1 #include <linux/module.h> 2 #include <linux/string.h> 3 #include <linux/bitops.h> 4 #include <linux/slab.h> 5 #include <linux/init.h> 6 #include <linux/log2.h> 7 #include <linux/usb.h> 8 #include <linux/wait.h> 9 #include <linux/usb/hcd.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, incrementes the usage counter, and returns a pointer to it. 56 * 57 * If no memory is available, NULL is returned. 58 * 59 * If the driver want to use this urb for interrupt, control, or bulk 60 * endpoints, pass '0' as the number of iso packets. 61 * 62 * The driver must call usb_free_urb() when it is finished with the urb. 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 printk(KERN_ERR "alloc_urb: kmalloc failed\n"); 73 return NULL; 74 } 75 usb_init_urb(urb); 76 return urb; 77 } 78 EXPORT_SYMBOL_GPL(usb_alloc_urb); 79 80 /** 81 * usb_free_urb - frees the memory used by a urb when all users of it are finished 82 * @urb: pointer to the urb to free, may be NULL 83 * 84 * Must be called when a user of a urb is finished with it. When the last user 85 * of the urb calls this function, the memory of the urb is freed. 86 * 87 * Note: The transfer buffer associated with the urb is not freed unless the 88 * URB_FREE_BUFFER transfer flag is set. 89 */ 90 void usb_free_urb(struct urb *urb) 91 { 92 if (urb) 93 kref_put(&urb->kref, urb_destroy); 94 } 95 EXPORT_SYMBOL_GPL(usb_free_urb); 96 97 /** 98 * usb_get_urb - increments the reference count of the urb 99 * @urb: pointer to the urb to modify, may be NULL 100 * 101 * This must be called whenever a urb is transferred from a device driver to a 102 * host controller driver. This allows proper reference counting to happen 103 * for urbs. 104 * 105 * A pointer to the urb with the incremented reference counter is returned. 106 */ 107 struct urb *usb_get_urb(struct urb *urb) 108 { 109 if (urb) 110 kref_get(&urb->kref); 111 return urb; 112 } 113 EXPORT_SYMBOL_GPL(usb_get_urb); 114 115 /** 116 * usb_anchor_urb - anchors an URB while it is processed 117 * @urb: pointer to the urb to anchor 118 * @anchor: pointer to the anchor 119 * 120 * This can be called to have access to URBs which are to be executed 121 * without bothering to track them 122 */ 123 void usb_anchor_urb(struct urb *urb, struct usb_anchor *anchor) 124 { 125 unsigned long flags; 126 127 spin_lock_irqsave(&anchor->lock, flags); 128 usb_get_urb(urb); 129 list_add_tail(&urb->anchor_list, &anchor->urb_list); 130 urb->anchor = anchor; 131 132 if (unlikely(anchor->poisoned)) { 133 atomic_inc(&urb->reject); 134 } 135 136 spin_unlock_irqrestore(&anchor->lock, flags); 137 } 138 EXPORT_SYMBOL_GPL(usb_anchor_urb); 139 140 /** 141 * usb_unanchor_urb - unanchors an URB 142 * @urb: pointer to the urb to anchor 143 * 144 * Call this to stop the system keeping track of this URB 145 */ 146 void usb_unanchor_urb(struct urb *urb) 147 { 148 unsigned long flags; 149 struct usb_anchor *anchor; 150 151 if (!urb) 152 return; 153 154 anchor = urb->anchor; 155 if (!anchor) 156 return; 157 158 spin_lock_irqsave(&anchor->lock, flags); 159 if (unlikely(anchor != urb->anchor)) { 160 /* we've lost the race to another thread */ 161 spin_unlock_irqrestore(&anchor->lock, flags); 162 return; 163 } 164 urb->anchor = NULL; 165 list_del(&urb->anchor_list); 166 spin_unlock_irqrestore(&anchor->lock, flags); 167 usb_put_urb(urb); 168 if (list_empty(&anchor->urb_list)) 169 wake_up(&anchor->wait); 170 } 171 EXPORT_SYMBOL_GPL(usb_unanchor_urb); 172 173 /*-------------------------------------------------------------------*/ 174 175 /** 176 * usb_submit_urb - issue an asynchronous transfer request for an endpoint 177 * @urb: pointer to the urb describing the request 178 * @mem_flags: the type of memory to allocate, see kmalloc() for a list 179 * of valid options for this. 180 * 181 * This submits a transfer request, and transfers control of the URB 182 * describing that request to the USB subsystem. Request completion will 183 * be indicated later, asynchronously, by calling the completion handler. 