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1#include <linux/module.h>
2#include <linux/string.h>
3#include <linux/bitops.h>
4#include <linux/slab.h>
5#include <linux/log2.h>
6#include <linux/usb.h>
7#include <linux/wait.h>
8#include <linux/usb/hcd.h>
9#include <linux/scatterlist.h>
10
11#define to_urb(d) container_of(d, struct urb, kref)
12
13
14static void urb_destroy(struct kref *kref)
15{
16 struct urb *urb = to_urb(kref);
17
18 if (urb->transfer_flags & URB_FREE_BUFFER)
19 kfree(urb->transfer_buffer);
20
21 kfree(urb);
22}
23
24/**
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
27 *
28 * Initializes a urb so that the USB subsystem can use it properly.
29 *
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.
35 *
36 * Only use this function if you _really_ understand what you are doing.
37 */
38void usb_init_urb(struct urb *urb)
39{
40 if (urb) {
41 memset(urb, 0, sizeof(*urb));
42 kref_init(&urb->kref);
43 INIT_LIST_HEAD(&urb->anchor_list);
44 }
45}
46EXPORT_SYMBOL_GPL(usb_init_urb);
47
48/**
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.
53 *
54 * Creates an urb for the USB driver to use, initializes a few internal
55 * structures, increments the usage counter, and returns a pointer to it.
56 *
57 * If the driver want to use this urb for interrupt, control, or bulk
58 * endpoints, pass '0' as the number of iso packets.
59 *
60 * The driver must call usb_free_urb() when it is finished with the urb.
61 *
62 * Return: A pointer to the new urb, or %NULL if no memory is available.
63 */
64struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags)
65{
66 struct urb *urb;
67
68 urb = kmalloc(sizeof(struct urb) +
69 iso_packets * sizeof(struct usb_iso_packet_descriptor),
70 mem_flags);
71 if (!urb) {
72 printk(KERN_ERR "alloc_urb: kmalloc failed\n");
73 return NULL;
74 }
75 usb_init_urb(urb);
76 return urb;
77}
78EXPORT_SYMBOL_GPL(usb_alloc_urb);
79
80/**
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
83 *
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.
86 *
87 * Note: The transfer buffer associated with the urb is not freed unless the
88 * URB_FREE_BUFFER transfer flag is set.
89 */
90void usb_free_urb(struct urb *urb)
91{
92 if (urb)
93 kref_put(&urb->kref, urb_destroy);
94}
95EXPORT_SYMBOL_GPL(usb_free_urb);
96
97/**
98 * usb_get_urb - increments the reference count of the urb
99 * @urb: pointer to the urb to modify, may be NULL
100 *
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
103 * for urbs.
104 *
105 * Return: A pointer to the urb with the incremented reference counter.
106 */
107struct urb *usb_get_urb(struct urb *urb)
108{
109 if (urb)
110 kref_get(&urb->kref);
111 return urb;
112}
113EXPORT_SYMBOL_GPL(usb_get_urb);
114
115/**
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
119 *
120 * This can be called to have access to URBs which are to be executed
121 * without bothering to track them
122 */
123void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor)
124{
125 unsigned long flags;
126
127 spin_lock_irqsave(&anchor->lock, flags);
128 usb_get_urb(urb);
129 list_add_tail(&urb->anchor_list, &anchor->urb_list);
130 urb->anchor = anchor;
131
132 if (unlikely(anchor->poisoned))
133 atomic_inc(&urb->reject);
134
135 spin_unlock_irqrestore(&anchor->lock, flags);
136}
137EXPORT_SYMBOL_GPL(usb_anchor_urb);
138
139static int usb_anchor_check_wakeup(struct usb_anchor *anchor)
140{
141 return atomic_read(&anchor->suspend_wakeups) == 0 &&
142 list_empty(&anchor->urb_list);
143}
144
145/* Callers must hold anchor->lock */
146static void __usb_unanchor_urb(struct urb *urb, struct usb_anchor *anchor)
147{
148 urb->anchor = NULL;
149 list_del(&urb->anchor_list);
150 usb_put_urb(urb);
151 if (usb_anchor_check_wakeup(anchor))
152 wake_up(&anchor->wait);
153}
154
155/**
156 * usb_unanchor_urb - unanchors an URB
157 * @urb: pointer to the urb to anchor
158 *
159 * Call this to stop the system keeping track of this URB
160 */
161void usb_unanchor_urb(struct urb *urb)
162{
163 unsigned long flags;
164 struct usb_anchor *anchor;
165
166 if (!urb)
167 return;
168
169 anchor = urb->anchor;
170 if (!anchor)
171 return;
172
173 spin_lock_irqsave(&anchor->lock, flags);
174 /*
175 * At this point, we could be competing with another thread which
176 * has the same intention. To protect the urb from being unanchored
177 * twice, only the winner of the race gets the job.
178 */
179 if (likely(anchor == urb->anchor))
180 __usb_unanchor_urb(urb, anchor);
181 spin_unlock_irqrestore(&anchor->lock, flags);
182}
183EXPORT_SYMBOL_GPL(usb_unanchor_urb);
184
185/*-------------------------------------------------------------------*/
186
187/**
188 * usb_submit_urb - issue an asynchronous transfer request for an endpoint
189 * @urb: pointer to the urb describing the request
190 * @mem_flags: the type of memory to allocate, see kmalloc() for a list
191 * of valid options for this.
192 *
193 * This submits a transfer request, and transfers control of the URB
194 * describing that request to the USB subsystem. Request completion will
195 * be indicated later, asynchronously, by calling the completion handler.
196 * The three types of completion are success, error, and unlink
197 * (a software-induced fault, also called "request cancellation").
198 *
199 * URBs may be submitted in interrupt context.
200 *
201 * The caller must have correctly initialized the URB before submitting
202 * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are
203 * available to ensure that most fields are correctly initialized, for
204 * the particular kind of transfer, although they will not initialize
205 * any transfer flags.
206 *
207 * If the submission is successful, the complete() callback from the URB
208 * will be called exactly once, when the USB core and Host Controller Driver
209 * (HCD) are finished with the URB. When the completion function is called,
210 * control of the URB is returned to the device driver which issued the
211 * request. The completion handler may then immediately free or reuse that
212 * URB.
213 *
214 * With few exceptions, USB device drivers should never access URB fields
215 * provided by usbcore or the HCD until its complete() is called.
216 * The exceptions relate to periodic transfer scheduling. For both
217 * interrupt and isochronous urbs, as part of successful URB submission
218 * urb->interval is modified to reflect the actual transfer period used
219 * (normally some power of two units). And for isochronous urbs,
220 * urb->start_frame is modified to reflect when the URB's transfers were
221 * scheduled to start.
222 *
223 * Not all isochronous transfer scheduling policies will work, but most
224 * host controller drivers should easily handle ISO queues going from now
225 * until 10-200 msec into the future. Drivers should try to keep at
226 * least one or two msec of data in the queue; many controllers require
227 * that new transfers start at least 1 msec in the future when they are
228 * added. If the driver is unable to keep up and the queue empties out,
229 * the behavior for new submissions is governed by the URB_ISO_ASAP flag.
230 * If the flag is set, or if the queue is idle, then the URB is always
231 * assigned to the first available (and not yet expired) slot in the
232 * endpoint's schedule. If the flag is not set and the queue is active
233 * then the URB is always assigned to the next slot in the schedule
234 * following the end of the endpoint's previous URB, even if that slot is
235 * in the past. When a packet is assigned in this way to a slot that has
236 * already expired, the packet is not transmitted and the corresponding
237 * usb_iso_packet_descriptor's status field will return -EXDEV. If this
238 * would happen to all the packets in the URB, submission fails with a
239 * -EXDEV error code.
240 *
241 * For control endpoints, the synchronous usb_control_msg() call is
242 * often used (in non-interrupt context) instead of this call.
243 * That is often used through convenience wrappers, for the requests
244 * that are standardized in the USB 2.0 specification. For bulk
245 * endpoints, a synchronous usb_bulk_msg() call is available.
246 *
247 * Return:
248 * 0 on successful submissions. A negative error number otherwise.
