blob: ff53acb4fab2ac895be1b58e0e6a93bd66ee33af [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001#include <linux/module.h>
2#include <linux/string.h>
3#include <linux/bitops.h>
4#include <linux/slab.h>
5#include <linux/init.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07006#include <linux/usb.h>
Oliver Neukum51a2f072007-05-25 13:40:56 +02007#include <linux/wait.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008#include "hcd.h"
9
10#define to_urb(d) container_of(d, struct urb, kref)
11
12static void urb_destroy(struct kref *kref)
13{
14 struct urb *urb = to_urb(kref);
Oliver Neukum51a2f072007-05-25 13:40:56 +020015
Marcel Holtmann8b3b01c2007-06-13 08:02:11 +020016 if (urb->transfer_flags & URB_FREE_BUFFER)
17 kfree(urb->transfer_buffer);
18
Linus Torvalds1da177e2005-04-16 15:20:36 -070019 kfree(urb);
20}
21
22/**
23 * usb_init_urb - initializes a urb so that it can be used by a USB driver
24 * @urb: pointer to the urb to initialize
25 *
26 * Initializes a urb so that the USB subsystem can use it properly.
27 *
28 * If a urb is created with a call to usb_alloc_urb() it is not
29 * necessary to call this function. Only use this if you allocate the
30 * space for a struct urb on your own. If you call this function, be
31 * careful when freeing the memory for your urb that it is no longer in
32 * use by the USB core.
33 *
34 * Only use this function if you _really_ understand what you are doing.
35 */
36void usb_init_urb(struct urb *urb)
37{
38 if (urb) {
39 memset(urb, 0, sizeof(*urb));
40 kref_init(&urb->kref);
41 spin_lock_init(&urb->lock);
Oliver Neukum51a2f072007-05-25 13:40:56 +020042 INIT_LIST_HEAD(&urb->anchor_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 }
44}
45
46/**
47 * usb_alloc_urb - creates a new urb for a USB driver to use
48 * @iso_packets: number of iso packets for this urb
49 * @mem_flags: the type of memory to allocate, see kmalloc() for a list of
50 * valid options for this.
51 *
52 * Creates an urb for the USB driver to use, initializes a few internal
53 * structures, incrementes the usage counter, and returns a pointer to it.
54 *
55 * If no memory is available, NULL is returned.
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 */
Al Viro55016f12005-10-21 03:21:58 -040062struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -070063{
64 struct urb *urb;
65
Tobias Klauserec17cf12006-09-13 21:38:41 +020066 urb = kmalloc(sizeof(struct urb) +
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 iso_packets * sizeof(struct usb_iso_packet_descriptor),
68 mem_flags);
69 if (!urb) {
70 err("alloc_urb: kmalloc failed");
71 return NULL;
72 }
73 usb_init_urb(urb);
74 return urb;
75}
76
77/**
78 * usb_free_urb - frees the memory used by a urb when all users of it are finished
79 * @urb: pointer to the urb to free, may be NULL
80 *
81 * Must be called when a user of a urb is finished with it. When the last user
82 * of the urb calls this function, the memory of the urb is freed.
83 *
84 * Note: The transfer buffer associated with the urb is not freed, that must be
85 * done elsewhere.
86 */
87void usb_free_urb(struct urb *urb)
88{
89 if (urb)
90 kref_put(&urb->kref, urb_destroy);
91}
92
93/**
94 * usb_get_urb - increments the reference count of the urb
95 * @urb: pointer to the urb to modify, may be NULL
96 *
97 * This must be called whenever a urb is transferred from a device driver to a
98 * host controller driver. This allows proper reference counting to happen
99 * for urbs.
100 *
101 * A pointer to the urb with the incremented reference counter is returned.