184 * The three types of completion are success, error, and unlink 185 * (a software-induced fault, also called "request cancellation"). 186 * 187 * URBs may be submitted in interrupt context. 188 * 189 * The caller must have correctly initialized the URB before submitting 190 * it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are 191 * available to ensure that most fields are correctly initialized, for 192 * the particular kind of transfer, although they will not initialize 193 * any transfer flags. 194 * 195 * Successful submissions return 0; otherwise this routine returns a 196 * negative error number. If the submission is successful, the complete() 197 * callback from the URB will be called exactly once, when the USB core and 198 * Host Controller Driver (HCD) are finished with the URB. When the completion 199 * function is called, control of the URB is returned to the device 200 * driver which issued the request. The completion handler may then 201 * immediately free or reuse that URB. 202 * 203 * With few exceptions, USB device drivers should never access URB fields 204 * provided by usbcore or the HCD until its complete() is called. 205 * The exceptions relate to periodic transfer scheduling. For both 206 * interrupt and isochronous urbs, as part of successful URB submission 207 * urb->interval is modified to reflect the actual transfer period used 208 * (normally some power of two units). And for isochronous urbs, 209 * urb->start_frame is modified to reflect when the URB's transfers were 210 * scheduled to start. Not all isochronous transfer scheduling policies 211 * will work, but most host controller drivers should easily handle ISO 212 * queues going from now until 10-200 msec into the future. 213 * 214 * For control endpoints, the synchronous usb_control_msg() call is 215 * often used (in non-interrupt context) instead of this call. 216 * That is often used through convenience wrappers, for the requests 217 * that are standardized in the USB 2.0 specification. For bulk 218 * endpoints, a synchronous usb_bulk_msg() call is available. 219 * 220 * Request Queuing: 221 * 222 * URBs may be submitted to endpoints before previous ones complete, to 223 * minimize the impact of interrupt latencies and system overhead on data 224 * throughput. With that queuing policy, an endpoint's queue would never 225 * be empty. This is required for continuous isochronous data streams, 226 * and may also be required for some kinds of interrupt transfers. Such 227 * queuing also maximizes bandwidth utilization by letting USB controllers 228 * start work on later requests before driver software has finished the 229 * completion processing for earlier (successful) requests. 230 * 231 * As of Linux 2.6, all USB endpoint transfer queues support depths greater 232 * than one. This was previously a HCD-specific behavior, except for ISO 233 * transfers. Non-isochronous endpoint queues are inactive during cleanup 234 * after faults (transfer errors or cancellation). 235 * 236 * Reserved Bandwidth Transfers: 237 * 238 * Periodic transfers (interrupt or isochronous) are performed repeatedly, 239 * using the interval specified in the urb. Submitting the first urb to 240 * the endpoint reserves the bandwidth necessary to make those transfers. 