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1da177e4 LT |
1 | #include <linux/module.h> |
2 | #include <linux/string.h> | |
3 | #include <linux/bitops.h> | |
4 | #include <linux/slab.h> | |
d617bc83 | 5 | #include <linux/log2.h> |
1da177e4 | 6 | #include <linux/usb.h> |
51a2f077 | 7 | #include <linux/wait.h> |
27729aad | 8 | #include <linux/usb/hcd.h> |
10e232c5 | 9 | #include <linux/scatterlist.h> |
1da177e4 LT |
10 | |
11 | #define to_urb(d) container_of(d, struct urb, kref) | |
12 | ||
6a2839be | 13 | |
1da177e4 LT |
14 | static void urb_destroy(struct kref *kref) |
15 | { | |
16 | struct urb *urb = to_urb(kref); | |
51a2f077 | 17 | |
8b3b01c8 MH |
18 | if (urb->transfer_flags & URB_FREE_BUFFER) |
19 | kfree(urb->transfer_buffer); | |
20 | ||
1da177e4 LT |
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 | */ | |
38 | void usb_init_urb(struct urb *urb) | |
39 | { | |
40 | if (urb) { | |
41 | memset(urb, 0, sizeof(*urb)); | |
42 | kref_init(&urb->kref); | |
51a2f077 | 43 | INIT_LIST_HEAD(&urb->anchor_list); |
1da177e4 LT |
44 | } |
45 | } | |
782e70c6 | 46 | EXPORT_SYMBOL_GPL(usb_init_urb); |
1da177e4 LT |
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 | |
025d4430 | 55 | * structures, increments the usage counter, and returns a pointer to it. |
1da177e4 | 56 | * |
1da177e4 LT |
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. | |
626f090c YB |
61 | * |
62 | * Return: A pointer to the new urb, or %NULL if no memory is available. | |
1da177e4 | 63 | */ |
55016f10 | 64 | struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags) |
1da177e4 LT |
65 | { |
66 | struct urb *urb; | |
67 | ||
ec17cf1c | 68 | urb = kmalloc(sizeof(struct urb) + |
1da177e4 LT |
69 | iso_packets * sizeof(struct usb_iso_packet_descriptor), |
70 | mem_flags); | |
b62a7a99 | 71 | if (!urb) |
1da177e4 | 72 | return NULL; |
1da177e4 LT |
73 | usb_init_urb(urb); |
74 | return urb; | |
75 | } | |
782e70c6 | 76 | EXPORT_SYMBOL_GPL(usb_alloc_urb); |
1da177e4 LT |
77 | |
78 | /** | |
79 | * usb_free_urb - frees the memory used by a urb when all users of it are finished | |
80 | * @urb: pointer to the urb to free, may be NULL | |
81 | * | |
82 | * Must be called when a user of a urb is finished with it. When the last user | |
83 | * of the urb calls this function, the memory of the urb is freed. | |
84 | * | |
2870fde7 RV |
85 | * Note: The transfer buffer associated with the urb is not freed unless the |
86 | * URB_FREE_BUFFER transfer flag is set. | |
1da177e4 LT |
87 | */ |
88 | void usb_free_urb(struct urb *urb) | |
89 | { | |
90 | if (urb) | |
91 | kref_put(&urb->kref, urb_destroy); | |
92 | } | |
782e70c6 | 93 | EXPORT_SYMBOL_GPL(usb_free_urb); |
1da177e4 LT |
94 | |
95 | /** | |
96 | * usb_get_urb - increments the reference count of the urb | |
97 | * @urb: pointer to the urb to modify, may be NULL | |
98 | * | |
99 | * This must be called whenever a urb is transferred from a device driver to a | |
100 | * host controller driver. This allows proper reference counting to happen | |
101 | * for urbs. | |
102 | * | |
626f090c | 103 | * Return: A pointer to the urb with the incremented reference counter. |
1da177e4 | 104 | */ |
2c044a48 | 105 | struct urb *usb_get_urb(struct urb *urb) |
1da177e4 LT |
106 | { |
107 | if (urb) | |
108 | kref_get(&urb->kref); | |
109 | return urb; | |
110 | } | |
782e70c6 | 111 | EXPORT_SYMBOL_GPL(usb_get_urb); |
51a2f077 ON |
112 | |
113 | /** | |
114 | * usb_anchor_urb - anchors an URB while it is processed | |
115 | * @urb: pointer to the urb to anchor | |
116 | * @anchor: pointer to the anchor | |
117 | * | |
118 | * This can be called to have access to URBs which are to be executed | |
119 | * without bothering to track them | |
120 | */ | |
121 | void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor) | |
122 | { | |
123 | unsigned long flags; | |
124 | ||
125 | spin_lock_irqsave(&anchor->lock, flags); | |
126 | usb_get_urb(urb); | |
127 | list_add_tail(&urb->anchor_list, &anchor->urb_list); | |
128 | urb->anchor = anchor; | |
6a2839be | 129 | |
ae416ba4 | 130 | if (unlikely(anchor->poisoned)) |
49367d8f | 131 | atomic_inc(&urb->reject); |
6a2839be | 132 | |
51a2f077 ON |
133 | spin_unlock_irqrestore(&anchor->lock, flags); |
134 | } | |
135 | EXPORT_SYMBOL_GPL(usb_anchor_urb); | |
136 | ||
6ec4147e HG |
137 | static int usb_anchor_check_wakeup(struct usb_anchor *anchor) |
138 | { | |
139 | return atomic_read(&anchor->suspend_wakeups) == 0 && | |
140 | list_empty(&anchor->urb_list); | |
141 | } | |
142 | ||
b3e67044 CL |
143 | /* Callers must hold anchor->lock */ |
144 | static void __usb_unanchor_urb(struct urb *urb, struct usb_anchor *anchor) | |
145 | { | |
146 | urb->anchor = NULL; | |
147 | list_del(&urb->anchor_list); | |
148 | usb_put_urb(urb); | |
6ec4147e | 149 | if (usb_anchor_check_wakeup(anchor)) |
b3e67044 CL |
150 | wake_up(&anchor->wait); |
151 | } | |
152 | ||
51a2f077 ON |
153 | /** |
154 | * usb_unanchor_urb - unanchors an URB | |
155 | * @urb: pointer to the urb to anchor | |
156 | * | |
157 | * Call this to stop the system keeping track of this URB | |
158 | */ | |
159 | void usb_unanchor_urb(struct urb *urb) | |
160 | { | |
161 | unsigned long flags; | |
162 | struct usb_anchor *anchor; | |
163 | ||
164 | if (!urb) | |
