1 #include <linux/module.h>
2 #include <linux/string.h>
3 #include <linux/bitops.h>
4 #include <linux/slab.h>
5 #include <linux/init.h>
6 #include <linux/log2.h>
8 #include <linux/wait.h>
11 #define to_urb(d) container_of(d, struct urb, kref)
14 static void urb_destroy(struct kref
*kref
)
16 struct urb
*urb
= to_urb(kref
);
18 if (urb
->transfer_flags
& URB_FREE_BUFFER
)
19 kfree(urb
->transfer_buffer
);
25 * usb_init_urb - initializes a urb so that it can be used by a USB driver
26 * @urb: pointer to the urb to initialize
28 * Initializes a urb so that the USB subsystem can use it properly.
30 * If a urb is created with a call to usb_alloc_urb() it is not
31 * necessary to call this function. Only use this if you allocate the
32 * space for a struct urb on your own. If you call this function, be
33 * careful when freeing the memory for your urb that it is no longer in
34 * use by the USB core.
36 * Only use this function if you _really_ understand what you are doing.
38 void usb_init_urb(struct urb
*urb
)
41 memset(urb
, 0, sizeof(*urb
));
42 kref_init(&urb
->kref
);
43 INIT_LIST_HEAD(&urb
->anchor_list
);
46 EXPORT_SYMBOL_GPL(usb_init_urb
);
49 * usb_alloc_urb - creates a new urb for a USB driver to use
50 * @iso_packets: number of iso packets for this urb
51 * @mem_flags: the type of memory to allocate, see kmalloc() for a list of
52 * valid options for this.
54 * Creates an urb for the USB driver to use, initializes a few internal
55 * structures, incrementes the usage counter, and returns a pointer to it.
57 * If no memory is available, NULL is returned.
59 * If the driver want to use this urb for interrupt, control, or bulk
60 * endpoints, pass '0' as the number of iso packets.
62 * The driver must call usb_free_urb() when it is finished with the urb.
64 struct urb
*usb_alloc_urb(int iso_packets
, gfp_t mem_flags
)
68 urb
= kmalloc(sizeof(struct urb
) +
69 iso_packets
* sizeof(struct usb_iso_packet_descriptor
),
72 err("alloc_urb: kmalloc failed");
78 EXPORT_SYMBOL(usb_alloc_urb
);
81 * usb_free_urb - frees the memory used by a urb when all users of it are finished
82 * @urb: pointer to the urb to free, may be NULL
84 * Must be called when a user of a urb is finished with it. When the last user
85 * of the urb calls this function, the memory of the urb is freed.
87 * Note: The transfer buffer associated with the urb is not freed, that must be
90 void usb_free_urb(struct urb
*urb
)
93 kref_put(&urb
->kref
, urb_destroy
);
95 EXPORT_SYMBOL(usb_free_urb
);
98 * usb_get_urb - increments the reference count of the urb
99 * @urb: pointer to the urb to modify, may be NULL
101 * This must be called whenever a urb is transferred from a device driver to a
102 * host controller driver. This allows proper reference counting to happen
105 * A pointer to the urb with the incremented reference counter is returned.
107 struct urb
*usb_get_urb(struct urb
*urb
)
110 kref_get(&urb
->kref
);
113 EXPORT_SYMBOL_GPL(usb_get_urb
);
116 * usb_anchor_urb - anchors an URB while it is processed
117 * @urb: pointer to the urb to anchor
118 * @anchor: pointer to the anchor
120 * This can be called to have access to URBs which are to be executed
121 * without bothering to track them
123 void usb_anchor_urb(struct urb
*urb
, struct usb_anchor
*anchor
)
127 spin_lock_irqsave(&anchor
->lock
, flags
);
129 list_add_tail(&urb
->anchor_list
, &anchor
->urb_list
);
130 urb
->anchor
= anchor
;
132 if (unlikely(anchor
->poisoned
)) {
133 atomic_inc(&urb
->reject
);
136 spin_unlock_irqrestore(&anchor
->lock
, flags
);
138 EXPORT_SYMBOL_GPL(usb_anchor_urb
);
140 /* Callers must hold anchor->lock */
141 static void __usb_unanchor_urb(struct urb
*urb
, struct usb_anchor
*anchor
)
144 list_del(&urb
->anchor_list
);
146 if (list_empty(&anchor
->urb_list
))
147 wake_up(&anchor
->wait
);
151 * usb_unanchor_urb - unanchors an URB
152 * @urb: pointer to the urb to anchor
154 * Call this to stop the system keeping track of this URB
156 void usb_unanchor_urb(struct urb
*urb
)
159 struct usb_anchor
*anchor
;
164 anchor
= urb
->anchor
;
168 spin_lock_irqsave(&anchor
->lock
, flags
);
170 * At this point, we could be competing with another thread which
171 * has the same intention. To protect the urb from being unanchored
172 * twice, only the winner of the race gets the job.