249 *
250 * Request Queuing:
251 *
252 * URBs may be submitted to endpoints before previous ones complete, to
253 * minimize the impact of interrupt latencies and system overhead on data
254 * throughput. With that queuing policy, an endpoint's queue would never
255 * be empty. This is required for continuous isochronous data streams,
256 * and may also be required for some kinds of interrupt transfers. Such
257 * queuing also maximizes bandwidth utilization by letting USB controllers
258 * start work on later requests before driver software has finished the
259 * completion processing for earlier (successful) requests.
260 *
261 * As of Linux 2.6, all USB endpoint transfer queues support depths greater
262 * than one. This was previously a HCD-specific behavior, except for ISO
263 * transfers. Non-isochronous endpoint queues are inactive during cleanup
264 * after faults (transfer errors or cancellation).
265 *
266 * Reserved Bandwidth Transfers:
267 *
268 * Periodic transfers (interrupt or isochronous) are performed repeatedly,
269 * using the interval specified in the urb. Submitting the first urb to
270 * the endpoint reserves the bandwidth necessary to make those transfers.
271 * If the USB subsystem can't allocate sufficient bandwidth to perform
272 * the periodic request, submitting such a periodic request should fail.
273 *
274 * For devices under xHCI, the bandwidth is reserved at configuration time, or
275 * when the alt setting is selected. If there is not enough bus bandwidth, the
276 * configuration/alt setting request will fail. Therefore, submissions to
277 * periodic endpoints on devices under xHCI should never fail due to bandwidth
278 * constraints.
279 *
280 * Device drivers must explicitly request that repetition, by ensuring that
281 * some URB is always on the endpoint's queue (except possibly for short
282 * periods during completion callbacks). When there is no longer an urb
283 * queued, the endpoint's bandwidth reservation is canceled. This means
284 * drivers can use their completion handlers to ensure they keep bandwidth
285 * they need, by reinitializing and resubmitting the just-completed urb
286 * until the driver longer needs that periodic bandwidth.
287 *
288 * Memory Flags:
289 *
290 * The general rules for how to decide which mem_flags to use
291 * are the same as for kmalloc. There are four
292 * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and
293 * GFP_ATOMIC.
294 *
295 * GFP_NOFS is not ever used, as it has not been implemented yet.
296 *
297 * GFP_ATOMIC is used when
298 * (a) you are inside a completion handler, an interrupt, bottom half,
299 * tasklet or timer, or
300 * (b) you are holding a spinlock or rwlock (does not apply to
301 * semaphores), or
302 * (c) current->state != TASK_RUNNING, this is the case only after
303 * you've changed it.
304 *
305 * GFP_NOIO is used in the block io path and error handling of storage
306 * devices.
307 *
308 * All other situations use GFP_KERNEL.
309 *
310 * Some more specific rules for mem_flags can be inferred, such as
311 * (1) start_xmit, timeout, and receive methods of network drivers must
312 * use GFP_ATOMIC (they are called with a spinlock held);
313 * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also
314 * called with a spinlock held);
315 * (3) If you use a kernel thread with a network driver you must use
316 * GFP_NOIO, unless (b) or (c) apply;
317 * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)
318 * apply or your are in a storage driver's block io path;
319 * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and
320 * (6) changing firmware on a running storage or net device uses
321 * GFP_NOIO, unless b) or c) apply
322 *
323 */
324int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
325{
326 static int pipetypes[4] = {
327 PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT
328 };
329 int xfertype, max;
330 struct usb_device *dev;
331 struct usb_host_endpoint *ep;
332 int is_out;
333 unsigned int allowed;
334
335 if (!urb || !urb->complete)
336 return -EINVAL;
337 if (urb->hcpriv) {
338 WARN_ONCE(1, "URB %p submitted while active\n", urb);
339 return -EBUSY;
340 }
341
342 dev = urb->dev;
343 if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED))
344 return -ENODEV;
345
346 /* For now, get the endpoint from the pipe. Eventually drivers
347 * will be required to set urb->ep directly and we will eliminate
348 * urb->pipe.
349 */
350 ep = usb_pipe_endpoint(dev, urb->pipe);
351 if (!ep)
352 return -ENOENT;
353
354 urb->ep = ep;
355 urb->status = -EINPROGRESS;
356 urb->actual_length = 0;
357
358 /* Lots of sanity checks, so HCDs can rely on clean data
359 * and don't need to duplicate tests
360 */
361 xfertype = usb_endpoint_type(&ep->desc);
362 if (xfertype == USB_ENDPOINT_XFER_CONTROL) {
363 struct usb_ctrlrequest *setup =
364 (struct usb_ctrlrequest *) urb->setup_packet;
365
366 if (!setup)
367 return -ENOEXEC;
368 is_out = !(setup->bRequestType & USB_DIR_IN) ||
369 !setup->wLength;
370 } else {
371 is_out = usb_endpoint_dir_out(&ep->desc);
372 }
373
374 /* Clear the internal flags and cache the direction for later use */
375 urb->transfer_flags &= ~(URB_DIR_MASK | URB_DMA_MAP_SINGLE |
376 URB_DMA_MAP_PAGE | URB_DMA_MAP_SG | URB_MAP_LOCAL |
377 URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL |
378 URB_DMA_SG_COMBINED);
379 urb->transfer_flags |= (is_out ? URB_DIR_OUT : URB_DIR_IN);
380
381 if (xfertype != USB_ENDPOINT_XFER_CONTROL &&
382 dev->state < USB_STATE_CONFIGURED)
383 return -ENODEV;
384
385 max = usb_endpoint_maxp(&ep->desc);
386 if (max <= 0) {
387 dev_dbg(&dev->dev,
388 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
389 usb_endpoint_num(&ep->desc), is_out ? "out" : "in",
390 __func__, max);
391 return -EMSGSIZE;
392 }
393
394 /* periodic transfers limit size per frame/uframe,
395 * but drivers only control those sizes for ISO.
396 * while we're checking, initialize return status.
397 */
398 if (xfertype == USB_ENDPOINT_XFER_ISOC) {
399 int n, len;
400
401 /* SuperSpeed isoc endpoints have up to 16 bursts of up to
402 * 3 packets each
403 */
404 if (dev->speed >= USB_SPEED_SUPER) {
405 int burst = 1 + ep->ss_ep_comp.bMaxBurst;
406 int mult = USB_SS_MULT(ep->ss_ep_comp.bmAttributes);
407 max *= burst;
408 max *= mult;
409 }
410
411 /* "high bandwidth" mode, 1-3 packets/uframe? */
412 if (dev->speed == USB_SPEED_HIGH) {
413 int mult = 1 + ((max >> 11) & 0x03);
414 max &= 0x07ff;
415 max *= mult;
416 }
417
418 if (urb->number_of_packets <= 0)
419 return -EINVAL;
420 for (n = 0; n < urb->number_of_packets; n++) {
421 len = urb->iso_frame_desc[n].length;
422 if (len < 0 || len > max)
423 return -EMSGSIZE;
424 urb->iso_frame_desc[n].status = -EXDEV;
425 urb->iso_frame_desc[n].actual_length = 0;
426 }
427 } else if (urb->num_sgs && !urb->dev->bus->no_sg_constraint &&
428 dev->speed != USB_SPEED_WIRELESS) {
429 struct scatterlist *sg;
430 int i;
431
432 for_each_sg(urb->sg, sg, urb->num_sgs - 1, i)
433 if (sg->length % max)
434 return -EINVAL;
435 }
436
437 /* the I/O buffer must be mapped/unmapped, except when length=0 */
438 if (urb->transfer_buffer_length > INT_MAX)
439 return -EMSGSIZE;
440
441 /*
442 * stuff that drivers shouldn't do, but which shouldn't
443 * cause problems in HCDs if they get it wrong.
