1 /* 2 * Released under the GPLv2 only. 3 * SPDX-License-Identifier: GPL-2.0 4 */ 5 6 #include <linux/module.h> 7 #include <linux/string.h> 8 #include <linux/bitops.h> 9 #include <linux/slab.h> 10 #include <linux/log2.h> 11 #include <linux/usb.h> 12 #include <linux/wait.h> 13 #include <linux/usb/hcd.h> 14 #include <linux/scatterlist.h> 15 16 #define to_urb(d) container_of(d, struct urb, kref) 17 18 19 static void urb_destroy(struct kref *kref) 20 { 21 struct urb *urb = to_urb(kref); 22 23 if (urb->transfer_flags & URB_FREE_BUFFER) 24 kfree(urb->transfer_buffer); 25 26 kfree(urb); 27 } 28 29 /** 30 * usb_init_urb - initializes a urb so that it can be used by a USB driver 31 * @urb: pointer to the urb to initialize 32 * 33 * Initializes a urb so that the USB subsystem can use it properly. 34 * 35 * If a urb is created with a call to usb_alloc_urb() it is not 36 * necessary to call this function. Only use this if you allocate the 37 * space for a struct urb on your own. If you call this function, be 38 * careful when freeing the memory for your urb that it is no longer in 39 * use by the USB core. 40 * 41 * Only use this function if you _really_ understand what you are doing. 42 */ 43 void usb_init_urb(struct urb *urb) 44 { 45 if (urb) { 46 memset(urb, 0, sizeof(*urb)); 47 kref_init(&urb->kref); 48 INIT_LIST_HEAD(&urb->anchor_list); 49 } 50 } 51 EXPORT_SYMBOL_GPL(usb_init_urb); 52 53 /** 54 * usb_alloc_urb - creates a new urb for a USB driver to use 55 * @iso_packets: number of iso packets for this urb 56 * @mem_flags: the type of memory to allocate, see kmalloc() for a list of 57 * valid options for this. 58 * 59 * Creates an urb for the USB driver to use, initializes a few internal 60 * structures, increments the usage counter, and returns a pointer to it. 61 * 62 * If the driver want to use this urb for interrupt, control, or bulk 63 * endpoints, pass '0' as the number of iso packets. 64 * 65 * The driver must call usb_free_urb() when it is finished with the urb. 66 * 67 * Return: A pointer to the new urb, or %NULL if no memory is available. 68 */ 69 struct urb *usb_alloc_urb(int iso_packets, gfp_t mem_flags) 70 { 71 struct urb *urb; 72 73 urb = kmalloc(sizeof(struct urb) + 74 iso_packets * sizeof(struct usb_iso_packet_descriptor), 75 mem_flags); 76 if (!urb) 77 return NULL; 78 usb_init_urb(urb); 79 return urb; 80 } 81 EXPORT_SYMBOL_GPL(usb_alloc_urb); 82 83 /** 84 * usb_free_urb - frees the memory used by a urb when all users of it are finished 85 * @urb: pointer to the urb to free, may be NULL 86 * 87 * Must be called when a user of a urb is finished with it. When the last user 88 * of the urb calls this function, the memory of the urb is freed. 89 * 90 * Note: The transfer buffer associated with the urb is not freed unless the 91 * URB_FREE_BUFFER transfer flag is set. 92 */ 93 void usb_free_urb(struct urb *urb) 94 { 95 if (urb) 96 kref_put(&urb->kref, urb_destroy); 97 } 98 EXPORT_SYMBOL_GPL(usb_free_urb); 99 100 /** 101 * usb_get_urb - increments the reference count of the urb 102 * @urb: pointer to the urb to modify, may be NULL 103 * 104 * This must be called whenever a urb is transferred from a device driver to a 105 * host controller driver. This allows proper reference counting to happen 106 * for urbs. 107 * 108 * Return: A pointer to the urb with the incremented reference counter. 109 */ 110 struct urb *usb_get_urb(struct urb *urb) 111 { 112 if (urb) 113 kref_get(&urb->kref); 114 return urb; 115 } 116 EXPORT_SYMBOL_GPL(usb_get_urb); 117 118 /** 119 * usb_anchor_urb - anchors an URB while it is processed 120 * @urb: pointer to the urb to anchor 121 * @anchor: pointer to the anchor 122 * 123 * This can be called to have access to URBs which are to be executed 124 * without bothering to track them 125 */ 126 void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor) 127 { 128 unsigned long flags; 129 130 spin_lock_irqsave(&anchor->lock, flags); 131 usb_get_urb(urb); 132 list_add_tail(&urb->anchor_list, &anchor->urb_list); 133 urb->anchor = anchor; 134 135 if (unlikely(anchor->poisoned)) 136 atomic_inc(&urb->reject); 137 138 spin_unlock_irqrestore(&anchor->lock, flags); 139 } 140 EXPORT_SYMBOL_GPL(usb_anchor_urb); 141 142 static int usb_anchor_check_wakeup(struct usb_anchor *anchor) 143 { 144 return atomic_read(&anchor->suspend_wakeups) == 0 && 145 list_empty(&anchor->urb_list); 