241 * If the USB subsystem can't allocate sufficient bandwidth to perform 242 * the periodic request, submitting such a periodic request should fail. 243 * 244 * For devices under xHCI, the bandwidth is reserved at configuration time, or 245 * when the alt setting is selected. If there is not enough bus bandwidth, the 246 * configuration/alt setting request will fail. Therefore, submissions to 247 * periodic endpoints on devices under xHCI should never fail due to bandwidth 248 * constraints. 249 * 250 * Device drivers must explicitly request that repetition, by ensuring that 251 * some URB is always on the endpoint's queue (except possibly for short 252 * periods during completion callacks). When there is no longer an urb 253 * queued, the endpoint's bandwidth reservation is canceled. This means 254 * drivers can use their completion handlers to ensure they keep bandwidth 255 * they need, by reinitializing and resubmitting the just-completed urb 256 * until the driver longer needs that periodic bandwidth. 257 * 258 * Memory Flags: 259 * 260 * The general rules for how to decide which mem_flags to use 261 * are the same as for kmalloc. There are four 262 * different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and 263 * GFP_ATOMIC. 264 * 265 * GFP_NOFS is not ever used, as it has not been implemented yet. 266 * 267 * GFP_ATOMIC is used when 268 * (a) you are inside a completion handler, an interrupt, bottom half, 269 * tasklet or timer, or 270 * (b) you are holding a spinlock or rwlock (does not apply to 271 * semaphores), or 272 * (c) current->state != TASK_RUNNING, this is the case only after 273 * you've changed it. 274 * 275 * GFP_NOIO is used in the block io path and error handling of storage 276 * devices. 277 * 278 * All other situations use GFP_KERNEL. 279 * 280 * Some more specific rules for mem_flags can be inferred, such as 281 * (1) start_xmit, timeout, and receive methods of network drivers must 282 * use GFP_ATOMIC (they are called with a spinlock held); 283 * (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also 284 * called with a spinlock held); 285 * (3) If you use a kernel thread with a network driver you must use 286 * GFP_NOIO, unless (b) or (c) apply; 287 * (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c) 288 * apply or your are in a storage driver's block io path; 289 * (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and 290 * (6) changing firmware on a running storage or net device uses 291 * GFP_NOIO, unless b) or c) apply 292 * 293 */ 294 int usb_submit_urb(struct urb *urb, gfp_t mem_flags) 295 { 296 int xfertype, max; 297 struct usb_device *dev; 298 struct usb_host_endpoint *ep; 299 int is_out; 300 301 if (!urb || urb->hcpriv || !urb->complete) 302 return -EINVAL; 303 dev = urb->dev; 304 if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED)) 305 return -ENODEV; 306 307 /* For now, get the endpoint from the pipe. Eventually drivers 308 * will be required to set urb->ep directly and we will eliminate 309 * urb->pipe. 310 */ 311 ep = usb_pipe_endpoint(dev, urb->pipe); 312 if (!ep) 313 return -ENOENT; 314 315 urb->ep = ep; 316 urb->status = -EINPROGRESS; 317 urb->actual_length = 0; 318 319 /* Lots of sanity checks, so HCDs can rely on clean data 320 * and don't need to duplicate tests 321 */ 322 xfertype = usb_endpoint_type(&ep->desc); 323 if (xfertype == USB_ENDPOINT_XFER_CONTROL) { 324 struct usb_ctrlrequest *setup = 325 (struct usb_ctrlrequest *) urb->setup_packet; 326 327 if (!setup) 328 return -ENOEXEC; 329 is_out = !