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/kthread.h> 24 #include <linux/interrupt.h> 25 #include <linux/blkdev.h> 26 #include <linux/delay.h> 27 28 #include <scsi/scsi.h> 29 #include <scsi/scsi_dbg.h> 30 #include <scsi/scsi_device.h> 31 #include <scsi/scsi_eh.h> 32 #include <scsi/scsi_host.h> 33 #include <scsi/scsi_ioctl.h> 34 #include <scsi/scsi_request.h> 35 36 #include "scsi_priv.h" 37 #include "scsi_logging.h" 38 39 #define SENSE_TIMEOUT (10*HZ) 40 #define START_UNIT_TIMEOUT (30*HZ) 41 42 /* 43 * These should *probably* be handled by the host itself. 44 * Since it is allowed to sleep, it probably should. 45 */ 46 #define BUS_RESET_SETTLE_TIME (10) 47 #define HOST_RESET_SETTLE_TIME (10) 48 49 /* called with shost->host_lock held */ 50 void scsi_eh_wakeup(struct Scsi_Host *shost) 51 { 52 if (shost->host_busy == shost->host_failed) { 53 up(shost->eh_wait); 54 SCSI_LOG_ERROR_RECOVERY(5, 55 printk("Waking error handler thread\n")); 56 } 57 } 58 59 /** 60 * scsi_eh_scmd_add - add scsi cmd to error handling. 61 * @scmd: scmd to run eh on. 62 * @eh_flag: optional SCSI_EH flag. 63 * 64 * Return value: 65 * 0 on failure. 66 **/ 67 int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag) 68 { 69 struct Scsi_Host *shost = scmd->device->host; 70 unsigned long flags; 71 72 if (shost->eh_wait == NULL) 73 return 0; 74 75 spin_lock_irqsave(shost->host_lock, flags); 76 77 scmd->eh_eflags |= eh_flag; 78 list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q); 79 scsi_host_set_state(shost, SHOST_RECOVERY); 80 shost->host_failed++; 81 scsi_eh_wakeup(shost); 82 spin_unlock_irqrestore(shost->host_lock, flags); 83 return 1; 84 } 85 86 /** 87 * scsi_add_timer - Start timeout timer for a single scsi command. 88 * @scmd: scsi command that is about to start running. 89 * @timeout: amount of time to allow this command to run. 90 * @complete: timeout function to call if timer isn't canceled. 91 * 92 * Notes: 93 * This should be turned into an inline function. Each scsi command 94 * has its own timer, and as it is added to the queue, we set up the 95 * timer. When the command completes, we cancel the timer. 96 **/ 97 void scsi_add_timer(struct scsi_cmnd *scmd, int timeout, 98 void (*complete)(struct scsi_cmnd *)) 99 { 100 101 /* 102 * If the clock was already running for this command, then 103 * first delete the timer. The timer handling code gets rather 104 * confused if we don't do this. 105 */ 106 if (scmd->eh_timeout.function) 107 del_timer(&scmd->eh_timeout); 108 109 scmd->eh_timeout.data = (unsigned long)scmd; 110 scmd->eh_timeout.expires = jiffies + timeout; 111 scmd->eh_timeout.function = (void (*)(unsigned long)) complete; 112 113 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p, time:" 114 " %d, (%p)\n", __FUNCTION__, 115 scmd, timeout, complete)); 116 117 add_timer(&scmd->eh_timeout); 118 } 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 } 146 147 /** 148 * scsi_times_out - Timeout function for normal scsi commands. 149 * @scmd: Cmd that is timing out. 150 * 151 * Notes: 152 * We do not need to lock this. There is the potential for a race 153 * only in that the normal completion handling might run, but if the 154 * normal completion function determines that the timer has already 155 * fired, then it mustn't do anything. 156 **/ 157 void scsi_times_out(struct scsi_cmnd *scmd) 158 { 159 scsi_log_completion(scmd, TIMEOUT_ERROR); 160 161 if (scmd->device->host->hostt->eh_timed_out) 162 switch (scmd->device->host->hostt->eh_timed_out(scmd)) { 163 case EH_HANDLED: 164 __scsi_done(scmd); 165 return; 166 case EH_RESET_TIMER: 167 /* This allows a single retry even of a command 168 * with allowed == 0 */ 169 if (scmd->retries++ > scmd->allowed) 170 break; 171 scsi_add_timer(scmd, scmd->timeout_per_command, 172 scsi_times_out); 173 return; 174 case EH_NOT_HANDLED: 175 break; 176 } 177 178 if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) { 179 panic("Error handler thread not present at %p %p %s %d", 180 scmd, scmd->device->host, __FILE__, __LINE__); 181 } 182 } 183 184 /** 185 * scsi_block_when_processing_errors - Prevent cmds from being queued. 