174 if (likely(anchor
== urb
->anchor
))
175 __usb_unanchor_urb(urb
, anchor
);
176 spin_unlock_irqrestore(&anchor
->lock
, flags
);
178 EXPORT_SYMBOL_GPL(usb_unanchor_urb
);
180 /*-------------------------------------------------------------------*/
183 * usb_submit_urb - issue an asynchronous transfer request for an endpoint
184 * @urb: pointer to the urb describing the request
185 * @mem_flags: the type of memory to allocate, see kmalloc() for a list
186 * of valid options for this.
188 * This submits a transfer request, and transfers control of the URB
189 * describing that request to the USB subsystem. Request completion will
190 * be indicated later, asynchronously, by calling the completion handler.
191 * The three types of completion are success, error, and unlink
192 * (a software-induced fault, also called "request cancellation").
194 * URBs may be submitted in interrupt context.
196 * The caller must have correctly initialized the URB before submitting
197 * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are
198 * available to ensure that most fields are correctly initialized, for
199 * the particular kind of transfer, although they will not initialize
200 * any transfer flags.
202 * Successful submissions return 0; otherwise this routine returns a
203 * negative error number. If the submission is successful, the complete()
204 * callback from the URB will be called exactly once, when the USB core and
205 * Host Controller Driver (HCD) are finished with the URB. When the completion
206 * function is called, control of the URB is returned to the device
207 * driver which issued the request. The completion handler may then
208 * immediately free or reuse that URB.
210 * With few exceptions, USB device drivers should never access URB fields
211 * provided by usbcore or the HCD until its complete() is called.
212 * The exceptions relate to periodic transfer scheduling. For both
213 * interrupt and isochronous urbs, as part of successful URB submission
214 * urb->interval is modified to reflect the actual transfer period used
215 * (normally some power of two units). And for isochronous urbs,
216 * urb->start_frame is modified to reflect when the URB's transfers were
217 * scheduled to start. Not all isochronous transfer scheduling policies
218 * will work, but most host controller drivers should easily handle ISO
219 * queues going from now until 10-200 msec into the future.
221 * For control endpoints, the synchronous usb_control_msg() call is
222 * often used (in non-interrupt context) instead of this call.
223 * That is often used through convenience wrappers, for the requests
224 * that are standardized in the USB 2.0 specification. For bulk
225 * endpoints, a synchronous usb_bulk_msg() call is available.
229 * URBs may be submitted to endpoints before previous ones complete, to
230 * minimize the impact of interrupt latencies and system overhead on data
231 * throughput. With that queuing policy, an endpoint's queue would never
232 * be empty. This is required for continuous isochronous data streams,
233 * and may also be required for some kinds of interrupt transfers. Such
234 * queuing also maximizes bandwidth utilization by letting USB controllers
235 * start work on later requests before driver software has finished the
236 * completion processing for earlier (successful) requests.
238 * As of Linux 2.6, all USB endpoint transfer queues support depths greater
239 * than one. This was previously a HCD-specific behavior, except for ISO
240 * transfers. Non-isochronous endpoint queues are inactive during cleanup
241 * after faults (transfer errors or cancellation).
243 * Reserved Bandwidth Transfers:
245 * Periodic transfers (interrupt or isochronous) are performed repeatedly,
246 * using the interval specified in the urb. Submitting the first urb to
247 * the endpoint reserves the bandwidth necessary to make those transfers.
248 * If the USB subsystem can't allocate sufficient bandwidth to perform
249 * the periodic request, submitting such a periodic request should fail.
251 * Device drivers must explicitly request that repetition, by ensuring that
252 * some URB is always on the endpoint's queue (except possibly for short
253 * periods during completion callacks). When there is no longer an urb
254 * queued, the endpoint's bandwidth reservation is canceled. This means
255 * drivers can use their completion handlers to ensure they keep bandwidth
256 * they need, by reinitializing and resubmitting the just-completed urb
257 * until the driver longer needs that periodic bandwidth.
261 * The general rules for how to decide which mem_flags to use
262 * are the same as for kmalloc. There are four
263 * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and
266 * GFP_NOFS is not ever used, as it has not been implemented yet.