146 } 147 148 /* Callers must hold anchor->lock */ 149 static void __usb_unanchor_urb(struct urb *urb, struct usb_anchor *anchor) 150 { 151 urb->anchor = NULL; 152 list_del(&urb->anchor_list); 153 usb_put_urb(urb); 154 if (usb_anchor_check_wakeup(anchor)) 155 wake_up(&anchor->wait); 156 } 157 158 /** 159 * usb_unanchor_urb - unanchors an URB 160 * @urb: pointer to the urb to anchor 161 * 162 * Call this to stop the system keeping track of this URB 163 */ 164 void usb_unanchor_urb(struct urb *urb) 165 { 166 unsigned long flags; 167 struct usb_anchor *anchor; 168 169 if (!urb) 170 return; 171 172 anchor = urb->anchor; 173 if (!anchor) 174 return; 175 176 spin_lock_irqsave(&anchor->lock, flags); 177 /* 178 * At this point, we could be competing with another thread which 179 * has the same intention. To protect the urb from being unanchored 180 * twice, only the winner of the race gets the job. 181 */ 182 if (likely(anchor == urb->anchor)) 183 __usb_unanchor_urb(urb, anchor); 184 spin_unlock_irqrestore(&anchor->lock, flags); 185 } 186 EXPORT_SYMBOL_GPL(usb_unanchor_urb); 187 188 /*-------------------------------------------------------------------*/ 189 190 /** 191 * usb_submit_urb - issue an asynchronous transfer request for an endpoint 192 * @urb: pointer to the urb describing the request 193 * @mem_flags: the type of memory to allocate, see kmalloc() for a list 194 * of valid options for this. 195 * 196 * This submits a transfer request, and transfers control of the URB 197 * describing that request to the USB subsystem. Request completion will 198 * be indicated later, asynchronously, by calling the completion handler. 199 * The three types of completion are success, error, and unlink 200 * (a software-induced fault, also called "request cancellation"). 201 * 202 * URBs may be submitted in interrupt context. 203 * 204 * The caller must have correctly initialized the URB before submitting 205 * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are 206 * available to ensure that most fields are correctly initialized, for 207 * the particular kind of transfer, although they will not initialize 208 * any transfer flags. 209 * 210 * If the submission is successful, the complete() callback from the URB 211 * will be called exactly once, when the USB core and Host Controller Driver 212 * (HCD) are finished with the URB. When the completion function is called, 213 * control of the URB is returned to the device driver which issued the 214 * request. The completion handler may then immediately free or reuse that 215 * URB. 216 * 217 * With few exceptions, USB device drivers should never access URB fields 218 * provided by usbcore or the HCD until its complete() is called. 219 * The exceptions relate to periodic transfer scheduling. For both 220 * interrupt and isochronous urbs, as part of successful URB submission 221 * urb->interval is modified to reflect the actual transfer period used 222 * (normally some power of two units). And for isochronous urbs, 223 * urb->start_frame is modified to reflect when the URB's transfers were 224 * scheduled to start. 225 * 226 * Not all isochronous transfer scheduling policies will work, but most 227 * host controller drivers should easily handle ISO queues going from now 228 * until 10-200 msec into the future. Drivers should try to keep at 229 * least one or two msec of data in the queue; many controllers require 230 * that new transfers start at least 1 msec in the future when they are 231 * added. If the driver is unable to keep up and the queue empties out, 232 * the behavior for new submissions is governed by the URB_ISO_ASAP flag. 233 * If the flag is set, or if the queue is idle, then the URB is always 234 * assigned to the first available (and not yet expired) slot in the 235 * endpoint's schedule. If the flag is not set and the queue is active 236 * then the URB is always assigned to the next slot in the schedule 237 * following the end of the endpoint's previous URB, even if that slot is 238 * in the past. When a packet is assigned in this way to a slot that has 239 * already expired, the packet is not transmitted and the corresponding 240 * usb_iso_packet_descriptor's status field will return -EXDEV. If this 241 * would happen to all the packets in the URB, submission fails with a 242 * -EXDEV error code. 243 * 244 * For control endpoints, the synchronous usb_control_msg() call is 245 * often used (in non-interrupt context) instead of this call. 246 * That is often used through convenience wrappers, for the requests 247 * that are standardized in the USB 2.0 specification. For bulk 248 * endpoints, a synchronous usb_bulk_msg() call is available. 