186 * @sdev: Device on which we are performing recovery. 187 * 188 * Description: 189 * We block until the host is out of error recovery, and then check to 190 * see whether the host or the device is offline. 191 * 192 * Return value: 193 * 0 when dev was taken offline by error recovery. 1 OK to proceed. 194 **/ 195 int scsi_block_when_processing_errors(struct scsi_device *sdev) 196 { 197 int online; 198 199 wait_event(sdev->host->host_wait, (sdev->host->shost_state != 200 SHOST_RECOVERY)); 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 0; 782 } 783 return 1; 784 } 785 786 /** 787 * scsi_eh_abort_cmds - abort canceled commands. 788 * @shost: scsi host being recovered. 789 * @eh_done_q: list_head for processed commands. 790 * 791 * Decription: 792 * Try and see whether or not it makes sense to try and abort the 793 * running command. this only works out to be the case if we have one 794 * command that has timed out. if the command simply failed, it makes 795 * no sense to try and abort the command, since as far as the shost 796 * adapter is concerned, it isn't running. 797 **/ 798 static int scsi_eh_abort_cmds(struct list_head *work_q, 799 struct list_head *done_q) 800 { 801 struct scsi_cmnd *scmd, *next; 802 int rtn; 803 804 list_for_each_entry_safe(scmd, next, work_q, eh_entry) { 805 if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD)) 806 continue; 807 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:" 808 "0x%p\n", current->comm, 809 scmd)); 810 rtn = scsi_try_to_abort_cmd(scmd); 811 if (rtn == SUCCESS) { 812 scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD; 813 if (!scsi_device_online(scmd->device) || 814 !scsi_eh_tur(scmd)) { 815 scsi_eh_finish_cmd(scmd, done_q); 816 } 817 818 } else 819 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting" 820 " cmd failed:" 821 "0x%p\n", 822 current->comm, 823 scmd)); 824 } 825 826 return list_empty(work_q); 827 } 828 829 /** 830 * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev 831 * @scmd: SCSI cmd used to send BDR 832 * 833 * Notes: 834 * There is no timeout for this operation. if this operation is 835 * unreliable for a given host, then the host itself needs to put a 836 * timer on it, and set the host back to a consistent state prior to 837 * returning. 838 **/ 839 static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd) 840 { 841 int rtn; 842 843 if (!scmd->device->host->hostt->eh_device_reset_handler) 844 return FAILED; 845 846 rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd); 847 if (rtn == SUCCESS) { 848 scmd->device->was_reset = 1; 849 scmd->device->expecting_cc_ua = 1; 850 } 851 852 return rtn; 853 } 854 855 /** 856 * scsi_eh_try_stu - Send START_UNIT to device. 857 * @scmd: Scsi cmd to send START_UNIT 858 * 859 * Return value: 860 * 0 - Device is ready. 1 - Device NOT ready. 