444 */
445
446 /* Check that the pipe's type matches the endpoint's type */
447 if (usb_pipetype(urb->pipe) != pipetypes[xfertype])
448 dev_WARN(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n",
449 usb_pipetype(urb->pipe), pipetypes[xfertype]);
450
451 /* Check against a simple/standard policy */
452 allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT | URB_DIR_MASK |
453 URB_FREE_BUFFER);
454 switch (xfertype) {
455 case USB_ENDPOINT_XFER_BULK:
456 case USB_ENDPOINT_XFER_INT:
457 if (is_out)
458 allowed |= URB_ZERO_PACKET;
459 /* FALLTHROUGH */
460 case USB_ENDPOINT_XFER_CONTROL:
461 allowed |= URB_NO_FSBR; /* only affects UHCI */
462 /* FALLTHROUGH */
463 default: /* all non-iso endpoints */
464 if (!is_out)
465 allowed |= URB_SHORT_NOT_OK;
466 break;
467 case USB_ENDPOINT_XFER_ISOC:
468 allowed |= URB_ISO_ASAP;
469 break;
470 }
471 allowed &= urb->transfer_flags;
472
473 /* warn if submitter gave bogus flags */
474 if (allowed != urb->transfer_flags)
475 dev_WARN(&dev->dev, "BOGUS urb flags, %x --> %x\n",
476 urb->transfer_flags, allowed);
477
478 /*
479 * Force periodic transfer intervals to be legal values that are
480 * a power of two (so HCDs don't need to).
481 *
482 * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC
483 * supports different values... this uses EHCI/UHCI defaults (and
484 * EHCI can use smaller non-default values).
485 */
486 switch (xfertype) {
487 case USB_ENDPOINT_XFER_ISOC:
488 case USB_ENDPOINT_XFER_INT:
489 /* too small? */
490 switch (dev->speed) {
491 case USB_SPEED_WIRELESS:
492 if ((urb->interval < 6)
493 && (xfertype == USB_ENDPOINT_XFER_INT))
494 return -EINVAL;
495 default:
496 if (urb->interval <= 0)
497 return -EINVAL;
498 break;
499 }
500 /* too big? */
501 switch (dev->speed) {
502 case USB_SPEED_SUPER_PLUS:
503 case USB_SPEED_SUPER: /* units are 125us */
504 /* Handle up to 2^(16-1) microframes */
505 if (urb->interval > (1 << 15))
506 return -EINVAL;
507 max = 1 << 15;
508 break;
509 case USB_SPEED_WIRELESS:
510 if (urb->interval > 16)
511 return -EINVAL;
512 break;
513 case USB_SPEED_HIGH: /* units are microframes */
514 /* NOTE usb handles 2^15 */
515 if (urb->interval > (1024 * 8))
516 urb->interval = 1024 * 8;
517 max = 1024 * 8;
518 break;
519 case USB_SPEED_FULL: /* units are frames/msec */
520 case USB_SPEED_LOW:
521 if (xfertype == USB_ENDPOINT_XFER_INT) {
522 if (urb->interval > 255)
523 return -EINVAL;
524 /* NOTE ohci only handles up to 32 */
525 max = 128;
526 } else {
527 if (urb->interval > 1024)
528 urb->interval = 1024;
529 /* NOTE usb and ohci handle up to 2^15 */
530 max = 1024;
531 }
532 break;
533 default:
534 return -EINVAL;
535 }
536 if (dev->speed != USB_SPEED_WIRELESS) {
537 /* Round down to a power of 2, no more than max */
538 urb->interval = min(max, 1 << ilog2(urb->interval));
539 }
540 }
541
542 return usb_hcd_submit_urb(urb, mem_flags);
543}
544EXPORT_SYMBOL_GPL(usb_submit_urb);
545
546/*-------------------------------------------------------------------*/
547
548/**
549 * usb_unlink_urb - abort/cancel a transfer request for an endpoint
550 * @urb: pointer to urb describing a previously submitted request,
551 * may be NULL
552 *
553 * This routine cancels an in-progress request. URBs complete only once
554 * per submission, and may be canceled only once per submission.
555 * Successful cancellation means termination of @urb will be expedited
556 * and the completion handler will be called with a status code
557 * indicating that the request has been canceled (rather than any other
558 * code).
559 *
560 * Drivers should not call this routine or related routines, such as
561 * usb_kill_urb() or usb_unlink_anchored_urbs(), after their disconnect
562 * method has returned. The disconnect function should synchronize with
563 * a driver's I/O routines to insure that all URB-related activity has
564 * completed before it returns.
565 *
566 * This request is asynchronous, however the HCD might call the ->complete()
567 * callback during unlink. Therefore when drivers call usb_unlink_urb(), they
568 * must not hold any locks that may be taken by the completion function.
569 * Success is indicated by returning -EINPROGRESS, at which time the URB will
570 * probably not yet have been given back to the device driver. When it is
571 * eventually called, the completion function will see @urb->status ==
572 * -ECONNRESET.
573 * Failure is indicated by usb_unlink_urb() returning any other value.
574 * Unlinking will fail when @urb is not currently "linked" (i.e., it was
575 * never submitted, or it was unlinked before, or the hardware is already
576 * finished with it), even if the completion handler has not yet run.
577 *
578 * The URB must not be deallocated while this routine is running. In
579 * particular, when a driver calls this routine, it must insure that the
580 * completion handler cannot deallocate the URB.
581 *
582 * Return: -EINPROGRESS on success. See description for other values on
583 * failure.
584 *
585 * Unlinking and Endpoint Queues:
586 *
587 * [The behaviors and guarantees described below do not apply to virtual
588 * root hubs but only to endpoint queues for physical USB devices.]
589 *
590 * Host Controller Drivers (HCDs) place all the URBs for a particular
591 * endpoint in a queue. Normally the queue advances as the controller
592 * hardware processes each request. But when an URB terminates with an
593 * error its queue generally stops (see below), at least until that URB's
594 * completion routine returns. It is guaranteed that a stopped queue
595 * will not restart until all its unlinked URBs have been fully retired,
596 * with their completion routines run, even if that's not until some time
597 * after the original completion handler returns. The same behavior and
598 * guarantee apply when an URB terminates because it was unlinked.
599 *
600 * Bulk and interrupt endpoint queues are guaranteed to stop whenever an
601 * URB terminates with any sort of error, including -ECONNRESET, -ENOENT,
602 * and -EREMOTEIO. Control endpoint queues behave the same way except
603 * that they are not guaranteed to stop for -EREMOTEIO errors. Queues
604 * for isochronous endpoints are treated differently, because they must
605 * advance at fixed rates. Such queues do not stop when an URB
606 * encounters an error or is unlinked. An unlinked isochronous URB may
607 * leave a gap in the stream of packets; it is undefined whether such
608 * gaps can be filled in.
609 *
610 * Note that early termination of an URB because a short packet was
611 * received will generate a -EREMOTEIO error if and only if the
612 * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device
613 * drivers can build deep queues for large or complex bulk transfers
614 * and clean them up reliably after any sort of aborted transfer by
615 * unlinking all pending URBs at the first fault.
616 *
617 * When a control URB terminates with an error other than -EREMOTEIO, it
618 * is quite likely that the status stage of the transfer will not take
619 * place.
620 */
621int usb_unlink_urb(struct urb *urb)
622{
623 if (!urb)
624 return -EINVAL;
625 if (!urb->dev)
626 return -ENODEV;
627 if (!urb->ep)
628 return -EIDRM;
629 return usb_hcd_unlink_urb(urb, -ECONNRESET);
630}
631EXPORT_SYMBOL_GPL(usb_unlink_urb);
632
633/**
634 * usb_kill_urb - cancel a transfer request and wait for it to finish
635 * @urb: pointer to URB describing a previously submitted request,
636 * may be NULL
637 *
638 * This routine cancels an in-progress request. It is guaranteed that
639 * upon return all completion handlers will have finished and the URB
640 * will be totally idle and available for reuse. These features make
641 * this an ideal way to stop I/O in a disconnect() callback or close()
642 * function. If the request has not already finished or been unlinked
643 * the completion handler will see urb->status == -ENOENT.
644 *
645 * While the routine is running, attempts to resubmit the URB will fail
646 * with error -EPERM. Thus even if the URB's completion handler always
647 * tries to resubmit, it will not succeed and the URB will become idle.
648 *
649 * The URB must not be deallocated while this routine is running. In
650 * particular, when a driver calls this routine, it must insure that the
651 * completion handler cannot deallocate the URB.
652 *
653 * This routine may not be used in an interrupt context (such as a bottom
654 * half or a completion handler), or when holding a spinlock, or in other
655 * situations where the caller can't schedule().
656 *
657 * This routine should not be called by a driver after its disconnect
658 * method has returned.
