1 #include <linux/module.h>
2 #include <linux/string.h>
3 #include <linux/bitops.h>
4 #include <linux/slab.h>
5 #include <linux/init.h>
6 #include <linux/log2.h>
8 #include <linux/wait.h>
9 #include <linux/usb/hcd.h>
11 #define to_urb(d) container_of(d, struct urb, kref)
14 static void urb_destroy(struct kref
*kref
)
16 struct urb
*urb
= to_urb(kref
);
18 if (urb
->transfer_flags
& URB_FREE_BUFFER
)
19 kfree(urb
->transfer_buffer
);
25 * usb_init_urb - initializes a urb so that it can be used by a USB driver
26 * @urb: pointer to the urb to initialize
28 * Initializes a urb so that the USB subsystem can use it properly.
30 * If a urb is created with a call to usb_alloc_urb() it is not
31 * necessary to call this function. Only use this if you allocate the
32 * space for a struct urb on your own. If you call this function, be
33 * careful when freeing the memory for your urb that it is no longer in
34 * use by the USB core.
36 * Only use this function if you _really_ understand what you are doing.
38 void usb_init_urb(struct urb
*urb
)
41 memset(urb
, 0, sizeof(*urb
));
42 kref_init(&urb
->kref
);
43 INIT_LIST_HEAD(&urb
->anchor_list
);
46 EXPORT_SYMBOL_GPL(usb_init_urb
);
49 * usb_alloc_urb - creates a new urb for a USB driver to use
50 * @iso_packets: number of iso packets for this urb
51 * @mem_flags: the type of memory to allocate, see kmalloc() for a list of
52 * valid options for this.
54 * Creates an urb for the USB driver to use, initializes a few internal
55 * structures, incrementes the usage counter, and returns a pointer to it.
57 * If no memory is available, NULL is returned.
59 * If the driver want to use this urb for interrupt, control, or bulk
60 * endpoints, pass '0' as the number of iso packets.
62 * The driver must call usb_free_urb() when it is finished with the urb.
64 struct urb
*usb_alloc_urb(int iso_packets
, gfp_t mem_flags
)
68 urb
= kmalloc(sizeof(struct urb
) +
69 iso_packets
* sizeof(struct usb_iso_packet_descriptor
),
72 printk(KERN_ERR
"alloc_urb: kmalloc failed\n");
78 EXPORT_SYMBOL_GPL(usb_alloc_urb
);
81 * usb_free_urb - frees the memory used by a urb when all users of it are finished
82 * @urb: pointer to the urb to free, may be NULL
84 * Must be called when a user of a urb is finished with it. When the last user
85 * of the urb calls this function, the memory of the urb is freed.
87 * Note: The transfer buffer associated with the urb is not freed unless the
88 * URB_FREE_BUFFER transfer flag is set.
90 void usb_free_urb(struct urb
*urb
)
93 kref_put(&urb
->kref
, urb_destroy
);
95 EXPORT_SYMBOL_GPL(usb_free_urb
);
98 * usb_get_urb - increments the reference count of the urb
99 * @urb: pointer to the urb to modify, may be NULL
101 * This must be called whenever a urb is transferred from a device driver to a
102 * host controller driver. This allows proper reference counting to happen
105 * A pointer to the urb with the incremented reference counter is returned.