249 * 250 * Return: 251 * 0 on successful submissions. A negative error number otherwise. 252 * 253 * Request Queuing: 254 * 255 * URBs may be submitted to endpoints before previous ones complete, to 256 * minimize the impact of interrupt latencies and system overhead on data 257 * throughput. With that queuing policy, an endpoint's queue would never 258 * be empty. This is required for continuous isochronous data streams, 259 * and may also be required for some kinds of interrupt transfers. Such 260 * queuing also maximizes bandwidth utilization by letting USB controllers 261 * start work on later requests before driver software has finished the 262 * completion processing for earlier (successful) requests. 263 * 264 * As of Linux 2.6, all USB endpoint transfer queues support depths greater 265 * than one. This was previously a HCD-specific behavior, except for ISO 266 * transfers. Non-isochronous endpoint queues are inactive during cleanup 267 * after faults (transfer errors or cancellation). 268 * 269 * Reserved Bandwidth Transfers: 270 * 271 * Periodic transfers (interrupt or isochronous) are performed repeatedly, 272 * using the interval specified in the urb. Submitting the first urb to 273 * the endpoint reserves the bandwidth necessary to make those transfers. 274 * If the USB subsystem can't allocate sufficient bandwidth to perform 275 * the periodic request, submitting such a periodic request should fail. 276 * 277 * For devices under xHCI, the bandwidth is reserved at configuration time, or 278 * when the alt setting is selected. If there is not enough bus bandwidth, the 279 * configuration/alt setting request will fail. Therefore, submissions to 280 * periodic endpoints on devices under xHCI should never fail due to bandwidth 281 * constraints. 282 * 283 * Device drivers must explicitly request that repetition, by ensuring that 284 * some URB is always on the endpoint's queue (except possibly for short 285 * periods during completion callbacks). When there is no longer an urb 286 * queued, the endpoint's bandwidth reservation is canceled. This means 287 * drivers can use their completion handlers to ensure they keep bandwidth 288 * they need, by reinitializing and resubmitting the just-completed urb 289 * until the driver longer needs that periodic bandwidth. 290 * 291 * Memory Flags: 292 * 293 * The general rules for how to decide which mem_flags to use 294 * are the same as for kmalloc. There are four 295 * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and 296 * GFP_ATOMIC. 297 * 298 * GFP_NOFS is not ever used, as it has not been implemented yet. 299 * 300 * GFP_ATOMIC is used when 301 * (a) you are inside a completion handler, an interrupt, bottom half, 302 * tasklet or timer, or 303 * (b) you are holding a spinlock or rwlock (does not apply to 304 * semaphores), or 305 * (c) current->state != TASK_RUNNING, this is the case only after 306 * you've changed it. 307 * 308 * GFP_NOIO is used in the block io path and error handling of storage 309 * devices. 310 * 311 * All other situations use GFP_KERNEL. 312 * 313 * Some more specific rules for mem_flags can be inferred, such as 314 * (1) start_xmit, timeout, and receive methods of network drivers must 315 * use GFP_ATOMIC (they are called with a spinlock held); 316 * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also 317 * called with a spinlock held); 318 * (3) If you use a kernel thread with a network driver you must use 319 * GFP_NOIO, unless (b) or (c) apply; 320 * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c) 321 * apply or your are in a storage driver's block io path; 322 * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and 323 * (6) changing firmware on a running storage or net device uses 324 * GFP_NOIO, unless b) or c) apply 325 * 326 */ 327 int usb_submit_urb(struct urb *urb, gfp_t mem_flags) 328 { 329 static int pipetypes[4] = { 330 PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT 331 }; 332 int xfertype, max; 333 struct usb_device *dev; 334 struct