165 | return; | |
166 | ||
167 | anchor = urb->anchor; | |
168 | if (!anchor) | |
169 | return; | |
170 | ||
171 | spin_lock_irqsave(&anchor->lock, flags); | |
b3e67044 CL |
172 | /* |
173 | * At this point, we could be competing with another thread which | |
174 | * has the same intention. To protect the urb from being unanchored | |
175 | * twice, only the winner of the race gets the job. | |
176 | */ | |
177 | if (likely(anchor == urb->anchor)) | |
178 | __usb_unanchor_urb(urb, anchor); | |
51a2f077 | 179 | spin_unlock_irqrestore(&anchor->lock, flags); |
51a2f077 ON |
180 | } |
181 | EXPORT_SYMBOL_GPL(usb_unanchor_urb); | |
182 | ||
1da177e4 LT |
183 | /*-------------------------------------------------------------------*/ |
184 | ||
185 | /** | |
186 | * usb_submit_urb - issue an asynchronous transfer request for an endpoint | |
187 | * @urb: pointer to the urb describing the request | |
188 | * @mem_flags: the type of memory to allocate, see kmalloc() for a list | |
189 | * of valid options for this. | |
190 | * | |
191 | * This submits a transfer request, and transfers control of the URB | |
192 | * describing that request to the USB subsystem. Request completion will | |
193 | * be indicated later, asynchronously, by calling the completion handler. | |
194 | * The three types of completion are success, error, and unlink | |
2c044a48 | 195 | * (a software-induced fault, also called "request cancellation"). |
1da177e4 LT |
196 | * |
197 | * URBs may be submitted in interrupt context. | |
198 | * | |
199 | * The caller must have correctly initialized the URB before submitting | |
200 | * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are | |
201 | * available to ensure that most fields are correctly initialized, for | |
202 | * the particular kind of transfer, although they will not initialize | |
203 | * any transfer flags. | |
204 | * | |
626f090c YB |
205 | * If the submission is successful, the complete() callback from the URB |
206 | * will be called exactly once, when the USB core and Host Controller Driver | |
207 | * (HCD) are finished with the URB. When the completion function is called, | |
208 | * control of the URB is returned to the device driver which issued the | |
209 | * request. The completion handler may then immediately free or reuse that | |
210 | * URB. | |
1da177e4 LT |
211 | * |
212 | * With few exceptions, USB device drivers should never access URB fields | |
213 | * provided by usbcore or the HCD until its complete() is called. | |
214 | * The exceptions relate to periodic transfer scheduling. For both | |
215 | * interrupt and isochronous urbs, as part of successful URB submission | |
216 | * urb->interval is modified to reflect the actual transfer period used | |
217 | * (normally some power of two units). And for isochronous urbs, | |
218 | * urb->start_frame is modified to reflect when the URB's transfers were | |
a03bede5 AS |
219 | * scheduled to start. |
220 | * | |
221 | * Not all isochronous transfer scheduling policies will work, but most | |
222 | * host controller drivers should easily handle ISO queues going from now | |
223 | * until 10-200 msec into the future. Drivers should try to keep at | |
224 | * least one or two msec of data in the queue; many controllers require | |
225 | * that new transfers start at least 1 msec in the future when they are | |
226 | * added. If the driver is unable to keep up and the queue empties out, | |
227 | * the behavior for new submissions is governed by the URB_ISO_ASAP flag. | |
228 | * If the flag is set, or if the queue is idle, then the URB is always | |
229 | * assigned to the first available (and not yet expired) slot in the | |
230 | * endpoint's schedule. If the flag is not set and the queue is active | |
231 | * then the URB is always assigned to the next slot in the schedule | |
232 | * following the end of the endpoint's previous URB, even if that slot is | |
233 | * in the past. When a packet is assigned in this way to a slot that has | |
234 | * already expired, the packet is not transmitted and the corresponding | |
235 | * usb_iso_packet_descriptor's status field will return -EXDEV. If this | |
236 | * would happen to all the packets in the URB, submission fails with a | |
237 | * -EXDEV error code. | |
1da177e4 LT |
238 | * |
239 | * For control endpoints, the synchronous usb_control_msg() call is | |
240 | * often used (in non-interrupt context) instead of this call. | |
241 | * That is often used through convenience wrappers, for the requests | |
242 | * that are standardized in the USB 2.0 specification. For bulk | |
243 | * endpoints, a synchronous usb_bulk_msg() call is available. | |
244 | * | |
626f090c YB |
245 | * Return: |
246 | * 0 on successful submissions. A negative error number otherwise. | |
247 | * | |
1da177e4 LT |
248 | * Request Queuing: |
249 | * | |
250 | * URBs may be submitted to endpoints before previous ones complete, to | |
251 | * minimize the impact of interrupt latencies and system overhead on data | |
252 | * throughput. With that queuing policy, an endpoint's queue would never | |
253 | * be empty. This is required for continuous isochronous data streams, | |
254 | * and may also be required for some kinds of interrupt transfers. Such | |
