1 /* 2 * scsi_error.c Copyright (C) 1997 Eric Youngdale 3 * 4 * SCSI error/timeout handling 5 * Initial versions: Eric Youngdale. Based upon conversations with 6 * Leonard Zubkoff and David Miller at Linux Expo, 7 * ideas originating from all over the place. 8 * 9 * Restructured scsi_unjam_host and associated functions. 10 * September 04, 2002 Mike Anderson (andmike@us.ibm.com) 11 * 12 * Forward port of Russell King's (rmk@arm.linux.org.uk) changes and 13 * minor cleanups. 14 * September 30, 2002 Mike Anderson (andmike@us.ibm.com) 15 */ 16 17 #include <linux/module.h> 18 #include <linux/sched.h> 19 #include <linux/timer.h> 20 #include <linux/string.h> 21 #include <linux/slab.h> 22 #include <linux/kernel.h> 23 #include <linux/interrupt.h> 24 #include <linux/blkdev.h> 25 #include <linux/delay.h> 26 27 #include <scsi/scsi.h> 28 #include <scsi/scsi_dbg.h> 29 #include <scsi/scsi_device.h> 30 #include <scsi/scsi_eh.h> 31 #include <scsi/scsi_host.h> 32 #include <scsi/scsi_ioctl.h> 33 #include <scsi/scsi_request.h> 34 35 #include "scsi_priv.h" 36 #include "scsi_logging.h" 37 38 #define SENSE_TIMEOUT (10*HZ) 39 #define START_UNIT_TIMEOUT (30*HZ) 40 41 /* 42 * These should *probably* be handled by the host itself. 43 * Since it is allowed to sleep, it probably should. 44 */ 45 #define BUS_RESET_SETTLE_TIME (10) 46 #define HOST_RESET_SETTLE_TIME (10) 47 48 /* called with shost->host_lock held */ 49 void scsi_eh_wakeup(struct Scsi_Host *shost) 50 { 51 if (shost->host_busy == shost->host_failed) { 52 up(shost->eh_wait); 53 SCSI_LOG_ERROR_RECOVERY(5, 54 printk("Waking error handler thread\n")); 55 } 56 } 57 58 /** 59 * scsi_eh_scmd_add - add scsi cmd to error handling. 60 * @scmd: scmd to run eh on. 61 * @eh_flag: optional SCSI_EH flag. 62 * 63 * Return value: 64 * 0 on failure. 65 **/ 66 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag) 67 { 68 struct Scsi_Host *shost = scmd->device->host; 69 unsigned long flags; 70 71 if (shost->eh_wait == NULL) 72 return 0; 73 74 spin_lock_irqsave(shost->host_lock, flags); 75 76 scmd->eh_eflags |= eh_flag; 77 list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q); 78 set_bit(SHOST_RECOVERY, &shost->shost_state); 79 shost->host_failed++; 80 scsi_eh_wakeup(shost); 81 spin_unlock_irqrestore(shost->host_lock, flags); 82 return 1; 83 } 84 85 /** 86 * scsi_add_timer - Start timeout timer for a single scsi command. 87 * @scmd: scsi command that is about to start running. 88 * @timeout: amount of time to allow this command to run. 89 * @complete: timeout function to call if timer isn't canceled. 90 * 91 * Notes: 92 * This should be turned into an inline function. Each scsi command 93 * has its own timer, and as it is added to the queue, we set up the 94 * timer. When the command completes, we cancel the timer. 95 **/ 96 void scsi_add_timer(struct scsi_cmnd *scmd, int timeout, 97 void (*complete)(struct scsi_cmnd *)) 98 { 99 100 /* 101 * If the clock was already running for this command, then 102 * first delete the timer. The timer handling code gets rather 103 * confused if we don't do this. 104 */ 105 if (scmd->eh_timeout.function) 106 del_timer(&scmd->eh_timeout); 107 108 scmd->eh_timeout.data = (unsigned long)scmd; 109 scmd->eh_timeout.expires = jiffies + timeout; 110 scmd->eh_timeout.function = (void (*)(unsigned long)) complete; 111 112 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p, time:" 113 " %d, (%p)\n", __FUNCTION__, 114 scmd, timeout, complete)); 115 116 add_timer(&scmd->eh_timeout); 117 } 118 EXPORT_SYMBOL(scsi_add_timer); 119 120 /** 121 * scsi_delete_timer - Delete/cancel timer for a given function. 122 * @scmd: Cmd that we are canceling timer for 123 * 124 * Notes: 125 * This should be turned into an inline function. 126 * 127 * Return value: 128 * 1 if we were able to detach the timer. 0 if we blew it, and the 129 * timer function has already started to run. 130 **/ 131 int scsi_delete_timer(struct scsi_cmnd *scmd) 132 { 133 int rtn; 134 135 rtn = del_timer(&scmd->eh_timeout); 136 137 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p," 138 " rtn: %d\n", __FUNCTION__, 139 scmd, rtn)); 140 141 scmd->eh_timeout.data = (unsigned long)NULL; 142 scmd->eh_timeout.function = NULL; 143 144 return rtn; 145 } 146 EXPORT_SYMBOL(scsi_delete_timer); 147 148 /** 149 * scsi_times_out - Timeout function for normal scsi commands. 150 * @scmd: Cmd that is timing out. 151 * 152 * Notes: 153 * We do not need to lock this. There is the potential for a race 154 * only in that the normal completion handling might run, but if the 155 * normal completion function determines that the timer has already 156 * fired, then it mustn't do anything. 157 **/ 158 void scsi_times_out(struct scsi_cmnd *scmd) 159 { 160 scsi_log_completion(scmd, TIMEOUT_ERROR); 161 162 if (scmd->device->host->hostt->eh_timed_out) 163 switch (scmd->device->host->hostt->eh_timed_out(scmd)) { 164 case EH_HANDLED: 165 __scsi_done(scmd); 166 return; 167 case EH_RESET_TIMER: 168 /* This allows a single retry even of a command 169 * with allowed == 0 */ 170 if (scmd->retries++ > scmd->allowed) 171 break; 172 scsi_add_timer(scmd, scmd->timeout_per_command, 173 scsi_times_out); 174 return; 175 case EH_NOT_HANDLED: 176 break; 177 } 178 179 if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) { 180 panic("Error handler thread not present at %p %p %s %d", 181 scmd, scmd->device->host, __FILE__, __LINE__); 182 } 183 } 184 185 /** 186 * scsi_block_when_processing_errors - Prevent cmds from being queued. 187 * @sdev: Device on which we are performing recovery. 188 * 189 * Description: 190 * We block until the host is out of error recovery, and then check to 191 * see whether the host or the device is offline. 192 * 193 * Return value: 194 * 0 when dev was taken offline by error recovery. 1 OK to proceed. 195 **/ 196 int scsi_block_when_processing_errors(struct scsi_device *sdev) 197 { 198 int online; 199 200 wait_event(sdev->host->host_wait, (!test_bit(SHOST_RECOVERY, &sdev->host->shost_state))); 201 202 online = scsi_device_online(sdev); 203 204 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __FUNCTION__, 205 online)); 206 207 return online; 208 } 209 EXPORT_SYMBOL(scsi_block_when_processing_errors); 210 211 #ifdef CONFIG_SCSI_LOGGING 212 /** 213 * scsi_eh_prt_fail_stats - Log info on failures. 214 * @shost: scsi host being recovered. 215 * @work_q: Queue of scsi cmds to process. 216 **/ 217 static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost, 218 struct list_head *work_q) 219 { 220 struct scsi_cmnd *scmd; 221 struct scsi_device *sdev; 222 int total_failures = 0; 223 int cmd_failed = 0; 224 int cmd_cancel = 0; 225 int devices_failed = 0; 226 227 shost_for_each_device(sdev, shost) { 228 list_for_each_entry(scmd, work_q, eh_entry) { 229 if (scmd->device == sdev) { 230 ++total_failures; 231 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) 232 ++cmd_cancel; 233 else 234 ++cmd_failed; 235 } 236 } 237 238 if (cmd_cancel || cmd_failed) { 239 SCSI_LOG_ERROR_RECOVERY(3, 240 printk("%s: %d:%d:%d:%d cmds failed: %d," 241 " cancel: %d\n", 242 __FUNCTION__, shost->host_no, 243 sdev->channel, sdev->id, sdev->lun, 244 cmd_failed, cmd_cancel)); 245 cmd_cancel = 0; 246 cmd_failed = 0; 247 ++devices_failed; 248 } 249 } 250 251 SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d" 252 " devices require eh work\n", 253 total_failures, devices_failed)); 254 } 255 #endif 256 257 /** 258 * scsi_check_sense - Examine scsi cmd sense 259 * @scmd: Cmd to have sense checked. 