102 */
103struct urb * usb_get_urb(struct urb *urb)
104{
105 if (urb)
106 kref_get(&urb->kref);
107 return urb;
108}
Oliver Neukum51a2f072007-05-25 13:40:56 +0200109
110/**
111 * usb_anchor_urb - anchors an URB while it is processed
112 * @urb: pointer to the urb to anchor
113 * @anchor: pointer to the anchor
114 *
115 * This can be called to have access to URBs which are to be executed
116 * without bothering to track them
117 */
118void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor)
119{
120 unsigned long flags;
121
122 spin_lock_irqsave(&anchor->lock, flags);
123 usb_get_urb(urb);
124 list_add_tail(&urb->anchor_list, &anchor->urb_list);
125 urb->anchor = anchor;
126 spin_unlock_irqrestore(&anchor->lock, flags);
127}
128EXPORT_SYMBOL_GPL(usb_anchor_urb);
129
130/**
131 * usb_unanchor_urb - unanchors an URB
132 * @urb: pointer to the urb to anchor
133 *
134 * Call this to stop the system keeping track of this URB
135 */
136void usb_unanchor_urb(struct urb *urb)
137{
138 unsigned long flags;
139 struct usb_anchor *anchor;
140
141 if (!urb)
142 return;
143
144 anchor = urb->anchor;
145 if (!anchor)
146 return;
147
148 spin_lock_irqsave(&anchor->lock, flags);
149 if (unlikely(anchor != urb->anchor)) {
150 /* we've lost the race to another thread */
151 spin_unlock_irqrestore(&anchor->lock, flags);
152 return;
153 }
154 urb->anchor = NULL;
155 list_del(&urb->anchor_list);
156 spin_unlock_irqrestore(&anchor->lock, flags);
157 usb_put_urb(urb);
158 if (list_empty(&anchor->urb_list))
159 wake_up(&anchor->wait);
160}
161EXPORT_SYMBOL_GPL(usb_unanchor_urb);
162
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163/*-------------------------------------------------------------------*/
164
165/**
166 * usb_submit_urb - issue an asynchronous transfer request for an endpoint
167 * @urb: pointer to the urb describing the request
168 * @mem_flags: the type of memory to allocate, see kmalloc() for a list
169 * of valid options for this.
170 *
171 * This submits a transfer request, and transfers control of the URB
172 * describing that request to the USB subsystem. Request completion will
173 * be indicated later, asynchronously, by calling the completion handler.
174 * The three types of completion are success, error, and unlink
Steven Cole093cf722005-05-03 19:07:24 -0600175 * (a software-induced fault, also called "request cancellation").
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 *
177 * URBs may be submitted in interrupt context.
178 *
179 * The caller must have correctly initialized the URB before submitting
180 * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are
181 * available to ensure that most fields are correctly initialized, for
182 * the particular kind of transfer, although they will not initialize
183 * any transfer flags.
184 *
185 * Successful submissions return 0; otherwise this routine returns a
186 * negative error number. If the submission is successful, the complete()
187 * callback from the URB will be called exactly once, when the USB core and
188 * Host Controller Driver (HCD) are finished with the URB. When the completion
189 * function is called, control of the URB is returned to the device
190 * driver which issued the request. The completion handler may then
191 * immediately free or reuse that URB.
192 *
193 * With few exceptions, USB device drivers should never access URB fields
194 * provided by usbcore or the HCD until its complete() is called.
195 * The exceptions relate to periodic transfer scheduling. For both
196 * interrupt and isochronous urbs, as part of successful URB submission
197 * urb->interval is modified to reflect the actual transfer period used
198 * (normally some power of two units). And for isochronous urbs,
199 * urb->start_frame is modified to reflect when the URB's transfers were
200 * scheduled to start. Not all isochronous transfer scheduling policies
201 * will work, but most host controller drivers should easily handle ISO
202 * queues going from now until 10-200 msec into the future.
203 *
204 * For control endpoints, the synchronous usb_control_msg() call is
205 * often used (in non-interrupt context) instead of this call.
206 * That is often used through convenience wrappers, for the requests
207 * that are standardized in the USB 2.0 specification. For bulk
208 * endpoints, a synchronous usb_bulk_msg() call is available.
209 *
210 * Request Queuing:
211 *
212 * URBs may be submitted to endpoints before previous ones complete, to
213 * minimize the impact of interrupt latencies and system overhead on data
214 * throughput. With that queuing policy, an endpoint's queue would never
215 * be empty. This is required for continuous isochronous data streams,
216 * and may also be required for some kinds of interrupt transfers. Such
217 * queuing also maximizes bandwidth utilization by letting USB controllers
218 * start work on later requests before driver software has finished the
219 * completion processing for earlier (successful) requests.