usb_host_endpoint *ep; 335 int is_out; 336 unsigned int allowed; 337 338 if (!urb || !urb->complete) 339 return -EINVAL; 340 if (urb->hcpriv) { 341 WARN_ONCE(1, "URB %p submitted while active\n", urb); 342 return -EBUSY; 343 } 344 345 dev = urb->dev; 346 if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED)) 347 return -ENODEV; 348 349 /* For now, get the endpoint from the pipe. Eventually drivers 350 * will be required to set urb->ep directly and we will eliminate 351 * urb->pipe. 352 */ 353 ep = usb_pipe_endpoint(dev, urb->pipe); 354 if (!ep) 355 return -ENOENT; 356 357 urb->ep = ep; 358 urb->status = -EINPROGRESS; 359 urb->actual_length = 0; 360 361 /* Lots of sanity checks, so HCDs can rely on clean data 362 * and don't need to duplicate tests 363 */ 364 xfertype = usb_endpoint_type(&ep->desc); 365 if (xfertype == USB_ENDPOINT_XFER_CONTROL) { 366 struct usb_ctrlrequest *setup = 367 (struct usb_ctrlrequest *) urb->setup_packet; 368 369 if (!setup) 370 return -ENOEXEC; 371 is_out = !(setup->bRequestType & USB_DIR_IN) || 372 !setup->wLength; 373 } else { 374 is_out = usb_endpoint_dir_out(&ep->desc); 375 } 376 377 /* Clear the internal flags and cache the direction for later use */ 378 urb->transfer_flags &= ~(URB_DIR_MASK | URB_DMA_MAP_SINGLE | 379 URB_DMA_MAP_PAGE | URB_DMA_MAP_SG | URB_MAP_LOCAL | 380 URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL | 381 URB_DMA_SG_COMBINED); 382 urb->transfer_flags |= (is_out ? URB_DIR_OUT : URB_DIR_IN); 383 384 if (xfertype != USB_ENDPOINT_XFER_CONTROL && 385 dev->state < USB_STATE_CONFIGURED) 386 return -ENODEV; 387 388 max = usb_endpoint_maxp(&ep->desc); 389 if (max <= 0) { 390 dev_dbg(&dev->dev, 391 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n", 392 usb_endpoint_num(&ep->desc), is_out ? "out" : "in", 393 __func__, max); 394 return -EMSGSIZE; 395 } 396 397 /* periodic transfers limit size per frame/uframe, 398 * but drivers only control those sizes for ISO. 399 * while we're checking, initialize return status. 400 */ 401 if (xfertype == USB_ENDPOINT_XFER_ISOC) { 402 int n, len; 403 404 /* SuperSpeed isoc endpoints have up to 16 bursts of up to 405 * 3 packets each 406 */ 407 if (dev->speed >= USB_SPEED_SUPER) { 408 int burst = 1 + ep->ss_ep_comp.bMaxBurst; 409 int mult = USB_SS_MULT(ep->ss_ep_comp.bmAttributes); 410 max *= burst; 411 max *= mult; 412 } 413 414 /* "high bandwidth" mode, 1-3 packets/uframe? */ 415 if (dev->speed == USB_SPEED_HIGH) { 416 int mult = 1 + ((max >> 11) & 0x03); 417 max &= 0x07ff; 418 max *= mult; 419 } 420 421 if (urb->number_of_packets <= 0) 422 return -EINVAL; 423 for (n = 0; n < urb->number_of_packets; n++) { 424 len = urb->iso_frame_desc[n].length; 425 if (len < 0 || len > max) 426 return -EMSGSIZE; 427 urb->iso_frame_desc[n].status = -EXDEV; 428 urb->iso_frame_desc[n].actual_length = 0; 429 } 430 } else if (urb->num_sgs && !urb->dev->bus->no_sg_constraint && 431 dev->speed != USB_SPEED_WIRELESS) { 432 struct scatterlist *sg; 433 int i; 434 435 for_each_sg(urb->sg, sg, urb->num_sgs - 1, i) 436 if (sg->length % max) 437 return -EINVAL; 438 } 439 440 /* the I/O buffer must be mapped/unmapped, except when length=0 */ 441 if (urb->transfer_buffer_length > INT_MAX) 442 return -EMSGSIZE; 443 444 /* 445 * stuff that drivers shouldn't do, but which shouldn't 446 * cause problems in HCDs if they get it wrong. 447 */ 448 449 /* Check that the pipe's type matches the endpoint's type */ 450 if (usb_pipetype(urb->pipe) != pipetypes[xfertype]) 451 dev_WARN(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n", 452 usb_pipetype(urb->pipe), pipetypes[xfertype]); 453 454 /* Check against a simple/standard policy */ 455 allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT | URB_DIR_MASK | 456 URB_FREE_BUFFER); 457 switch (xfertype) { 458 case USB_ENDPOINT_XFER_BULK: 459 case USB_ENDPOINT_XFER_INT: 460 if (is_out) 461 allowed |= URB_ZERO_PACKET; 462 /* FALLTHROUGH */ 463 case USB_ENDPOINT_XFER_CONTROL: 464 allowed |= URB_NO_FSBR; /* only affects UHCI */ 465 /* FALLTHROUGH */ 466 default: /* all non-iso endpoints */ 467 if (!is_out) 468 allowed |= URB_SHORT_NOT_OK; 469 break; 470 case USB_ENDPOINT_XFER_ISOC: 471 allowed |= URB_ISO_ASAP; 472 break; 473 } 474 allowed &= urb->transfer_flags; 475 476 /* warn if submitter gave bogus flags */ 477 if (allowed != urb->transfer_flags) 478 dev_WARN(&dev->dev, "BOGUS urb flags, %x --> %x\n", 479 urb->transfer_flags, allowed); 480 481 /* 482 * Force periodic transfer intervals to be legal values that are 483 * a power of two (so HCDs don't need to). 