861 **/ 862 static int scsi_eh_try_stu(struct scsi_cmnd *scmd) 863 { 864 static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0}; 865 int rtn; 866 int saved_result; 867 868 if (!scmd->device->allow_restart) 869 return 1; 870 871 memcpy(scmd->cmnd, stu_command, sizeof(stu_command)); 872 873 /* 874 * zero the sense buffer. the scsi spec mandates that any 875 * untransferred sense data should be interpreted as being zero. 876 */ 877 memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer)); 878 879 saved_result = scmd->result; 880 scmd->request_buffer = NULL; 881 scmd->request_bufflen = 0; 882 scmd->use_sg = 0; 883 scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]); 884 scmd->underflow = 0; 885 scmd->sc_data_direction = DMA_NONE; 886 887 rtn = scsi_send_eh_cmnd(scmd, START_UNIT_TIMEOUT); 888 889 /* 890 * when we eventually call scsi_finish, we really wish to complete 891 * the original request, so let's restore the original data. (db) 892 */ 893 scsi_setup_cmd_retry(scmd); 894 scmd->result = saved_result; 895 896 /* 897 * hey, we are done. let's look to see what happened. 898 */ 899 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n", 900 __FUNCTION__, scmd, rtn)); 901 if (rtn == SUCCESS) 902 return 0; 903 return 1; 904 } 905 906 /** 907 * scsi_eh_stu - send START_UNIT if needed 908 * @shost: scsi host being recovered. 909 * @eh_done_q: list_head for processed commands. 910 * 911 * Notes: 912 * If commands are failing due to not ready, initializing command required, 913 * try revalidating the device, which will end up sending a start unit. 914 **/ 915 static int scsi_eh_stu(struct Scsi_Host *shost, 916 struct list_head *work_q, 917 struct list_head *done_q) 918 { 919 struct scsi_cmnd *scmd, *stu_scmd, *next; 920 struct scsi_device *sdev; 921 922 shost_for_each_device(sdev, shost) { 923 stu_scmd = NULL; 924 list_for_each_entry(scmd, work_q, eh_entry) 925 if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) && 926 scsi_check_sense(scmd) == FAILED ) { 927 stu_scmd = scmd; 928 break; 929 } 930 931 if (!stu_scmd) 932 continue; 933 934 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:" 935 " 0x%p\n", current->comm, sdev)); 936 937 if (!scsi_eh_try_stu(stu_scmd)) { 938 if (!scsi_device_online(sdev) || 939 !scsi_eh_tur(stu_scmd)) { 940 list_for_each_entry_safe(scmd, next, 941 work_q, eh_entry) { 942 if (scmd->device == sdev) 943 scsi_eh_finish_cmd(scmd, done_q); 944 } 945 } 946 } else { 947 SCSI_LOG_ERROR_RECOVERY(3, 948 printk("%s: START_UNIT failed to sdev:" 949 " 0x%p\n", current->comm, sdev)); 950 } 951 } 952 953 return list_empty(work_q); 954 } 955 956 957 /** 958 * scsi_eh_bus_device_reset - send bdr if needed 959 * @shost: scsi host being recovered. 960 * @eh_done_q: list_head for processed commands. 961 * 962 * Notes: 963 * Try a bus device reset. still, look to see whether we have multiple 964 * devices that are jammed or not - if we have multiple devices, it 965 * makes no sense to try bus_device_reset - we really would need to try 966 * a bus_reset instead. 967 **/ 968 static int scsi_eh_bus_device_reset(struct Scsi_Host *shost, 969 struct list_head *work_q, 970 struct list_head *done_q) 971 { 972 struct scsi_cmnd *scmd, *bdr_scmd, *next; 973 struct scsi_device *sdev; 974 int rtn; 975 976 shost_for_each_device(sdev, shost) { 977 bdr_scmd = NULL; 978 list_for_each_entry(scmd, work_q, eh_entry) 979 if (scmd->device == sdev) { 980 bdr_scmd = scmd; 981 break; 982 } 983 984 if (!bdr_scmd) 985 continue; 986 987 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:" 988 " 0x%p\n", current->comm, 989 sdev)); 990 rtn = scsi_try_bus_device_reset(bdr_scmd); 991 if (rtn == SUCCESS) { 992 if (!scsi_device_online(sdev) || 993 !scsi_eh_tur(bdr_scmd)) { 994 list_for_each_entry_safe(scmd, next, 995 work_q, eh_entry) { 996 if (scmd->device == sdev) 997 scsi_eh_finish_cmd(scmd, 998 done_q); 999 } 1000 } 1001 } else { 1002 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR" 1003 " failed sdev:" 1004 "0x%p\n", 1005 current->comm, 1006 sdev)); 1007 } 1008 } 1009 1010 return list_empty(work_q); 1011 } 1012 1013 /** 1014 * scsi_try_bus_reset - ask host to perform a bus reset 1015 * @scmd: SCSI cmd to send bus reset. 