107 struct urb
*usb_get_urb(struct urb
*urb
)
110 kref_get(&urb
->kref
);
113 EXPORT_SYMBOL_GPL(usb_get_urb
);
116 * usb_anchor_urb - anchors an URB while it is processed
117 * @urb: pointer to the urb to anchor
118 * @anchor: pointer to the anchor
120 * This can be called to have access to URBs which are to be executed
121 * without bothering to track them
123 void usb_anchor_urb(struct urb
*urb
, struct usb_anchor
*anchor
)
127 spin_lock_irqsave(&anchor
->lock
, flags
);
129 list_add_tail(&urb
->anchor_list
, &anchor
->urb_list
);
130 urb
->anchor
= anchor
;
132 if (unlikely(anchor
->poisoned
)) {
133 atomic_inc(&urb
->reject
);
136 spin_unlock_irqrestore(&anchor
->lock
, flags
);
138 EXPORT_SYMBOL_GPL(usb_anchor_urb
);
140 /* Callers must hold anchor->lock */
141 static void __usb_unanchor_urb(struct urb
*urb
, struct usb_anchor
*anchor
)
144 list_del(&urb
->anchor_list
);
146 if (list_empty(&anchor
->urb_list
))
147 wake_up(&anchor
->wait
);
151 * usb_unanchor_urb - unanchors an URB
152 * @urb: pointer to the urb to anchor
154 * Call this to stop the system keeping track of this URB
156 void usb_unanchor_urb(struct urb
*urb
)
159 struct usb_anchor
*anchor
;
164 anchor
= urb
->anchor
;
168 spin_lock_irqsave(&anchor
->lock
, flags
);
170 * At this point, we could be competing with another thread which
171 * has the same intention. To protect the urb from being unanchored
172 * twice, only the winner of the race gets the job.
174 if (likely(anchor
== urb
->anchor
))
175 __usb_unanchor_urb(urb
, anchor
);
176 spin_unlock_irqrestore(&anchor
->lock
, flags
);
178 EXPORT_SYMBOL_GPL(usb_unanchor_urb
);
180 /*-------------------------------------------------------------------*/
183 * usb_submit_urb - issue an asynchronous transfer request for an endpoint
184 * @urb: pointer to the urb describing the request
185 * @mem_flags: the type of memory to allocate, see kmalloc() for a list
186 * of valid options for this.
188 * This submits a transfer request, and transfers control of the URB
189 * describing that request to the USB subsystem. Request completion will
190 * be indicated later, asynchronously, by calling the completion handler.
191 * The three types of completion are success, error, and unlink
192 * (a software-induced fault, also called "request cancellation").
194 * URBs may be submitted in interrupt context.
196 * The caller must have correctly initialized the URB before submitting
197 * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are
198 * available to ensure that most fields are correctly initialized, for
199 * the particular kind of transfer, although they will not initialize
200 * any transfer flags.
202 * Successful submissions return 0; otherwise this routine returns a
203 * negative error number. If the submission is successful, the complete()
204 * callback from the URB will be called exactly once, when the USB core and
205 * Host Controller Driver (HCD) are finished with the URB. When the completion
206 * function is called, control of the URB is returned to the device
207 * driver which issued the request. The completion handler may then
208 * immediately free or reuse that URB.
210 * With few exceptions, USB device drivers should never access URB fields
211 * provided by usbcore or the HCD until its complete() is called.
212 * The exceptions relate to periodic transfer scheduling. For both
213 * interrupt and isochronous urbs, as part of successful URB submission
214 * urb->interval is modified to reflect the actual transfer period used
215 * (normally some power of two units). And for isochronous urbs,
216 * urb->start_frame is modified to reflect when the URB's transfers were
217 * scheduled to start.
219 * Not all isochronous transfer scheduling policies will work, but most
220 * host controller drivers should easily handle ISO queues going from now
221 * until 10-200 msec into the future. Drivers should try to keep at
222 * least one or two msec of data in the queue; many controllers require
223 * that new transfers start at least 1 msec in the future when they are
224 * added. If the driver is unable to keep up and the queue empties out,
225 * the behavior for new submissions is governed by the URB_ISO_ASAP flag.