659 */
660void usb_kill_urb(struct urb *urb)
661{
662 might_sleep();
663 if (!(urb && urb->dev && urb->ep))
664 return;
665 atomic_inc(&urb->reject);
666
667 usb_hcd_unlink_urb(urb, -ENOENT);
668 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
669
670 atomic_dec(&urb->reject);
671}
672EXPORT_SYMBOL_GPL(usb_kill_urb);
673
674/**
675 * usb_poison_urb - reliably kill a transfer and prevent further use of an URB
676 * @urb: pointer to URB describing a previously submitted request,
677 * may be NULL
678 *
679 * This routine cancels an in-progress request. It is guaranteed that
680 * upon return all completion handlers will have finished and the URB
681 * will be totally idle and cannot be reused. These features make
682 * this an ideal way to stop I/O in a disconnect() callback.
683 * If the request has not already finished or been unlinked
684 * the completion handler will see urb->status == -ENOENT.
685 *
686 * After and while the routine runs, attempts to resubmit the URB will fail
687 * with error -EPERM. Thus even if the URB's completion handler always
688 * tries to resubmit, it will not succeed and the URB will become idle.
689 *
690 * The URB must not be deallocated while this routine is running. In
691 * particular, when a driver calls this routine, it must insure that the
692 * completion handler cannot deallocate the URB.
693 *
694 * This routine may not be used in an interrupt context (such as a bottom
695 * half or a completion handler), or when holding a spinlock, or in other
696 * situations where the caller can't schedule().
697 *
698 * This routine should not be called by a driver after its disconnect
699 * method has returned.
700 */
701void usb_poison_urb(struct urb *urb)
702{
703 might_sleep();
704 if (!urb)
705 return;
706 atomic_inc(&urb->reject);
707
708 if (!urb->dev || !urb->ep)
709 return;
710
711 usb_hcd_unlink_urb(urb, -ENOENT);
712 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
713}
714EXPORT_SYMBOL_GPL(usb_poison_urb);
715
716void usb_unpoison_urb(struct urb *urb)
717{
718 if (!urb)
719 return;
720
721 atomic_dec(&urb->reject);
722}
723EXPORT_SYMBOL_GPL(usb_unpoison_urb);
724
725/**
726 * usb_block_urb - reliably prevent further use of an URB
727 * @urb: pointer to URB to be blocked, may be NULL
728 *
729 * After the routine has run, 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.
732 *
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.
736 */
737void usb_block_urb(struct urb *urb)
738{
739 if (!urb)
740 return;
741
742 atomic_inc(&urb->reject);
743}
744EXPORT_SYMBOL_GPL(usb_block_urb);
745
746/**
747 * usb_kill_anchored_urbs - cancel transfer requests en masse
748 * @anchor: anchor the requests are bound to
749 *
750 * this allows all outstanding URBs to be killed starting
751 * from the back of the queue
752 *
753 * This routine should not be called by a driver after its disconnect
754 * method has returned.
755 */
756void usb_kill_anchored_urbs(struct usb_anchor *anchor)
757{
758 struct urb *victim;
759
760 spin_lock_irq(&anchor->lock);
761 while (!list_empty(&anchor->urb_list)) {
762 victim = list_entry(anchor->urb_list.prev, struct urb,
763 anchor_list);
764 /* we must make sure the URB isn't freed before we kill it*/
765 usb_get_urb(victim);
766 spin_unlock_irq(&anchor->lock);
767 /* this will unanchor the URB */
768 usb_kill_urb(victim);
769 usb_put_urb(victim);
770 spin_lock_irq(&anchor->lock);
771 }
772 spin_unlock_irq(&anchor->lock);
773}
774EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs);
775
776
777/**
778 * usb_poison_anchored_urbs - cease all traffic from an anchor
779 * @anchor: anchor the requests are bound to
780 *
781 * this allows all outstanding URBs to be poisoned starting
782 * from the back of the queue. Newly added URBs will also be
783 * poisoned
784 *
785 * This routine should not be called by a driver after its disconnect
786 * method has returned.
787 */
788void usb_poison_anchored_urbs(struct usb_anchor *anchor)
789{
790 struct urb *victim;
791
792 spin_lock_irq(&anchor->lock);
793 anchor->poisoned = 1;
794 while (!list_empty(&anchor->urb_list)) {
795 victim = list_entry(anchor->urb_list.prev, struct urb,
796 anchor_list);
797 /* we must make sure the URB isn't freed before we kill it*/
798 usb_get_urb(victim);
799 spin_unlock_irq(&anchor->lock);
800 /* this will unanchor the URB */
801 usb_poison_urb(victim);
802 usb_put_urb(victim);
803 spin_lock_irq(&anchor->lock);
804 }
805 spin_unlock_irq(&anchor->lock);
806}
807EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs);
808
809/**
810 * usb_unpoison_anchored_urbs - let an anchor be used successfully again
811 * @anchor: anchor the requests are bound to
812 *
813 * Reverses the effect of usb_poison_anchored_urbs
814 * the anchor can be used normally after it returns
815 */
816void usb_unpoison_anchored_urbs(struct usb_anchor *anchor)
817{
818 unsigned long flags;
819 struct urb *lazarus;
820
821 spin_lock_irqsave(&anchor->lock, flags);
822 list_for_each_entry(lazarus, &anchor->urb_list, anchor_list) {
823 usb_unpoison_urb(lazarus);
824 }
825 anchor->poisoned = 0;
826 spin_unlock_irqrestore(&anchor->lock, flags);
827}
828EXPORT_SYMBOL_GPL(usb_unpoison_anchored_urbs);
829/**
830 * usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse
831 * @anchor: anchor the requests are bound to
832 *
833 * this allows all outstanding URBs to be unlinked starting
834 * from the back of the queue. This function is asynchronous.
835 * The unlinking is just triggered. It may happen after this
836 * function has returned.
837 *
838 * This routine should not be called by a driver after its disconnect
839 * method has returned.
840 */
841void usb_unlink_anchored_urbs(struct usb_anchor *anchor)
842{
843 struct urb *victim;
844
845 while ((victim = usb_get_from_anchor(anchor)) != NULL) {
846 usb_unlink_urb(victim);
847 usb_put_urb(victim);
848 }
849}
850EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs);
851
852/**
853 * usb_anchor_suspend_wakeups
854 * @anchor: the anchor you want to suspend wakeups on
855 *
856 * Call this to stop the last urb being unanchored from waking up any
857 * usb_wait_anchor_empty_timeout waiters. This is used in the hcd urb give-
858 * back path to delay waking up until after the completion handler has run.
859 */
860void usb_anchor_suspend_wakeups(struct usb_anchor *anchor)
861{
862 if (anchor)
863 atomic_inc(&anchor->suspend_wakeups);
864}
865EXPORT_SYMBOL_GPL(usb_anchor_suspend_wakeups);
866
867/**
868 * usb_anchor_resume_wakeups
869 * @anchor: the anchor you want to resume wakeups on
870 *
871 * Allow usb_wait_anchor_empty_timeout waiters to be woken up again, and
872 * wake up any current waiters if the anchor is empty.
873 */
874void usb_anchor_resume_wakeups(struct usb_anchor *anchor)
875{
876 if (!anchor)
877 return;
878
879 atomic_dec(&anchor->suspend_wakeups);
880 if (usb_anchor_check_wakeup(anchor))
881 wake_up(&anchor->wait);
882}
883EXPORT_SYMBOL_GPL(usb_anchor_resume_wakeups);
884
885/**
886 * usb_wait_anchor_empty_timeout - wait for an anchor to be unused
887 * @anchor: the anchor you want to become unused
888 * @timeout: how long you are willing to wait in milliseconds
889 *
890 * Call this is you want to be sure all an anchor's
891 * URBs have finished
892 *
893 * Return: Non-zero if the anchor became unused. Zero on timeout.
894 */
895int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,
896 unsigned int timeout)
897{
898 return wait_event_timeout(anchor->wait,
899 usb_anchor_check_wakeup(anchor),
900 msecs_to_jiffies(timeout));
901}
902EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout);
903
904/**
905 * usb_get_from_anchor - get an anchor's oldest urb
906 * @anchor: the anchor whose urb you want
907 *
908 * This will take the oldest urb from an anchor,
909 * unanchor and return it
910 *
911 * Return: The oldest urb from @anchor, or %NULL if @anchor has no
912 * urbs associated with it.
