empty - is an anchor empty
1021 * @anchor: the anchor you want to query
1023 * Return: 1 if the anchor has no urbs associated with it.
1025 int usb_anchor_empty(struct usb_anchor
*anchor
)
1027 return list_empty(&anchor
->urb_list
);
1030 EXPORT_SYMBOL_GPL(usb_anchor_empty
);