260 * 261 * Return value: 262 * SUCCESS or FAILED or NEEDS_RETRY 263 * 264 * Notes: 265 * When a deferred error is detected the current command has 266 * not been executed and needs retrying. 267 **/ 268 static int scsi_check_sense(struct scsi_cmnd *scmd) 269 { 270 struct scsi_sense_hdr sshdr; 271 272 if (! scsi_command_normalize_sense(scmd, &sshdr)) 273 return FAILED; /* no valid sense data */ 274 275 if (scsi_sense_is_deferred(&sshdr)) 276 return NEEDS_RETRY; 277 278 /* 279 * Previous logic looked for FILEMARK, EOM or ILI which are 280 * mainly associated with tapes and returned SUCCESS. 281 */ 282 if (sshdr.response_code == 0x70) { 283 /* fixed format */ 284 if (scmd->sense_buffer[2] & 0xe0) 285 return SUCCESS; 286 } else { 287 /* 288 * descriptor format: look for "stream commands sense data 289 * descriptor" (see SSC-3). Assume single sense data 290 * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG. 291 */ 292 if ((sshdr.additional_length > 3) && 293 (scmd->sense_buffer[8] == 0x4) && 294 (scmd->sense_buffer[11] & 0xe0)) 295 return SUCCESS; 296 } 297 298 switch (sshdr.sense_key) { 299 case NO_SENSE: 300 return SUCCESS; 301 case RECOVERED_ERROR: 302 return /* soft_error */ SUCCESS; 303 304 case ABORTED_COMMAND: 305 return NEEDS_RETRY; 306 case NOT_READY: 307 case UNIT_ATTENTION: 308 /* 309 * if we are expecting a cc/ua because of a bus reset that we 310 * performed, treat this just as a retry. otherwise this is 311 * information that we should pass up to the upper-level driver 312 * so that we can deal with it there. 313 */ 314 if (scmd->device->expecting_cc_ua) { 315 scmd->device->expecting_cc_ua = 0; 316 return NEEDS_RETRY; 317 } 318 /* 319 * if the device is in the process of becoming ready, we 320 * should retry. 321 */ 322 if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01)) 323 return NEEDS_RETRY; 324 /* 325 * if the device is not started, we need to wake 326 * the error handler to start the motor 327 */ 328 if (scmd->device->allow_restart && 329 (sshdr.asc == 0x04) && (sshdr.ascq == 0x02)) 330 return FAILED; 331 return SUCCESS; 332 333 /* these three are not supported */ 334 case COPY_ABORTED: 335 case VOLUME_OVERFLOW: 336 case MISCOMPARE: 337 return SUCCESS; 338 339 case MEDIUM_ERROR: 340 return NEEDS_RETRY; 341 342 case HARDWARE_ERROR: 343 if (scmd->device->retry_hwerror) 344 return NEEDS_RETRY; 345 else 346 return SUCCESS; 347 348 case ILLEGAL_REQUEST: 349 case BLANK_CHECK: 350 case DATA_PROTECT: 351 default: 352 return SUCCESS; 353 } 354 } 355 356 /** 357 * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD. 358 * @scmd: SCSI cmd to examine. 359 * 360 * Notes: 361 * This is *only* called when we are examining the status of commands 362 * queued during error recovery. the main difference here is that we 363 * don't allow for the possibility of retries here, and we are a lot 364 * more restrictive about what we consider acceptable. 365 **/ 366 static int scsi_eh_completed_normally(struct scsi_cmnd *scmd) 367 { 368 /* 369 * first check the host byte, to see if there is anything in there 370 * that would indicate what we need to do. 371 */ 372 if (host_byte(scmd->result) == DID_RESET) { 373 /* 374 * rats. we are already in the error handler, so we now 375 * get to try and figure out what to do next. if the sense 376 * is valid, we have a pretty good idea of what to do. 377 * if not, we mark it as FAILED. 378 */ 379 return scsi_check_sense(scmd); 380 } 381 if (host_byte(scmd->result) != DID_OK) 382 return FAILED; 383 384 /* 385 * next, check the message byte. 386 */ 387 if (msg_byte(scmd->result) != COMMAND_COMPLETE) 388 return FAILED; 389 390 /* 391 * now, check the status byte to see if this indicates 392 * anything special. 393 */ 394 switch (status_byte(scmd->result)) { 395 case GOOD: 396 case COMMAND_TERMINATED: 397 return SUCCESS; 398 case CHECK_CONDITION: 399 return scsi_check_sense(scmd); 400 case CONDITION_GOOD: 401 case INTERMEDIATE_GOOD: 402 case INTERMEDIATE_C_GOOD: 403 /* 404 * who knows? FIXME(eric) 405 */ 406 return SUCCESS; 407 case BUSY: 408 case QUEUE_FULL: 409 case RESERVATION_CONFLICT: 410 default: 411 return FAILED; 412 } 413 return FAILED; 414 } 415 416 /** 417 * scsi_eh_times_out - timeout function for error handling. 418 * @scmd: Cmd that is timing out. 419 * 420 * Notes: 421 * During error handling, the kernel thread will be sleeping waiting 422 * for some action to complete on the device. our only job is to 423 * record that it timed out, and to wake up the thread. 424 **/ 425 static void scsi_eh_times_out(struct scsi_cmnd *scmd) 426 { 427 scmd->eh_eflags |= SCSI_EH_REC_TIMEOUT; 428 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd:%p\n", __FUNCTION__, 429 scmd)); 430 431 up(scmd->device->host->eh_action); 432 } 433 434 /** 435 * scsi_eh_done - Completion function for error handling. 436 * @scmd: Cmd that is done. 437 **/ 438 static void scsi_eh_done(struct scsi_cmnd *scmd) 439 { 440 /* 441 * if the timeout handler is already running, then just set the 442 * flag which says we finished late, and return. we have no 443 * way of stopping the timeout handler from running, so we must 444 * always defer to it. 445 */ 446 if (del_timer(&scmd->eh_timeout)) { 447 scmd->request->rq_status = RQ_SCSI_DONE; 448 449 SCSI_LOG_ERROR_RECOVERY(3, printk("%s scmd: %p result: %x\n", 450 __FUNCTION__, scmd, scmd->result)); 451 452 up(scmd->device->host->eh_action); 453 } 454 } 455 456 /** 457 * scsi_send_eh_cmnd - send a cmd to a device as part of error recovery. 458 * @scmd: SCSI Cmd to send. 459 * @timeout: Timeout for cmd. 460 * 461 * Notes: 462 * The initialization of the structures is quite a bit different in 463 * this case, and furthermore, there is a different completion handler 464 * vs scsi_dispatch_cmd. 465 * Return value: 466 * SUCCESS or FAILED or NEEDS_RETRY 467 **/ 468 static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, int timeout) 469 { 470 struct scsi_device *sdev = scmd->device; 471 struct Scsi_Host *shost = sdev->host; 472 DECLARE_MUTEX_LOCKED(sem); 473 unsigned long flags; 474 int rtn = SUCCESS; 475 476 /* 477 * we will use a queued command if possible, otherwise we will 478 * emulate the queuing and calling of completion function ourselves. 479 */ 480 if (sdev->scsi_level <= SCSI_2) 481 scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) | 482 (sdev->lun << 5 & 0xe0); 483 484 scsi_add_timer(scmd, timeout, scsi_eh_times_out); 485 486 /* 487 * set up the semaphore so we wait for the command to complete. 488 */ 489 shost->eh_action = &sem; 490 scmd->request->rq_status = RQ_SCSI_BUSY; 491 492 spin_lock_irqsave(shost->host_lock, flags); 493 scsi_log_send(scmd); 494 shost->hostt->queuecommand(scmd, scsi_eh_done); 495 spin_unlock_irqrestore(shost->host_lock, flags); 496 497 down(&sem); 498 scsi_log_completion(scmd, SUCCESS); 499 500 shost->eh_action = NULL; 501 502 /* 503 * see if timeout. if so, tell the host to forget about it. 504 * in other words, we don't want a callback any more. 505 */ 506 if (scmd->eh_eflags & SCSI_EH_REC_TIMEOUT) { 507 scmd->eh_eflags &= ~SCSI_EH_REC_TIMEOUT; 508 509 /* 510 * as far as the low level driver is 511 * concerned, this command is still active, so 512 * we must give the low level driver a chance 513 * to abort it. (db) 514 * 515 * FIXME(eric) - we are not tracking whether we could 516 * abort a timed out command or not. not sure how 517 * we should treat them differently anyways. 