1016 **/ 1017 static int scsi_try_bus_reset(struct scsi_cmnd *scmd) 1018 { 1019 unsigned long flags; 1020 int rtn; 1021 1022 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n", 1023 __FUNCTION__)); 1024 1025 if (!scmd->device->host->hostt->eh_bus_reset_handler) 1026 return FAILED; 1027 1028 rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd); 1029 1030 if (rtn == SUCCESS) { 1031 if (!scmd->device->host->hostt->skip_settle_delay) 1032 ssleep(BUS_RESET_SETTLE_TIME); 1033 spin_lock_irqsave(scmd->device->host->host_lock, flags); 1034 scsi_report_bus_reset(scmd->device->host, scmd->device->channel); 1035 spin_unlock_irqrestore(scmd->device->host->host_lock, flags); 1036 } 1037 1038 return rtn; 1039 } 1040 1041 /** 1042 * scsi_try_host_reset - ask host adapter to reset itself 1043 * @scmd: SCSI cmd to send hsot reset. 1044 **/ 1045 static int scsi_try_host_reset(struct scsi_cmnd *scmd) 1046 { 1047 unsigned long flags; 1048 int rtn; 1049 1050 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n", 1051 __FUNCTION__)); 1052 1053 if (!scmd->device->host->hostt->eh_host_reset_handler) 1054 return FAILED; 1055 1056 rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd); 1057 1058 if (rtn == SUCCESS) { 1059 if (!scmd->device->host->hostt->skip_settle_delay) 1060 ssleep(HOST_RESET_SETTLE_TIME); 1061 spin_lock_irqsave(scmd->device->host->host_lock, flags); 1062 scsi_report_bus_reset(scmd->device->host, scmd->device->channel); 1063 spin_unlock_irqrestore(scmd->device->host->host_lock, flags); 1064 } 1065 1066 return rtn; 1067 } 1068 1069 /** 1070 * scsi_eh_bus_reset - send a bus reset 1071 * @shost: scsi host being recovered. 1072 * @eh_done_q: list_head for processed commands. 1073 **/ 1074 static int scsi_eh_bus_reset(struct Scsi_Host *shost, 1075 struct list_head *work_q, 1076 struct list_head *done_q) 1077 { 1078 struct scsi_cmnd *scmd, *chan_scmd, *next; 1079 unsigned int channel; 1080 int rtn; 1081 1082 /* 1083 * we really want to loop over the various channels, and do this on 1084 * a channel by channel basis. we should also check to see if any 1085 * of the failed commands are on soft_reset devices, and if so, skip 1086 * the reset. 1087 */ 1088 1089 for (channel = 0; channel <= shost->max_channel; channel++) { 1090 chan_scmd = NULL; 1091 list_for_each_entry(scmd, work_q, eh_entry) { 1092 if (channel == scmd->device->channel) { 1093 chan_scmd = scmd; 1094 break; 1095 /* 1096 * FIXME add back in some support for 1097 * soft_reset devices. 1098 */ 1099 } 1100 } 1101 1102 if (!chan_scmd) 1103 continue; 1104 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:" 1105 " %d\n", current->comm, 1106 channel)); 1107 rtn = scsi_try_bus_reset(chan_scmd); 1108 if (rtn == SUCCESS) { 1109 list_for_each_entry_safe(scmd, next, work_q, eh_entry) { 1110 if (channel == scmd->device->channel) 1111 if (!scsi_device_online(scmd->device) || 1112 !scsi_eh_tur(scmd)) 1113 scsi_eh_finish_cmd(scmd, 1114 done_q); 1115 } 1116 } else { 1117 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST" 1118 " failed chan: %d\n", 1119 current->comm, 1120 channel)); 1121 } 1122 } 1123 return list_empty(work_q); 1124 } 1125 1126 /** 1127 * scsi_eh_host_reset - send a host reset 1128 * @work_q: list_head for processed commands. 1129 * @done_q: list_head for processed commands. 1130 **/ 1131 static int scsi_eh_host_reset(struct list_head *work_q, 1132 struct list_head *done_q) 1133 { 1134 struct scsi_cmnd *scmd, *next; 1135 int rtn; 1136 1137 if (!list_empty(work_q)) { 1138 scmd = list_entry(work_q->next, 1139 struct scsi_cmnd, eh_entry); 1140 1141 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n" 1142 , current->comm)); 1143 1144 rtn = scsi_try_host_reset(scmd); 1145 if (rtn == SUCCESS) { 1146 list_for_each_entry_safe(scmd, next, work_q, eh_entry) { 1147 if (!scsi_device_online(scmd->device) || 1148 (!