1 #include <linux/module.h> 2 #include <linux/string.h> 3 #include <linux/bitops.h> 4 #include <linux/slab.h> 5 #include <linux/log2.h> 6 #include <linux/usb.h> 7 #include <linux/wait.h> 8 #include <linux/usb/hcd.h> 9 #include <linux/scatterlist.h> 10 11 #define to_urb(d) container_of(d, struct urb, kref) 12 13 14 static void urb_destroy(struct kref *kref) 15 { 16 struct urb *urb = to_urb(kref); 17 18 if (urb->transfer_flags & URB_FREE_BUFFER) 19 kfree(urb->transfer_buffer); 20 21 kfree(urb); 22 } 23 24 /** 25 * usb_init_urb - initializes a urb so that it can be used by a USB driver 26 * @urb: pointer to the urb to initialize 27 * 28 * Initializes a urb so that the USB subsystem can use it properly. 29 * 30 * If a urb is created with a call to usb_alloc_urb() it is not 31 * necessary to call this function. Only use this if you allocate the 32 * space for a struct urb on your own. If you call this function, be 33 * careful when freeing the memory for your urb that it is no longer in 34 * use by the USB core. 35 * 36 * Only use this function if you _really_ understand what you are doing. 37 */ 38 void usb_init_urb(struct urb *urb) 39 { 40 if (urb) { 41 memset(urb, 0, sizeof(*urb)); 42 kref_init(&urb->kref); 43 INIT_LIST_HEAD(&urb->anchor_list); 44 } 45 } 46 EXPORT_SYMBOL_GPL(usb_init_urb); 47 48 /** 49 * usb_alloc_urb - creates a new urb for a USB driver to use 50 * @iso_packets: number of iso packets for this urb 51 * @mem_flags: the type of memory to allocate, see kmalloc() for a list of 52 * valid options for this. 53 * 54 * Creates an urb for the USB driver to use, initializes a few internal 55 * structures, increments the usage counter, and returns a pointer to it. 56 * 57 * If the driver want to use this urb for interrupt, control, or bulk 58 * endpoints, pass '0' as the number of iso packets. 59 * 60 * The driver must call usb_free_urb() when it is finished with the urb. 61 * 62 * Return: A pointer to the new urb, or %NULL if no memory is available. 63 */ 64 struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags) 65 { 66 struct urb *urb; 67 68 urb = kmalloc(sizeof(struct urb) + 69 iso_packets * sizeof(struct usb_iso_packet_descriptor), 70 mem_flags); 71 if (!urb) 72 return NULL; 73 usb_init_urb(urb); 74 return urb; 75 } 76 EXPORT_SYMBOL_GPL(usb_alloc_urb); 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 * 85 * Note: The transfer buffer associated with the urb is not freed unless the 86 * URB_FREE_BUFFER transfer flag is set. 87 */ 88 void usb_free_urb(struct urb *urb) 89 { 90 if (urb) 91 kref_put(&urb->kref, urb_destroy); 92 } 93 EXPORT_SYMBOL_GPL(usb_free_urb); 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 * 103 * Return: A pointer to the urb with the incremented reference counter. 104 */ 105 struct urb *usb_get_urb(struct urb *urb) 106 { 107 if (urb) 108 kref_get(&urb->kref); 109 return urb; 110 } 111 EXPORT_SYMBOL_GPL(usb_get_urb); 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; 129 130 if (unlikely(anchor->poisoned)) 131 atomic_inc(&urb->reject); 132 133 spin_unlock_irqrestore(&anchor->lock, flags); 134 } 135 EXPORT_SYMBOL_GPL(usb_anchor_urb); 136 137 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 } 142 143 /* 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); 149 if (usb_anchor_check_wakeup(anchor)) 150 wake_up(&anchor->wait); 151 } 152 153 /** 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); 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); 179 spin_unlock_irqrestore(&anchor->lock, flags); 180 } 181 EXPORT_SYMBOL_GPL(usb_unanchor_urb); 182 183 /*-------------------------------------------------------------------*/ 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 195 * (a software-induced fault, also called "request cancellation"). 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 * 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. 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 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. 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 * 245 * Return: 246 * 0 on successful submissions. A negative error number otherwise. 247 * 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 262 * after faults (transfer errors or cancellation). 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 * 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 * 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 280 * periods during completion callbacks). When there is no longer an urb 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. 