518 */ 519 if (shost->hostt->eh_abort_handler) 520 shost->hostt->eh_abort_handler(scmd); 521 522 scmd->request->rq_status = RQ_SCSI_DONE; 523 rtn = FAILED; 524 } 525 526 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd: %p, rtn:%x\n", 527 __FUNCTION__, scmd, rtn)); 528 529 /* 530 * now examine the actual status codes to see whether the command 531 * actually did complete normally. 532 */ 533 if (rtn == SUCCESS) { 534 rtn = scsi_eh_completed_normally(scmd); 535 SCSI_LOG_ERROR_RECOVERY(3, 536 printk("%s: scsi_eh_completed_normally %x\n", 537 __FUNCTION__, rtn)); 538 switch (rtn) { 539 case SUCCESS: 540 case NEEDS_RETRY: 541 case FAILED: 542 break; 543 default: 544 rtn = FAILED; 545 break; 546 } 547 } 548 549 return rtn; 550 } 551 552 /** 553 * scsi_request_sense - Request sense data from a particular target. 554 * @scmd: SCSI cmd for request sense. 555 * 556 * Notes: 557 * Some hosts automatically obtain this information, others require 558 * that we obtain it on our own. This function will *not* return until 559 * the command either times out, or it completes. 560 **/ 561 static int scsi_request_sense(struct scsi_cmnd *scmd) 562 { 563 static unsigned char generic_sense[6] = 564 {REQUEST_SENSE, 0, 0, 0, 252, 0}; 565 unsigned char *scsi_result; 566 int saved_result; 567 int rtn; 568 569 memcpy(scmd->cmnd, generic_sense, sizeof(generic_sense)); 570 571 scsi_result = kmalloc(252, GFP_ATOMIC | ((scmd->device->host->hostt->unchecked_isa_dma) ? __GFP_DMA : 0)); 572 573 574 if (unlikely(!scsi_result)) { 575 printk(KERN_ERR "%s: cannot allocate scsi_result.\n", 576 __FUNCTION__); 577 return FAILED; 578 } 579 580 /* 581 * zero the sense buffer. some host adapters automatically always 582 * request sense, so it is not a good idea that 583 * scmd->request_buffer and scmd->sense_buffer point to the same 584 * address (db). 0 is not a valid sense code. 585 */ 586 memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer)); 587 memset(scsi_result, 0, 252); 588 589 saved_result = scmd->result; 590 scmd->request_buffer = scsi_result; 591 scmd->request_bufflen = 252; 592 scmd->use_sg = 0; 593 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]); 594 scmd->sc_data_direction = DMA_FROM_DEVICE; 595 scmd->underflow = 0; 596 597 rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT); 598 599 /* last chance to have valid sense data */ 600 if(!SCSI_SENSE_VALID(scmd)) { 601 memcpy(scmd->sense_buffer, scmd->request_buffer, 602 sizeof(scmd->sense_buffer)); 603 } 604 605 kfree(scsi_result); 606 607 /* 608 * when we eventually call scsi_finish, we really wish to complete 609 * the original request, so let's restore the original data. (db) 610 */ 611 scsi_setup_cmd_retry(scmd); 612 scmd->result = saved_result; 613 return rtn; 614 } 615 616 /** 617 * scsi_eh_finish_cmd - Handle a cmd that eh is finished with. 618 * @scmd: Original SCSI cmd that eh has finished. 619 * @done_q: Queue for processed commands. 620 * 621 * Notes: 622 * We don't want to use the normal command completion while we are are 623 * still handling errors - it may cause other commands to be queued, 624 * and that would disturb what we are doing. thus we really want to 625 * keep a list of pending commands for final completion, and once we 626 * are ready to leave error handling we handle completion for real. 627 **/ 628 static void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, 629 struct list_head *done_q) 630 { 631 scmd->device->host->host_failed--; 632 scmd->eh_eflags = 0; 633 634 /* 635 * set this back so that the upper level can correctly free up 636 * things. 637 */ 638 scsi_setup_cmd_retry(scmd); 639 list_move_tail(&scmd->eh_entry, done_q); 640 } 641 642 /** 643 * scsi_eh_get_sense - Get device sense data. 644 * @work_q: Queue of commands to process. 645 * @done_q: Queue of proccessed commands.. 646 * 647 * Description: 648 * See if we need to request sense information. if so, then get it 649 * now, so we have a better idea of what to do. 650 * 651 * Notes: 652 * This has the unfortunate side effect that if a shost adapter does 653 * not automatically request sense information, that we end up shutting 654 * it down before we request it. 655 * 656 * All drivers should request sense information internally these days, 657 * so for now all I have to say is tough noogies if you end up in here. 658 * 659 * XXX: Long term this code should go away, but that needs an audit of 660 * all LLDDs first. 661 **/ 662 static int scsi_eh_get_sense(struct list_head *work_q, 663 struct list_head *done_q) 664 { 665 struct scsi_cmnd *scmd, *next; 666 int rtn; 667 668 list_for_each_entry_safe(scmd, next, work_q, eh_entry) { 669 if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) || 670 SCSI_SENSE_VALID(scmd)) 671 continue; 672 673 SCSI_LOG_ERROR_RECOVERY(2, printk("%s: requesting sense" 674 " for id: %d\n", 675 current->comm, 676 scmd->device->id)); 677 rtn = scsi_request_sense(scmd); 678 if (rtn != SUCCESS) 679 continue; 680 681 SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p" 682 " result %x\n", scmd, 683 scmd->result)); 684 SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd)); 685 686 rtn = scsi_decide_disposition(scmd); 687 688 /* 689 * if the result was normal, then just pass it along to the 690 * upper level. 691 */ 692 if (rtn == SUCCESS) 693 /* we don't want this command reissued, just 694 * finished with the sense data, so set 695 * retries to the max allowed to ensure it 696 * won't get reissued */ 697 scmd->retries = scmd->allowed; 698 else if (rtn != NEEDS_RETRY) 699 continue; 700 701 scsi_eh_finish_cmd(scmd, done_q); 702 } 703 704 return list_empty(work_q); 705 } 706 707 /** 708 * scsi_try_to_abort_cmd - Ask host to abort a running command. 709 * @scmd: SCSI cmd to abort from Lower Level. 710 * 711 * Notes: 712 * This function will not return until the user's completion function 713 * has been called. there is no timeout on this operation. if the 714 * author of the low-level driver wishes this operation to be timed, 715 * they can provide this facility themselves. helper functions in 716 * scsi_error.c can be supplied to make this easier to do. 717 **/ 718 static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd) 719 { 720 if (!scmd->device->host->hostt->eh_abort_handler) 721 return FAILED; 722 723 /* 724 * scsi_done was called just after the command timed out and before 725 * we had a chance to process it. (db) 726 */ 727 if (scmd->serial_number == 0) 728 return SUCCESS; 729 return scmd->device->host->hostt->eh_abort_handler(scmd); 730 } 731 732 /** 733 * scsi_eh_tur - Send TUR to device. 734 * @scmd: Scsi cmd to send TUR 735 * 736 * Return value: 737 * 0 - Device is ready. 1 - Device NOT ready. 738 **/ 739 static int scsi_eh_tur(struct scsi_cmnd *scmd) 740 { 741 static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0}; 742 int retry_cnt = 1, rtn; 743 int saved_result; 744 745 retry_tur: 746 memcpy(scmd->cmnd, tur_command, sizeof(tur_command)); 747 748 /* 749 * zero the sense buffer. the scsi spec mandates that any 750 * untransferred sense data should be interpreted as being zero. 751 */ 752 memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer)); 753 754 saved_result = scmd->result; 755 scmd->request_buffer = NULL; 756 scmd->request_bufflen = 0; 757 scmd->use_sg = 0; 758 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]); 759 scmd->underflow = 0; 760 scmd->sc_data_direction = DMA_NONE; 761 762 rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT); 763 764 /* 765 * when we eventually call scsi_finish, we really wish to complete 766 * the original request, so let's restore the original data. (db) 767 */ 768 scsi_setup_cmd_retry(scmd); 769 scmd->result = saved_result; 770 771 /* 772 * hey, we are done. let's look to see what happened. 