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) || 1149 !scsi_eh_tur(scmd)) 1150 scsi_eh_finish_cmd(scmd, done_q); 1151 } 1152 } else { 1153 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST" 1154 " failed\n", 1155 current->comm)); 1156 } 1157 } 1158 return list_empty(work_q); 1159 } 1160 1161 /** 1162 * scsi_eh_offline_sdevs - offline scsi devices that fail to recover 1163 * @work_q: list_head for processed commands. 1164 * @done_q: list_head for processed commands. 1165 * 1166 **/ 1167 static void scsi_eh_offline_sdevs(struct list_head *work_q, 1168 struct list_head *done_q) 1169 { 1170 struct scsi_cmnd *scmd, *next; 1171 1172 list_for_each_entry_safe(scmd, next, work_q, eh_entry) { 1173 printk(KERN_INFO "scsi: Device offlined - not" 1174 " ready after error recovery: host" 1175 " %d channel %d id %d lun %d\n", 1176 scmd->device->host->host_no, 1177 scmd->device->channel, 1178 scmd->device->id, 1179 scmd->device->lun); 1180 scsi_device_set_state(scmd->device, SDEV_OFFLINE); 1181 if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) { 1182 /* 1183 * FIXME: Handle lost cmds. 1184 */ 1185 } 1186 scsi_eh_finish_cmd(scmd, done_q); 1187 } 1188 return; 1189 } 1190 1191 /** 1192 * scsi_decide_disposition - Disposition a cmd on return from LLD. 1193 * @scmd: SCSI cmd to examine. 1194 * 1195 * Notes: 1196 * This is *only* called when we are examining the status after sending 1197 * out the actual data command. any commands that are queued for error 1198 * recovery (e.g. test_unit_ready) do *not* come through here. 1199 * 1200 * When this routine returns failed, it means the error handler thread 1201 * is woken. In cases where the error code indicates an error that 1202 * doesn't require the error handler read (i.e. we don't need to 1203 * abort/reset), this function should return SUCCESS. 1204 **/ 1205 int scsi_decide_disposition(struct scsi_cmnd *scmd) 1206 { 1207 int rtn; 1208 1209 /* 1210 * if the device is offline, then we clearly just pass the result back 1211 * up to the top level. 1212 */ 1213 if (!scsi_device_online(scmd->device)) { 1214 SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report" 1215 " as SUCCESS\n", 1216 __FUNCTION__)); 1217 return SUCCESS; 1218 } 1219 1220 /* 1221 * first check the host byte, to see if there is anything in there 1222 * that would indicate what we need to do. 1223 */ 1224 switch (host_byte(scmd->result)) { 1225 case DID_PASSTHROUGH: 1226 /* 1227 * no matter what, pass this through to the upper layer. 1228 * nuke this special code so that it looks like we are saying 1229 * did_ok. 1230 */ 1231 scmd->result &= 0xff00ffff; 1232 return SUCCESS; 1233 case DID_OK: 1234 /* 1235 * looks good. drop through, and check the next byte. 1236 */ 1237 break; 1238 case DID_NO_CONNECT: 1239 case DID_BAD_TARGET: 1240 case DID_ABORT: 1241 /* 1242 * note - this means that we just report the status back 1243 * to the top level driver, not that we actually think 1244 * that it indicates SUCCESS. 1245 */ 1246 return SUCCESS; 1247 /* 1248 * when the low level driver returns did_soft_error, 1249 * it is responsible for keeping an internal retry counter 1250 * in order to avoid endless loops (db) 1251 * 1252 * actually this is a bug in this function here. we should 1253 * be mindful of the maximum number of retries specified 1254 * and not get stuck in a loop. 1255 */ 1256 case DID_SOFT_ERROR: 1257 goto maybe_retry; 1258 case DID_IMM_RETRY: 1259 return NEEDS_RETRY; 1260 1261 case DID_REQUEUE: 1262 return ADD_TO_MLQUEUE; 1263 1264 case DID_ERROR: 1265 if (msg_byte(scmd->result) == COMMAND_COMPLETE && 1266 status_byte(scmd->result) == RESERVATION_CONFLICT) 1267 /* 1268 * execute reservation conflict processing code 1269 * lower down 1270 */ 1271 break; 1272 /* fallthrough */ 1273 1274 case DID_BUS_BUSY: 1275 case DID_PARITY: 1276 goto maybe_retry; 1277 case DID_TIME_OUT: 1278 /* 1279 * when we scan the bus, we get timeout messages for 1280 * these commands if there is no device available. 