(setup->bRequestType & USB_DIR_IN) || 330 !setup->wLength; 331 } else { 332 is_out = usb_endpoint_dir_out(&ep->desc); 333 } 334 335 /* Clear the internal flags and cache the direction for later use */ 336 urb->transfer_flags &= ~(URB_DIR_MASK | URB_DMA_MAP_SINGLE | 337 URB_DMA_MAP_PAGE | URB_DMA_MAP_SG | URB_MAP_LOCAL | 338 URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL | 339 URB_DMA_SG_COMBINED); 340 urb->transfer_flags |= (is_out ? URB_DIR_OUT : URB_DIR_IN); 341 342 if (xfertype != USB_ENDPOINT_XFER_CONTROL && 343 dev->state < USB_STATE_CONFIGURED) 344 return -ENODEV; 345 346 max = le16_to_cpu(ep->desc.wMaxPacketSize); 347 if (max <= 0) { 348 dev_dbg(&dev->dev, 349 "bogus endpoint ep%d%s in %s (bad maxpacket %d)\n", 350 usb_endpoint_num(&ep->desc), is_out ? "out" : "in", 351 __func__, max); 352 return -EMSGSIZE; 353 } 354 355 /* periodic transfers limit size per frame/uframe, 356 * but drivers only control those sizes for ISO. 357 * while we're checking, initialize return status. 358 */ 359 if (xfertype == USB_ENDPOINT_XFER_ISOC) { 360 int n, len; 361 362 /* FIXME SuperSpeed isoc endpoints have up to 16 bursts */ 363 /* "high bandwidth" mode, 1-3 packets/uframe? */ 364 if (dev->speed == USB_SPEED_HIGH) { 365 int mult = 1 + ((max >> 11) & 0x03); 366 max &= 0x07ff; 367 max *= mult; 368 } 369 370 if (urb->number_of_packets <= 0) 371 return -EINVAL; 372 for (n = 0; n < urb->number_of_packets; n++) { 373 len = urb->iso_frame_desc[n].length; 374 if (len < 0 || len > max) 375 return -EMSGSIZE; 376 urb->iso_frame_desc[n].status = -EXDEV; 377 urb->iso_frame_desc[n].actual_length = 0; 378 } 379 } 380 381 /* the I/O buffer must be mapped/unmapped, except when length=0 */ 382 if (urb->transfer_buffer_length > INT_MAX) 383 return -EMSGSIZE; 384 385 #ifdef DEBUG 386 /* stuff that drivers shouldn't do, but which shouldn't 387 * cause problems in HCDs if they get it wrong. 388 */ 389 { 390 unsigned int orig_flags = urb->transfer_flags; 391 unsigned int allowed; 392 static int pipetypes[4] = { 393 PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT 394 }; 395 396 /* Check that the pipe's type matches the endpoint's type */ 397 if (usb_pipetype(urb->pipe) != pipetypes[xfertype]) 398 return -EPIPE; /* The most suitable error code :-) */ 399 400 /* enforce simple/standard policy */ 401 allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT | URB_DIR_MASK | 402 URB_FREE_BUFFER); 403 switch (xfertype) { 404 case USB_ENDPOINT_XFER_BULK: 405 if (is_out) 406 allowed |= URB_ZERO_PACKET; 407 /* FALLTHROUGH */ 408 case USB_ENDPOINT_XFER_CONTROL: 409 allowed |= URB_NO_FSBR; /* only affects UHCI */ 410 /* FALLTHROUGH */ 411 default: /* all non-iso endpoints */ 412 if (!is_out) 413 allowed |= URB_SHORT_NOT_OK; 414 break; 415 case USB_ENDPOINT_XFER_ISOC: 416 allowed |= URB_ISO_ASAP; 417 break; 418 } 419 urb->transfer_flags &= allowed; 420 421 /* fail if submitter gave bogus flags */ 422 if (urb->transfer_flags != orig_flags) { 423 dev_err(&dev->dev, "BOGUS urb flags, %x --> %x\n", 424 orig_flags, urb->transfer_flags); 425 return -EINVAL; 426 } 427 } 428 #endif 429 /* 430 * Force periodic transfer intervals to be legal values that are 431 * a power of two (so HCDs don't need to). 432 * 433 * FIXME want bus->{intr,iso}_sched_horizon values here. Each HC 434 * supports different values... this uses EHCI/UHCI defaults (and 435 * EHCI can use smaller non-default values). 