773 */ 774 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n", 775 __FUNCTION__, scmd, rtn)); 776 if (rtn == SUCCESS) 777 return 0; 778 else if (rtn == NEEDS_RETRY) 779 if (retry_cnt--) 780 goto retry_tur; 781 return 1; 782 } 783 784 /** 785 * scsi_eh_abort_cmds - abort canceled commands. 786 * @shost: scsi host being recovered. 787 * @eh_done_q: list_head for processed commands. 788 * 789 * Decription: 790 * Try and see whether or not it makes sense to try and abort the 791 * running command. this only works out to be the case if we have one 792 * command that has timed out. if the command simply failed, it makes 793 * no sense to try and abort the command, since as far as the shost 794 * adapter is concerned, it isn't running. 795 **/ 796 static int scsi_eh_abort_cmds(struct list_head *work_q, 797 struct list_head *done_q) 798 { 799 struct scsi_cmnd *scmd, *next; 800 int rtn; 801 802 list_for_each_entry_safe(scmd, next, work_q, eh_entry) { 803 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD)) 804 continue; 805 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:" 806 "0x%p\n", current->comm, 807 scmd)); 808 rtn = scsi_try_to_abort_cmd(scmd); 809 if (rtn == SUCCESS) { 810 scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD; 811 if (!scsi_device_online(scmd->device) || 812 !scsi_eh_tur(scmd)) { 813 scsi_eh_finish_cmd(scmd, done_q); 814 } 815 816 } else 817 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting" 818 " cmd failed:" 819 "0x%p\n", 820 current->comm, 821 scmd)); 822 } 823 824 return list_empty(work_q); 825 } 826 827 /** 828 * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev 829 * @scmd: SCSI cmd used to send BDR 830 * 831 * Notes: 832 * There is no timeout for this operation. if this operation is 833 * unreliable for a given host, then the host itself needs to put a 834 * timer on it, and set the host back to a consistent state prior to 835 * returning. 836 **/ 837 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd) 838 { 839 int rtn; 840 841 if (!scmd->device->host->hostt->eh_device_reset_handler) 842 return FAILED; 843 844 rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd); 845 if (rtn == SUCCESS) { 846 scmd->device->was_reset = 1; 847 scmd->device->expecting_cc_ua = 1; 848 } 849 850 return rtn; 851 } 852 853 /** 854 * scsi_eh_try_stu - Send START_UNIT to device. 855 * @scmd: Scsi cmd to send START_UNIT 856 * 857 * Return value: 858 * 0 - Device is ready. 1 - Device NOT ready. 859 **/ 860 static int scsi_eh_try_stu(struct scsi_cmnd *scmd) 861 { 862 static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0}; 863 int rtn; 864 int saved_result; 865 866 if (!scmd->device->allow_restart) 867 return 1; 868 869 memcpy(scmd->cmnd, stu_command, sizeof(stu_command)); 870 871 /* 872 * zero the sense buffer. the scsi spec mandates that any 873 * untransferred sense data should be interpreted as being zero. 874 */ 875 memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer)); 876 877 saved_result = scmd->result; 878 scmd->request_buffer = NULL; 879 scmd->request_bufflen = 0; 880 scmd->use_sg = 0; 881 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]); 882 scmd->underflow = 0; 883 scmd->sc_data_direction = DMA_NONE; 884 885 rtn = scsi_send_eh_cmnd(scmd, START_UNIT_TIMEOUT); 886 887 /* 888 * when we eventually call scsi_finish, we really wish to complete 889 * the original request, so let's restore the original data. (db) 890 */ 891 scsi_setup_cmd_retry(scmd); 892 scmd->result = saved_result; 893 894 /* 895 * hey, we are done. let's look to see what happened. 896 */ 897 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n", 898 __FUNCTION__, scmd, rtn)); 899 if (rtn == SUCCESS) 900 return 0; 901 return 1; 902 } 903 904 /** 905 * scsi_eh_stu - send START_UNIT if needed 906 * @shost: scsi host being recovered. 907 * @eh_done_q: list_head for processed commands. 908 * 909 * Notes: 910 * If commands are failing due to not ready, initializing command required, 911 * try revalidating the device, which will end up sending a start unit. 912 **/ 913 static int scsi_eh_stu(struct Scsi_Host *shost, 914 struct list_head *work_q, 915 struct list_head *done_q) 916 { 917 struct scsi_cmnd *scmd, *stu_scmd, *next; 918 struct scsi_device *sdev; 919 920 shost_for_each_device(sdev, shost) { 921 stu_scmd = NULL; 922 list_for_each_entry(scmd, work_q, eh_entry) 923 if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) && 924 scsi_check_sense(scmd) == FAILED ) { 925 stu_scmd = scmd; 926 break; 927 } 928 929 if (!stu_scmd) 930 continue; 931 932 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:" 933 " 0x%p\n", current->comm, sdev)); 934 935 if (!scsi_eh_try_stu(stu_scmd)) { 936 if (!scsi_device_online(sdev) || 937 !scsi_eh_tur(stu_scmd)) { 938 list_for_each_entry_safe(scmd, next, 939 work_q, eh_entry) { 940 if (scmd->device == sdev) 941 scsi_eh_finish_cmd(scmd, done_q); 942 } 943 } 944 } else { 945 SCSI_LOG_ERROR_RECOVERY(3, 946 printk("%s: START_UNIT failed to sdev:" 947 " 0x%p\n", current->comm, sdev)); 948 } 949 } 950 951 return list_empty(work_q); 952 } 953 954 955 /** 956 * scsi_eh_bus_device_reset - send bdr if needed 957 * @shost: scsi host being recovered. 958 * @eh_done_q: list_head for processed commands. 959 * 960 * Notes: 961 * Try a bus device reset. still, look to see whether we have multiple 962 * devices that are jammed or not - if we have multiple devices, it 963 * makes no sense to try bus_device_reset - we really would need to try 964 * a bus_reset instead. 965 **/ 966 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost, 967 struct list_head *work_q, 968 struct list_head *done_q) 969 { 970 struct scsi_cmnd *scmd, *bdr_scmd, *next; 971 struct scsi_device *sdev; 972 int rtn; 973 974 shost_for_each_device(sdev, shost) { 975 bdr_scmd = NULL; 976 list_for_each_entry(scmd, work_q, eh_entry) 977 if (scmd->device == sdev) { 978 bdr_scmd = scmd; 979 break; 980 } 981 982 if (!bdr_scmd) 983 continue; 984 985 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:" 986 " 0x%p\n", current->comm, 987 sdev)); 988 rtn = scsi_try_bus_device_reset(bdr_scmd); 989 if (rtn == SUCCESS) { 990 if (!scsi_device_online(sdev) || 991 !scsi_eh_tur(bdr_scmd)) { 992 list_for_each_entry_safe(scmd, next, 993 work_q, eh_entry) { 994 if (scmd->device == sdev) 995 scsi_eh_finish_cmd(scmd, 996 done_q); 997 } 998 } 999 } else { 1000 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR" 1001 " failed sdev:" 1002 "0x%p\n", 1003 current->comm, 1004 sdev)); 1005 } 1006 } 1007 1008 return list_empty(work_q); 1009 } 1010 1011 /** 1012 * scsi_try_bus_reset - ask host to perform a bus reset 1013 * @scmd: SCSI cmd to send bus reset. 