1281 * other hosts report did_no_connect for the same thing. 1282 */ 1283 if ((scmd->cmnd[0] == TEST_UNIT_READY || 1284 scmd->cmnd[0] == INQUIRY)) { 1285 return SUCCESS; 1286 } else { 1287 return FAILED; 1288 } 1289 case DID_RESET: 1290 return SUCCESS; 1291 default: 1292 return FAILED; 1293 } 1294 1295 /* 1296 * next, check the message byte. 1297 */ 1298 if (msg_byte(scmd->result) != COMMAND_COMPLETE) 1299 return FAILED; 1300 1301 /* 1302 * check the status byte to see if this indicates anything special. 1303 */ 1304 switch (status_byte(scmd->result)) { 1305 case QUEUE_FULL: 1306 /* 1307 * the case of trying to send too many commands to a 1308 * tagged queueing device. 1309 */ 1310 case BUSY: 1311 /* 1312 * device can't talk to us at the moment. Should only 1313 * occur (SAM-3) when the task queue is empty, so will cause 1314 * the empty queue handling to trigger a stall in the 1315 * device. 1316 */ 1317 return ADD_TO_MLQUEUE; 1318 case GOOD: 1319 case COMMAND_TERMINATED: 1320 case TASK_ABORTED: 1321 return SUCCESS; 1322 case CHECK_CONDITION: 1323 rtn = scsi_check_sense(scmd); 1324 if (rtn == NEEDS_RETRY) 1325 goto maybe_retry; 1326 /* if rtn == FAILED, we have no sense information; 1327 * returning FAILED will wake the error handler thread 1328 * to collect the sense and redo the decide 1329 * disposition */ 1330 return rtn; 1331 case CONDITION_GOOD: 1332 case INTERMEDIATE_GOOD: 1333 case INTERMEDIATE_C_GOOD: 1334 case ACA_ACTIVE: 1335 /* 1336 * who knows? FIXME(eric) 1337 */ 1338 return SUCCESS; 1339 1340 case RESERVATION_CONFLICT: 1341 printk(KERN_INFO "scsi: reservation conflict: host" 1342 " %d channel %d id %d lun %d\n", 1343 scmd->device->host->host_no, scmd->device->channel, 1344 scmd->device->id, scmd->device->lun); 1345 return SUCCESS; /* causes immediate i/o error */ 1346 default: 1347 return FAILED; 1348 } 1349 return FAILED; 1350 1351 maybe_retry: 1352 1353 /* we requeue for retry because the error was retryable, and 1354 * the request was not marked fast fail. Note that above, 1355 * even if the request is marked fast fail, we still requeue 1356 * for queue congestion conditions (QUEUE_FULL or BUSY) */ 1357 if ((++scmd->retries) < scmd->allowed 1358 && !blk_noretry_request(scmd->request)) { 1359 return NEEDS_RETRY; 1360 } else { 1361 /* 1362 * no more retries - report this one back to upper level. 1363 */ 1364 return SUCCESS; 1365 } 1366 } 1367 1368 /** 1369 * scsi_eh_lock_done - done function for eh door lock request 1370 * @scmd: SCSI command block for the door lock request 1371 * 1372 * Notes: 1373 * We completed the asynchronous door lock request, and it has either 1374 * locked the door or failed. We must free the command structures 1375 * associated with this request. 1376 **/ 1377 static void scsi_eh_lock_done(struct scsi_cmnd *scmd) 1378 { 1379 struct scsi_request *sreq = scmd->sc_request; 1380 1381 scsi_release_request(sreq); 1382 } 1383 1384 1385 /** 1386 * scsi_eh_lock_door - Prevent medium removal for the specified device 1387 * @sdev: SCSI device to prevent medium removal 1388 * 1389 * Locking: 1390 * We must be called from process context; scsi_allocate_request() 1391 * may sleep. 1392 * 1393 * Notes: 1394 * We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the 1395 * head of the devices request queue, and continue. 