484 * 485 * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC 486 * supports different values... this uses EHCI/UHCI defaults (and 487 * EHCI can use smaller non-default values). 488 */ 489 switch (xfertype) { 490 case USB_ENDPOINT_XFER_ISOC: 491 case USB_ENDPOINT_XFER_INT: 492 /* too small? */ 493 switch (dev->speed) { 494 case USB_SPEED_WIRELESS: 495 if ((urb->interval < 6) 496 && (xfertype == USB_ENDPOINT_XFER_INT)) 497 return -EINVAL; 498 default: 499 if (urb->interval <= 0) 500 return -EINVAL; 501 break; 502 } 503 /* too big? */ 504 switch (dev->speed) { 505 case USB_SPEED_SUPER_PLUS: 506 case USB_SPEED_SUPER: /* units are 125us */ 507 /* Handle up to 2^(16-1) microframes */ 508 if (urb->interval > (1 << 15)) 509 return -EINVAL; 510 max = 1 << 15; 511 break; 512 case USB_SPEED_WIRELESS: 513 if (urb->interval > 16) 514 return -EINVAL; 515 break; 516 case USB_SPEED_HIGH: /* units are microframes */ 517 /* NOTE usb handles 2^15 */ 518 if (urb->interval > (1024 * 8)) 519 urb->interval = 1024 * 8; 520 max = 1024 * 8; 521 break; 522 case USB_SPEED_FULL: /* units are frames/msec */ 523 case USB_SPEED_LOW: 524 if (xfertype == USB_ENDPOINT_XFER_INT) { 525 if (urb->interval > 255) 526 return -EINVAL; 527 /* NOTE ohci only handles up to 32 */ 528 max = 128; 529 } else { 530 if (urb->interval > 1024) 531 urb->interval = 1024; 532 /* NOTE usb and ohci handle up to 2^15 */ 533 max = 1024; 534 } 535 break; 536 default: 537 return -EINVAL; 538 } 539 if (dev->speed != USB_SPEED_WIRELESS) { 540 /* Round down to a power of 2, no more than max */ 541 urb->interval = min(max, 1 << ilog2(urb->interval)); 542 } 543 } 544 545 return usb_hcd_submit_urb(urb, mem_flags); 546 } 547 EXPORT_SYMBOL_GPL(usb_submit_urb); 548 549 /*-------------------------------------------------------------------*/ 550 551 /** 552 * usb_unlink_urb - abort/cancel a transfer request for an endpoint 553 * @urb: pointer to urb describing a previously submitted request, 554 * may be NULL 555 * 556 * This routine cancels an in-progress request. URBs complete only once 557 * per submission, and may be canceled only once per submission. 558 * Successful cancellation means termination of @urb will be expedited 559 * and the completion handler will be called with a status code 560 * indicating that the request has been canceled (rather than any other 561 * code). 562 * 563 * Drivers should not call this routine or related routines, such as 564 * usb_kill_urb() or usb_unlink_anchored_urbs(), after their disconnect 565 * method has returned. The disconnect function should synchronize with 566 * a driver's I/O routines to insure that all URB-related activity has 567 * completed before it returns. 568 * 569 * This request is asynchronous, however the HCD might call the ->complete() 570 * callback during unlink. Therefore when drivers call usb_unlink_urb(), they 571 * must not hold any locks that may be taken by the completion function. 572 * Success is indicated by returning -EINPROGRESS, at which time the URB will 573 * probably not yet have been given back to the device driver. When it is 574 * eventually called, the completion function will see @urb->status == 575 * -ECONNRESET. 576 * Failure is indicated by usb_unlink_urb() returning any other value. 577 * Unlinking will fail when @urb is not currently "linked" (i.e., it was 578 * never submitted, or it was unlinked before, or the hardware is already 579 * finished with it), even if the completion handler has not yet run. 580 * 581 * The URB must not be deallocated while this routine is running. In 582 * particular, when a driver calls this routine, it must insure that the 583 * completion handler cannot deallocate the URB. 584 * 585 * Return: -EINPROGRESS on success. See description for other values on 586 * failure. 587 * 588 * Unlinking and Endpoint Queues: 589 * 590 * [The behaviors and guarantees described below do not apply to virtual 591 * root hubs but only to endpoint queues for physical USB devices.] 