1014 **/ 1015 static int scsi_try_bus_reset(struct scsi_cmnd *scmd) 1016 { 1017 unsigned long flags; 1018 int rtn; 1019 1020 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n", 1021 __FUNCTION__)); 1022 1023 if (!scmd->device->host->hostt->eh_bus_reset_handler) 1024 return FAILED; 1025 1026 rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd); 1027 1028 if (rtn == SUCCESS) { 1029 if (!scmd->device->host->hostt->skip_settle_delay) 1030 ssleep(BUS_RESET_SETTLE_TIME); 1031 spin_lock_irqsave(scmd->device->host->host_lock, flags); 1032 scsi_report_bus_reset(scmd->device->host, scmd->device->channel); 1033 spin_unlock_irqrestore(scmd->device->host->host_lock, flags); 1034 } 1035 1036 return rtn; 1037 } 1038 1039 /** 1040 * scsi_try_host_reset - ask host adapter to reset itself 1041 * @scmd: SCSI cmd to send hsot reset. 1042 **/ 1043 static int scsi_try_host_reset(struct scsi_cmnd *scmd) 1044 { 1045 unsigned long flags; 1046 int rtn; 1047 1048 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n", 1049 __FUNCTION__)); 1050 1051 if (!scmd->device->host->hostt->eh_host_reset_handler) 1052 return FAILED; 1053 1054 rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd); 1055 1056 if (rtn == SUCCESS) { 1057 if (!scmd->device->host->hostt->skip_settle_delay) 1058 ssleep(HOST_RESET_SETTLE_TIME); 1059 spin_lock_irqsave(scmd->device->host->host_lock, flags); 1060 scsi_report_bus_reset(scmd->device->host, scmd->device->channel); 1061 spin_unlock_irqrestore(scmd->device->host->host_lock, flags); 1062 } 1063 1064 return rtn; 1065 } 1066 1067 /** 1068 * scsi_eh_bus_reset - send a bus reset 1069 * @shost: scsi host being recovered. 1070 * @eh_done_q: list_head for processed commands. 1071 **/ 1072 static int scsi_eh_bus_reset(struct Scsi_Host *shost, 1073 struct list_head *work_q, 1074 struct list_head *done_q) 1075 { 1076 struct scsi_cmnd *scmd, *chan_scmd, *next; 1077 unsigned int channel; 1078 int rtn; 1079 1080 /* 1081 * we really want to loop over the various channels, and do this on 1082 * a channel by channel basis. we should also check to see if any 1083 * of the failed commands are on soft_reset devices, and if so, skip 1084 * the reset. 1085 */ 1086 1087 for (channel = 0; channel <= shost->max_channel; channel++) { 1088 chan_scmd = NULL; 1089 list_for_each_entry(scmd, work_q, eh_entry) { 1090 if (channel == scmd->device->channel) { 1091 chan_scmd = scmd; 1092 break; 1093 /* 1094 * FIXME add back in some support for 1095 * soft_reset devices. 1096 */ 1097 } 1098 } 1099 1100 if (!chan_scmd) 1101 continue; 1102 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:" 1103 " %d\n", current->comm, 1104 channel)); 1105 rtn = scsi_try_bus_reset(chan_scmd); 1106 if (rtn == SUCCESS) { 1107 list_for_each_entry_safe(scmd, next, work_q, eh_entry) { 1108 if (channel == scmd->device->channel) 1109 if (!scsi_device_online(scmd->device) || 1110 !scsi_eh_tur(scmd)) 1111 scsi_eh_finish_cmd(scmd, 1112 done_q); 1113 } 1114 } else { 1115 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST" 1116 " failed chan: %d\n", 1117 current->comm, 1118 channel)); 1119 } 1120 } 1121 return list_empty(work_q); 1122 } 1123 1124 /** 1125 * scsi_eh_host_reset - send a host reset 1126 * @work_q: list_head for processed commands. 1127 * @done_q: list_head for processed commands. 1128 **/ 1129 static int scsi_eh_host_reset(struct list_head *work_q, 1130 struct list_head *done_q) 1131 { 1132 struct scsi_cmnd *scmd, *next; 1133 int rtn; 1134 1135 if (!list_empty(work_q)) { 1136 scmd = list_entry(work_q->next, 1137 struct scsi_cmnd, eh_entry); 1138 1139 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n" 1140 , current->comm)); 1141 1142 rtn = scsi_try_host_reset(scmd); 1143 if (rtn == SUCCESS) { 1144 list_for_each_entry_safe(scmd, next, work_q, eh_entry) { 1145 if (!scsi_device_online(scmd->device) || 1146 (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) || 1147 !scsi_eh_tur(scmd)) 1148 scsi_eh_finish_cmd(scmd, done_q); 1149 } 1150 } else { 1151 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST" 1152 " failed\n", 1153 current->comm)); 1154 } 1155 } 1156 return list_empty(work_q); 1157 } 1158 1159 /** 1160 * scsi_eh_offline_sdevs - offline scsi devices that fail to recover 1161 * @work_q: list_head for processed commands. 1162 * @done_q: list_head for processed commands. 1163 * 1164 **/ 1165 static void scsi_eh_offline_sdevs(struct list_head *work_q, 1166 struct list_head *done_q) 1167 { 1168 struct scsi_cmnd *scmd, *next; 1169 1170 list_for_each_entry_safe(scmd, next, work_q, eh_entry) { 1171 printk(KERN_INFO "scsi: Device offlined - not" 1172 " ready after error recovery: host" 1173 " %d channel %d id %d lun %d\n", 1174 scmd->device->host->host_no, 1175 scmd->device->channel, 1176 scmd->device->id, 1177 scmd->device->lun); 1178 scsi_device_set_state(scmd->device, SDEV_OFFLINE); 1179 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) { 1180 /* 1181 * FIXME: Handle lost cmds. 1182 */ 1183 } 1184 scsi_eh_finish_cmd(scmd, done_q); 1185 } 1186 return; 1187 } 1188 1189 /** 1190 * scsi_decide_disposition - Disposition a cmd on return from LLD. 1191 * @scmd: SCSI cmd to examine. 1192 * 1193 * Notes: 1194 * This is *only* called when we are examining the status after sending 1195 * out the actual data command. any commands that are queued for error 1196 * recovery (e.g. test_unit_ready) do *not* come through here. 1197 * 1198 * When this routine returns failed, it means the error handler thread 1199 * is woken. In cases where the error code indicates an error that 1200 * doesn't require the error handler read (i.e. we don't need to 1201 * abort/reset), this function should return SUCCESS. 1202 **/ 1203 int scsi_decide_disposition(struct scsi_cmnd *scmd) 1204 { 1205 int rtn; 1206 1207 /* 1208 * if the device is offline, then we clearly just pass the result back 1209 * up to the top level. 1210 */ 1211 if (!scsi_device_online(scmd->device)) { 1212 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report" 1213 " as SUCCESS\n", 1214 __FUNCTION__)); 1215 return SUCCESS; 1216 } 1217 1218 /* 1219 * first check the host byte, to see if there is anything in there 1220 * that would indicate what we need to do. 1221 */ 1222 switch (host_byte(scmd->result)) { 1223 case DID_PASSTHROUGH: 1224 /* 1225 * no matter what, pass this through to the upper layer. 1226 * nuke this special code so that it looks like we are saying 1227 * did_ok. 1228 */ 1229 scmd->result &= 0xff00ffff; 1230 return SUCCESS; 1231 case DID_OK: 1232 /* 1233 * looks good. drop through, and check the next byte. 1234 */ 1235 break; 1236 case DID_NO_CONNECT: 1237 case DID_BAD_TARGET: 1238 case DID_ABORT: 1239 /* 1240 * note - this means that we just report the status back 1241 * to the top level driver, not that we actually think 1242 * that it indicates SUCCESS. 1243 */ 1244 return SUCCESS; 1245 /* 1246 * when the low level driver returns did_soft_error, 1247 * it is responsible for keeping an internal retry counter 1248 * in order to avoid endless loops (db) 1249 * 1250 * actually this is a bug in this function here. we should 1251 * be mindful of the maximum number of retries specified 1252 * and not get stuck in a loop. 1253 */ 1254 case DID_SOFT_ERROR: 1255 goto maybe_retry; 1256 case DID_IMM_RETRY: 1257 return NEEDS_RETRY; 1258 1259 case DID_REQUEUE: 1260 return ADD_TO_MLQUEUE; 1261 1262 case DID_ERROR: 1263 if (msg_byte(scmd->result) == COMMAND_COMPLETE && 1264 status_byte(scmd->result) == RESERVATION_CONFLICT) 1265 /* 1266 * execute reservation conflict processing code 1267 * lower down 1268 */ 1269 break; 1270 /* fallthrough */ 1271 1272 case DID_BUS_BUSY: 1273 case DID_PARITY: 1274 goto maybe_retry; 1275 case DID_TIME_OUT: 1276 /* 1277 * when we scan the bus, we get timeout messages for 1278 * these commands if there is no device available. 