268 * GFP_ATOMIC is used when
269 * (a) you are inside a completion handler, an interrupt, bottom half,
270 * tasklet or timer, or
271 * (b) you are holding a spinlock or rwlock (does not apply to
273 * (c) current->state != TASK_RUNNING, this is the case only after
276 * GFP_NOIO is used in the block io path and error handling of storage
279 * All other situations use GFP_KERNEL.
281 * Some more specific rules for mem_flags can be inferred, such as
282 * (1) start_xmit, timeout, and receive methods of network drivers must
283 * use GFP_ATOMIC (they are called with a spinlock held);
284 * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also
285 * called with a spinlock held);
286 * (3) If you use a kernel thread with a network driver you must use
287 * GFP_NOIO, unless (b) or (c) apply;
288 * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)
289 * apply or your are in a storage driver's block io path;
290 * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and
291 * (6) changing firmware on a running storage or net device uses
292 * GFP_NOIO, unless b) or c) apply
295 int usb_submit_urb(struct urb
*urb
, gfp_t mem_flags
)
298 struct usb_device
*dev
;
299 struct usb_host_endpoint
*ep
;
302 if (!urb
|| urb
->hcpriv
|| !urb
->complete
)
305 if ((!dev
) || (dev
->state
< USB_STATE_DEFAULT
))
308 /* For now, get the endpoint from the pipe. Eventually drivers
309 * will be required to set urb->ep directly and we will eliminate
312 ep
= (usb_pipein(urb
->pipe
) ? dev
->ep_in
: dev
->ep_out
)
313 [usb_pipeendpoint(urb
->pipe
)];
318 urb
->status
= -EINPROGRESS
;
319 urb
->actual_length
= 0;
321 /* Lots of sanity checks, so HCDs can rely on clean data
322 * and don't need to duplicate tests
324 xfertype
= usb_endpoint_type(&ep
->desc
);
325 if (xfertype
== USB_ENDPOINT_XFER_CONTROL
) {
326 struct usb_ctrlrequest
*setup
=
327 (struct usb_ctrlrequest
*) urb
->setup_packet
;
331 is_out
= !(setup
->bRequestType
& USB_DIR_IN
) ||
334 is_out
= usb_endpoint_dir_out(&ep
->desc
);
337 /* Cache the direction for later use */
338 urb
->transfer_flags
= (urb
->transfer_flags
& ~URB_DIR_MASK
) |
339 (is_out
? URB_DIR_OUT
: URB_DIR_IN
);
341 if (xfertype
!= USB_ENDPOINT_XFER_CONTROL
&&
342 dev
->state
< USB_STATE_CONFIGURED
)
345 max
= le16_to_cpu(ep
->desc
.wMaxPacketSize
);
348 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
349 usb_endpoint_num(&ep
->desc
), is_out
? "out" : "in",
354 /* periodic transfers limit size per frame/uframe,
355 * but drivers only control those sizes for ISO.
356 * while we're checking, initialize return status.
358 if (xfertype
== USB_ENDPOINT_XFER_ISOC
) {
361 /* "high bandwidth" mode, 1-3 packets/uframe? */
362 if (dev
->speed
== USB_SPEED_HIGH
) {
363 int mult
= 1 + ((max
>> 11) & 0x03);
368 if (urb
->number_of_packets
<= 0)
370 for (n
= 0; n
< urb
->number_of_packets
; n
++) {
371 len
= urb
->iso_frame_desc
[n
].length
;
372 if (len
< 0 || len
> max
)
374 urb
->iso_frame_desc
[n
].status
= -EXDEV
;
375 urb
->iso_frame_desc
[n
].actual_length
= 0;
379 /* the I/O buffer must be mapped/unmapped, except when length=0 */
380 if (urb
->transfer_buffer_length
> INT_MAX
)
384 /* stuff that drivers shouldn't do, but which shouldn't
385 * cause problems in HCDs if they get it wrong.