255 | * queuing also maximizes bandwidth utilization by letting USB controllers | |
256 | * start work on later requests before driver software has finished the | |
257 | * completion processing for earlier (successful) requests. | |
258 | * | |
259 | * As of Linux 2.6, all USB endpoint transfer queues support depths greater | |
260 | * than one. This was previously a HCD-specific behavior, except for ISO | |
261 | * transfers. Non-isochronous endpoint queues are inactive during cleanup | |
093cf723 | 262 | * after faults (transfer errors or cancellation). |
1da177e4 LT |
263 | * |
264 | * Reserved Bandwidth Transfers: | |
265 | * | |
266 | * Periodic transfers (interrupt or isochronous) are performed repeatedly, | |
267 | * using the interval specified in the urb. Submitting the first urb to | |
268 | * the endpoint reserves the bandwidth necessary to make those transfers. | |
269 | * If the USB subsystem can't allocate sufficient bandwidth to perform | |
270 | * the periodic request, submitting such a periodic request should fail. | |
271 | * | |
79abb1ab SS |
272 | * For devices under xHCI, the bandwidth is reserved at configuration time, or |
273 | * when the alt setting is selected. If there is not enough bus bandwidth, the | |
274 | * configuration/alt setting request will fail. Therefore, submissions to | |
275 | * periodic endpoints on devices under xHCI should never fail due to bandwidth | |
276 | * constraints. | |
277 | * | |
1da177e4 LT |
278 | * Device drivers must explicitly request that repetition, by ensuring that |
279 | * some URB is always on the endpoint's queue (except possibly for short | |
025d4430 | 280 | * periods during completion callbacks). When there is no longer an urb |
1da177e4 LT |
281 | * queued, the endpoint's bandwidth reservation is canceled. This means |
282 | * drivers can use their completion handlers to ensure they keep bandwidth | |
283 | * they need, by reinitializing and resubmitting the just-completed urb | |
284 | * until the driver longer needs that periodic bandwidth. | |
285 | * | |
286 | * Memory Flags: | |
287 | * | |
288 | * The general rules for how to decide which mem_flags to use | |
289 | * are the same as for kmalloc. There are four | |
290 | * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and | |
291 | * GFP_ATOMIC. | |
292 | * | |
293 | * GFP_NOFS is not ever used, as it has not been implemented yet. | |
294 | * | |
295 | * GFP_ATOMIC is used when | |
296 | * (a) you are inside a completion handler, an interrupt, bottom half, | |
297 | * tasklet or timer, or | |
298 | * (b) you are holding a spinlock or rwlock (does not apply to | |
299 | * semaphores), or | |
300 | * (c) current->state != TASK_RUNNING, this is the case only after | |
301 | * you've changed it. | |
2c044a48 | 302 | * |
1da177e4 LT |
303 | * GFP_NOIO is used in the block io path and error handling of storage |
304 | * devices. | |
305 | * | |
306 | * All other situations use GFP_KERNEL. | |
307 | * | |
308 | * Some more specific rules for mem_flags can be inferred, such as | |
309 | * (1) start_xmit, timeout, and receive methods of network drivers must | |
310 | * use GFP_ATOMIC (they are called with a spinlock held); | |
311 | * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also | |
312 | * called with a spinlock held); | |
313 | * (3) If you use a kernel thread with a network driver you must use | |
314 | * GFP_NOIO, unless (b) or (c) apply; | |
315 | * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c) | |
316 | * apply or your are in a storage driver's block io path; | |
317 | * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and | |
318 | * (6) changing firmware on a running storage or net device uses | |
319 | * GFP_NOIO, unless b) or c) apply | |
320 | * | |
321 | */ | |
55016f10 | 322 | int usb_submit_urb(struct urb *urb, gfp_t mem_flags) |
1da177e4 | 323 | { |
3482528e GKH |
324 | static int pipetypes[4] = { |
325 | PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT | |
326 | }; | |
5b653c79 AS |
327 | int xfertype, max; |
328 | struct usb_device *dev; | |
329 | struct usb_host_endpoint *ep; | |
330 | int is_out; | |
3482528e | 331 | unsigned int allowed; |
1da177e4 | 332 | |
2f02bc8a | 333 | if (!urb || !urb->complete) |
1da177e4 | 334 | return -EINVAL; |
2f02bc8a AS |
335 | if (urb->hcpriv) { |
336 | WARN_ONCE(1, "URB %p submitted while active\n", urb); | |
337 | return -EBUSY; | |
338 | } | |
339 | ||
2c044a48 | 340 | dev = urb->dev; |
6da9c990 | 341 | if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED)) |
1da177e4 | 342 | return -ENODEV; |
1da177e4 | 343 | |
5b653c79 AS |
344 | /* For now, get the endpoint from the pipe. Eventually drivers |
345 | * will be required to set urb->ep directly and we will eliminate | |
346 | * urb->pipe. | |
347 | */ | |
fe54b058 | 348 | ep = usb_pipe_endpoint(dev, urb->pipe); |
5b653c79 AS |
349 | if (!ep) |
350 | return -ENOENT; | |
351 | ||
352 | urb->ep = ep; | |
1da177e4 LT |
353 | urb->status = -EINPROGRESS; |
354 | urb->actual_length = 0; | |
1da177e4 LT |
355 | |
356 | /* Lots of sanity checks, so HCDs can rely on clean data | |
357 | * and don't need to duplicate tests | |
358 | */ | |
5b653c79 | 359 | xfertype = usb_endpoint_type(&ep->desc); |
fea34091 AS |