913 */
914struct urb *usb_get_from_anchor(struct usb_anchor *anchor)
915{
916 struct urb *victim;
917 unsigned long flags;
918
919 spin_lock_irqsave(&anchor->lock, flags);
920 if (!list_empty(&anchor->urb_list)) {
921 victim = list_entry(anchor->urb_list.next, struct urb,
922 anchor_list);
923 usb_get_urb(victim);
924 __usb_unanchor_urb(victim, anchor);
925 } else {
926 victim = NULL;
927 }
928 spin_unlock_irqrestore(&anchor->lock, flags);
929
930 return victim;
931}
932
933EXPORT_SYMBOL_GPL(usb_get_from_anchor);
934
935/**
936 * usb_scuttle_anchored_urbs - unanchor all an anchor's urbs
937 * @anchor: the anchor whose urbs you want to unanchor
938 *
939 * use this to get rid of all an anchor's urbs
940 */
941void usb_scuttle_anchored_urbs(struct usb_anchor *anchor)
942{
943 struct urb *victim;
944 unsigned long flags;
945
946 spin_lock_irqsave(&anchor->lock, flags);
947 while (!list_empty(&anchor->urb_list)) {
948 victim = list_entry(anchor->urb_list.prev, struct urb,
949 anchor_list);
950 __usb_unanchor_urb(victim, anchor);
951 }
952 spin_unlock_irqrestore(&anchor->lock, flags);
953}
954
955EXPORT_SYMBOL_GPL(usb_scuttle_anchored_urbs);
956
957/**
958 * usb_anchor_empty - is an anchor empty
959 * @anchor: the anchor you want to query
960 *
961 * Return: 1 if the anchor has no urbs associated with it.
962 */
963int usb_anchor_empty(struct usb_anchor *anchor)
964{
965 return list_empty(&anchor->urb_list);
966}
967
968EXPORT_SYMBOL_GPL(usb_anchor_empty);
969
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Released under the GPLv2 only.
4 */
5
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>
15
16#define to_urb(d) container_of(d, struct urb, kref)
17
18
19static void urb_destroy(struct kref *kref)
20{
21 struct urb *urb = to_urb(kref);
22
23 if (urb->transfer_flags & URB_FREE_BUFFER)
24 kfree(urb->transfer_buffer);
25
26 kfree(urb);
27}
28
29/**
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
32 *
33 * Initializes a urb so that the USB subsystem can use it properly.
34 *
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.
40 *
41 * Only use this function if you _really_ understand what you are doing.
42 */
43void usb_init_urb(struct urb *urb)
44{
45 if (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);
50 }
51}
52EXPORT_SYMBOL_GPL(usb_init_urb);
53
54/**
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.
59 *
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.
62 *
63 * If the driver want to use this urb for interrupt, control, or bulk
64 * endpoints, pass '0' as the number of iso packets.
65 *
66 * The driver must call usb_free_urb() when it is finished with the urb.
67 *
68 * Return: A pointer to the new urb, or %NULL if no memory is available.
69 */
70struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags)
71{
72 struct urb *urb;
73
74 urb = kmalloc(struct_size(urb, iso_frame_desc, iso_packets),
75 mem_flags);
76 if (!urb)
77 return NULL;
78 usb_init_urb(urb);
79 return urb;
80}
81EXPORT_SYMBOL_GPL(usb_alloc_urb);
82
83/**
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
86 *
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.
89 *
90 * Note: The transfer buffer associated with the urb is not freed unless the
91 * URB_FREE_BUFFER transfer flag is set.
92 */
93void usb_free_urb(struct urb *urb)
94{
95 if (urb)
96 kref_put(&urb->kref, urb_destroy);
97}
98EXPORT_SYMBOL_GPL(usb_free_urb);
99
100/**
101 * usb_get_urb - increments the reference count of the urb
102 * @urb: pointer to the urb to modify, may be NULL
103 *
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
106 * for urbs.
107 *
108 * Return: A pointer to the urb with the incremented reference counter.
109 */
110struct urb *usb_get_urb(struct urb *urb)
111{
112 if (urb)
113 kref_get(&urb->kref);
114 return urb;
115}
116EXPORT_SYMBOL_GPL(usb_get_urb);
117
118/**
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
122 *
123 * This can be called to have access to URBs which are to be executed
124 * without bothering to track them
125 */
126void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor)
127{
128 unsigned long flags;
129
130 spin_lock_irqsave(&anchor->lock, flags);
131 usb_get_urb(urb);
132 list_add_tail(&urb->anchor_list, &anchor->urb_list);
133 urb->anchor = anchor;
134
135 if (unlikely(anchor->poisoned))
136 atomic_inc(&urb->reject);
137
138 spin_unlock_irqrestore(&anchor->lock, flags);
139}
140EXPORT_SYMBOL_GPL(usb_anchor_urb);
141
142static int usb_anchor_check_wakeup(struct usb_anchor *anchor)
143{
144 return atomic_read(&anchor->suspend_wakeups) == 0 &&
145 list_empty(&anchor->urb_list);
146}
147
148/* Callers must hold anchor->lock */
149static void __usb_unanchor_urb(struct urb *urb, struct usb_anchor *anchor)
150{
151 urb->anchor = NULL;
152 list_del(&urb->anchor_list);
153 usb_put_urb(urb);
154 if (usb_anchor_check_wakeup(anchor))
155 wake_up(&anchor->wait);
156}
157
158/**
159 * usb_unanchor_urb - unanchors an URB
160 * @urb: pointer to the urb to anchor
161 *
162 * Call this to stop the system keeping track of this URB
163 */
164void usb_unanchor_urb(struct urb *urb)
165{
166 unsigned long flags;
167 struct usb_anchor *anchor;
168
169 if (!urb)
170 return;
171
172 anchor = urb->anchor;
173 if (!anchor)
174 return;
175
176 spin_lock_irqsave(&anchor->lock, flags);
177 /*
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.
181 */
182 if (likely(anchor == urb->anchor))
183 __usb_unanchor_urb(urb, anchor);
184 spin_unlock_irqrestore(&anchor->lock, flags);
185}
186EXPORT_SYMBOL_GPL(usb_unanchor_urb);
187
188/*-------------------------------------------------------------------*/
189
190static const int pipetypes[4] = {
191 PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT
192};
193
194/**
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
198 *
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.
202 */
203int usb_pipe_type_check(struct usb_device *dev, unsigned int pipe)
204{
205 const struct usb_host_endpoint *ep;
206
207 ep = usb_pipe_endpoint(dev, pipe);
208 if (!ep)
209 return -EINVAL;
210 if (usb_pipetype(pipe) != pipetypes[usb_endpoint_type(&ep->desc)])
211 return -EINVAL;
212 return 0;
213}
214EXPORT_SYMBOL_GPL(usb_pipe_type_check);
215
216/**
217 * usb_urb_ep_type_check - sanity check of endpoint in the given urb
218 * @urb: urb to be checked
219 *
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.
223 */
224int usb_urb_ep_type_check(const struct urb *urb)
225{
226 return usb_pipe_type_check(urb->dev, urb->pipe);
227}
228EXPORT_SYMBOL_GPL(usb_urb_ep_type_check);
229
230/**
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.
235 *
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").
241 *
242 * URBs may be submitted in interrupt context.
243 *
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.
249 *
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
255 * URB.
256 *
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.
265 *
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
282 * -EXDEV error code.
283 *
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.
289 *
290 * Return:
291 * 0 on successful submissions. A negative error number otherwise.
292 *
293 * Request Queuing:
294 *
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.
303 *
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).
308 *
309 * Reserved Bandwidth Transfers:
310 *
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.
316 *
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
321 * constraints.
322 *
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.
330 *
331 * Memory Flags:
332 *
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
336 * GFP_ATOMIC.
337 *
338 * GFP_NOFS is not ever used, as it has not been implemented yet.
339 *
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
344 * semaphores), or
345 * (c) current->state != TASK_RUNNING, this is the case only after
346 * you've changed it.
347 *
348 * GFP_NOIO is used in the block io path and error handling of storage
349 * devices.
350 *
351 * All other situations use GFP_KERNEL.