436 */ 437 switch (xfertype) { 438 case USB_ENDPOINT_XFER_ISOC: 439 case USB_ENDPOINT_XFER_INT: 440 /* too small? */ 441 switch (dev->speed) { 442 case USB_SPEED_WIRELESS: 443 if (urb->interval < 6) 444 return -EINVAL; 445 break; 446 default: 447 if (urb->interval <= 0) 448 return -EINVAL; 449 break; 450 } 451 /* too big? */ 452 switch (dev->speed) { 453 case USB_SPEED_SUPER: /* units are 125us */ 454 /* Handle up to 2^(16-1) microframes */ 455 if (urb->interval > (1 << 15)) 456 return -EINVAL; 457 max = 1 << 15; 458 break; 459 case USB_SPEED_WIRELESS: 460 if (urb->interval > 16) 461 return -EINVAL; 462 break; 463 case USB_SPEED_HIGH: /* units are microframes */ 464 /* NOTE usb handles 2^15 */ 465 if (urb->interval > (1024 * 8)) 466 urb->interval = 1024 * 8; 467 max = 1024 * 8; 468 break; 469 case USB_SPEED_FULL: /* units are frames/msec */ 470 case USB_SPEED_LOW: 471 if (xfertype == USB_ENDPOINT_XFER_INT) { 472 if (urb->interval > 255) 473 return -EINVAL; 474 /* NOTE ohci only handles up to 32 */ 475 max = 128; 476 } else { 477 if (urb->interval > 1024) 478 urb->interval = 1024; 479 /* NOTE usb and ohci handle up to 2^15 */ 480 max = 1024; 481 } 482 break; 483 default: 484 return -EINVAL; 485 } 486 if (dev->speed != USB_SPEED_WIRELESS) { 487 /* Round down to a power of 2, no more than max */ 488 urb->interval = min(max, 1 << ilog2(urb->interval)); 489 } 490 } 491 492 return usb_hcd_submit_urb(urb, mem_flags); 493 } 494 EXPORT_SYMBOL_GPL(usb_submit_urb); 495 496 /*-------------------------------------------------------------------*/ 497 498 /** 499 * usb_unlink_urb - abort/cancel a transfer request for an endpoint 500 * @urb: pointer to urb describing a previously submitted request, 501 * may be NULL 502 * 503 * This routine cancels an in-progress request. URBs complete only once 504 * per submission, and may be canceled only once per submission. 505 * Successful cancellation means termination of @urb will be expedited 506 * and the completion handler will be called with a status code 507 * indicating that the request has been canceled (rather than any other 508 * code). 509 * 510 * Drivers should not call this routine or related routines, such as 511 * usb_kill_urb() or usb_unlink_anchored_urbs(), after their disconnect 512 * method has returned. The disconnect function should synchronize with 513 * a driver's I/O routines to insure that all URB-related activity has 514 * completed before it returns. 515 * 516 * This request is always asynchronous. Success is indicated by 517 * returning -EINPROGRESS, at which time the URB will probably not yet 518 * have been given back to the device driver. When it is eventually 519 * called, the completion function will see @urb->status == -ECONNRESET. 520 * Failure is indicated by usb_unlink_urb() returning any other value. 521 * Unlinking will fail when @urb is not currently "linked" (i.e., it was 522 * never submitted, or it was unlinked before, or the hardware is already 523 * finished with it), even if the completion handler has not yet run. 524 * 525 * Unlinking and Endpoint Queues: 526 * 527 * [The behaviors and guarantees described below do not apply to virtual 528 * root hubs but only to endpoint queues for physical USB devices.] 529 * 530 * Host Controller Drivers (HCDs) place all the URBs for a particular 531 * endpoint in a queue. Normally the queue advances as the controller 532 * hardware processes each request. But when an URB terminates with an 533 * error its queue generally stops (see below), at least until that URB's 534 * completion routine returns. It is guaranteed that a stopped queue 535 * will not restart until all its unlinked URBs have been fully retired, 536 * with their completion routines run, even if that's not until some time 537 * after the original completion handler returns. The same behavior and 538 * guarantee apply when an URB terminates because it was unlinked. 