360 | if (xfertype == USB_ENDPOINT_XFER_CONTROL) { |
361 | struct usb_ctrlrequest *setup = | |
362 | (struct usb_ctrlrequest *) urb->setup_packet; | |
363 | ||
364 | if (!setup) | |
365 | return -ENOEXEC; | |
366 | is_out = !(setup->bRequestType & USB_DIR_IN) || | |
367 | !setup->wLength; | |
368 | } else { | |
369 | is_out = usb_endpoint_dir_out(&ep->desc); | |
370 | } | |
371 | ||
ff9c895f AS |
372 | /* Clear the internal flags and cache the direction for later use */ |
373 | urb->transfer_flags &= ~(URB_DIR_MASK | URB_DMA_MAP_SINGLE | | |
374 | URB_DMA_MAP_PAGE | URB_DMA_MAP_SG | URB_MAP_LOCAL | | |
375 | URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL | | |
376 | URB_DMA_SG_COMBINED); | |
377 | urb->transfer_flags |= (is_out ? URB_DIR_OUT : URB_DIR_IN); | |
1da177e4 | 378 | |
5b653c79 AS |
379 | if (xfertype != USB_ENDPOINT_XFER_CONTROL && |
380 | dev->state < USB_STATE_CONFIGURED) | |
1da177e4 LT |
381 | return -ENODEV; |
382 | ||
29cc8897 | 383 | max = usb_endpoint_maxp(&ep->desc); |
1da177e4 LT |
384 | if (max <= 0) { |
385 | dev_dbg(&dev->dev, | |
386 | "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n", | |
5b653c79 | 387 | usb_endpoint_num(&ep->desc), is_out ? "out" : "in", |
441b62c1 | 388 | __func__, max); |
1da177e4 LT |
389 | return -EMSGSIZE; |
390 | } | |
391 | ||
392 | /* periodic transfers limit size per frame/uframe, | |
393 | * but drivers only control those sizes for ISO. | |
394 | * while we're checking, initialize return status. | |
395 | */ | |
5b653c79 | 396 | if (xfertype == USB_ENDPOINT_XFER_ISOC) { |
1da177e4 LT |
397 | int n, len; |
398 | ||
500132a0 PZ |
399 | /* SuperSpeed isoc endpoints have up to 16 bursts of up to |
400 | * 3 packets each | |
401 | */ | |
8a1b2725 | 402 | if (dev->speed >= USB_SPEED_SUPER) { |
500132a0 PZ |
403 | int burst = 1 + ep->ss_ep_comp.bMaxBurst; |
404 | int mult = USB_SS_MULT(ep->ss_ep_comp.bmAttributes); | |
405 | max *= burst; | |
406 | max *= mult; | |
407 | } | |
408 | ||
1da177e4 LT |
409 | /* "high bandwidth" mode, 1-3 packets/uframe? */ |
410 | if (dev->speed == USB_SPEED_HIGH) { | |
411 | int mult = 1 + ((max >> 11) & 0x03); | |
412 | max &= 0x07ff; | |
413 | max *= mult; | |
414 | } | |
415 | ||
2c044a48 | 416 | if (urb->number_of_packets <= 0) |
1da177e4 LT |
417 | return -EINVAL; |
418 | for (n = 0; n < urb->number_of_packets; n++) { | |
9251644a | 419 | len = urb->iso_frame_desc[n].length; |
2c044a48 | 420 | if (len < 0 || len > max) |
1da177e4 | 421 | return -EMSGSIZE; |
9251644a ON |
422 | urb->iso_frame_desc[n].status = -EXDEV; |
423 | urb->iso_frame_desc[n].actual_length = 0; | |
1da177e4 | 424 | } |
bcc48f1a ML |
425 | } else if (urb->num_sgs && !urb->dev->bus->no_sg_constraint && |
426 | dev->speed != USB_SPEED_WIRELESS) { | |
10e232c5 ML |
427 | struct scatterlist *sg; |
428 | int i; | |
429 | ||
430 | for_each_sg(urb->sg, sg, urb->num_sgs - 1, i) | |
431 | if (sg->length % max) | |
432 | return -EINVAL; | |
1da177e4 LT |
433 | } |
434 | ||
435 | /* the I/O buffer must be mapped/unmapped, except when length=0 */ | |
71d2718f | 436 | if (urb->transfer_buffer_length > INT_MAX) |
1da177e4 LT |
437 | return -EMSGSIZE; |
438 | ||
3482528e GKH |
439 | /* |
440 | * stuff that drivers shouldn't do, but which shouldn't | |
1da177e4 LT |
441 | * cause problems in HCDs if they get it wrong. |
442 | */ | |
f661c6f8 AS |
443 | |
444 | /* Check that the pipe's type matches the endpoint's type */ | |
0cb54a3e AS |
445 | if (usb_pipetype(urb->pipe) != pipetypes[xfertype]) |
446 | dev_WARN(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n", | |
f7dd6491 | 447 | usb_pipetype(urb->pipe), pipetypes[xfertype]); |
1da177e4 | 448 | |
0cb54a3e | 449 | /* Check against a simple/standard policy */ |
0ede76fc AS |
450 | allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT | URB_DIR_MASK | |
451 | URB_FREE_BUFFER); | |
5b653c79 AS |
452 | switch (xfertype) { |
453 | case USB_ENDPOINT_XFER_BULK: | |
9672f0fe | 454 | case USB_ENDPOINT_XFER_INT: |
1da177e4 LT |
455 | if (is_out) |
456 | allowed |= URB_ZERO_PACKET; | |
457 | /* FALLTHROUGH */ | |
5b653c79 | 458 | case USB_ENDPOINT_XFER_CONTROL: |
1da177e4 LT |
459 | allowed |= URB_NO_FSBR; /* only affects UHCI */ |
460 | /* FALLTHROUGH */ | |
461 | default: /* all non-iso endpoints */ | |
462 | if (!is_out) | |
463 | allowed |= URB_SHORT_NOT_OK; | |
464 | break; | |
5b653c79 | 465 | case USB_ENDPOINT_XFER_ISOC: |
1da177e4 LT |
466 | allowed |= URB_ISO_ASAP; |
467 | break; | |
468 | } | |
0cb54a3e | 469 | allowed &= urb->transfer_flags; |
1da177e4 | 470 | |
0cb54a3e AS |
471 | /* warn if submitter gave bogus flags */ |
472 | if (allowed != urb->transfer_flags) | |
473 | dev_WARN(&dev->dev, "BOGUS urb flags, %x --> %x\n", | |
474 | urb->transfer_flags, allowed); | |
3482528e | 475 | |
1da177e4 LT |
476 | /* |
477 | * Force periodic transfer intervals to be legal values that are | |
478 | * a power of two (so HCDs don't need to). | |
479 | * | |
480 | * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC | |
481 | * supports different values... this uses EHCI/UHCI defaults (and | |
482 | * EHCI can use smaller non-default values). | |
483 | */ | |
5b653c79 AS |
484 | switch (xfertype) { |
485 | case USB_ENDPOINT_XFER_ISOC: | |
486 | case USB_ENDPOINT_XFER_INT: | |