226 * If the flag is set, or if the queue is idle, then the URB is always
227 * assigned to the first available (and not yet expired) slot in the
228 * endpoint's schedule. If the flag is not set and the queue is active
229 * then the URB is always assigned to the next slot in the schedule
230 * following the end of the endpoint's previous URB, even if that slot is
231 * in the past. When a packet is assigned in this way to a slot that has
232 * already expired, the packet is not transmitted and the corresponding
233 * usb_iso_packet_descriptor's status field will return -EXDEV. If this
234 * would happen to all the packets in the URB, submission fails with a
237 * For control endpoints, the synchronous usb_control_msg() call is
238 * often used (in non-interrupt context) instead of this call.
239 * That is often used through convenience wrappers, for the requests
240 * that are standardized in the USB 2.0 specification. For bulk
241 * endpoints, a synchronous usb_bulk_msg() call is available.
245 * URBs may be submitted to endpoints before previous ones complete, to
246 * minimize the impact of interrupt latencies and system overhead on data
247 * throughput. With that queuing policy, an endpoint's queue would never
248 * be empty. This is required for continuous isochronous data streams,
249 * and may also be required for some kinds of interrupt transfers. Such
250 * queuing also maximizes bandwidth utilization by letting USB controllers
251 * start work on later requests before driver software has finished the
252 * completion processing for earlier (successful) requests.
254 * As of Linux 2.6, all USB endpoint transfer queues support depths greater
255 * than one. This was previously a HCD-specific behavior, except for ISO
256 * transfers. Non-isochronous endpoint queues are inactive during cleanup
257 * after faults (transfer errors or cancellation).
259 * Reserved Bandwidth Transfers:
261 * Periodic transfers (interrupt or isochronous) are performed repeatedly,
262 * using the interval specified in the urb. Submitting the first urb to
263 * the endpoint reserves the bandwidth necessary to make those transfers.
264 * If the USB subsystem can't allocate sufficient bandwidth to perform
265 * the periodic request, submitting such a periodic request should fail.
267 * For devices under xHCI, the bandwidth is reserved at configuration time, or
268 * when the alt setting is selected. If there is not enough bus bandwidth, the
269 * configuration/alt setting request will fail. Therefore, submissions to
270 * periodic endpoints on devices under xHCI should never fail due to bandwidth
273 * Device drivers must explicitly request that repetition, by ensuring that
274 * some URB is always on the endpoint's queue (except possibly for short
275 * periods during completion callacks). When there is no longer an urb
276 * queued, the endpoint's bandwidth reservation is canceled. This means
277 * drivers can use their completion handlers to ensure they keep bandwidth
278 * they need, by reinitializing and resubmitting the just-completed urb
279 * until the driver longer needs that periodic bandwidth.
283 * The general rules for how to decide which mem_flags to use
284 * are the same as for kmalloc. There are four
285 * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and
288 * GFP_NOFS is not ever used, as it has not been implemented yet.
290 * GFP_ATOMIC is used when
291 * (a) you are inside a completion handler, an interrupt, bottom half,
292 * tasklet or timer, or
293 * (b) you are holding a spinlock or rwlock (does not apply to
295 * (c) current->state != TASK_RUNNING, this is the case only after
298 * GFP_NOIO is used in the block io path and error handling of storage
301 * All other situations use GFP_KERNEL.