302 * 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 */ 322 int usb_submit_urb(struct urb *urb, gfp_t mem_flags) 323 { 324 static int pipetypes[4] = { 325 PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT 326 }; 327 int xfertype, max; 328 struct usb_device *dev; 329 struct usb_host_endpoint *ep; 330 int is_out; 331 unsigned int allowed; 332 333 if (!urb || !urb->complete) 334 return -EINVAL; 335 if (urb->hcpriv) { 336 WARN_ONCE(1, "URB %p submitted while active\n", urb); 337 return -EBUSY; 338 } 339 340 dev = urb->dev; 341 if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED)) 342 return -ENODEV; 343 344 /* 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 */ 348 ep = usb_pipe_endpoint(dev, urb->pipe); 349 if (!ep) 350 return -ENOENT; 351 352 urb->ep = ep; 353 urb->status = -EINPROGRESS; 354 urb->actual_length = 0; 355 356 /* Lots of sanity checks, so HCDs can rely on clean data 357 * and don't need to duplicate tests 358 */ 359 xfertype = usb_endpoint_type(&ep->desc); 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 } 371 372 /* 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); 378 379 if (xfertype != USB_ENDPOINT_XFER_CONTROL && 380 dev->state < USB_STATE_CONFIGURED) 381 return -ENODEV; 382 383 max = usb_endpoint_maxp(&ep->desc); 384 if (max <= 0) { 385 dev_dbg(&dev->dev, 386 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n", 387 usb_endpoint_num(&ep->desc), is_out ? "out" : "in", 388 __func__, max); 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 */ 396 if (xfertype == USB_ENDPOINT_XFER_ISOC) { 397 int n, len; 398 399 /* SuperSpeed isoc endpoints have up to 16 bursts of up to 400 * 3 packets each 401 */ 402 if (dev->speed >= USB_SPEED_SUPER) { 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 } 408 409 /* "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 } 415 416 if (urb->number_of_packets <= 0) 417 return -EINVAL; 418 for (n = 0; n < urb->number_of_packets; n++) { 419 len = urb->iso_frame_desc[n].length; 420 if (len < 0 || len > max) 421 return -EMSGSIZE; 422 urb->iso_frame_desc[n].status = -EXDEV; 423 urb->iso_frame_desc[n].actual_length = 0; 424 } 425 } else if (urb->num_sgs && !urb->dev->bus->no_sg_constraint && 426 dev->speed != USB_SPEED_WIRELESS) { 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; 433 } 434 435 /* the I/O buffer must be mapped/unmapped, except when length=0 */ 436 if (urb->transfer_buffer_length > INT_MAX) 437 return -EMSGSIZE; 438 439 /* 440 * stuff that drivers shouldn't do, but which shouldn't 441 * cause problems in HCDs if they get it wrong. 442 */ 443 444 /* Check that the pipe's type matches the endpoint's type */ 445 if (usb_pipetype(urb->pipe) != pipetypes[xfertype]) 446 dev_WARN(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n", 447 usb_pipetype(urb->pipe), pipetypes[xfertype]); 448 449 /* Check against a simple/standard policy */ 450 allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT | URB_DIR_MASK | 451 URB_FREE_BUFFER); 452 switch (xfertype) { 453 case USB_ENDPOINT_XFER_BULK: 454 case USB_ENDPOINT_XFER_INT: 455 if (is_out) 456 allowed |= URB_ZERO_PACKET; 457 /* FALLTHROUGH */ 458 case USB_ENDPOINT_XFER_CONTROL: 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; 465 case USB_ENDPOINT_XFER_ISOC: 466 allowed |= URB_ISO_ASAP; 467 break; 468 } 469 allowed &= urb->transfer_flags; 470 471 /* 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); 475 476 /* 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 */ 484 switch (xfertype) { 485 case USB_ENDPOINT_XFER_ISOC: 486 case USB_ENDPOINT_XFER_INT: 487 /* too small? */ 488 switch (dev->speed) { 489 case USB_SPEED_WIRELESS: 490 if ((urb->interval < 6) 491 && (xfertype == USB_ENDPOINT_XFER_INT)) 492 return -EINVAL; 493 default: 494 if (urb->interval <= 0) 495 return -EINVAL; 496 break; 497 } 498 /* too big? */ 499 switch (dev->speed) { 500 case USB_SPEED_SUPER_PLUS: 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; 506 break; 507 case USB_SPEED_WIRELESS: 508 if (urb->interval > 16) 509 return -EINVAL; 510 break; 511 case USB_SPEED_HIGH: /* units are microframes */ 512 /* NOTE usb handles 2^15 */ 513 if (urb->interval > (1024 * 8)) 514 urb->interval = 1024 * 8; 515 max = 1024 * 8; 516 break; 517 case USB_SPEED_FULL: /* units are frames/msec */ 518 case USB_SPEED_LOW: 519 if (xfertype == USB_ENDPOINT_XFER_INT) { 520 if (urb->interval > 255) 521 return -EINVAL; 522 /* NOTE ohci only handles up to 32 */ 523 max = 128; 524 } else { 525 if (urb->interval > 1024) 526 urb->interval = 1024; 527 /* NOTE usb and ohci handle up to 2^15 */ 528 max = 1024; 529 } 530 break; 531 default: 532 return -EINVAL; 533 } 534 if (dev->speed != USB_SPEED_WIRELESS) { 535 /* Round down to a power of 2, no more than max */ 536 urb->interval = min(max, 1 << ilog2(urb->interval)); 537 } 538 } 539 540 return usb_hcd_submit_urb(urb, mem_flags); 541 } 542 EXPORT_SYMBOL_GPL(usb_submit_urb); 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 * 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 * 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 * 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. 