539 * 540 * Bulk and interrupt endpoint queues are guaranteed to stop whenever an 541 * URB terminates with any sort of error, including -ECONNRESET, -ENOENT, 542 * and -EREMOTEIO. Control endpoint queues behave the same way except 543 * that they are not guaranteed to stop for -EREMOTEIO errors. Queues 544 * for isochronous endpoints are treated differently, because they must 545 * advance at fixed rates. Such queues do not stop when an URB 546 * encounters an error or is unlinked. An unlinked isochronous URB may 547 * leave a gap in the stream of packets; it is undefined whether such 548 * gaps can be filled in. 549 * 550 * Note that early termination of an URB because a short packet was 551 * received will generate a -EREMOTEIO error if and only if the 552 * URB_SHORT_NOT_OK flag is set. By setting this flag, USB device 553 * drivers can build deep queues for large or complex bulk transfers 554 * and clean them up reliably after any sort of aborted transfer by 555 * unlinking all pending URBs at the first fault. 556 * 557 * When a control URB terminates with an error other than -EREMOTEIO, it 558 * is quite likely that the status stage of the transfer will not take 559 * place. 560 */ 561 int usb_unlink_urb(struct urb *urb) 562 { 563 if (!urb) 564 return -EINVAL; 565 if (!urb->dev) 566 return -ENODEV; 567 if (!urb->ep) 568 return -EIDRM; 569 return usb_hcd_unlink_urb(urb, -ECONNRESET); 570 } 571 EXPORT_SYMBOL_GPL(usb_unlink_urb); 572 573 /** 574 * usb_kill_urb - cancel a transfer request and wait for it to finish 575 * @urb: pointer to URB describing a previously submitted request, 576 * may be NULL 577 * 578 * This routine cancels an in-progress request. It is guaranteed that 579 * upon return all completion handlers will have finished and the URB 580 * will be totally idle and available for reuse. These features make 581 * this an ideal way to stop I/O in a disconnect() callback or close() 582 * function. If the request has not already finished or been unlinked 583 * the completion handler will see urb->status == -ENOENT. 584 * 585 * While the routine is running, attempts to resubmit the URB will fail 586 * with error -EPERM. Thus even if the URB's completion handler always 587 * tries to resubmit, it will not succeed and the URB will become idle. 588 * 589 * This routine may not be used in an interrupt context (such as a bottom 590 * half or a completion handler), or when holding a spinlock, or in other 591 * situations where the caller can't schedule(). 592 * 593 * This routine should not be called by a driver after its disconnect 594 * method has returned. 595 */ 596 void usb_kill_urb(struct urb *urb) 597 { 598 might_sleep(); 599 if (!(urb && urb->dev && urb->ep)) 600 return; 601 atomic_inc(&urb->reject); 602 603 usb_hcd_unlink_urb(urb, -ENOENT); 604 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0); 605 606 atomic_dec(&urb->reject); 607 } 608 EXPORT_SYMBOL_GPL(usb_kill_urb); 609 610 /** 611 * usb_poison_urb - reliably kill a transfer and prevent further use of an URB 612 * @urb: pointer to URB describing a previously submitted request, 613 * may be NULL 614 * 615 * This routine cancels an in-progress request. It is guaranteed that 616 * upon return all completion handlers will have finished and the URB 617 * will be totally idle and cannot be reused. These features make 618 * this an ideal way to stop I/O in a disconnect() callback. 619 * If the request has not already finished or been unlinked 620 * the completion handler will see urb->status == -ENOENT. 