303 * Some more specific rules for mem_flags can be inferred, such as
304 * (1) start_xmit, timeout, and receive methods of network drivers must
305 * use GFP_ATOMIC (they are called with a spinlock held);
306 * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also
307 * called with a spinlock held);
308 * (3) If you use a kernel thread with a network driver you must use
309 * GFP_NOIO, unless (b) or (c) apply;
310 * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)
311 * apply or your are in a storage driver's block io path;
312 * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and
313 * (6) changing firmware on a running storage or net device uses
314 * GFP_NOIO, unless b) or c) apply
317 int usb_submit_urb(struct urb
*urb
, gfp_t mem_flags
)
320 struct usb_device
*dev
;
321 struct usb_host_endpoint
*ep
;
324 if (!urb
|| !urb
->complete
)
327 WARN_ONCE(1, "URB %p submitted while active\n", urb
);
332 if ((!dev
) || (dev
->state
< USB_STATE_UNAUTHENTICATED
))
335 /* For now, get the endpoint from the pipe. Eventually drivers
336 * will be required to set urb->ep directly and we will eliminate
339 ep
= usb_pipe_endpoint(dev
, urb
->pipe
);
344 urb
->status
= -EINPROGRESS
;
345 urb
->actual_length
= 0;
347 /* Lots of sanity checks, so HCDs can rely on clean data
348 * and don't need to duplicate tests
350 xfertype
= usb_endpoint_type(&ep
->desc
);
351 if (xfertype
== USB_ENDPOINT_XFER_CONTROL
) {
352 struct usb_ctrlrequest
*setup
=
353 (struct usb_ctrlrequest
*) urb
->setup_packet
;
357 is_out
= !(setup
->bRequestType
& USB_DIR_IN
) ||
360 is_out
= usb_endpoint_dir_out(&ep
->desc
);
363 /* Clear the internal flags and cache the direction for later use */
364 urb
->transfer_flags
&= ~(URB_DIR_MASK
| URB_DMA_MAP_SINGLE
|
365 URB_DMA_MAP_PAGE
| URB_DMA_MAP_SG
| URB_MAP_LOCAL
|
366 URB_SETUP_MAP_SINGLE
| URB_SETUP_MAP_LOCAL
|
367 URB_DMA_SG_COMBINED
);
368 urb
->transfer_flags
|= (is_out
? URB_DIR_OUT
: URB_DIR_IN
);
370 if (xfertype
!= USB_ENDPOINT_XFER_CONTROL
&&
371 dev
->state
< USB_STATE_CONFIGURED
)
374 max
= usb_endpoint_maxp(&ep
->desc
);
377 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
378 usb_endpoint_num(&ep
->desc
), is_out
? "out" : "in",
383 /* periodic transfers limit size per frame/uframe,
384 * but drivers only control those sizes for ISO.
385 * while we're checking, initialize return status.
387 if (xfertype
== USB_ENDPOINT_XFER_ISOC
) {
390 /* SuperSpeed isoc endpoints have up to 16 bursts of up to
393 if (dev
->speed
== USB_SPEED_SUPER
) {
394 int burst
= 1 + ep
->ss_ep_comp
.bMaxBurst
;
395 int mult
= USB_SS_MULT(ep
->ss_ep_comp
.bmAttributes
);
400 /* "high bandwidth" mode, 1-3 packets/uframe? */
401 if (dev
->speed
== USB_SPEED_HIGH
) {
402 int mult
= 1 + ((max
>> 11) & 0x03);
407 if (urb
->number_of_packets
<= 0)
409 for (n
= 0; n
< urb
->number_of_packets
; n
++) {
410 len
= urb
->iso_frame_desc
[n
].length
;
411 if (len
< 0 || len
> max
)
413 urb
->iso_frame_desc
[n
].status
= -EXDEV
;
414 urb
->iso_frame_desc
[n
].actual_length
= 0;
418 /* the I/O buffer must be mapped/unmapped, except when length=0 */
419 if (urb
->transfer_buffer_length
> INT_MAX
)
423 /* stuff that drivers shouldn't do, but which shouldn't
424 * cause problems in HCDs if they get it wrong.