220 *
221 * As of Linux 2.6, all USB endpoint transfer queues support depths greater
222 * than one. This was previously a HCD-specific behavior, except for ISO
223 * transfers. Non-isochronous endpoint queues are inactive during cleanup
Steven Cole093cf722005-05-03 19:07:24 -0600224 * after faults (transfer errors or cancellation).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 *
226 * Reserved Bandwidth Transfers:
227 *
228 * Periodic transfers (interrupt or isochronous) are performed repeatedly,
229 * using the interval specified in the urb. Submitting the first urb to
230 * the endpoint reserves the bandwidth necessary to make those transfers.
231 * If the USB subsystem can't allocate sufficient bandwidth to perform
232 * the periodic request, submitting such a periodic request should fail.
233 *
234 * Device drivers must explicitly request that repetition, by ensuring that
235 * some URB is always on the endpoint's queue (except possibly for short
236 * periods during completion callacks). When there is no longer an urb
237 * queued, the endpoint's bandwidth reservation is canceled. This means
238 * drivers can use their completion handlers to ensure they keep bandwidth
239 * they need, by reinitializing and resubmitting the just-completed urb
240 * until the driver longer needs that periodic bandwidth.
241 *
242 * Memory Flags:
243 *
244 * The general rules for how to decide which mem_flags to use
245 * are the same as for kmalloc. There are four
246 * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and
247 * GFP_ATOMIC.
248 *
249 * GFP_NOFS is not ever used, as it has not been implemented yet.
250 *
251 * GFP_ATOMIC is used when
252 * (a) you are inside a completion handler, an interrupt, bottom half,
253 * tasklet or timer, or
254 * (b) you are holding a spinlock or rwlock (does not apply to
255 * semaphores), or
256 * (c) current->state != TASK_RUNNING, this is the case only after
257 * you've changed it.
258 *
259 * GFP_NOIO is used in the block io path and error handling of storage
260 * devices.
261 *
262 * All other situations use GFP_KERNEL.
263 *
264 * Some more specific rules for mem_flags can be inferred, such as
265 * (1) start_xmit, timeout, and receive methods of network drivers must
266 * use GFP_ATOMIC (they are called with a spinlock held);
267 * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also
268 * called with a spinlock held);
269 * (3) If you use a kernel thread with a network driver you must use
270 * GFP_NOIO, unless (b) or (c) apply;
271 * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)
272 * apply or your are in a storage driver's block io path;
273 * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and
274 * (6) changing firmware on a running storage or net device uses
275 * GFP_NOIO, unless b) or c) apply
276 *
277 */
Al Viro55016f12005-10-21 03:21:58 -0400278int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279{
Alan Stern5b653c72007-07-30 17:04:37 -0400280 int xfertype, max;
281 struct usb_device *dev;
282 struct usb_host_endpoint *ep;
283 int is_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284
285 if (!urb || urb->hcpriv || !urb->complete)
286 return -EINVAL;
287 if (!(dev = urb->dev) ||
288 (dev->state < USB_STATE_DEFAULT) ||
289 (!dev->bus) || (dev->devnum <= 0))
290 return -ENODEV;
David Brownellb13296c2005-09-27 10:38:54 -0700291 if (dev->bus->controller->power.power_state.event != PM_EVENT_ON
292 || dev->state == USB_STATE_SUSPENDED)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 return -EHOSTUNREACH;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294
Alan Stern5b653c72007-07-30 17:04:37 -0400295 /* For now, get the endpoint from the pipe. Eventually drivers
296 * will be required to set urb->ep directly and we will eliminate
297 * urb->pipe.
298 */
299 ep = (usb_pipein(urb->pipe) ? dev->ep_in : dev->ep_out)
300 [usb_pipeendpoint(urb->pipe)];
301 if (!ep)
302 return -ENOENT;
303
304 urb->ep = ep;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 urb->status = -EINPROGRESS;
306 urb->actual_length = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307
308 /* Lots of sanity checks, so HCDs can rely on clean data
309 * and don't need to duplicate tests
310 */
Alan Stern5b653c72007-07-30 17:04:37 -0400311 xfertype = usb_endpoint_type(&ep->desc);
312 is_out = usb_pipeout(urb->pipe);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313
Alan Stern5b653c72007-07-30 17:04:37 -0400314 if (xfertype != USB_ENDPOINT_XFER_CONTROL &&
315 dev->state < USB_STATE_CONFIGURED)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 return -ENODEV;
317
Alan Stern5b653c72007-07-30 17:04:37 -0400318 max = le16_to_cpu(ep->desc.wMaxPacketSize);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 if (max <= 0) {
320 dev_dbg(&dev->dev,
321 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
Alan Stern5b653c72007-07-30 17:04:37 -0400322 usb_endpoint_num(&ep->desc), is_out ? "out" : "in",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 __FUNCTION__, max);
324 return -EMSGSIZE;
325 }
326
327 /* periodic transfers limit size per frame/uframe,
328 * but drivers only control those sizes for ISO.