1da177e4 | 487 | /* too small? */ |
8e08b976 | 488 | switch (dev->speed) { |
551cdbbe | 489 | case USB_SPEED_WIRELESS: |
a2cd612d TP |
490 | if ((urb->interval < 6) |
491 | && (xfertype == USB_ENDPOINT_XFER_INT)) | |
8e08b976 | 492 | return -EINVAL; |
8e08b976 DV |
493 | default: |
494 | if (urb->interval <= 0) | |
495 | return -EINVAL; | |
496 | break; | |
497 | } | |
1da177e4 LT |
498 | /* too big? */ |
499 | switch (dev->speed) { | |
8a1b2725 | 500 | case USB_SPEED_SUPER_PLUS: |
6b403b02 SS |
501 | case USB_SPEED_SUPER: /* units are 125us */ |
502 | /* Handle up to 2^(16-1) microframes */ | |
503 | if (urb->interval > (1 << 15)) | |
504 | return -EINVAL; | |
505 | max = 1 << 15; | |
f09a15e6 | 506 | break; |
551cdbbe | 507 | case USB_SPEED_WIRELESS: |
8e08b976 DV |
508 | if (urb->interval > 16) |
509 | return -EINVAL; | |
510 | break; | |
1da177e4 | 511 | case USB_SPEED_HIGH: /* units are microframes */ |
2c044a48 | 512 | /* NOTE usb handles 2^15 */ |
1da177e4 LT |
513 | if (urb->interval > (1024 * 8)) |
514 | urb->interval = 1024 * 8; | |
5b653c79 | 515 | max = 1024 * 8; |
1da177e4 LT |
516 | break; |
517 | case USB_SPEED_FULL: /* units are frames/msec */ | |
518 | case USB_SPEED_LOW: | |
5b653c79 | 519 | if (xfertype == USB_ENDPOINT_XFER_INT) { |
1da177e4 LT |
520 | if (urb->interval > 255) |
521 | return -EINVAL; | |
2c044a48 | 522 | /* NOTE ohci only handles up to 32 */ |
5b653c79 | 523 | max = 128; |
1da177e4 LT |
524 | } else { |
525 | if (urb->interval > 1024) | |
526 | urb->interval = 1024; | |
2c044a48 | 527 | /* NOTE usb and ohci handle up to 2^15 */ |
5b653c79 | 528 | max = 1024; |
1da177e4 LT |
529 | } |
530 | break; | |
531 | default: | |
532 | return -EINVAL; | |
533 | } | |
551cdbbe | 534 | if (dev->speed != USB_SPEED_WIRELESS) { |
8e08b976 DV |
535 | /* Round down to a power of 2, no more than max */ |
536 | urb->interval = min(max, 1 << ilog2(urb->interval)); | |
537 | } | |
1da177e4 LT |
538 | } |
539 | ||
9251644a | 540 | return usb_hcd_submit_urb(urb, mem_flags); |
1da177e4 | 541 | } |
782e70c6 | 542 | EXPORT_SYMBOL_GPL(usb_submit_urb); |
1da177e4 LT |
543 | |
544 | /*-------------------------------------------------------------------*/ | |
545 | ||
546 | /** | |
547 | * usb_unlink_urb - abort/cancel a transfer request for an endpoint | |
548 | * @urb: pointer to urb describing a previously submitted request, | |
549 | * may be NULL | |
550 | * | |
beafef07 AS |
551 | * This routine cancels an in-progress request. URBs complete only once |
552 | * per submission, and may be canceled only once per submission. | |
553 | * Successful cancellation means termination of @urb will be expedited | |
554 | * and the completion handler will be called with a status code | |
555 | * indicating that the request has been canceled (rather than any other | |
556 | * code). | |
557 | * | |
cde217a5 AS |
558 | * Drivers should not call this routine or related routines, such as |
559 | * usb_kill_urb() or usb_unlink_anchored_urbs(), after their disconnect | |
560 | * method has returned. The disconnect function should synchronize with | |
561 | * a driver's I/O routines to insure that all URB-related activity has | |
562 | * completed before it returns. | |
563 | * | |
371f3b49 SAS |
564 | * This request is asynchronous, however the HCD might call the ->complete() |
565 | * callback during unlink. Therefore when drivers call usb_unlink_urb(), they | |
566 | * must not hold any locks that may be taken by the completion function. | |
567 | * Success is indicated by returning -EINPROGRESS, at which time the URB will | |
568 | * probably not yet have been given back to the device driver. When it is | |
569 | * eventually called, the completion function will see @urb->status == | |
570 | * -ECONNRESET. | |
beafef07 AS |
571 | * Failure is indicated by usb_unlink_urb() returning any other value. |
572 | * Unlinking will fail when @urb is not currently "linked" (i.e., it was | |
573 | * never submitted, or it was unlinked before, or the hardware is already | |
574 | * finished with it), even if the completion handler has not yet run. | |
1da177e4 | 575 | * |
da8bfb09 AS |
576 | * The URB must not be deallocated while this routine is running. In |
577 | * particular, when a driver calls this routine, it must insure that the | |
578 | * completion handler cannot deallocate the URB. | |
579 | * | |
626f090c YB |
580 | * Return: -EINPROGRESS on success. See description for other values on |
581 | * failure. | |
582 | * | |
1da177e4 LT |
583 | * Unlinking and Endpoint Queues: |
584 | * | |
beafef07 AS |
585 | * [The behaviors and guarantees described below do not apply to virtual |
586 | * root hubs but only to endpoint queues for physical USB devices.] | |
587 | * | |
1da177e4 LT |
588 | * Host Controller Drivers (HCDs) place all the URBs for a particular |
589 | * endpoint in a queue. Normally the queue advances as the controller | |
8835f665 | 590 | * hardware processes each request. But when an URB terminates with an |
beafef07 AS |
591 | * error its queue generally stops (see below), at least until that URB's |
592 | * completion routine returns. It is guaranteed that a stopped queue | |
593 | * will not restart until all its unlinked URBs have been fully retired, | |