427 unsigned int allowed
;
428 static int pipetypes
[4] = {
429 PIPE_CONTROL
, PIPE_ISOCHRONOUS
, PIPE_BULK
, PIPE_INTERRUPT
432 /* Check that the pipe's type matches the endpoint's type */
433 if (usb_pipetype(urb
->pipe
) != pipetypes
[xfertype
])
434 dev_WARN(&dev
->dev
, "BOGUS urb xfer, pipe %x != type %x\n",
435 usb_pipetype(urb
->pipe
), pipetypes
[xfertype
]);
437 /* Check against a simple/standard policy */
438 allowed
= (URB_NO_TRANSFER_DMA_MAP
| URB_NO_INTERRUPT
| URB_DIR_MASK
|
441 case USB_ENDPOINT_XFER_BULK
:
443 allowed
|= URB_ZERO_PACKET
;
445 case USB_ENDPOINT_XFER_CONTROL
:
446 allowed
|= URB_NO_FSBR
; /* only affects UHCI */
448 default: /* all non-iso endpoints */
450 allowed
|= URB_SHORT_NOT_OK
;
452 case USB_ENDPOINT_XFER_ISOC
:
453 allowed
|= URB_ISO_ASAP
;
456 allowed
&= urb
->transfer_flags
;
458 /* warn if submitter gave bogus flags */
459 if (allowed
!= urb
->transfer_flags
)
460 dev_WARN(&dev
->dev
, "BOGUS urb flags, %x --> %x\n",
461 urb
->transfer_flags
, allowed
);
465 * Force periodic transfer intervals to be legal values that are
466 * a power of two (so HCDs don't need to).
468 * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC
469 * supports different values... this uses EHCI/UHCI defaults (and
470 * EHCI can use smaller non-default values).
473 case USB_ENDPOINT_XFER_ISOC
:
474 case USB_ENDPOINT_XFER_INT
:
476 switch (dev
->speed
) {
477 case USB_SPEED_WIRELESS
:
478 if (urb
->interval
< 6)
482 if (urb
->interval
<= 0)
487 switch (dev
->speed
) {
488 case USB_SPEED_SUPER
: /* units are 125us */
489 /* Handle up to 2^(16-1) microframes */
490 if (urb
->interval
> (1 << 15))
494 case USB_SPEED_WIRELESS
:
495 if (urb
->interval
> 16)
498 case USB_SPEED_HIGH
: /* units are microframes */
499 /* NOTE usb handles 2^15 */
500 if (urb
->interval
> (1024 * 8))
501 urb
->interval
= 1024 * 8;
504 case USB_SPEED_FULL
: /* units are frames/msec */
506 if (xfertype
== USB_ENDPOINT_XFER_INT
) {
507 if (urb
->interval
> 255)
509 /* NOTE ohci only handles up to 32 */
512 if (urb
->interval
> 1024)
513 urb
->interval
= 1024;
514 /* NOTE usb and ohci handle up to 2^15 */
521 if (dev
->speed
!= USB_SPEED_WIRELESS
) {
522 /* Round down to a power of 2, no more than max */
523 urb
->interval
= min(max
, 1 << ilog2(urb
->interval
));
527 return usb_hcd_submit_urb(urb
, mem_flags
);
529 EXPORT_SYMBOL_GPL(usb_submit_urb
);
531 /*-------------------------------------------------------------------*/
534 * usb_unlink_urb - abort/cancel a transfer request for an endpoint
535 * @urb: pointer to urb describing a previously submitted request,
538 * This routine cancels an in-progress request. URBs complete only once
539 * per submission, and may be canceled only once per submission.
540 * Successful cancellation means termination of @urb will be expedited
541 * and the completion handler will be called with a status code
542 * indicating that the request has been canceled (rather than any other
545 * Drivers should not call this routine or related routines, such as
546 * usb_kill_urb() or usb_unlink_anchored_urbs(), after their disconnect
547 * method has returned. The disconnect function should synchronize with
548 * a driver's I/O routines to insure that all URB-related activity has
549 * completed before it returns.
551 * This request is asynchronous, however the HCD might call the ->complete()
552 * callback during unlink. Therefore when drivers call usb_unlink_urb(), they
553 * must not hold any locks that may be taken by the completion function.
554 * Success is indicated by returning -EINPROGRESS, at which time the URB will
555 * probably not yet have been given back to the device driver. When it is
556 * eventually called, the completion function will see @urb->status ==
558 * Failure is indicated by usb_unlink_urb() returning any other value.