621 * 622 * After and while the routine runs, attempts to resubmit the URB will fail 623 * with error -EPERM. Thus even if the URB's completion handler always 624 * tries to resubmit, it will not succeed and the URB will become idle. 625 * 626 * This routine may not be used in an interrupt context (such as a bottom 627 * half or a completion handler), or when holding a spinlock, or in other 628 * situations where the caller can't schedule(). 629 * 630 * This routine should not be called by a driver after its disconnect 631 * method has returned. 632 */ 633 void usb_poison_urb(struct urb *urb) 634 { 635 might_sleep(); 636 if (!(urb && urb->dev && urb->ep)) 637 return; 638 atomic_inc(&urb->reject); 639 640 usb_hcd_unlink_urb(urb, -ENOENT); 641 wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0); 642 } 643 EXPORT_SYMBOL_GPL(usb_poison_urb); 644 645 void usb_unpoison_urb(struct urb *urb) 646 { 647 if (!urb) 648 return; 649 650 atomic_dec(&urb->reject); 651 } 652 EXPORT_SYMBOL_GPL(usb_unpoison_urb); 653 654 /** 655 * usb_kill_anchored_urbs - cancel transfer requests en masse 656 * @anchor: anchor the requests are bound to 657 * 658 * this allows all outstanding URBs to be killed starting 659 * from the back of the queue 660 * 661 * This routine should not be called by a driver after its disconnect 662 * method has returned. 663 */ 664 void usb_kill_anchored_urbs(struct usb_anchor *anchor) 665 { 666 struct urb *victim; 667 668 spin_lock_irq(&anchor->lock); 669 while (!list_empty(&anchor->urb_list)) { 670 victim = list_entry(anchor->urb_list.prev, struct urb, 671 anchor_list); 672 /* we must make sure the URB isn't freed before we kill it*/ 673 usb_get_urb(victim); 674 spin_unlock_irq(&anchor->lock); 675 /* this will unanchor the URB */ 676 usb_kill_urb(victim); 677 usb_put_urb(victim); 678 spin_lock_irq(&anchor->lock); 679 } 680 spin_unlock_irq(&anchor->lock); 681 } 682 EXPORT_SYMBOL_GPL(usb_kill_anchored_urbs); 683 684 685 /** 686 * usb_poison_anchored_urbs - cease all traffic from an anchor 687 * @anchor: anchor the requests are bound to 688 * 689 * this allows all outstanding URBs to be poisoned starting 690 * from the back of the queue. Newly added URBs will also be 691 * poisoned 692 * 693 * This routine should not be called by a driver after its disconnect 694 * method has returned. 695 */ 696 void usb_poison_anchored_urbs(struct usb_anchor *anchor) 697 { 698 struct urb *victim; 699 700 spin_lock_irq(&anchor->lock); 701 anchor->poisoned = 1; 702 while (!list_empty(&anchor->urb_list)) { 703 victim = list_entry(anchor->urb_list.prev, struct urb, 704 anchor_list); 705 /* we must make sure the URB isn't freed before we kill it*/ 706 usb_get_urb(victim); 707 spin_unlock_irq(&anchor->lock); 708 /* this will unanchor the URB */ 709 usb_poison_urb(victim); 710 usb_put_urb(victim); 711 spin_lock_irq(&anchor->lock); 712 } 713 spin_unlock_irq(&anchor->lock); 714 } 715 EXPORT_SYMBOL_GPL(usb_poison_anchored_urbs); 716 717 /** 718 * usb_unpoison_anchored_urbs - let an anchor be used successfully again 719 * @anchor: anchor the requests are bound to 720 * 721 * Reverses the effect of usb_poison_anchored_urbs 722 * the anchor can be used normally after it returns 723 */ 724 void usb_unpoison_anchored_urbs(struct usb_anchor *anchor) 725 { 726 unsigned long flags; 727 struct urb *lazarus; 728 729 spin_lock_irqsave(&anchor->lock, flags); 730 list_for_each_entry(lazarus, &anchor->urb_list, anchor_list) { 731 usb_unpoison_urb(lazarus); 732 } 733 anchor->poisoned = 0; 734 spin_unlock_irqrestore(&anchor->lock, flags); 735 } 736 EXPORT_SYMBOL_GPL(usb_unpoison_anchored_urbs); 737 /** 738 * usb_unlink_anchored_urbs - asynchronously cancel transfer requests en masse 739 * @anchor: anchor the requests are bound to 740 * 741 * this allows all outstanding URBs to be unlinked starting 742 * from the back of the queue. This function is asynchronous. 