1279 * other hosts report did_no_connect for the same thing. 1280 */ 1281 if ((scmd->cmnd[0] == TEST_UNIT_READY || 1282 scmd->cmnd[0] == INQUIRY)) { 1283 return SUCCESS; 1284 } else { 1285 return FAILED; 1286 } 1287 case DID_RESET: 1288 return SUCCESS; 1289 default: 1290 return FAILED; 1291 } 1292 1293 /* 1294 * next, check the message byte. 1295 */ 1296 if (msg_byte(scmd->result) != COMMAND_COMPLETE) 1297 return FAILED; 1298 1299 /* 1300 * check the status byte to see if this indicates anything special. 1301 */ 1302 switch (status_byte(scmd->result)) { 1303 case QUEUE_FULL: 1304 /* 1305 * the case of trying to send too many commands to a 1306 * tagged queueing device. 1307 */ 1308 case BUSY: 1309 /* 1310 * device can't talk to us at the moment. Should only 1311 * occur (SAM-3) when the task queue is empty, so will cause 1312 * the empty queue handling to trigger a stall in the 1313 * device. 1314 */ 1315 return ADD_TO_MLQUEUE; 1316 case GOOD: 1317 case COMMAND_TERMINATED: 1318 case TASK_ABORTED: 1319 return SUCCESS; 1320 case CHECK_CONDITION: 1321 rtn = scsi_check_sense(scmd); 1322 if (rtn == NEEDS_RETRY) 1323 goto maybe_retry; 1324 /* if rtn == FAILED, we have no sense information; 1325 * returning FAILED will wake the error handler thread 1326 * to collect the sense and redo the decide 1327 * disposition */ 1328 return rtn; 1329 case CONDITION_GOOD: 1330 case INTERMEDIATE_GOOD: 1331 case INTERMEDIATE_C_GOOD: 1332 case ACA_ACTIVE: 1333 /* 1334 * who knows? FIXME(eric) 1335 */ 1336 return SUCCESS; 1337 1338 case RESERVATION_CONFLICT: 1339 printk(KERN_INFO "scsi: reservation conflict: host" 1340 " %d channel %d id %d lun %d\n", 1341 scmd->device->host->host_no, scmd->device->channel, 1342 scmd->device->id, scmd->device->lun); 1343 return SUCCESS; /* causes immediate i/o error */ 1344 default: 1345 return FAILED; 1346 } 1347 return FAILED; 1348 1349 maybe_retry: 1350 1351 /* we requeue for retry because the error was retryable, and 1352 * the request was not marked fast fail. Note that above, 1353 * even if the request is marked fast fail, we still requeue 1354 * for queue congestion conditions (QUEUE_FULL or BUSY) */ 1355 if ((++scmd->retries) < scmd->allowed 1356 && !blk_noretry_request(scmd->request)) { 1357 return NEEDS_RETRY; 1358 } else { 1359 /* 1360 * no more retries - report this one back to upper level. 1361 */ 1362 return SUCCESS; 1363 } 1364 } 1365 1366 /** 1367 * scsi_eh_lock_done - done function for eh door lock request 1368 * @scmd: SCSI command block for the door lock request 1369 * 1370 * Notes: 1371 * We completed the asynchronous door lock request, and it has either 1372 * locked the door or failed. We must free the command structures 1373 * associated with this request. 1374 **/ 1375 static void scsi_eh_lock_done(struct scsi_cmnd *scmd) 1376 { 1377 struct scsi_request *sreq = scmd->sc_request; 1378 1379 scsi_release_request(sreq); 1380 } 1381 1382 1383 /** 1384 * scsi_eh_lock_door - Prevent medium removal for the specified device 1385 * @sdev: SCSI device to prevent medium removal 1386 * 1387 * Locking: 1388 * We must be called from process context; scsi_allocate_request() 1389 * may sleep. 1390 * 1391 * Notes: 1392 * We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the 1393 * head of the devices request queue, and continue. 1394 * 1395 * Bugs: 1396 * scsi_allocate_request() may sleep waiting for existing requests to 1397 * be processed. However, since we haven't kicked off any request 1398 * processing for this host, this may deadlock. 1399 * 1400 * If scsi_allocate_request() fails for what ever reason, we 1401 * completely forget to lock the door. 1402 **/ 1403 static void scsi_eh_lock_door(struct scsi_device *sdev) 1404 { 1405 struct scsi_request *sreq = scsi_allocate_request(sdev, GFP_KERNEL); 1406 1407 if (unlikely(!sreq)) { 1408 printk(KERN_ERR "%s: request allocate failed," 1409 "prevent media removal cmd not sent\n", __FUNCTION__); 1410 return; 1411 } 1412 1413 sreq->sr_cmnd[0] = ALLOW_MEDIUM_REMOVAL; 1414 sreq->sr_cmnd[1] = 0; 1415 sreq->sr_cmnd[2] = 0; 1416 sreq->sr_cmnd[3] = 0; 1417 sreq->sr_cmnd[4] = SCSI_REMOVAL_PREVENT; 1418 sreq->sr_cmnd[5] = 0; 1419 sreq->sr_data_direction = DMA_NONE; 1420 sreq->sr_bufflen = 0; 1421 sreq->sr_buffer = NULL; 1422 sreq->sr_allowed = 5; 1423 sreq->sr_done = scsi_eh_lock_done; 1424 sreq->sr_timeout_per_command = 10 * HZ; 1425 sreq->sr_cmd_len = COMMAND_SIZE(sreq->sr_cmnd[0]); 1426 1427 scsi_insert_special_req(sreq, 1); 1428 } 1429 1430 1431 /** 1432 * scsi_restart_operations - restart io operations to the specified host. 1433 * @shost: Host we are restarting. 1434 * 1435 * Notes: 1436 * When we entered the error handler, we blocked all further i/o to 1437 * this device. we need to 'reverse' this process. 1438 **/ 1439 static void scsi_restart_operations(struct Scsi_Host *shost) 1440 { 1441 struct scsi_device *sdev; 1442 1443 /* 1444 * If the door was locked, we need to insert a door lock request 1445 * onto the head of the SCSI request queue for the device. There 1446 * is no point trying to lock the door of an off-line device. 1447 */ 1448 shost_for_each_device(sdev, shost) { 1449 if (scsi_device_online(sdev) && sdev->locked) 1450 scsi_eh_lock_door(sdev); 1451 } 1452 1453 /* 1454 * next free up anything directly waiting upon the host. this 1455 * will be requests for character device operations, and also for 1456 * ioctls to queued block devices. 1457 */ 1458 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n", 1459 __FUNCTION__)); 1460 1461 clear_bit(SHOST_RECOVERY, &shost->shost_state); 1462 1463 wake_up(&shost->host_wait); 1464 1465 /* 1466 * finally we need to re-initiate requests that may be pending. we will 1467 * have had everything blocked while error handling is taking place, and 1468 * now that error recovery is done, we will need to ensure that these 1469 * requests are started. 1470 */ 1471 scsi_run_host_queues(shost); 1472 } 1473 1474 /** 1475 * scsi_eh_ready_devs - check device ready state and recover if not. 1476 * @shost: host to be recovered. 1477 * @eh_done_q: list_head for processed commands. 1478 * 1479 **/ 1480 static void scsi_eh_ready_devs(struct Scsi_Host *shost, 1481 struct list_head *work_q, 1482 struct list_head *done_q) 1483 { 1484 if (!scsi_eh_stu(shost, work_q, done_q)) 1485 if (!scsi_eh_bus_device_reset(shost, work_q, done_q)) 1486 if (!scsi_eh_bus_reset(shost, work_q, done_q)) 1487 if (!scsi_eh_host_reset(work_q, done_q)) 1488 scsi_eh_offline_sdevs(work_q, done_q); 1489 } 1490 1491 /** 1492 * scsi_eh_flush_done_q - finish processed commands or retry them. 1493 * @done_q: list_head of processed commands. 1494 * 1495 **/ 1496 static void scsi_eh_flush_done_q(struct list_head *done_q) 1497 { 1498 struct scsi_cmnd *scmd, *next; 1499 1500 list_for_each_entry_safe(scmd, next, done_q, eh_entry) { 1501 list_del_init(&scmd->eh_entry); 1502 if (scsi_device_online(scmd->device) && 1503 !blk_noretry_request(scmd->request) && 1504 (++scmd->retries < scmd->allowed)) { 1505 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush" 1506 " retry cmd: %p\n", 1507 current->comm, 1508 scmd)); 1509 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY); 1510 } else { 1511 /* 1512 * If just we got sense for the device (called 1513 * scsi_eh_get_sense), scmd->result is already 1514 * set, do not set DRIVER_TIMEOUT. 