559 * Unlinking will fail when @urb is not currently "linked" (i.e., it was
560 * never submitted, or it was unlinked before, or the hardware is already
561 * finished with it), even if the completion handler has not yet run.
563 * The URB must not be deallocated while this routine is running. In
564 * particular, when a driver calls this routine, it must insure that the
565 * completion handler cannot deallocate the URB.
567 * Unlinking and Endpoint Queues:
569 * [The behaviors and guarantees described below do not apply to virtual
570 * root hubs but only to endpoint queues for physical USB devices.]
572 * Host Controller Drivers (HCDs) place all the URBs for a particular
573 * endpoint in a queue. Normally the queue advances as the controller
574 * hardware processes each request. But when an URB terminates with an
575 * error its queue generally stops (see below), at least until that URB's
576 * completion routine returns. It is guaranteed that a stopped queue
577 * will not restart until all its unlinked URBs have been fully retired,
578 * with their completion routines run, even if that's not until some time
579 * after the original completion handler returns. The same behavior and
580 * guarantee apply when an URB terminates because it was unlinked.
582 * Bulk and interrupt endpoint queues are guaranteed to stop whenever an
583 * URB terminates with any sort of error, including -ECONNRESET, -ENOENT,
584 * and -EREMOTEIO. Control endpoint queues behave the same way except
585 * that they are not guaranteed to stop for -EREMOTEIO errors. Queues
586 * for isochronous endpoints are treated differently, because they must
587 * advance at fixed rates. Such queues do not stop when an URB
588 * encounters an error or is unlinked. An unlinked isochronous URB may
589 * leave a gap in the stream of packets; it is undefined whether such
590 * gaps can be filled in.
592 * Note that early termination of an URB because a short packet was
593 * received will generate a -EREMOTEIO error if and only if the
594 * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device
595 * drivers can build deep queues for large or complex bulk transfers
596 * and clean them up reliably after any sort of aborted transfer by
597 * unlinking all pending URBs at the first fault.
599 * When a control URB terminates with an error other than -EREMOTEIO, it
600 * is quite likely that the status stage of the transfer will not take
603 int usb_unlink_urb(struct urb
*urb
)
611 return usb_hcd_unlink_urb(urb
, -ECONNRESET
);
613 EXPORT_SYMBOL_GPL(usb_unlink_urb
);
616 * usb_kill_urb - cancel a transfer request and wait for it to finish
617 * @urb: pointer to URB describing a previously submitted request,
620 * This routine cancels an in-progress request. It is guaranteed that
621 * upon return all completion handlers will have finished and the URB
622 * will be totally idle and available for reuse. These features make
623 * this an ideal way to stop I/O in a disconnect() callback or close()
624 * function. If the request has not already finished or been unlinked
625 * the completion handler will see urb->status == -ENOENT.
627 * While the routine is running, attempts to resubmit the URB will fail
628 * with error -EPERM. Thus even if the URB's completion handler always
629 * tries to resubmit, it will not succeed and the URB will become idle.
631 * The URB must not be deallocated while this routine is running. In
632 * particular, when a driver calls this routine, it must insure that the
633 * completion handler cannot deallocate the URB.
635 * This routine may not be used in an interrupt context (such as a bottom
636 * half or a completion handler), or when holding a spinlock, or in other
637 * situations where the caller can't schedule().
639 * This routine should not be called by a driver after its disconnect
640 * method has returned.
642 void usb_kill_urb(struct urb
*urb
)
645 if (!(urb
&& urb
->dev
&& urb
->ep
))
647 atomic_inc(&urb
->reject
);
649 usb_hcd_unlink_urb(urb
, -ENOENT
);
650 wait_event(usb_kill_urb_queue
, atomic_read(&urb
->use_count
) == 0);
652 atomic_dec(&urb
->reject
);
654 EXPORT_SYMBOL_GPL(usb_kill_urb
);
657 * usb_poison_urb - reliably kill a transfer and prevent further use of an URB
658 * @urb: pointer to URB describing a previously submitted request,
661 * This routine cancels an in-progress request. It is guaranteed that
662 * upon return all completion handlers will have finished and the URB
663 * will be totally idle and cannot be reused. These features make
664 * this an ideal way to stop I/O in a disconnect() callback.