329 * while we're checking, initialize return status.
330 */
Alan Stern5b653c72007-07-30 17:04:37 -0400331 if (xfertype == USB_ENDPOINT_XFER_ISOC) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332 int n, len;
333
334 /* "high bandwidth" mode, 1-3 packets/uframe? */
335 if (dev->speed == USB_SPEED_HIGH) {
336 int mult = 1 + ((max >> 11) & 0x03);
337 max &= 0x07ff;
338 max *= mult;
339 }
340
341 if (urb->number_of_packets <= 0)
342 return -EINVAL;
343 for (n = 0; n < urb->number_of_packets; n++) {
Oliver Neukum92516442007-01-23 15:55:28 -0500344 len = urb->iso_frame_desc[n].length;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 if (len < 0 || len > max)
346 return -EMSGSIZE;
Oliver Neukum92516442007-01-23 15:55:28 -0500347 urb->iso_frame_desc[n].status = -EXDEV;
348 urb->iso_frame_desc[n].actual_length = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 }
350 }
351
352 /* the I/O buffer must be mapped/unmapped, except when length=0 */
353 if (urb->transfer_buffer_length < 0)
354 return -EMSGSIZE;
355
356#ifdef DEBUG
357 /* stuff that drivers shouldn't do, but which shouldn't
358 * cause problems in HCDs if they get it wrong.
359 */
360 {
361 unsigned int orig_flags = urb->transfer_flags;
362 unsigned int allowed;
363
364 /* enforce simple/standard policy */
Alan Sternb375a042005-07-29 16:11:07 -0400365 allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_SETUP_DMA_MAP |
366 URB_NO_INTERRUPT);
Alan Stern5b653c72007-07-30 17:04:37 -0400367 switch (xfertype) {
368 case USB_ENDPOINT_XFER_BULK:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 if (is_out)
370 allowed |= URB_ZERO_PACKET;
371 /* FALLTHROUGH */
Alan Stern5b653c72007-07-30 17:04:37 -0400372 case USB_ENDPOINT_XFER_CONTROL:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 allowed |= URB_NO_FSBR; /* only affects UHCI */
374 /* FALLTHROUGH */
375 default: /* all non-iso endpoints */
376 if (!is_out)
377 allowed |= URB_SHORT_NOT_OK;
378 break;
Alan Stern5b653c72007-07-30 17:04:37 -0400379 case USB_ENDPOINT_XFER_ISOC:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 allowed |= URB_ISO_ASAP;
381 break;
382 }
383 urb->transfer_flags &= allowed;
384
385 /* fail if submitter gave bogus flags */
386 if (urb->transfer_flags != orig_flags) {
Oliver Neukum92516442007-01-23 15:55:28 -0500387 err("BOGUS urb flags, %x --> %x",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 orig_flags, urb->transfer_flags);
389 return -EINVAL;
390 }
391 }
392#endif
393 /*
394 * Force periodic transfer intervals to be legal values that are
395 * a power of two (so HCDs don't need to).
396 *
397 * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC
398 * supports different values... this uses EHCI/UHCI defaults (and
399 * EHCI can use smaller non-default values).