1515 */ 1516 if (!scmd->result) 1517 scmd->result |= (DRIVER_TIMEOUT << 24); 1518 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish" 1519 " cmd: %p\n", 1520 current->comm, scmd)); 1521 scsi_finish_command(scmd); 1522 } 1523 } 1524 } 1525 1526 /** 1527 * scsi_unjam_host - Attempt to fix a host which has a cmd that failed. 1528 * @shost: Host to unjam. 1529 * 1530 * Notes: 1531 * When we come in here, we *know* that all commands on the bus have 1532 * either completed, failed or timed out. we also know that no further 1533 * commands are being sent to the host, so things are relatively quiet 1534 * and we have freedom to fiddle with things as we wish. 1535 * 1536 * This is only the *default* implementation. it is possible for 1537 * individual drivers to supply their own version of this function, and 1538 * if the maintainer wishes to do this, it is strongly suggested that 1539 * this function be taken as a template and modified. this function 1540 * was designed to correctly handle problems for about 95% of the 1541 * different cases out there, and it should always provide at least a 1542 * reasonable amount of error recovery. 1543 * 1544 * Any command marked 'failed' or 'timeout' must eventually have 1545 * scsi_finish_cmd() called for it. we do all of the retry stuff 1546 * here, so when we restart the host after we return it should have an 1547 * empty queue. 1548 **/ 1549 static void scsi_unjam_host(struct Scsi_Host *shost) 1550 { 1551 unsigned long flags; 1552 LIST_HEAD(eh_work_q); 1553 LIST_HEAD(eh_done_q); 1554 1555 spin_lock_irqsave(shost->host_lock, flags); 1556 list_splice_init(&shost->eh_cmd_q, &eh_work_q); 1557 spin_unlock_irqrestore(shost->host_lock, flags); 1558 1559 SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q)); 1560 1561 if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q)) 1562 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q)) 1563 scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q); 1564 1565 scsi_eh_flush_done_q(&eh_done_q); 1566 } 1567 1568 /** 1569 * scsi_error_handler - Handle errors/timeouts of SCSI cmds. 1570 * @data: Host for which we are running. 1571 * 1572 * Notes: 1573 * This is always run in the context of a kernel thread. The idea is 1574 * that we start this thing up when the kernel starts up (one per host 1575 * that we detect), and it immediately goes to sleep and waits for some 1576 * event (i.e. failure). When this takes place, we have the job of 1577 * trying to unjam the bus and restarting things. 1578 **/ 1579 int scsi_error_handler(void *data) 1580 { 1581 struct Scsi_Host *shost = (struct Scsi_Host *) data; 1582 int rtn; 1583 DECLARE_MUTEX_LOCKED(sem); 1584 1585 /* 1586 * Flush resources 1587 */ 1588 1589 daemonize("scsi_eh_%d", shost->host_no); 1590 1591 current->flags |= PF_NOFREEZE; 1592 1593 shost->eh_wait = &sem; 1594 shost->ehandler = current; 1595 1596 /* 1597 * Wake up the thread that created us. 1598 */ 1599 SCSI_LOG_ERROR_RECOVERY(3, printk("Wake up parent of" 1600 " scsi_eh_%d\n",shost->host_no)); 1601 1602 complete(shost->eh_notify); 1603 1604 while (1) { 1605 /* 1606 * If we get a signal, it means we are supposed to go 1607 * away and die. This typically happens if the user is 1608 * trying to unload a module. 1609 */ 1610 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler" 1611 " scsi_eh_%d" 1612 " sleeping\n",shost->host_no)); 1613 1614 /* 1615 * Note - we always use down_interruptible with the semaphore 1616 * even if the module was loaded as part of the kernel. The 1617 * reason is that down() will cause this thread to be counted 1618 * in the load average as a running process, and down 1619 * interruptible doesn't. Given that we need to allow this 1620 * thread to die if the driver was loaded as a module, using 1621 * semaphores isn't unreasonable. 1622 */ 1623 down_interruptible(&sem); 1624 if (shost->eh_kill) 1625 break; 1626 1627 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler" 1628 " scsi_eh_%d waking" 1629 " up\n",shost->host_no)); 1630 1631 shost->eh_active = 1; 1632 1633 /* 1634 * We have a host that is failing for some reason. Figure out 1635 * what we need to do to get it up and online again (if we can). 1636 * If we fail, we end up taking the thing offline. 1637 */ 1638 if (shost->hostt->eh_strategy_handler) 1639 rtn = shost->hostt->eh_strategy_handler(shost); 1640 else 1641 scsi_unjam_host(shost); 1642 1643 shost->eh_active = 0; 1644 1645 /* 1646 * Note - if the above fails completely, the action is to take 1647 * individual devices offline and flush the queue of any 1648 * outstanding requests that may have been pending. When we 1649 * restart, we restart any I/O to any other devices on the bus 1650 * which are still online. 1651 */ 1652 scsi_restart_operations(shost); 1653 1654 } 1655 1656 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler scsi_eh_%d" 1657 " exiting\n",shost->host_no)); 1658 1659 /* 1660 * Make sure that nobody tries to wake us up again. 1661 */ 1662 shost->eh_wait = NULL; 1663 1664 /* 1665 * Knock this down too. From this point on, the host is flying 1666 * without a pilot. If this is because the module is being unloaded, 1667 * that's fine. If the user sent a signal to this thing, we are 1668 * potentially in real danger. 1669 */ 1670 shost->eh_active = 0; 1671 shost->ehandler = NULL; 1672 1673 /* 1674 * If anyone is waiting for us to exit (i.e. someone trying to unload 1675 * a driver), then wake up that process to let them know we are on 1676 * the way out the door. 1677 */ 1678 complete_and_exit(shost->eh_notify, 0); 1679 return 0; 1680 } 1681 1682 /* 1683 * Function: scsi_report_bus_reset() 1684 * 1685 * Purpose: Utility function used by low-level drivers to report that 1686 * they have observed a bus reset on the bus being handled. 1687 * 1688 * Arguments: shost - Host in question 1689 * channel - channel on which reset was observed. 1690 * 1691 * Returns: Nothing 1692 * 1693 * Lock status: Host lock must be held. 1694 * 1695 * Notes: This only needs to be called if the reset is one which 1696 * originates from an unknown location. Resets originated 1697 * by the mid-level itself don't need to call this, but there 1698 * should be no harm. 1699 * 1700 * The main purpose of this is to make sure that a CHECK_CONDITION 1701 * is properly treated. 1702 */ 1703 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel) 1704 { 1705 struct scsi_device *sdev; 1706 1707 __shost_for_each_device(sdev, shost) { 1708 if (channel == sdev->channel) { 1709 sdev->was_reset = 1; 1710 sdev->expecting_cc_ua = 1; 1711 } 1712 } 1713 } 1714 EXPORT_SYMBOL(scsi_report_bus_reset); 1715 1716 /* 1717 * Function: scsi_report_device_reset() 1718 * 1719 * Purpose: Utility function used by low-level drivers to report that 1720 * they have observed a device reset on the device being handled. 1721 * 1722 * Arguments: shost - Host in question 1723 * channel - channel on which reset was observed 1724 * target - target on which reset was observed 1725 * 1726 * Returns: Nothing 1727 * 1728 * Lock status: Host lock must be held 1729 * 1730 * Notes: This only needs to be called if the reset is one which 1731 * originates from an unknown location. Resets originated 1732 * by the mid-level itself don't need to call this, but there 1733 * should be no harm. 1734 * 1735 * The main purpose of this is to make sure that a CHECK_CONDITION 1736 * is properly treated. 