352 *
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
365 *
366 */
367int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
368{
369 int xfertype, max;
370 struct usb_device *dev;
371 struct usb_host_endpoint *ep;
372 int is_out;
373 unsigned int allowed;
374
375 if (!urb || !urb->complete)
376 return -EINVAL;
377 if (urb->hcpriv) {
378 WARN_ONCE(1, "URB %pK submitted while active\n", urb);
379 return -EBUSY;
380 }
381
382 dev = urb->dev;
383 if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED))
384 return -ENODEV;
385
386 /* For now, get the endpoint from the pipe. Eventually drivers
387 * will be required to set urb->ep directly and we will eliminate
388 * urb->pipe.
389 */
390 ep = usb_pipe_endpoint(dev, urb->pipe);
391 if (!ep)
392 return -ENOENT;
393
394 urb->ep = ep;
395 urb->status = -EINPROGRESS;
396 urb->actual_length = 0;
397
398 /* Lots of sanity checks, so HCDs can rely on clean data
399 * and don't need to duplicate tests
400 */
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;
405
406 if (!setup)
407 return -ENOEXEC;
408 is_out = !(setup->bRequestType & USB_DIR_IN) ||
409 !setup->wLength;
410 dev_WARN_ONCE(&dev->dev, (usb_pipeout(urb->pipe) != is_out),
411 "BOGUS control dir, pipe %x doesn't match bRequestType %x\n",
412 urb->pipe, setup->bRequestType);
413 if (le16_to_cpu(setup->wLength) != urb->transfer_buffer_length) {
414 dev_dbg(&dev->dev, "BOGUS control len %d doesn't match transfer length %d\n",
415 le16_to_cpu(setup->wLength),
416 urb->transfer_buffer_length);
417 return -EBADR;
418 }
419 } else {
420 is_out = usb_endpoint_dir_out(&ep->desc);
421 }
422
423 /* Clear the internal flags and cache the direction for later use */
424 urb->transfer_flags &= ~(URB_DIR_MASK | URB_DMA_MAP_SINGLE |
425 URB_DMA_MAP_PAGE | URB_DMA_MAP_SG | URB_MAP_LOCAL |
426 URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL |
427 URB_DMA_SG_COMBINED);
428 urb->transfer_flags |= (is_out ? URB_DIR_OUT : URB_DIR_IN);
429
430 if (xfertype != USB_ENDPOINT_XFER_CONTROL &&
431 dev->state < USB_STATE_CONFIGURED)
432 return -ENODEV;
433
434 max = usb_endpoint_maxp(&ep->desc);
435 if (max <= 0) {
436 dev_dbg(&dev->dev,
437 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
438 usb_endpoint_num(&ep->desc), is_out ? "out" : "in",
439 __func__, max);
440 return -EMSGSIZE;
441 }
442
443 /* periodic transfers limit size per frame/uframe,
444 * but drivers only control those sizes for ISO.
445 * while we're checking, initialize return status.
446 */
447 if (xfertype == USB_ENDPOINT_XFER_ISOC) {
448 int n, len;
449
450 /* SuperSpeed isoc endpoints have up to 16 bursts of up to
451 * 3 packets each
452 */
453 if (dev->speed >= USB_SPEED_SUPER) {
454 int burst = 1 + ep->ss_ep_comp.bMaxBurst;
455 int mult = USB_SS_MULT(ep->ss_ep_comp.bmAttributes);
456 max *= burst;
457 max *= mult;
458 }
459
460 if (dev->speed == USB_SPEED_SUPER_PLUS &&
461 USB_SS_SSP_ISOC_COMP(ep->ss_ep_comp.bmAttributes)) {
462 struct usb_ssp_isoc_ep_comp_descriptor *isoc_ep_comp;
463
464 isoc_ep_comp = &ep->ssp_isoc_ep_comp;
465 max = le32_to_cpu(isoc_ep_comp->dwBytesPerInterval);
466 }
467
468 /* "high bandwidth" mode, 1-3 packets/uframe? */
469 if (dev->speed == USB_SPEED_HIGH)
470 max *= usb_endpoint_maxp_mult(&ep->desc);
471
472 if (urb->number_of_packets <= 0)
473 return -EINVAL;
474 for (n = 0; n < urb->number_of_packets; n++) {
475 len = urb->iso_frame_desc[n].length;
476 if (len < 0 || len > max)
477 return -EMSGSIZE;
478 urb->iso_frame_desc[n].status = -EXDEV;
479 urb->iso_frame_desc[n].actual_length = 0;
480 }
481 } else if (urb->num_sgs && !urb->dev->bus->no_sg_constraint &&
482 dev->speed != USB_SPEED_WIRELESS) {
483 struct scatterlist *sg;
484 int i;
485
486 for_each_sg(urb->sg, sg, urb->num_sgs - 1, i)
487 if (sg->length % max)
488 return -EINVAL;
489 }
490
491 /* the I/O buffer must be mapped/unmapped, except when length=0 */
492 if (urb->transfer_buffer_length > INT_MAX)
493 return -EMSGSIZE;
494
495 /*
496 * stuff that drivers shouldn't do, but which shouldn't
497 * cause problems in HCDs if they get it wrong.
498 */
499
500 /* Check that the pipe's type matches the endpoint's type */
501 if (usb_pipe_type_check(urb->dev, urb->pipe))
502 dev_WARN(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n",
503 usb_pipetype(urb->pipe), pipetypes[xfertype]);
504
505 /* Check against a simple/standard policy */
506 allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT | URB_DIR_MASK |
507 URB_FREE_BUFFER);
508 switch (xfertype) {
509 case USB_ENDPOINT_XFER_BULK:
510 case USB_ENDPOINT_XFER_INT:
511 if (is_out)
512 allowed |= URB_ZERO_PACKET;
513 fallthrough;
514 default: /* all non-iso endpoints */
515 if (!is_out)
516 allowed |= URB_SHORT_NOT_OK;
517 break;
518 case USB_ENDPOINT_XFER_ISOC:
519 allowed |= URB_ISO_ASAP;
520 break;
521 }
522 allowed &= urb->transfer_flags;
523
524 /* warn if submitter gave bogus flags */
525 if (allowed != urb->transfer_flags)
526 dev_WARN(&dev->dev, "BOGUS urb flags, %x --> %x\n",
527 urb->transfer_flags, allowed);
528
529 /*
530 * Force periodic transfer intervals to be legal values that are
531 * a power of two (so HCDs don't need to).
532 *
533 * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC
534 * supports different values... this uses EHCI/UHCI defaults (and
535 * EHCI can use smaller non-default values).
536 */
537 switch (xfertype) {
538 case USB_ENDPOINT_XFER_ISOC:
539 case USB_ENDPOINT_XFER_INT:
540 /* too small? */
541 switch (dev->speed) {
542 case USB_SPEED_WIRELESS:
543 if ((urb->interval < 6)
544 && (xfertype == USB_ENDPOINT_XFER_INT))
545 return -EINVAL;
546 fallthrough;
547 default:
548 if (urb->interval <= 0)
549 return -EINVAL;
550 break;
551 }
552 /* too big? */
553 switch (dev->speed) {
554 case USB_SPEED_SUPER_PLUS:
555 case USB_SPEED_SUPER: /* units are 125us */
556 /* Handle up to 2^(16-1) microframes */
557 if (urb->interval > (1 << 15))
558 return -EINVAL;
559 max = 1 << 15;
560 break;
561 case USB_SPEED_WIRELESS:
562 if (urb->interval > 16)
563 return -EINVAL;
564 break;
565 case USB_SPEED_HIGH: /* units are microframes */
566 /* NOTE usb handles 2^15 */
567 if (urb->interval > (1024 * 8))
568 urb->interval = 1024 * 8;
569 max = 1024 * 8;
570 break;
571 case USB_SPEED_FULL: /* units are frames/msec */
572 case USB_SPEED_LOW:
573 if (xfertype == USB_ENDPOINT_XFER_INT) {
574 if (urb->interval > 255)
575 return -EINVAL;
576 /* NOTE ohci only handles up to 32 */
577 max = 128;
578 } else {
579 if (urb->interval > 1024)
580 urb->interval = 1024;
581 /* NOTE usb and ohci handle up to 2^15 */
582 max = 1024;
583 }
584 break;
585 default:
586 return -EINVAL;
587 }
588 if (dev->speed != USB_SPEED_WIRELESS) {
589 /* Round down to a power of 2, no more than max */
590 urb->interval = min(max, 1 << ilog2(urb->interval));
591 }
592 }
593
594 return usb_hcd_submit_urb(urb, mem_flags);
595}
596EXPORT_SYMBOL_GPL(usb_submit_urb);
597
598/*-------------------------------------------------------------------*/
599
600/**
601 * usb_unlink_urb - abort/cancel a transfer request for an endpoint
602 * @urb: pointer to urb describing a previously submitted request,
603 * may be NULL
604 *
605 * This routine cancels an in-progress request. URBs complete only once
606 * per submission, and may be canceled only once per submission.