592 * 593 * Host Controller Drivers (HCDs) place all the URBs for a particular 594 * endpoint in a queue. Normally the queue advances as the controller 595 * hardware processes each request. But when an URB terminates with an 596 * error its queue generally stops (see below), at least until that URB's 597 * completion routine returns. It is guaranteed that a stopped queue 598 * will not restart until all its unlinked URBs have been fully retired, 599 * with their completion routines run, even if that's not until some time 600 * after the original completion handler returns. The same behavior and 601 * guarantee apply when an URB terminates because it was unlinked. 602 * 603 * Bulk and interrupt endpoint queues are guaranteed to stop whenever an 604 * URB terminates with any sort of error, including -ECONNRESET, -ENOENT, 605 * and -EREMOTEIO. Control endpoint queues behave the same way except 606 * that they are not guaranteed to stop for -EREMOTEIO errors. Queues 607 * for isochronous endpoints are treated differently, because they must 608 * advance at fixed rates. Such queues do not stop when an URB 609 * encounters an error or is unlinked. An unlinked isochronous URB may 610 * leave a gap in the stream of packets; it is undefined whether such 611 * gaps can be filled in. 612 * 613 * Note that early termination of an URB because a short packet was 614 * received will generate a -EREMOTEIO error if and only if the 615 * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device 616 * drivers can build deep queues for large or complex bulk transfers 617 * and clean them up reliably after any sort of aborted transfer by 618 * unlinking all pending URBs at the first fault. 619 * 620 * When a control URB terminates with an error other than -EREMOTEIO, it 621 * is quite likely that the status stage of the transfer will not take 622 * place. 623 */ 624 int usb_unlink_urb(struct urb *urb) 625 { 626 if (!urb) 627 return -EINVAL; 628 if (!urb->dev) 629 return -ENODEV; 630 if (!urb->ep) 631 return -EIDRM; 632 return usb_hcd_unlink_urb(urb, -ECONNRESET); 633 } 634 EXPORT_SYMBOL_GPL(usb_unlink_urb); 635 636 /** 637 * usb_kill_urb - cancel a transfer request and wait for it to finish 638 * @urb: pointer to URB describing a previously submitted request, 639 * may be NULL 640 * 641 * This routine cancels an in-progress request. It is guaranteed that 642 * upon return all completion handlers will have finished and the URB 643 * will be totally idle and available for reuse. These features make 644 * this an ideal way to stop I/O in a disconnect() callback or close() 645 * function. If the request has not already finished or been unlinked 646 * the completion handler will see urb->status == -ENOENT. 647 * 648 * While the routine is running, attempts to resubmit the URB will fail 649 * with error -EPERM. Thus even if the URB's completion handler always 650 * tries to resubmit, it will not succeed and the URB will become idle. 651 * 652 * The URB must not be deallocated while this routine is running. In 653 * particular, when a driver calls this routine, it must insure that the 654 * completion handler cannot deallocate the URB. 655 * 656 * This routine may not be used in an interrupt context (such as a bottom 657 * half or a completion handler), or when holding a spinlock, or in other 658 * situations where the caller can't schedule(). 659 * 660 * This routine should not be called by a driver after its disconnect 661 * method has returned. 662 */ 663 void usb_kill_urb(struct urb *urb) 664 { 665 might_sleep(); 666 if (!(urb && urb->dev && urb->ep)) 667 return; 668 atomic_inc(&urb->reject); 669 670 usb_hcd_unlink_urb(urb, -ENOENT); 671 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0); 672 673 atomic_dec(&urb->reject); 674 } 675 EXPORT_SYMBOL_GPL(usb_kill_urb); 676 677 /** 678 * usb_poison_urb - reliably kill a transfer and prevent further use of an URB 679 * @urb: pointer to URB describing a previously submitted request, 680 * may be NULL 681 * 682 * This routine cancels an in-progress request. It is guaranteed that 683 * upon return all completion handlers will have finished and the URB 684 * will be totally idle and cannot be reused. These features make 685 * this an ideal way to stop I/O in a disconnect() callback. 686 * If the request has not already finished or been unlinked 687 * the completion handler will see urb->status == -ENOENT. 