594 | * with their completion routines run, even if that's not until some time | |
595 | * after the original completion handler returns. The same behavior and | |
596 | * guarantee apply when an URB terminates because it was unlinked. | |
597 | * | |
598 | * Bulk and interrupt endpoint queues are guaranteed to stop whenever an | |
599 | * URB terminates with any sort of error, including -ECONNRESET, -ENOENT, | |
600 | * and -EREMOTEIO. Control endpoint queues behave the same way except | |
601 | * that they are not guaranteed to stop for -EREMOTEIO errors. Queues | |
602 | * for isochronous endpoints are treated differently, because they must | |
603 | * advance at fixed rates. Such queues do not stop when an URB | |
604 | * encounters an error or is unlinked. An unlinked isochronous URB may | |
605 | * leave a gap in the stream of packets; it is undefined whether such | |
606 | * gaps can be filled in. | |
607 | * | |
608 | * Note that early termination of an URB because a short packet was | |
609 | * received will generate a -EREMOTEIO error if and only if the | |
610 | * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device | |
611 | * drivers can build deep queues for large or complex bulk transfers | |
612 | * and clean them up reliably after any sort of aborted transfer by | |
613 | * unlinking all pending URBs at the first fault. | |
614 | * | |
615 | * When a control URB terminates with an error other than -EREMOTEIO, it | |
616 | * is quite likely that the status stage of the transfer will not take | |
617 | * place. | |
1da177e4 LT |
618 | */ |
619 | int usb_unlink_urb(struct urb *urb) | |
620 | { | |
621 | if (!urb) | |
622 | return -EINVAL; | |
d617bc83 | 623 | if (!urb->dev) |
1da177e4 | 624 | return -ENODEV; |
d617bc83 AS |
625 | if (!urb->ep) |
626 | return -EIDRM; | |
a6d2bb9f | 627 | return usb_hcd_unlink_urb(urb, -ECONNRESET); |
1da177e4 | 628 | } |
782e70c6 | 629 | EXPORT_SYMBOL_GPL(usb_unlink_urb); |
1da177e4 LT |
630 | |
631 | /** | |
632 | * usb_kill_urb - cancel a transfer request and wait for it to finish | |
633 | * @urb: pointer to URB describing a previously submitted request, | |
634 | * may be NULL | |
635 | * | |
636 | * This routine cancels an in-progress request. It is guaranteed that | |
637 | * upon return all completion handlers will have finished and the URB | |
638 | * will be totally idle and available for reuse. These features make | |
639 | * this an ideal way to stop I/O in a disconnect() callback or close() | |
640 | * function. If the request has not already finished or been unlinked | |
641 | * the completion handler will see urb->status == -ENOENT. | |
642 | * | |
643 | * While the routine is running, attempts to resubmit the URB will fail | |
644 | * with error -EPERM. Thus even if the URB's completion handler always | |
645 | * tries to resubmit, it will not succeed and the URB will become idle. | |
646 | * | |
da8bfb09 AS |
647 | * The URB must not be deallocated while this routine is running. In |
648 | * particular, when a driver calls this routine, it must insure that the | |
649 | * completion handler cannot deallocate the URB. | |
650 | * | |
1da177e4 LT |
651 | * This routine may not be used in an interrupt context (such as a bottom |
652 | * half or a completion handler), or when holding a spinlock, or in other | |
653 | * situations where the caller can't schedule(). | |
cde217a5 AS |
654 | * |
655 | * This routine should not be called by a driver after its disconnect | |
656 | * method has returned. | |
1da177e4 LT |
657 | */ |
658 | void usb_kill_urb(struct urb *urb) | |
659 | { | |
e9aa795a | 660 | might_sleep(); |
d617bc83 | 661 | if (!(urb && urb->dev && urb->ep)) |
1da177e4 | 662 | return; |
49367d8f | 663 | atomic_inc(&urb->reject); |
1da177e4 | 664 | |
a6d2bb9f | 665 | usb_hcd_unlink_urb(urb, -ENOENT); |
1da177e4 LT |
666 | wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0); |
667 | ||
49367d8f | 668 | atomic_dec(&urb->reject); |
1da177e4 | 669 | } |
782e70c6 | 670 | EXPORT_SYMBOL_GPL(usb_kill_urb); |
1da177e4 | 671 | |
55b447bf ON |
672 | /** |
673 | * usb_poison_urb - reliably kill a transfer and prevent further use of an URB | |
674 | * @urb: pointer to URB describing a previously submitted request, | |
675 | * may be NULL | |
676 | * | |
677 | * This routine cancels an in-progress request. It is guaranteed that | |
678 | * upon return all completion handlers will have finished and the URB | |
679 | * will be totally idle and cannot be reused. These features make | |
680 | * this an ideal way to stop I/O in a disconnect() callback. | |
681 | * If the request has not already finished or been unlinked | |
682 | * the completion handler will see urb->status == -ENOENT. | |
683 | * | |
684 | * After and while the routine runs, attempts to resubmit the URB will fail | |
685 | * with error -EPERM. Thus even if the URB's completion handler always | |
686 | * tries to resubmit, it will not succeed and the URB will become idle. | |
687 | * | |
da8bfb09 AS |
688 | * The URB must not be deallocated while this routine is running. In |
689 | * particular, when a driver calls this routine, it must insure that the | |
690 | * completion handler cannot deallocate the URB. | |
691 | * | |
55b447bf ON |