388 unsigned int orig_flags
= urb
->transfer_flags
;
389 unsigned int allowed
;
391 /* enforce simple/standard policy */
392 allowed
= (URB_NO_TRANSFER_DMA_MAP
| URB_NO_SETUP_DMA_MAP
|
393 URB_NO_INTERRUPT
| URB_DIR_MASK
| URB_FREE_BUFFER
);
395 case USB_ENDPOINT_XFER_BULK
:
397 allowed
|= URB_ZERO_PACKET
;
399 case USB_ENDPOINT_XFER_CONTROL
:
400 allowed
|= URB_NO_FSBR
; /* only affects UHCI */
402 default: /* all non-iso endpoints */
404 allowed
|= URB_SHORT_NOT_OK
;
406 case USB_ENDPOINT_XFER_ISOC
:
407 allowed
|= URB_ISO_ASAP
;
410 urb
->transfer_flags
&= allowed
;
412 /* fail if submitter gave bogus flags */
413 if (urb
->transfer_flags
!= orig_flags
) {
414 err("BOGUS urb flags, %x --> %x",
415 orig_flags
, urb
->transfer_flags
);
421 * Force periodic transfer intervals to be legal values that are
422 * a power of two (so HCDs don't need to).
424 * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC
425 * supports different values... this uses EHCI/UHCI defaults (and
426 * EHCI can use smaller non-default values).
429 case USB_ENDPOINT_XFER_ISOC
:
430 case USB_ENDPOINT_XFER_INT
:
432 if (urb
->interval
<= 0)
435 switch (dev
->speed
) {
436 case USB_SPEED_HIGH
: /* units are microframes */
437 /* NOTE usb handles 2^15 */
438 if (urb
->interval
> (1024 * 8))
439 urb
->interval
= 1024 * 8;
442 case USB_SPEED_FULL
: /* units are frames/msec */
444 if (xfertype
== USB_ENDPOINT_XFER_INT
) {
445 if (urb
->interval
> 255)
447 /* NOTE ohci only handles up to 32 */
450 if (urb
->interval
> 1024)
451 urb
->interval
= 1024;
452 /* NOTE usb and ohci handle up to 2^15 */
459 /* Round down to a power of 2, no more than max */
460 urb
->interval
= min(max
, 1 << ilog2(urb
->interval
));
463 return usb_hcd_submit_urb(urb
, mem_flags
);
465 EXPORT_SYMBOL(usb_submit_urb
);
467 /*-------------------------------------------------------------------*/
470 * usb_unlink_urb - abort/cancel a transfer request for an endpoint
471 * @urb: pointer to urb describing a previously submitted request,
474 * This routine cancels an in-progress request. URBs complete only once
475 * per submission, and may be canceled only once per submission.
476 * Successful cancellation means termination of @urb will be expedited
477 * and the completion handler will be called with a status code
478 * indicating that the request has been canceled (rather than any other
481 * Drivers should not call this routine or related routines, such as
482 * usb_kill_urb() or usb_unlink_anchored_urbs(), after their disconnect
483 * method has returned. The disconnect function should synchronize with
484 * a driver's I/O routines to insure that all URB-related activity has
485 * completed before it returns.
487 * This request is always asynchronous. Success is indicated by
488 * returning -EINPROGRESS, at which time the URB will probably not yet
489 * have been given back to the device driver. When it is eventually
490 * called, the completion function will see @urb->status == -ECONNRESET.
491 * Failure is indicated by usb_unlink_urb() returning any other value.
492 * Unlinking will fail when @urb is not currently "linked" (i.e., it was
493 * never submitted, or it was unlinked before, or the hardware is already
494 * finished with it), even if the completion handler has not yet run.
496 * Unlinking and Endpoint Queues:
498 * [The behaviors and guarantees described below do not apply to virtual
499 * root hubs but only to endpoint queues for physical USB devices.]
501 * Host Controller Drivers (HCDs) place all the URBs for a particular
502 * endpoint in a queue. Normally the queue advances as the controller
503 * hardware processes each request. But when an URB terminates with an
504 * error its queue generally stops (see below), at least until that URB's
505 * completion routine returns. It is guaranteed that a stopped queue
506 * will not restart until all its unlinked URBs have been fully retired,
507 * with their completion routines run, even if that's not until some time
508 * after the original completion handler returns. The same behavior and
509 * guarantee apply when an URB terminates because it was unlinked.
511 * Bulk and interrupt endpoint queues are guaranteed to stop whenever an
512 * URB terminates with any sort of error, including -ECONNRESET, -ENOENT,
513 * and -EREMOTEIO. Control endpoint queues behave the same way except
514 * that they are not guaranteed to stop for -EREMOTEIO errors. Queues
515 * for isochronous endpoints are treated differently, because they must
516 * advance at fixed rates. Such queues do not stop when an URB
517 * encounters an error or is unlinked. An unlinked isochronous URB may
518 * leave a gap in the stream of packets; it is undefined whether such
519 * gaps can be filled in.