607 * Successful cancellation means termination of @urb will be expedited
608 * and the completion handler will be called with a status code
609 * indicating that the request has been canceled (rather than any other
610 * code).
611 *
612 * Drivers should not call this routine or related routines, such as
613 * usb_kill_urb() or usb_unlink_anchored_urbs(), after their disconnect
614 * method has returned. The disconnect function should synchronize with
615 * a driver's I/O routines to insure that all URB-related activity has
616 * completed before it returns.
617 *
618 * This request is asynchronous, however the HCD might call the ->complete()
619 * callback during unlink. Therefore when drivers call usb_unlink_urb(), they
620 * must not hold any locks that may be taken by the completion function.
621 * Success is indicated by returning -EINPROGRESS, at which time the URB will
622 * probably not yet have been given back to the device driver. When it is
623 * eventually called, the completion function will see @urb->status ==
624 * -ECONNRESET.
625 * Failure is indicated by usb_unlink_urb() returning any other value.
626 * Unlinking will fail when @urb is not currently "linked" (i.e., it was
627 * never submitted, or it was unlinked before, or the hardware is already
628 * finished with it), even if the completion handler has not yet run.
629 *
630 * The URB must not be deallocated while this routine is running. In
631 * particular, when a driver calls this routine, it must insure that the
632 * completion handler cannot deallocate the URB.
633 *
634 * Return: -EINPROGRESS on success. See description for other values on
635 * failure.
636 *
637 * Unlinking and Endpoint Queues:
638 *
639 * [The behaviors and guarantees described below do not apply to virtual
640 * root hubs but only to endpoint queues for physical USB devices.]
641 *
642 * Host Controller Drivers (HCDs) place all the URBs for a particular
643 * endpoint in a queue. Normally the queue advances as the controller
644 * hardware processes each request. But when an URB terminates with an
645 * error its queue generally stops (see below), at least until that URB's
646 * completion routine returns. It is guaranteed that a stopped queue
647 * will not restart until all its unlinked URBs have been fully retired,
648 * with their completion routines run, even if that's not until some time
649 * after the original completion handler returns. The same behavior and
650 * guarantee apply when an URB terminates because it was unlinked.
651 *
652 * Bulk and interrupt endpoint queues are guaranteed to stop whenever an
653 * URB terminates with any sort of error, including -ECONNRESET, -ENOENT,
654 * and -EREMOTEIO. Control endpoint queues behave the same way except
655 * that they are not guaranteed to stop for -EREMOTEIO errors. Queues
656 * for isochronous endpoints are treated differently, because they must
657 * advance at fixed rates. Such queues do not stop when an URB
658 * encounters an error or is unlinked. An unlinked isochronous URB may
659 * leave a gap in the stream of packets; it is undefined whether such
660 * gaps can be filled in.
661 *
662 * Note that early termination of an URB because a short packet was
663 * received will generate a -EREMOTEIO error if and only if the
664 * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device
665 * drivers can build deep queues for large or complex bulk transfers
666 * and clean them up reliably after any sort of aborted transfer by
667 * unlinking all pending URBs at the first fault.
668 *
669 * When a control URB terminates with an error other than -EREMOTEIO, it
670 * is quite likely that the status stage of the transfer will not take
671 * place.
672 */
673int usb_unlink_urb(struct urb *urb)
674{
675 if (!urb)
676 return -EINVAL;
677 if (!urb->dev)
678 return -ENODEV;
679 if (!urb->ep)
680 return -EIDRM;
681 return usb_hcd_unlink_urb(urb, -ECONNRESET);
682}
683EXPORT_SYMBOL_GPL(usb_unlink_urb);
684
685/**
686 * usb_kill_urb - cancel a transfer request and wait for it to finish
687 * @urb: pointer to URB describing a previously submitted request,
688 * may be NULL
689 *
690 * This routine cancels an in-progress request. It is guaranteed that
691 * upon return all completion handlers will have finished and the URB
692 * will be totally idle and available for reuse. These features make
693 * this an ideal way to stop I/O in a disconnect() callback or close()
694 * function. If the request has not already finished or been unlinked
695 * the completion handler will see urb->status == -ENOENT.
696 *
697 * While the routine is running, attempts to resubmit the URB will fail
698 * with error -EPERM. Thus even if the URB's completion handler always
699 * tries to resubmit, it will not succeed and the URB will become idle.
700 *
701 * The URB must not be deallocated while this routine is running. In
702 * particular, when a driver calls this routine, it must insure that the
703 * completion handler cannot deallocate the URB.
704 *
705 * This routine may not be used in an interrupt context (such as a bottom
706 * half or a completion handler), or when holding a spinlock, or in other
707 * situations where the caller can't schedule().
708 *
709 * This routine should not be called by a driver after its disconnect
710 * method has returned.
711 */
712void usb_kill_urb(struct urb *urb)
713{
714 might_sleep();
715 if (!(urb && urb->dev && urb->ep))
716 return;
717 atomic_inc(&urb->reject);
718
719 usb_hcd_unlink_urb(urb, -ENOENT);
720 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
721
722 atomic_dec(&urb->reject);
723}
724EXPORT_SYMBOL_GPL(usb_kill_urb);
725
726/**
727 * usb_poison_urb - reliably kill a transfer and prevent further use of an URB
728 * @urb: pointer to URB describing a previously submitted request,
729 * may be NULL
730 *
731 * This routine cancels an in-progress request. It is guaranteed that
732 * upon return all completion handlers will have finished and the URB
733 * will be totally idle and cannot be reused. These features make
734 * this an ideal way to stop I/O in a disconnect() callback.
735 * If the request has not already finished or been unlinked
736 * the completion handler will see urb->status == -ENOENT.
737 *
738 * After and while the routine runs, attempts to resubmit the URB will fail
739 * with error -EPERM. Thus even if the URB's completion handler always
740 * tries to resubmit, it will not succeed and the URB will become idle.
741 *
742 * The URB must not be deallocated while this routine is running. In
743 * particular, when a driver calls this routine, it must insure that the
744 * completion handler cannot deallocate the URB.
745 *
746 * This routine may not be used in an interrupt context (such as a bottom
747 * half or a completion handler), or when holding a spinlock, or in other
748 * situations where the caller can't schedule().
749 *
750 * This routine should not be called by a driver after its disconnect
751 * method has returned.
752 */
753void usb_poison_urb(struct urb *urb)
754{
755 might_sleep();
756 if (!urb)
757 return;
758 atomic_inc(&urb->reject);
759
760 if (!urb->dev || !urb->ep)
761 return;
762
763 usb_hcd_unlink_urb(urb, -ENOENT);
764 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
765}
766EXPORT_SYMBOL_GPL(usb_poison_urb);
767
768void usb_unpoison_urb(struct urb *urb)
769{
770 if (!urb)
771 return;
772
773 atomic_dec(&urb->reject);
774}
775EXPORT_SYMBOL_GPL(usb_unpoison_urb);
776
777/**
778 * usb_block_urb - reliably prevent further use of an URB
779 * @urb: pointer to URB to be blocked, may be NULL
780 *
781 * After the routine has run, attempts to resubmit the URB will fail
782 * with error -EPERM. Thus even if the URB's completion handler always
783 * tries to resubmit, it will not succeed and the URB will become idle.
784 *
785 * The URB must not be deallocated while this routine is running. In
786 * particular, when a driver calls this routine, it must insure that the
787 * completion handler cannot deallocate the URB.
788 */
789void usb_block_urb(struct urb *urb)
790{
791 if (!urb)
792 return;
793
794 atomic_inc(&urb->reject);
795}
796EXPORT_SYMBOL_GPL(usb_block_urb);
797
798/**
799 * usb_kill_anchored_urbs - kill all URBs associated with an anchor
800 * @anchor: anchor the requests are bound to
801 *
802 * This kills all outstanding URBs starting from the back of the queue,
803 * with guarantee that no completer callbacks will take place from the
804 * anchor after this function returns.