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. 575 * 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 * 580 * Return: -EINPROGRESS on success. See description for other values on 581 * failure. 582 * 583 * Unlinking and Endpoint Queues: 584 * 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 * 588 * Host Controller Drivers (HCDs) place all the URBs for a particular 589 * endpoint in a queue. Normally the queue advances as the controller 590 * hardware processes each request. But when an URB terminates with an 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. 618 */ 619 int usb_unlink_urb(struct urb *urb) 620 { 621 if (!urb) 622 return -EINVAL; 623 if (!urb->dev) 624 return -ENODEV; 625 if (!urb->ep) 626 return -EIDRM; 627 return usb_hcd_unlink_urb(urb, -ECONNRESET); 628 } 629 EXPORT_SYMBOL_GPL(usb_unlink_urb); 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 * 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 * 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(). 654 * 655 * This routine should not be called by a driver after its disconnect 656 * method has returned. 657 */ 658 void usb_kill_urb(struct urb *urb) 659 { 660 might_sleep(); 661 if (!(urb && urb->dev && urb->ep)) 662 return; 663 atomic_inc(&urb->reject); 664 665 usb_hcd_unlink_urb(urb, -ENOENT); 666 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0); 667 668 atomic_dec(&urb->reject); 669 } 670 EXPORT_SYMBOL_GPL(usb_kill_urb); 671 672 /** 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 * 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 * 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(). 695 * 696 * This routine should not be called by a driver after its disconnect 697 * method has returned. 698 */ 699 void usb_poison_urb(struct urb *urb) 700 { 701 might_sleep(); 702 if (!urb) 703 return; 704 atomic_inc(&urb->reject); 705 706 if (!urb->dev || !urb->ep) 707 return; 708 709 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; 718 719 atomic_dec(&urb->reject); 720 } 721 EXPORT_SYMBOL_GPL(usb_unpoison_urb); 722 723 /** 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); 743 744 /** 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 750 * 751 * This routine should not be called by a driver after its disconnect 752 * method has returned. 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)) { 760 victim = list_entry(anchor->urb_list.prev, struct urb, 761 anchor_list); 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); 773 774 775 /** 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 782 * 783 * This routine should not be called by a driver after its disconnect 784 * method has returned. 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); 806 807 /** 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); 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. 833 * The unlinking is just triggered. It may happen after this 834 * function has returned. 835 * 836 * This routine should not be called by a driver after its disconnect 837 * method has returned. 838 */ 839 void usb_unlink_anchored_urbs(struct usb_anchor *anchor) 840 { 841 struct urb *victim; 842 843 while ((victim = usb_get_from_anchor(anchor)) != NULL) { 844 usb_unlink_urb(victim); 845 usb_put_urb(victim); 846 } 847 } 848 EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs); 849 850 /** 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); 882 883 /** 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 890 * 891 * Return: Non-zero if the anchor became unused. Zero on timeout. 892 */ 893 int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor, 894 unsigned int timeout) 895 { 896 return wait_event_timeout(anchor->wait, 897 usb_anchor_check_wakeup(anchor), 898 msecs_to_jiffies(timeout)); 899 } 900 EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout); 901 902 /** 903 * usb_get_from_anchor - get an anchor's oldest urb 904 * @anchor: the anchor whose urb you want 905 * 906 * This will take the oldest urb from an anchor, 907 * unanchor and return it 908 * 909 * Return: The oldest urb from @anchor, or %NULL if @anchor has no 910 * urbs associated with it. 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); 922 __usb_unanchor_urb(victim, anchor); 923 } else { 924 victim = NULL; 925 } 926 spin_unlock_irqrestore(&anchor->lock, flags); 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); 948 __usb_unanchor_urb(victim, anchor); 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 * 959 * Return: 1 if the anchor has no urbs associated with it. 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); 967 968