688 * 689 * After and while the routine runs, attempts to resubmit the URB will fail 690 * with error -EPERM. Thus even if the URB's completion handler always 691 * tries to resubmit, it will not succeed and the URB will become idle. 692 * 693 * The URB must not be deallocated while this routine is running. In 694 * particular, when a driver calls this routine, it must insure that the 695 * completion handler cannot deallocate the URB. 696 * 697 * This routine may not be used in an interrupt context (such as a bottom 698 * half or a completion handler), or when holding a spinlock, or in other 699 * situations where the caller can't schedule(). 700 * 701 * This routine should not be called by a driver after its disconnect 702 * method has returned. 703 */ 704 void usb_poison_urb(struct urb *urb) 705 { 706 might_sleep(); 707 if (!urb) 708 return; 709 atomic_inc(&urb->reject); 710 711 if (!urb->dev || !urb->ep) 712 return; 713 714 usb_hcd_unlink_urb(urb, -ENOENT); 715 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0); 716 } 717 EXPORT_SYMBOL_GPL(usb_poison_urb); 718 719 void usb_unpoison_urb(struct urb *urb) 720 { 721 if (!urb) 722 return; 723 724 atomic_dec(&urb->reject); 725 } 726 EXPORT_SYMBOL_GPL(usb_unpoison_urb); 727 728 /** 729 * usb_block_urb - reliably prevent further use of an URB 730 * @urb: pointer to URB to be blocked, may be NULL 731 * 732 * After the routine has run, attempts to resubmit the URB will fail 733 * with error -EPERM. Thus even if the URB's completion handler always 734 * tries to resubmit, it will not succeed and the URB will become idle. 735 * 736 * The URB must not be deallocated while this routine is running. In 737 * particular, when a driver calls this routine, it must insure that the 738 * completion handler cannot deallocate the URB. 739 */ 740 void usb_block_urb(struct urb *urb) 741 { 742 if (!urb) 743 return; 744 745 atomic_inc(&urb->reject); 746 } 747 EXPORT_SYMBOL_GPL(usb_block_urb); 748 749 /** 750 * usb_kill_anchored_urbs - cancel transfer requests en masse 751 * @anchor: anchor the requests are bound to 752 * 753 * this allows all outstanding URBs to be killed starting 754 * from the back of the queue 755 * 756 * This routine should not be called by a driver after its disconnect 757 * method has returned. 758 */ 759 void usb_kill_anchored_urbs(struct usb_anchor *anchor) 760 { 761 struct urb *victim; 762 763 spin_lock_irq(&anchor->lock); 764 while (!list_empty(&anchor->urb_list)) { 765 victim = list_entry(anchor->urb_list.prev, struct urb, 766 anchor_list); 767 /* we must make sure the URB isn't freed before we kill it*/ 768 usb_get_urb(victim); 769 spin_unlock_irq(&anchor->lock); 770 /* this will unanchor the URB */ 771 usb_kill_urb(victim); 772 usb_put_urb(victim); 773 spin_lock_irq(&anchor->lock); 774 } 775 spin_unlock_irq(&anchor->lock); 776 } 777 EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs); 778 779 780 /** 781 * usb_poison_anchored_urbs - cease all traffic from an anchor 782 * @anchor: anchor the requests are bound to 783 * 784 * this allows all outstanding URBs to be poisoned starting 785 * from the back of the queue. Newly added URBs will also be 786 * poisoned 787 * 788 * This routine should not be called by a driver after its disconnect 789 * method has returned. 790 */ 791 void usb_poison_anchored_urbs(struct usb_anchor *anchor) 792 { 793 struct urb *victim; 794 795 spin_lock_irq(&anchor->lock); 796 anchor->poisoned = 1; 797 while (!list_empty(&anchor->urb_list)) { 798 victim = list_entry(anchor->urb_list.prev, struct urb, 799 anchor_list); 800 /* we must make sure the URB isn't freed before we kill it*/ 801 usb_get_urb(victim); 802 spin_unlock_irq(&anchor->lock); 803 /* this will unanchor the URB */ 804 usb_poison_urb(victim); 805 usb_put_urb(victim); 806 spin_lock_irq(&anchor->lock); 807 } 808 spin_unlock_irq(&anchor->lock); 809 } 810 EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs); 811 812 /** 813 * usb_unpoison_anchored_urbs - let an anchor be used successfully again 814 * @anchor: anchor the requests are bound to 815 * 816 * Reverses the effect of usb_poison_anchored_urbs 817 * the anchor can be used normally after it returns 818 */ 819 void usb_unpoison_anchored_urbs(struct usb_anchor *anchor) 820 { 821 unsigned long flags; 822 struct urb *lazarus; 823 824 spin_lock_irqsave(&anchor->lock, flags); 825 list_for_each_entry(lazarus, &anchor->urb_list, anchor_list) { 826 usb_unpoison_urb(lazarus); 827 } 828 anchor->poisoned = 0; 829 spin_unlock_irqrestore(&anchor->lock, flags); 830 } 831 EXPORT_SYMBOL_GPL(usb_unpoison_anchored_urbs); 832 /** 833 * usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse 834 * @anchor: anchor the requests are bound to 835 * 836 * this allows all outstanding URBs to be unlinked starting 837 * from the back of the queue. This function is asynchronous. 