743 * The unlinking is just tiggered. It may happen after this 744 * function has returned. 745 * 746 * This routine should not be called by a driver after its disconnect 747 * method has returned. 748 */ 749 void usb_unlink_anchored_urbs(struct usb_anchor *anchor) 750 { 751 struct urb *victim; 752 unsigned long flags; 753 754 spin_lock_irqsave(&anchor->lock, flags); 755 while (!list_empty(&anchor->urb_list)) { 756 victim = list_entry(anchor->urb_list.prev, struct urb, 757 anchor_list); 758 usb_get_urb(victim); 759 spin_unlock_irqrestore(&anchor->lock, flags); 760 /* this will unanchor the URB */ 761 usb_unlink_urb(victim); 762 usb_put_urb(victim); 763 spin_lock_irqsave(&anchor->lock, flags); 764 } 765 spin_unlock_irqrestore(&anchor->lock, flags); 766 } 767 EXPORT_SYMBOL_GPL(usb_unlink_anchored_urbs); 768 769 /** 770 * usb_wait_anchor_empty_timeout - wait for an anchor to be unused 771 * @anchor: the anchor you want to become unused 772 * @timeout: how long you are willing to wait in milliseconds 773 * 774 * Call this is you want to be sure all an anchor's 775 * URBs have finished 776 */ 777 int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor, 778 unsigned int timeout) 779 { 780 return wait_event_timeout(anchor->wait, list_empty(&anchor->urb_list), 781 msecs_to_jiffies(timeout)); 782 } 783 EXPORT_SYMBOL_GPL(usb_wait_anchor_empty_timeout); 784 785 /** 786 * usb_get_from_anchor - get an anchor's oldest urb 787 * @anchor: the anchor whose urb you want 788 * 789 * this will take the oldest urb from an anchor, 790 * unanchor and return it 791 */ 792 struct urb *usb_get_from_anchor(struct usb_anchor *anchor) 793 { 794 struct urb *victim; 795 unsigned long flags; 796 797 spin_lock_irqsave(&anchor->lock, flags); 798 if (!list_empty(&anchor->urb_list)) { 799 victim = list_entry(anchor->urb_list.next, struct urb, 800 anchor_list); 801 usb_get_urb(victim); 802 spin_unlock_irqrestore(&anchor->lock, flags); 803 usb_unanchor_urb(victim); 804 } else { 805 spin_unlock_irqrestore(&anchor->lock, flags); 806 victim = NULL; 807 } 808 809 return victim; 810 } 811 812 EXPORT_SYMBOL_GPL(usb_get_from_anchor); 813 814 /** 815 * usb_scuttle_anchored_urbs - unanchor all an anchor's urbs 816 * @anchor: the anchor whose urbs you want to unanchor 817 * 818 * use this to get rid of all an anchor's urbs 819 */ 820 void usb_scuttle_anchored_urbs(struct usb_anchor *anchor) 821 { 822 struct urb *victim; 823 unsigned long flags; 824 825 spin_lock_irqsave(&anchor->lock, flags); 826 while (!list_empty(&anchor->urb_list)) { 827 victim = list_entry(anchor->urb_list.prev, struct urb, 828 anchor_list); 829 usb_get_urb(victim); 830 spin_unlock_irqrestore(&anchor->lock, flags); 831 /* this may free the URB */ 832 usb_unanchor_urb(victim); 833 usb_put_urb(victim); 834 spin_lock_irqsave(&anchor->lock, flags); 835 } 836 spin_unlock_irqrestore(&anchor->lock, flags); 837 } 838 839 EXPORT_SYMBOL_GPL(usb_scuttle_anchored_urbs); 840 841 /** 842 * usb_anchor_empty - is an anchor empty 843 * @anchor: the anchor you want to query 844 * 845 * returns 1 if the anchor has no urbs associated with it 846 */ 847 int usb_anchor_empty(struct usb_anchor *anchor) 848 { 849 return list_empty(&anchor->urb_list); 850 } 851 852 EXPORT_SYMBOL_GPL(usb_anchor_empty); 853 854