805 *
806 * This routine should not be called by a driver after its disconnect
807 * method has returned.
808 */
809void usb_kill_anchored_urbs(struct usb_anchor *anchor)
810{
811 struct urb *victim;
812 int surely_empty;
813
814 do {
815 spin_lock_irq(&anchor->lock);
816 while (!list_empty(&anchor->urb_list)) {
817 victim = list_entry(anchor->urb_list.prev,
818 struct urb, anchor_list);
819 /* make sure the URB isn't freed before we kill it */
820 usb_get_urb(victim);
821 spin_unlock_irq(&anchor->lock);
822 /* this will unanchor the URB */
823 usb_kill_urb(victim);
824 usb_put_urb(victim);
825 spin_lock_irq(&anchor->lock);
826 }
827 surely_empty = usb_anchor_check_wakeup(anchor);
828
829 spin_unlock_irq(&anchor->lock);
830 cpu_relax();
831 } while (!surely_empty);
832}
833EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs);
834
835
836/**
837 * usb_poison_anchored_urbs - cease all traffic from an anchor
838 * @anchor: anchor the requests are bound to
839 *
840 * this allows all outstanding URBs to be poisoned starting
841 * from the back of the queue. Newly added URBs will also be
842 * poisoned
843 *
844 * This routine should not be called by a driver after its disconnect
845 * method has returned.
846 */
847void usb_poison_anchored_urbs(struct usb_anchor *anchor)
848{
849 struct urb *victim;
850 int surely_empty;
851
852 do {
853 spin_lock_irq(&anchor->lock);
854 anchor->poisoned = 1;
855 while (!list_empty(&anchor->urb_list)) {
856 victim = list_entry(anchor->urb_list.prev,
857 struct urb, anchor_list);
858 /* make sure the URB isn't freed before we kill it */
859 usb_get_urb(victim);
860 spin_unlock_irq(&anchor->lock);
861 /* this will unanchor the URB */
862 usb_poison_urb(victim);
863 usb_put_urb(victim);
864 spin_lock_irq(&anchor->lock);
865 }
866 surely_empty = usb_anchor_check_wakeup(anchor);
867
868 spin_unlock_irq(&anchor->lock);
869 cpu_relax();
870 } while (!surely_empty);
871}
872EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs);
873
874/**
875 * usb_unpoison_anchored_urbs - let an anchor be used successfully again
876 * @anchor: anchor the requests are bound to
877 *
878 * Reverses the effect of usb_poison_anchored_urbs
879 * the anchor can be used normally after it returns
880 */
881void usb_unpoison_anchored_urbs(struct usb_anchor *anchor)
882{
883 unsigned long flags;
884 struct urb *lazarus;
885
886 spin_lock_irqsave(&anchor->lock, flags);
887 list_for_each_entry(lazarus, &anchor->urb_list, anchor_list) {
888 usb_unpoison_urb(lazarus);
889 }
890 anchor->poisoned = 0;
891 spin_unlock_irqrestore(&anchor->lock, flags);
892}
893EXPORT_SYMBOL_GPL(usb_unpoison_anchored_urbs);
894/**
895 * usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse
896 * @anchor: anchor the requests are bound to
897 *
898 * this allows all outstanding URBs to be unlinked starting
899 * from the back of the queue. This function is asynchronous.
900 * The unlinking is just triggered. It may happen after this
901 * function has returned.
902 *
903 * This routine should not be called by a driver after its disconnect
904 * method has returned.
905 */
906void usb_unlink_anchored_urbs(struct usb_anchor *anchor)
907{
908 struct urb *victim;
909
910 while ((victim = usb_get_from_anchor(anchor)) != NULL) {
911 usb_unlink_urb(victim);
912 usb_put_urb(victim);
913 }
914}
915EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs);
916
917/**
918 * usb_anchor_suspend_wakeups
919 * @anchor: the anchor you want to suspend wakeups on
920 *
921 * Call this to stop the last urb being unanchored from waking up any
922 * usb_wait_anchor_empty_timeout waiters. This is used in the hcd urb give-
923 * back path to delay waking up until after the completion handler has run.
924 */
925void usb_anchor_suspend_wakeups(struct usb_anchor *anchor)
926{
927 if (anchor)
928 atomic_inc(&anchor->suspend_wakeups);
929}
930EXPORT_SYMBOL_GPL(usb_anchor_suspend_wakeups);
931
932/**
933 * usb_anchor_resume_wakeups
934 * @anchor: the anchor you want to resume wakeups on
935 *
936 * Allow usb_wait_anchor_empty_timeout waiters to be woken up again, and
937 * wake up any current waiters if the anchor is empty.
938 */
939void usb_anchor_resume_wakeups(struct usb_anchor *anchor)
940{
941 if (!anchor)
942 return;
943
944 atomic_dec(&anchor->suspend_wakeups);
945 if (usb_anchor_check_wakeup(anchor))
946 wake_up(&anchor->wait);
947}
948EXPORT_SYMBOL_GPL(usb_anchor_resume_wakeups);
949
950/**
951 * usb_wait_anchor_empty_timeout - wait for an anchor to be unused
952 * @anchor: the anchor you want to become unused
953 * @timeout: how long you are willing to wait in milliseconds
954 *
955 * Call this is you want to be sure all an anchor's
956 * URBs have finished
957 *
958 * Return: Non-zero if the anchor became unused. Zero on timeout.
959 */
960int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,
961 unsigned int timeout)
962{
963 return wait_event_timeout(anchor->wait,
964 usb_anchor_check_wakeup(anchor),
965 msecs_to_jiffies(timeout));
966}
967EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout);
968
969/**
970 * usb_get_from_anchor - get an anchor's oldest urb
971 * @anchor: the anchor whose urb you want
972 *
973 * This will take the oldest urb from an anchor,
974 * unanchor and return it
975 *
976 * Return: The oldest urb from @anchor, or %NULL if @anchor has no
977 * urbs associated with it.
978 */
979struct urb *usb_get_from_anchor(struct usb_anchor *anchor)
980{
981 struct urb *victim;
982 unsigned long flags;
983
984 spin_lock_irqsave(&anchor->lock, flags);
985 if (!list_empty(&anchor->urb_list)) {
986 victim = list_entry(anchor->urb_list.next, struct urb,
987 anchor_list);
988 usb_get_urb(victim);
989 __usb_unanchor_urb(victim, anchor);
990 } else {
991 victim = NULL;
992 }
993 spin_unlock_irqrestore(&anchor->lock, flags);
994
995 return victim;
996}
997
998EXPORT_SYMBOL_GPL(usb_get_from_anchor);
999
1000/**
1001 * usb_scuttle_anchored_urbs - unanchor all an anchor's urbs
1002 * @anchor: the anchor whose urbs you want to unanchor
1003 *
1004 * use this to get rid of all an anchor's urbs
1005 */
1006void usb_scuttle_anchored_urbs(struct usb_anchor *anchor)
1007{
1008 struct urb *victim;
1009 unsigned long flags;
1010 int surely_empty;
1011
1012 do {
1013 spin_lock_irqsave(&anchor->lock, flags);
1014 while (!list_empty(&anchor->urb_list)) {
1015 victim = list_entry(anchor->urb_list.prev,
1016 struct urb, anchor_list);
1017 __usb_unanchor_urb(victim, anchor);
1018 }
1019 surely_empty = usb_anchor_check_wakeup(anchor);
1020
1021 spin_unlock_irqrestore(&anchor->lock, flags);
1022 cpu_relax();
1023 } while (!surely_empty);
1024}
1025
1026EXPORT_SYMBOL_GPL(usb_scuttle_anchored_urbs);
1027
1028/**
1029 * usb_anchor_empty - is an anchor empty
1030 * @anchor: the anchor you want to query
1031 *
1032 * Return: 1 if the anchor has no urbs associated with it.
1033 */
1034int usb_anchor_empty(struct usb_anchor *anchor)
1035{
1036 return list_empty(&anchor->urb_list);
1037}
1038
1039EXPORT_SYMBOL_GPL(usb_anchor_empty);
1040