665 * If the request has not already finished or been unlinked
666 * the completion handler will see urb->status == -ENOENT.
668 * After and while the routine runs, attempts to resubmit the URB will fail
669 * with error -EPERM. Thus even if the URB's completion handler always
670 * tries to resubmit, it will not succeed and the URB will become idle.
672 * The URB must not be deallocated while this routine is running. In
673 * particular, when a driver calls this routine, it must insure that the
674 * completion handler cannot deallocate the URB.
676 * This routine may not be used in an interrupt context (such as a bottom
677 * half or a completion handler), or when holding a spinlock, or in other
678 * situations where the caller can't schedule().
680 * This routine should not be called by a driver after its disconnect
681 * method has returned.
683 void usb_poison_urb(struct urb
*urb
)
686 if (!(urb
&& urb
->dev
&& urb
->ep
))
688 atomic_inc(&urb
->reject
);
690 usb_hcd_unlink_urb(urb
, -ENOENT
);
691 wait_event(usb_kill_urb_queue
, atomic_read(&urb
->use_count
) == 0);
693 EXPORT_SYMBOL_GPL(usb_poison_urb
);
695 void usb_unpoison_urb(struct urb
*urb
)
700 atomic_dec(&urb
->reject
);
702 EXPORT_SYMBOL_GPL(usb_unpoison_urb
);
705 * usb_block_urb - reliably prevent further use of an URB
706 * @urb: pointer to URB to be blocked, may be NULL
708 * After the routine has run, attempts to resubmit the URB will fail
709 * with error -EPERM. Thus even if the URB's completion handler always
710 * tries to resubmit, it will not succeed and the URB will become idle.
712 * The URB must not be deallocated while this routine is running. In
713 * particular, when a driver calls this routine, it must insure that the
714 * completion handler cannot deallocate the URB.
716 void usb_block_urb(struct urb
*urb
)
721 atomic_inc(&urb
->reject
);
723 EXPORT_SYMBOL_GPL(usb_block_urb
);
726 * usb_kill_anchored_urbs - cancel transfer requests en masse
727 * @anchor: anchor the requests are bound to
729 * this allows all outstanding URBs to be killed starting
730 * from the back of the queue
732 * This routine should not be called by a driver after its disconnect
733 * method has returned.
735 void usb_kill_anchored_urbs(struct usb_anchor
*anchor
)
739 spin_lock_irq(&anchor
->lock
);
740 while (!list_empty(&anchor
->urb_list
)) {
741 victim
= list_entry(anchor
->urb_list
.prev
, struct urb
,
743 /* we must make sure the URB isn't freed before we kill it*/
745 spin_unlock_irq(&anchor
->lock
);
746 /* this will unanchor the URB */
747 usb_kill_urb(victim
);
749 spin_lock_irq(&anchor
->lock
);
751 spin_unlock_irq(&anchor
->lock
);
753 EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs
);
757 * usb_poison_anchored_urbs - cease all traffic from an anchor
758 * @anchor: anchor the requests are bound to
760 * this allows all outstanding URBs to be poisoned starting
761 * from the back of the queue. Newly added URBs will also be
764 * This routine should not be called by a driver after its disconnect
765 * method has returned.