1737 */ 1738 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target) 1739 { 1740 struct scsi_device *sdev; 1741 1742 __shost_for_each_device(sdev, shost) { 1743 if (channel == sdev->channel && 1744 target == sdev->id) { 1745 sdev->was_reset = 1; 1746 sdev->expecting_cc_ua = 1; 1747 } 1748 } 1749 } 1750 EXPORT_SYMBOL(scsi_report_device_reset); 1751 1752 static void 1753 scsi_reset_provider_done_command(struct scsi_cmnd *scmd) 1754 { 1755 } 1756 1757 /* 1758 * Function: scsi_reset_provider 1759 * 1760 * Purpose: Send requested reset to a bus or device at any phase. 1761 * 1762 * Arguments: device - device to send reset to 1763 * flag - reset type (see scsi.h) 1764 * 1765 * Returns: SUCCESS/FAILURE. 1766 * 1767 * Notes: This is used by the SCSI Generic driver to provide 1768 * Bus/Device reset capability. 1769 */ 1770 int 1771 scsi_reset_provider(struct scsi_device *dev, int flag) 1772 { 1773 struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL); 1774 struct request req; 1775 int rtn; 1776 1777 scmd->request = &req; 1778 memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout)); 1779 scmd->request->rq_status = RQ_SCSI_BUSY; 1780 1781 memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd)); 1782 1783 scmd->scsi_done = scsi_reset_provider_done_command; 1784 scmd->done = NULL; 1785 scmd->buffer = NULL; 1786 scmd->bufflen = 0; 1787 scmd->request_buffer = NULL; 1788 scmd->request_bufflen = 0; 1789 1790 scmd->cmd_len = 0; 1791 1792 scmd->sc_data_direction = DMA_BIDIRECTIONAL; 1793 scmd->sc_request = NULL; 1794 scmd->sc_magic = SCSI_CMND_MAGIC; 1795 1796 init_timer(&scmd->eh_timeout); 1797 1798 /* 1799 * Sometimes the command can get back into the timer chain, 1800 * so use the pid as an identifier. 1801 */ 1802 scmd->pid = 0; 1803 1804 switch (flag) { 1805 case SCSI_TRY_RESET_DEVICE: 1806 rtn = scsi_try_bus_device_reset(scmd); 1807 if (rtn == SUCCESS) 1808 break; 1809 /* FALLTHROUGH */ 1810 case SCSI_TRY_RESET_BUS: 1811 rtn = scsi_try_bus_reset(scmd); 1812 if (rtn == SUCCESS) 1813 break; 1814 /* FALLTHROUGH */ 1815 case SCSI_TRY_RESET_HOST: 1816 rtn = scsi_try_host_reset(scmd); 1817 break; 1818 default: 1819 rtn = FAILED; 1820 } 1821 1822 scsi_next_command(scmd); 1823 return rtn; 1824 } 1825 EXPORT_SYMBOL(scsi_reset_provider); 1826 1827 /** 1828 * scsi_normalize_sense - normalize main elements from either fixed or 1829 * descriptor sense data format into a common format. 1830 * 1831 * @sense_buffer: byte array containing sense data returned by device 1832 * @sb_len: number of valid bytes in sense_buffer 1833 * @sshdr: pointer to instance of structure that common 1834 * elements are written to. 1835 * 1836 * Notes: 1837 * The "main elements" from sense data are: response_code, sense_key, 1838 * asc, ascq and additional_length (only for descriptor format). 1839 * 1840 * Typically this function can be called after a device has 1841 * responded to a SCSI command with the CHECK_CONDITION status. 1842 * 1843 * Return value: 1844 * 1 if valid sense data information found, else 0; 1845 **/ 1846 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len, 1847 struct scsi_sense_hdr *sshdr) 1848 { 1849 if (!sense_buffer || !sb_len || (sense_buffer[0] & 0x70) != 0x70) 1850 return 0; 1851 1852 memset(sshdr, 0, sizeof(struct scsi_sense_hdr)); 1853 1854 sshdr->response_code = (sense_buffer[0] & 0x7f); 1855 if (sshdr->response_code >= 0x72) { 1856 /* 1857 * descriptor format 1858 */ 1859 if (sb_len > 1) 1860 sshdr->sense_key = (sense_buffer[1] & 0xf); 1861 if (sb_len > 2) 1862 sshdr->asc = sense_buffer[2]; 1863 if (sb_len > 3) 1864 sshdr->ascq = sense_buffer[3]; 1865 if (sb_len > 7) 1866 sshdr->additional_length = sense_buffer[7]; 1867 } else { 1868 /* 1869 * fixed format 1870 */ 1871 if (sb_len > 2) 1872 sshdr->sense_key = (sense_buffer[2] & 0xf); 1873 if (sb_len > 7) { 1874 sb_len = (sb_len < (sense_buffer[7] + 8)) ? 1875 sb_len : (sense_buffer[7] + 8); 1876 if (sb_len > 12) 1877 sshdr->asc = sense_buffer[12]; 1878 if (sb_len > 13) 1879 sshdr->ascq = sense_buffer[13]; 1880 } 1881 } 1882 1883 return 1; 1884 } 1885 EXPORT_SYMBOL(scsi_normalize_sense); 1886 1887 int scsi_request_normalize_sense(struct scsi_request *sreq, 1888 struct scsi_sense_hdr *sshdr) 1889 { 1890 return scsi_normalize_sense(sreq->sr_sense_buffer, 1891 sizeof(sreq->sr_sense_buffer), sshdr); 1892 } 1893 EXPORT_SYMBOL(scsi_request_normalize_sense); 1894 1895 int scsi_command_normalize_sense(struct scsi_cmnd *cmd, 1896 struct scsi_sense_hdr *sshdr) 1897 { 1898 return scsi_normalize_sense(cmd->sense_buffer, 1899 sizeof(cmd->sense_buffer), sshdr); 1900 } 1901 EXPORT_SYMBOL(scsi_command_normalize_sense); 1902 1903 /** 1904 * scsi_sense_desc_find - search for a given descriptor type in 1905 * descriptor sense data format. 1906 * 1907 * @sense_buffer: byte array of descriptor format sense data 1908 * @sb_len: number of valid bytes in sense_buffer 1909 * @desc_type: value of descriptor type to find 1910 * (e.g. 0 -> information) 1911 * 1912 * Notes: 1913 * only valid when sense data is in descriptor format 1914 * 1915 * Return value: 1916 * pointer to start of (first) descriptor if found else NULL 1917 **/ 1918 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len, 1919 int desc_type) 1920 { 1921 int add_sen_len, add_len, desc_len, k; 1922 const u8 * descp; 1923 1924 if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7]))) 1925 return NULL; 1926 if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73)) 1927 return NULL; 1928 add_sen_len = (add_sen_len < (sb_len - 8)) ? 1929 add_sen_len : (sb_len - 8); 1930 descp = &sense_buffer[8]; 1931 for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) { 1932 descp += desc_len; 1933 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1; 1934 desc_len = add_len + 2; 1935 if (descp[0] == desc_type) 1936 return descp; 1937 if (add_len < 0) // short descriptor ?? 1938 break; 1939 } 1940 return NULL; 1941 } 1942 EXPORT_SYMBOL(scsi_sense_desc_find); 1943 1944 /** 1945 * scsi_get_sense_info_fld - attempts to get information field from 1946 * sense data (either fixed or descriptor format) 1947 * 1948 * @sense_buffer: byte array of sense data 1949 * @sb_len: number of valid bytes in sense_buffer 1950 * @info_out: pointer to 64 integer where 8 or 4 byte information 1951 * field will be placed if found. 1952 * 1953 * Return value: 1954 * 1 if information field found, 0 if not found. 1955 **/ 1956 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len, 1957 u64 * info_out) 1958 { 1959 int j; 1960 const u8 * ucp; 1961 u64 ull; 1962 1963 if (sb_len < 7) 1964 return 0; 1965 switch (sense_buffer[0] & 0x7f) { 1966 case 0x70: 1967 case 0x71: 1968 if (sense_buffer[0] & 0x80) { 1969 *info_out = (sense_buffer[3] << 24) + 1970 (sense_buffer[4] << 16) + 1971 (sense_buffer[5] << 8) + sense_buffer[6]; 1972 return 1; 1973 } else 1974 return 0; 1975 case 0x72: 1976 case 0x73: 1977 ucp = scsi_sense_desc_find(sense_buffer, sb_len, 1978 0 /* info desc */); 1979 if (ucp && (0xa == ucp[1])) { 1980 ull = 0; 1981 for (j = 0; j < 8; ++j) { 1982 if (j > 0) 1983 ull <<= 8; 1984 ull |= ucp[4 + j]; 1985 } 1986 *info_out = ull; 1987 return 1; 1988 } else 1989 return 0; 1990 default: 1991 return 0; 1992 } 1993 } 1994 EXPORT_SYMBOL(scsi_get_sense_info_fld); 1995