400 */
Alan Stern5b653c72007-07-30 17:04:37 -0400401 switch (xfertype) {
402 case USB_ENDPOINT_XFER_ISOC:
403 case USB_ENDPOINT_XFER_INT:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 /* too small? */
405 if (urb->interval <= 0)
406 return -EINVAL;
407 /* too big? */
408 switch (dev->speed) {
409 case USB_SPEED_HIGH: /* units are microframes */
410 // NOTE usb handles 2^15
411 if (urb->interval > (1024 * 8))
412 urb->interval = 1024 * 8;
Alan Stern5b653c72007-07-30 17:04:37 -0400413 max = 1024 * 8;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 break;
415 case USB_SPEED_FULL: /* units are frames/msec */
416 case USB_SPEED_LOW:
Alan Stern5b653c72007-07-30 17:04:37 -0400417 if (xfertype == USB_ENDPOINT_XFER_INT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 if (urb->interval > 255)
419 return -EINVAL;
420 // NOTE ohci only handles up to 32
Alan Stern5b653c72007-07-30 17:04:37 -0400421 max = 128;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 } else {
423 if (urb->interval > 1024)
424 urb->interval = 1024;
425 // NOTE usb and ohci handle up to 2^15
Alan Stern5b653c72007-07-30 17:04:37 -0400426 max = 1024;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 }
428 break;
429 default:
430 return -EINVAL;
431 }
432 /* power of two? */
Alan Stern5b653c72007-07-30 17:04:37 -0400433 while (max > urb->interval)
434 max >>= 1;
435 urb->interval = max;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 }
437
Oliver Neukum92516442007-01-23 15:55:28 -0500438 return usb_hcd_submit_urb(urb, mem_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439}
440
441/*-------------------------------------------------------------------*/
442
443/**
444 * usb_unlink_urb - abort/cancel a transfer request for an endpoint
445 * @urb: pointer to urb describing a previously submitted request,
446 * may be NULL
447 *
Alan Sternbeafef02007-07-13 15:47:16 -0400448 * This routine cancels an in-progress request. URBs complete only once
449 * per submission, and may be canceled only once per submission.
450 * Successful cancellation means termination of @urb will be expedited
451 * and the completion handler will be called with a status code
452 * indicating that the request has been canceled (rather than any other
453 * code).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 *
Alan Sternbeafef02007-07-13 15:47:16 -0400455 * This request is always asynchronous. Success is indicated by
456 * returning -EINPROGRESS, at which time the URB will probably not yet
457 * have been given back to the device driver. When it is eventually
458 * called, the completion function will see @urb->status == -ECONNRESET.
459 * Failure is indicated by usb_unlink_urb() returning any other value.
460 * Unlinking will fail when @urb is not currently "linked" (i.e., it was
461 * never submitted, or it was unlinked before, or the hardware is already
462 * finished with it), even if the completion handler has not yet run.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 *
464 * Unlinking and Endpoint Queues:
465 *
Alan Sternbeafef02007-07-13 15:47:16 -0400466 * [The behaviors and guarantees described below do not apply to virtual
467 * root hubs but only to endpoint queues for physical USB devices.]
468 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 * Host Controller Drivers (HCDs) place all the URBs for a particular
470 * endpoint in a queue. Normally the queue advances as the controller
Alan Stern8835f662005-04-18 17:39:30 -0700471 * hardware processes each request. But when an URB terminates with an
Alan Sternbeafef02007-07-13 15:47:16 -0400472 * error its queue generally stops (see below), at least until that URB's
473 * completion routine returns. It is guaranteed that a stopped queue
474 * will not restart until all its unlinked URBs have been fully retired,
475 * with their completion routines run, even if that's not until some time
476 * after the original completion handler returns. The same behavior and
477 * guarantee apply when an URB terminates because it was unlinked.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 *
Alan Sternbeafef02007-07-13 15:47:16 -0400479 * Bulk and interrupt endpoint queues are guaranteed to stop whenever an
480 * URB terminates with any sort of error, including -ECONNRESET, -ENOENT,
481 * and -EREMOTEIO. Control endpoint queues behave the same way except
482 * that they are not guaranteed to stop for -EREMOTEIO errors. Queues
483 * for isochronous endpoints are treated differently, because they must
484 * advance at fixed rates. Such queues do not stop when an URB
485 * encounters an error or is unlinked. An unlinked isochronous URB may
486 * leave a gap in the stream of packets; it is undefined whether such
487 * gaps can be filled in.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 *
Alan Sternbeafef02007-07-13 15:47:16 -0400489 * Note that early termination of an URB because a short packet was
490 * received will generate a -EREMOTEIO error if and only if the
491 * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device
492 * drivers can build deep queues for large or complex bulk transfers
493 * and clean them up reliably after any sort of aborted transfer by
494 * unlinking all pending URBs at the first fault.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 *
Alan Sternbeafef02007-07-13 15:47:16 -0400496 * When a control URB terminates with an error other than -EREMOTEIO, it
497 * is quite likely that the status stage of the transfer will not take
498 * place.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 */
500int usb_unlink_urb(struct urb *urb)
501{
502 if (!urb)
503 return -EINVAL;
Alan Sterna6d2bb92006-08-30 11:27:36 -0400504 if (!(urb->dev && urb->dev->bus))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 return -ENODEV;
Alan Sterna6d2bb92006-08-30 11:27:36 -0400506 return usb_hcd_unlink_urb(urb, -ECONNRESET);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507}
508
509/**
510 * usb_kill_urb - cancel a transfer request and wait for it to finish
511 * @urb: pointer to URB describing a previously submitted request,
512 * may be NULL
513 *
514 * This routine cancels an in-progress request. It is guaranteed that
515 * upon return all completion handlers will have finished and the URB
516 * will be totally idle and available for reuse. These features make
517 * this an ideal way to stop I/O in a disconnect() callback or close()
518 * function. If the request has not already finished or been unlinked
519 * the completion handler will see urb->status == -ENOENT.