692 | * This routine may not be used in an interrupt context (such as a bottom |
693 | * half or a completion handler), or when holding a spinlock, or in other | |
694 | * situations where the caller can't schedule(). | |
cde217a5 AS |
695 | * |
696 | * This routine should not be called by a driver after its disconnect | |
697 | * method has returned. | |
55b447bf ON |
698 | */ |
699 | void usb_poison_urb(struct urb *urb) | |
700 | { | |
701 | might_sleep(); | |
68a2bed1 | 702 | if (!urb) |
55b447bf | 703 | return; |
49367d8f | 704 | atomic_inc(&urb->reject); |
55b447bf | 705 | |
68a2bed1 JH |
706 | if (!urb->dev || !urb->ep) |
707 | return; | |
708 | ||
55b447bf ON |
709 | usb_hcd_unlink_urb(urb, -ENOENT); |
710 | wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0); | |
711 | } | |
712 | EXPORT_SYMBOL_GPL(usb_poison_urb); | |
713 | ||
714 | void usb_unpoison_urb(struct urb *urb) | |
715 | { | |
716 | if (!urb) | |
717 | return; | |
718 | ||
49367d8f | 719 | atomic_dec(&urb->reject); |
55b447bf ON |
720 | } |
721 | EXPORT_SYMBOL_GPL(usb_unpoison_urb); | |
722 | ||
8815bb09 ON |
723 | /** |
724 | * usb_block_urb - reliably prevent further use of an URB | |
725 | * @urb: pointer to URB to be blocked, may be NULL | |
726 | * | |
727 | * After the routine has run, attempts to resubmit the URB will fail | |
728 | * with error -EPERM. Thus even if the URB's completion handler always | |
729 | * tries to resubmit, it will not succeed and the URB will become idle. | |
730 | * | |
731 | * The URB must not be deallocated while this routine is running. In | |
732 | * particular, when a driver calls this routine, it must insure that the | |
733 | * completion handler cannot deallocate the URB. | |
734 | */ | |
735 | void usb_block_urb(struct urb *urb) | |
736 | { | |
737 | if (!urb) | |
738 | return; | |
739 | ||
740 | atomic_inc(&urb->reject); | |
741 | } | |
742 | EXPORT_SYMBOL_GPL(usb_block_urb); | |
743 | ||
51a2f077 ON |
744 | /** |
745 | * usb_kill_anchored_urbs - cancel transfer requests en masse | |
746 | * @anchor: anchor the requests are bound to | |
747 | * | |
748 | * this allows all outstanding URBs to be killed starting | |
749 | * from the back of the queue | |
cde217a5 AS |
750 | * |
751 | * This routine should not be called by a driver after its disconnect | |
752 | * method has returned. | |
51a2f077 ON |
753 | */ |
754 | void usb_kill_anchored_urbs(struct usb_anchor *anchor) | |
755 | { | |
756 | struct urb *victim; | |
757 | ||
758 | spin_lock_irq(&anchor->lock); | |
759 | while (!list_empty(&anchor->urb_list)) { | |
2c044a48 GKH |
760 | victim = list_entry(anchor->urb_list.prev, struct urb, |
761 | anchor_list); | |
51a2f077 ON |
762 | /* we must make sure the URB isn't freed before we kill it*/ |
763 | usb_get_urb(victim); | |
764 | spin_unlock_irq(&anchor->lock); | |
765 | /* this will unanchor the URB */ | |
766 | usb_kill_urb(victim); | |
767 | usb_put_urb(victim); | |
768 | spin_lock_irq(&anchor->lock); | |
769 | } | |
770 | spin_unlock_irq(&anchor->lock); | |
771 | } | |
772 | EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs); | |
773 | ||
6a2839be ON |
774 | |
775 | /** | |
776 | * usb_poison_anchored_urbs - cease all traffic from an anchor | |
777 | * @anchor: anchor the requests are bound to | |
778 | * | |
779 | * this allows all outstanding URBs to be poisoned starting | |
780 | * from the back of the queue. Newly added URBs will also be | |
781 | * poisoned | |
cde217a5 AS |
782 | * |
783 | * This routine should not be called by a driver after its disconnect | |
784 | * method has returned. | |
6a2839be ON |
785 | */ |
786 | void usb_poison_anchored_urbs(struct usb_anchor *anchor) | |
787 | { | |
788 | struct urb *victim; | |
789 | ||
790 | spin_lock_irq(&anchor->lock); | |
791 | anchor->poisoned = 1; | |
792 | while (!list_empty(&anchor->urb_list)) { | |
793 | victim = list_entry(anchor->urb_list.prev, struct urb, | |
794 | anchor_list); | |
795 | /* we must make sure the URB isn't freed before we kill it*/ | |
796 | usb_get_urb(victim); | |
797 | spin_unlock_irq(&anchor->lock); | |
798 | /* this will unanchor the URB */ | |
799 | usb_poison_urb(victim); | |
800 | usb_put_urb(victim); | |
801 | spin_lock_irq(&anchor->lock); | |
802 | } | |
803 | spin_unlock_irq(&anchor->lock); | |
804 | } | |
805 | EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs); | |
cde217a5 | 806 | |
856395d6 ON |
807 | /** |
808 | * usb_unpoison_anchored_urbs - let an anchor be used successfully again | |
809 | * @anchor: anchor the requests are bound to | |
810 | * | |
811 | * Reverses the effect of usb_poison_anchored_urbs | |
812 | * the anchor can be used normally after it returns | |
813 | */ | |
814 | void usb_unpoison_anchored_urbs(struct usb_anchor *anchor) | |
815 | { | |
816 | unsigned long flags; | |
817 | struct urb *lazarus; | |
818 | ||
819 | spin_lock_irqsave(&anchor->lock, flags); | |
820 | list_for_each_entry(lazarus, &anchor->urb_list, anchor_list) { | |
821 | usb_unpoison_urb(lazarus); | |
822 | } | |
823 | anchor->poisoned = 0; | |
824 | spin_unlock_irqrestore(&anchor->lock, flags); | |
825 | } | |
826 | EXPORT_SYMBOL_GPL(usb_unpoison_anchored_urbs); | |
eda76959 ON |
827 | /** |
828 | * usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse | |
829 | * @anchor: anchor the requests are bound to | |
830 | * | |
831 | * this allows all outstanding URBs to be unlinked starting | |
832 | * from the back of the queue. This function is asynchronous. | |
e227867f | 833 | * The unlinking is just triggered. It may happen after this |
eda76959 | 834 | * function has returned. |
cde217a5 AS |
835 | * |
836 | * This routine should not be called by a driver after its disconnect | |
837 | * method has returned. | |
eda76959 ON |
838 | */ |
839 | void usb_unlink_anchored_urbs(struct usb_anchor *anchor) | |
840 | { | |
841 | struct urb *victim; | |
842 | ||
b3e67044 | 843 | while ((victim = usb_get_from_anchor(anchor)) != NULL) { |
eda76959 | 844 | usb_unlink_urb(victim); |
77571f05 | 845 | usb_put_urb(victim); |
eda76959 | 846 | } |
eda76959 ON |
847 | } |
848 | EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs); | |
849 | ||
6ec4147e HG |
850 | /** |
851 | * usb_anchor_suspend_wakeups | |
852 | * @anchor: the anchor you want to suspend wakeups on | |
853 | * | |
854 | * Call this to stop the last urb being unanchored from waking up any | |
855 | * usb_wait_anchor_empty_timeout waiters. This is used in the hcd urb give- | |
856 | * back path to delay waking up until after the completion handler has run. | |
857 | */ | |
858 | void usb_anchor_suspend_wakeups(struct usb_anchor *anchor) | |
859 | { | |
860 | if (anchor) | |
861 | atomic_inc(&anchor->suspend_wakeups); | |
862 | } | |
863 | EXPORT_SYMBOL_GPL(usb_anchor_suspend_wakeups); | |
864 | ||
865 | /** | |
866 | * usb_anchor_resume_wakeups | |
867 | * @anchor: the anchor you want to resume wakeups on | |
868 | * | |
869 | * Allow usb_wait_anchor_empty_timeout waiters to be woken up again, and | |
870 | * wake up any current waiters if the anchor is empty. | |
871 | */ | |
872 | void usb_anchor_resume_wakeups(struct usb_anchor *anchor) | |
873 | { | |
874 | if (!anchor) | |
875 | return; | |
876 | ||
877 | atomic_dec(&anchor->suspend_wakeups); | |
878 | if (usb_anchor_check_wakeup(anchor)) | |
879 | wake_up(&anchor->wait); | |
880 | } | |
881 | EXPORT_SYMBOL_GPL(usb_anchor_resume_wakeups); | |
882 | ||
51a2f077 ON |
883 | /** |
884 | * usb_wait_anchor_empty_timeout - wait for an anchor to be unused | |
885 | * @anchor: the anchor you want to become unused | |
886 | * @timeout: how long you are willing to wait in milliseconds | |
887 | * | |
888 | * Call this is you want to be sure all an anchor's | |
889 | * URBs have finished | |
626f090c YB |
890 | * |
891 | * Return: Non-zero if the anchor became unused. Zero on timeout. | |
51a2f077 ON |
892 | */ |
893 | int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor, | |
894 | unsigned int timeout) | |
895 | { | |
6ec4147e HG |
896 | return wait_event_timeout(anchor->wait, |
897 | usb_anchor_check_wakeup(anchor), | |
51a2f077 ON |
898 | msecs_to_jiffies(timeout)); |
899 | } | |
900 | EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout); | |
19876252 ON |
901 | |
902 | /** | |
903 | * usb_get_from_anchor - get an anchor's oldest urb | |
904 | * @anchor: the anchor whose urb you want | |
905 | * | |
626f090c | 906 | * This will take the oldest urb from an anchor, |
19876252 | 907 | * unanchor and return it |
626f090c YB |
908 | * |
909 | * Return: The oldest urb from @anchor, or %NULL if @anchor has no | |
910 | * urbs associated with it. | |
19876252 ON |
911 | */ |
912 | struct urb *usb_get_from_anchor(struct usb_anchor *anchor) | |
913 | { | |
914 | struct urb *victim; | |
915 | unsigned long flags; | |
916 | ||
917 | spin_lock_irqsave(&anchor->lock, flags); | |
918 | if (!list_empty(&anchor->urb_list)) { | |
919 | victim = list_entry(anchor->urb_list.next, struct urb, | |
920 | anchor_list); | |
921 | usb_get_urb(victim); | |
b3e67044 | 922 | __usb_unanchor_urb(victim, anchor); |
19876252 | 923 | } else { |
19876252 ON |
924 | victim = NULL; |
925 | } | |
b3e67044 | 926 | spin_unlock_irqrestore(&anchor->lock, flags); |
19876252 ON |
927 | |
928 | return victim; | |
929 | } | |
930 | ||
931 | EXPORT_SYMBOL_GPL(usb_get_from_anchor); | |
932 | ||
933 | /** | |
934 | * usb_scuttle_anchored_urbs - unanchor all an anchor's urbs | |
935 | * @anchor: the anchor whose urbs you want to unanchor | |
936 | * | |
937 | * use this to get rid of all an anchor's urbs | |
938 | */ | |
939 | void usb_scuttle_anchored_urbs(struct usb_anchor *anchor) | |
940 | { | |
941 | struct urb *victim; | |
942 | unsigned long flags; | |
943 | ||
944 | spin_lock_irqsave(&anchor->lock, flags); | |
945 | while (!list_empty(&anchor->urb_list)) { | |
946 | victim = list_entry(anchor->urb_list.prev, struct urb, | |
947 | anchor_list); | |
b3e67044 | 948 | __usb_unanchor_urb(victim, anchor); |
19876252 ON |
949 | } |
950 | spin_unlock_irqrestore(&anchor->lock, flags); | |
951 | } | |
952 | ||
953 | EXPORT_SYMBOL_GPL(usb_scuttle_anchored_urbs); | |
954 | ||
955 | /** | |
956 | * usb_anchor_empty - is an anchor empty | |
957 | * @anchor: the anchor you want to query | |
958 | * | |
626f090c | 959 | * Return: 1 if the anchor has no urbs associated with it. |
19876252 ON |
960 | */ |
961 | int usb_anchor_empty(struct usb_anchor *anchor) | |
962 | { | |
963 | return list_empty(&anchor->urb_list); | |
964 | } | |
965 | ||
966 | EXPORT_SYMBOL_GPL(usb_anchor_empty); | |
967 |