838 * The unlinking is just triggered. It may happen after this 839 * function has returned. 840 * 841 * This routine should not be called by a driver after its disconnect 842 * method has returned. 843 */ 844 void usb_unlink_anchored_urbs(struct usb_anchor *anchor) 845 { 846 struct urb *victim; 847 848 while ((victim = usb_get_from_anchor(anchor)) != NULL) { 849 usb_unlink_urb(victim); 850 usb_put_urb(victim); 851 } 852 } 853 EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs); 854 855 /** 856 * usb_anchor_suspend_wakeups 857 * @anchor: the anchor you want to suspend wakeups on 858 * 859 * Call this to stop the last urb being unanchored from waking up any 860 * usb_wait_anchor_empty_timeout waiters. This is used in the hcd urb give- 861 * back path to delay waking up until after the completion handler has run. 862 */ 863 void usb_anchor_suspend_wakeups(struct usb_anchor *anchor) 864 { 865 if (anchor) 866 atomic_inc(&anchor->suspend_wakeups); 867 } 868 EXPORT_SYMBOL_GPL(usb_anchor_suspend_wakeups); 869 870 /** 871 * usb_anchor_resume_wakeups 872 * @anchor: the anchor you want to resume wakeups on 873 * 874 * Allow usb_wait_anchor_empty_timeout waiters to be woken up again, and 875 * wake up any current waiters if the anchor is empty. 876 */ 877 void usb_anchor_resume_wakeups(struct usb_anchor *anchor) 878 { 879 if (!anchor) 880 return; 881 882 atomic_dec(&anchor->suspend_wakeups); 883 if (usb_anchor_check_wakeup(anchor)) 884 wake_up(&anchor->wait); 885 } 886 EXPORT_SYMBOL_GPL(usb_anchor_resume_wakeups); 887 888 /** 889 * usb_wait_anchor_empty_timeout - wait for an anchor to be unused 890 * @anchor: the anchor you want to become unused 891 * @timeout: how long you are willing to wait in milliseconds 892 * 893 * Call this is you want to be sure all an anchor's 894 * URBs have finished 895 * 896 * Return: Non-zero if the anchor became unused. Zero on timeout. 897 */ 898 int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor, 899 unsigned int timeout) 900 { 901 return wait_event_timeout(anchor->wait, 902 usb_anchor_check_wakeup(anchor), 903 msecs_to_jiffies(timeout)); 904 } 905 EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout); 906 907 /** 908 * usb_get_from_anchor - get an anchor's oldest urb 909 * @anchor: the anchor whose urb you want 910 * 911 * This will take the oldest urb from an anchor, 912 * unanchor and return it 913 * 914 * Return: The oldest urb from @anchor, or %NULL if @anchor has no 915 * urbs associated with it. 916 */ 917 struct urb *usb_get_from_anchor(struct usb_anchor *anchor) 918 { 919 struct urb *victim; 920 unsigned long flags; 921 922 spin_lock_irqsave(&anchor->lock, flags); 923 if (!list_empty(&anchor->urb_list)) { 924 victim = list_entry(anchor->urb_list.next, struct urb, 925 anchor_list); 926 usb_get_urb(victim); 927 __usb_unanchor_urb(victim, anchor); 928 } else { 929 victim = NULL; 930 } 931 spin_unlock_irqrestore(&anchor->lock, flags); 932 933 return victim; 934 } 935 936 EXPORT_SYMBOL_GPL(usb_get_from_anchor); 937 938 /** 939 * usb_scuttle_anchored_urbs - unanchor all an anchor's urbs 940 * @anchor: the anchor whose urbs you want to unanchor 941 * 942 * use this to get rid of all an anchor's urbs 943 */ 944 void usb_scuttle_anchored_urbs(struct usb_anchor *anchor) 945 { 946 struct urb *victim; 947 unsigned long flags; 948 949 spin_lock_irqsave(&anchor->lock, flags); 950 while (!list_empty(&anchor->urb_list)) { 951 victim = list_entry(anchor->urb_list.prev, struct urb, 952 anchor_list); 953 __usb_unanchor_urb(victim, anchor); 954 } 955 spin_unlock_irqrestore(&anchor->lock, flags); 956 } 957 958 EXPORT_SYMBOL_GPL(usb_scuttle_anchored_urbs); 959 960 /** 961 * usb_anchor_empty - is an anchor empty 962 * @anchor: the anchor you want to query 963 * 964 * Return: 1 if the anchor has no urbs associated with it. 965 */ 966 int usb_anchor_empty(struct usb_anchor *anchor) 967 { 968 return list_empty(&anchor->urb_list); 969 } 970 971 EXPORT_SYMBOL_GPL(usb_anchor_empty); 972 973