767 void usb_poison_anchored_urbs(struct usb_anchor
*anchor
)
771 spin_lock_irq(&anchor
->lock
);
772 anchor
->poisoned
= 1;
773 while (!list_empty(&anchor
->urb_list
)) {
774 victim
= list_entry(anchor
->urb_list
.prev
, struct urb
,
776 /* we must make sure the URB isn't freed before we kill it*/
778 spin_unlock_irq(&anchor
->lock
);
779 /* this will unanchor the URB */
780 usb_poison_urb(victim
);
782 spin_lock_irq(&anchor
->lock
);
784 spin_unlock_irq(&anchor
->lock
);
786 EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs
);
789 * usb_unpoison_anchored_urbs - let an anchor be used successfully again
790 * @anchor: anchor the requests are bound to
792 * Reverses the effect of usb_poison_anchored_urbs
793 * the anchor can be used normally after it returns
795 void usb_unpoison_anchored_urbs(struct usb_anchor
*anchor
)
800 spin_lock_irqsave(&anchor
->lock
, flags
);
801 list_for_each_entry(lazarus
, &anchor
->urb_list
, anchor_list
) {
802 usb_unpoison_urb(lazarus
);
804 anchor
->poisoned
= 0;
805 spin_unlock_irqrestore(&anchor
->lock
, flags
);
807 EXPORT_SYMBOL_GPL(usb_unpoison_anchored_urbs
);
809 * usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse
810 * @anchor: anchor the requests are bound to
812 * this allows all outstanding URBs to be unlinked starting
813 * from the back of the queue. This function is asynchronous.
814 * The unlinking is just tiggered. It may happen after this
815 * function has returned.
817 * This routine should not be called by a driver after its disconnect
818 * method has returned.
820 void usb_unlink_anchored_urbs(struct usb_anchor
*anchor
)
824 while ((victim
= usb_get_from_anchor(anchor
)) != NULL
) {
825 usb_unlink_urb(victim
);
829 EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs
);
832 * usb_wait_anchor_empty_timeout - wait for an anchor to be unused
833 * @anchor: the anchor you want to become unused
834 * @timeout: how long you are willing to wait in milliseconds
836 * Call this is you want to be sure all an anchor's
839 int usb_wait_anchor_empty_timeout(struct usb_anchor
*anchor
,
840 unsigned int timeout
)
842 return wait_event_timeout(anchor
->wait
, list_empty(&anchor
->urb_list
),
843 msecs_to_jiffies(timeout
));
845 EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout
);
848 * usb_get_from_anchor - get an anchor's oldest urb
849 * @anchor: the anchor whose urb you want
851 * this will take the oldest urb from an anchor,
852 * unanchor and return it
854 struct urb
*usb_get_from_anchor(struct usb_anchor
*anchor
)
859 spin_lock_irqsave(&anchor
->lock
, flags
);
860 if (!list_empty(&anchor
->urb_list
)) {
861 victim
= list_entry(anchor
->urb_list
.next
, struct urb
,
864 __usb_unanchor_urb(victim
, anchor
);
868 spin_unlock_irqrestore(&anchor
->lock
, flags
);
873 EXPORT_SYMBOL_GPL(usb_get_from_anchor
);
876 * usb_scuttle_anchored_urbs - unanchor all an anchor's urbs
877 * @anchor: the anchor whose urbs you want to unanchor
879 * use this to get rid of all an anchor's urbs
881 void usb_scuttle_anchored_urbs(struct usb_anchor
*anchor
)
886 spin_lock_irqsave(&anchor
->lock
, flags
);
887 while (!list_empty(&anchor
->urb_list
)) {
888 victim
= list_entry(anchor
->urb_list
.prev
, struct urb
,
890 __usb_unanchor_urb(victim
, anchor
);
892 spin_unlock_irqrestore(&anchor
->lock
, flags
);
895 EXPORT_SYMBOL_GPL(usb_scuttle_anchored_urbs
);
898 * usb_anchor_empty - is an anchor empty
899 * @anchor: the anchor you want to query
901 * returns 1 if the anchor has no urbs associated with it
903 int usb_anchor_empty(struct usb_anchor
*anchor
)
905 return list_empty(&anchor
->urb_list
);
908 EXPORT_SYMBOL_GPL(usb_anchor_empty
);