521 * Note that early termination of an URB because a short packet was
522 * received will generate a -EREMOTEIO error if and only if the
523 * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device
524 * drivers can build deep queues for large or complex bulk transfers
525 * and clean them up reliably after any sort of aborted transfer by
526 * unlinking all pending URBs at the first fault.
528 * When a control URB terminates with an error other than -EREMOTEIO, it
529 * is quite likely that the status stage of the transfer will not take
532 int usb_unlink_urb(struct urb
*urb
)
540 return usb_hcd_unlink_urb(urb
, -ECONNRESET
);
542 EXPORT_SYMBOL_GPL(usb_unlink_urb
);
545 * usb_kill_urb - cancel a transfer request and wait for it to finish
546 * @urb: pointer to URB describing a previously submitted request,
549 * This routine cancels an in-progress request. It is guaranteed that
550 * upon return all completion handlers will have finished and the URB
551 * will be totally idle and available for reuse. These features make
552 * this an ideal way to stop I/O in a disconnect() callback or close()
553 * function. If the request has not already finished or been unlinked
554 * the completion handler will see urb->status == -ENOENT.
556 * While the routine is running, attempts to resubmit the URB will fail
557 * with error -EPERM. Thus even if the URB's completion handler always
558 * tries to resubmit, it will not succeed and the URB will become idle.
560 * This routine may not be used in an interrupt context (such as a bottom
561 * half or a completion handler), or when holding a spinlock, or in other
562 * situations where the caller can't schedule().
564 * This routine should not be called by a driver after its disconnect
565 * method has returned.
567 void usb_kill_urb(struct urb
*urb
)
570 if (!(urb
&& urb
->dev
&& urb
->ep
))
572 atomic_inc(&urb
->reject
);
574 usb_hcd_unlink_urb(urb
, -ENOENT
);
575 wait_event(usb_kill_urb_queue
, atomic_read(&urb
->use_count
) == 0);
577 atomic_dec(&urb
->reject
);
579 EXPORT_SYMBOL(usb_kill_urb
);
582 * usb_poison_urb - reliably kill a transfer and prevent further use of an URB
583 * @urb: pointer to URB describing a previously submitted request,
586 * This routine cancels an in-progress request. It is guaranteed that
587 * upon return all completion handlers will have finished and the URB
588 * will be totally idle and cannot be reused. These features make
589 * this an ideal way to stop I/O in a disconnect() callback.
590 * If the request has not already finished or been unlinked
591 * the completion handler will see urb->status == -ENOENT.
593 * After and while the routine runs, attempts to resubmit the URB will fail
594 * with error -EPERM. Thus even if the URB's completion handler always
595 * tries to resubmit, it will not succeed and the URB will become idle.
597 * This routine may not be used in an interrupt context (such as a bottom
598 * half or a completion handler), or when holding a spinlock, or in other
599 * situations where the caller can't schedule().
601 * This routine should not be called by a driver after its disconnect
602 * method has returned.
604 void usb_poison_urb(struct urb
*urb
)
607 if (!(urb
&& urb
->dev
&& urb
->ep
))
609 atomic_inc(&urb
->reject
);
611 usb_hcd_unlink_urb(urb
, -ENOENT
);
612 wait_event(usb_kill_urb_queue
, atomic_read(&urb
->use_count
) == 0);
614 EXPORT_SYMBOL_GPL(usb_poison_urb
);
616 void usb_unpoison_urb(struct urb
*urb
)
621 atomic_dec(&urb
->reject
);
623 EXPORT_SYMBOL_GPL(usb_unpoison_urb
);
626 * usb_kill_anchored_urbs - cancel transfer requests en masse
627 * @anchor: anchor the requests are bound to
629 * this allows all outstanding URBs to be killed starting
630 * from the back of the queue
632 * This routine should not be called by a driver after its disconnect
633 * method has returned.
635 void usb_kill_anchored_urbs(struct usb_anchor
*anchor
)
639 spin_lock_irq(&anchor
->lock
);
640 while (!list_empty(&anchor
->urb_list
)) {
641 victim
= list_entry(anchor
->urb_list
.prev
, struct urb
,
643 /* we must make sure the URB isn't freed before we kill it*/
645 spin_unlock_irq(&anchor
->lock
);
646 /* this will unanchor the URB */
647 usb_kill_urb(victim
);
649 spin_lock_irq(&anchor
->lock
);
651 spin_unlock_irq(&anchor
->lock
);
653 EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs
);
657 * usb_poison_anchored_urbs - cease all traffic from an anchor
658 * @anchor: anchor the requests are bound to
660 * this allows all outstanding URBs to be poisoned starting
661 * from the back of the queue. Newly added URBs will also be
664 * This routine should not be called by a driver after its disconnect
665 * method has returned.