520 *
521 * While the routine is running, attempts to resubmit the URB will fail
522 * with error -EPERM. Thus even if the URB's completion handler always
523 * tries to resubmit, it will not succeed and the URB will become idle.
524 *
525 * This routine may not be used in an interrupt context (such as a bottom
526 * half or a completion handler), or when holding a spinlock, or in other
527 * situations where the caller can't schedule().
528 */
529void usb_kill_urb(struct urb *urb)
530{
Greg Kroah-Hartmane9aa7952006-01-23 17:17:21 -0500531 might_sleep();
Alan Sterna6d2bb92006-08-30 11:27:36 -0400532 if (!(urb && urb->dev && urb->dev->bus))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 return;
534 spin_lock_irq(&urb->lock);
535 ++urb->reject;
536 spin_unlock_irq(&urb->lock);
537
Alan Sterna6d2bb92006-08-30 11:27:36 -0400538 usb_hcd_unlink_urb(urb, -ENOENT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
540
541 spin_lock_irq(&urb->lock);
542 --urb->reject;
543 spin_unlock_irq(&urb->lock);
544}
545
Oliver Neukum51a2f072007-05-25 13:40:56 +0200546/**
547 * usb_kill_anchored_urbs - cancel transfer requests en masse
548 * @anchor: anchor the requests are bound to
549 *
550 * this allows all outstanding URBs to be killed starting
551 * from the back of the queue
552 */
553void usb_kill_anchored_urbs(struct usb_anchor *anchor)
554{
555 struct urb *victim;
556
557 spin_lock_irq(&anchor->lock);
558 while (!list_empty(&anchor->urb_list)) {
559 victim = list_entry(anchor->urb_list.prev, struct urb, anchor_list);
560 /* we must make sure the URB isn't freed before we kill it*/
561 usb_get_urb(victim);
562 spin_unlock_irq(&anchor->lock);
563 /* this will unanchor the URB */
564 usb_kill_urb(victim);
565 usb_put_urb(victim);
566 spin_lock_irq(&anchor->lock);
567 }
568 spin_unlock_irq(&anchor->lock);
569}
570EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs);
571
572/**
573 * usb_wait_anchor_empty_timeout - wait for an anchor to be unused
574 * @anchor: the anchor you want to become unused
575 * @timeout: how long you are willing to wait in milliseconds
576 *
577 * Call this is you want to be sure all an anchor's
578 * URBs have finished
579 */
580int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,
581 unsigned int timeout)
582{
583 return wait_event_timeout(anchor->wait, list_empty(&anchor->urb_list),
584 msecs_to_jiffies(timeout));
585}
586EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout);
587
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588EXPORT_SYMBOL(usb_init_urb);
589EXPORT_SYMBOL(usb_alloc_urb);
590EXPORT_SYMBOL(usb_free_urb);
591EXPORT_SYMBOL(usb_get_urb);
592EXPORT_SYMBOL(usb_submit_urb);
593EXPORT_SYMBOL(usb_unlink_urb);
594EXPORT_SYMBOL(usb_kill_urb);