667 void usb_poison_anchored_urbs(struct usb_anchor
*anchor
)
671 spin_lock_irq(&anchor
->lock
);
672 anchor
->poisoned
= 1;
673 while (!list_empty(&anchor
->urb_list
)) {
674 victim
= list_entry(anchor
->urb_list
.prev
, struct urb
,
676 /* we must make sure the URB isn't freed before we kill it*/
678 spin_unlock_irq(&anchor
->lock
);
679 /* this will unanchor the URB */
680 usb_poison_urb(victim
);
682 spin_lock_irq(&anchor
->lock
);
684 spin_unlock_irq(&anchor
->lock
);
686 EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs
);
689 * usb_unpoison_anchored_urbs - let an anchor be used successfully again
690 * @anchor: anchor the requests are bound to
692 * Reverses the effect of usb_poison_anchored_urbs
693 * the anchor can be used normally after it returns
695 void usb_unpoison_anchored_urbs(struct usb_anchor
*anchor
)
700 spin_lock_irqsave(&anchor
->lock
, flags
);
701 list_for_each_entry(lazarus
, &anchor
->urb_list
, anchor_list
) {
702 usb_unpoison_urb(lazarus
);
704 anchor
->poisoned
= 0;
705 spin_unlock_irqrestore(&anchor
->lock
, flags
);
707 EXPORT_SYMBOL_GPL(usb_unpoison_anchored_urbs
);
709 * usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse
710 * @anchor: anchor the requests are bound to
712 * this allows all outstanding URBs to be unlinked starting
713 * from the back of the queue. This function is asynchronous.
714 * The unlinking is just tiggered. It may happen after this
715 * function has returned.
717 * This routine should not be called by a driver after its disconnect
718 * method has returned.
720 void usb_unlink_anchored_urbs(struct usb_anchor
*anchor
)
724 while ((victim
= usb_get_from_anchor(anchor
)) != NULL
) {
725 usb_unlink_urb(victim
);
729 EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs
);
732 * usb_wait_anchor_empty_timeout - wait for an anchor to be unused
733 * @anchor: the anchor you want to become unused
734 * @timeout: how long you are willing to wait in milliseconds
736 * Call this is you want to be sure all an anchor's
739 int usb_wait_anchor_empty_timeout(struct usb_anchor
*anchor
,
740 unsigned int timeout
)
742 return wait_event_timeout(anchor
->wait
, list_empty(&anchor
->urb_list
),
743 msecs_to_jiffies(timeout
));
745 EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout
);
748 * usb_get_from_anchor - get an anchor's oldest urb
749 * @anchor: the anchor whose urb you want
751 * this will take the oldest urb from an anchor,
752 * unanchor and return it
754 struct urb
*usb_get_from_anchor(struct usb_anchor
*anchor
)
759 spin_lock_irqsave(&anchor
->lock
, flags
);
760 if (!list_empty(&anchor
->urb_list
)) {
761 victim
= list_entry(anchor
->urb_list
.next
, struct urb
,
764 __usb_unanchor_urb(victim
, anchor
);
768 spin_unlock_irqrestore(&anchor
->lock
, flags
);
773 EXPORT_SYMBOL_GPL(usb_get_from_anchor
);
776 * usb_scuttle_anchored_urbs - unanchor all an anchor's urbs
777 * @anchor: the anchor whose urbs you want to unanchor
779 * use this to get rid of all an anchor's urbs
781 void usb_scuttle_anchored_urbs(struct usb_anchor
*anchor
)
786 spin_lock_irqsave(&anchor
->lock
, flags
);
787 while (!list_empty(&anchor
->urb_list
)) {
788 victim
= list_entry(anchor
->urb_list
.prev
, struct urb
,
790 __usb_unanchor_urb(victim
, anchor
);
792 spin_unlock_irqrestore(&anchor
->lock
, flags
);
795 EXPORT_SYMBOL_GPL(usb_scuttle_anchored_urbs
);
798 * usb_anchor_empty - is an anchor empty
799 * @anchor: the anchor you want to query
801 * returns 1 if the anchor has no urbs associated with it
803 int usb_anchor_empty(struct usb_anchor
*anchor
)
805 return list_empty(&anchor
->urb_list
);
808 EXPORT_SYMBOL_GPL(usb_anchor_empty
);