1396 * 1397 * Bugs: 1398 * scsi_allocate_request() may sleep waiting for existing requests to 1399 * be processed. However, since we haven't kicked off any request 1400 * processing for this host, this may deadlock. 1401 * 1402 * If scsi_allocate_request() fails for what ever reason, we 1403 * completely forget to lock the door. 1404 **/ 1405 static void scsi_eh_lock_door(struct scsi_device *sdev) 1406 { 1407 struct scsi_request *sreq = scsi_allocate_request(sdev, GFP_KERNEL); 1408 1409 if (unlikely(!sreq)) { 1410 printk(KERN_ERR "%s: request allocate failed," 1411 "prevent media removal cmd not sent\n", __FUNCTION__); 1412 return; 1413 } 1414 1415 sreq->sr_cmnd[0] = ALLOW_MEDIUM_REMOVAL; 1416 sreq->sr_cmnd[1] = 0; 1417 sreq->sr_cmnd[2] = 0; 1418 sreq->sr_cmnd[3] = 0; 1419 sreq->sr_cmnd[4] = SCSI_REMOVAL_PREVENT; 1420 sreq->sr_cmnd[5] = 0; 1421 sreq->sr_data_direction = DMA_NONE; 1422 sreq->sr_bufflen = 0; 1423 sreq->sr_buffer = NULL; 1424 sreq->sr_allowed = 5; 1425 sreq->sr_done = scsi_eh_lock_done; 1426 sreq->sr_timeout_per_command = 10 * HZ; 1427 sreq->sr_cmd_len = COMMAND_SIZE(sreq->sr_cmnd[0]); 1428 1429 scsi_insert_special_req(sreq, 1); 1430 } 1431 1432 1433 /** 1434 * scsi_restart_operations - restart io operations to the specified host. 1435 * @shost: Host we are restarting. 1436 * 1437 * Notes: 1438 * When we entered the error handler, we blocked all further i/o to 1439 * this device. we need to 'reverse' this process. 1440 **/ 1441 static void scsi_restart_operations(struct Scsi_Host *shost) 1442 { 1443 struct scsi_device *sdev; 1444 1445 /* 1446 * If the door was locked, we need to insert a door lock request 1447 * onto the head of the SCSI request queue for the device. There 1448 * is no point trying to lock the door of an off-line device. 1449 */ 1450 shost_for_each_device(sdev, shost) { 1451 if (scsi_device_online(sdev) && sdev->locked) 1452 scsi_eh_lock_door(sdev); 1453 } 1454 1455 /* 1456 * next free up anything directly waiting upon the host. this 1457 * will be requests for character device operations, and also for 1458 * ioctls to queued block devices. 1459 */ 1460 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n", 1461 __FUNCTION__)); 1462 1463 scsi_host_set_state(shost, SHOST_RUNNING); 1464 1465 wake_up(&shost->host_wait); 1466 1467 /* 1468 * finally we need to re-initiate requests that may be pending. we will 1469 * have had everything blocked while error handling is taking place, and 1470 * now that error recovery is done, we will need to ensure that these 1471 * requests are started. 1472 */ 1473 scsi_run_host_queues(shost); 1474 } 1475 1476 /** 1477 * scsi_eh_ready_devs - check device ready state and recover if not. 1478 * @shost: host to be recovered. 1479 * @eh_done_q: list_head for processed commands. 1480 * 1481 **/ 1482 static void scsi_eh_ready_devs(struct Scsi_Host *shost, 1483 struct list_head *work_q, 1484 struct list_head *done_q) 1485 { 1486 if (!scsi_eh_stu(shost, work_q, done_q)) 1487 if (!scsi_eh_bus_device_reset(shost, work_q, done_q)) 1488 if (!scsi_eh_bus_reset(shost, work_q, done_q)) 1489 if (!scsi_eh_host_reset(work_q, done_q)) 1490 scsi_eh_offline_sdevs(work_q, done_q); 1491 } 1492 1493 /** 1494 * scsi_eh_flush_done_q - finish processed commands or retry them. 1495 * @done_q: list_head of processed commands. 1496 * 1497 **/ 1498 static void scsi_eh_flush_done_q(struct list_head *done_q) 1499 { 1500 struct scsi_cmnd *scmd, *next; 1501 1502 list_for_each_entry_safe(scmd, next, done_q, eh_entry) { 1503 list_del_init(&scmd->eh_entry); 1504 if (scsi_device_online(scmd->device) && 1505 !blk_noretry_request(scmd->request) && 1506 (++scmd->retries < scmd->allowed)) { 1507 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush" 1508 " retry cmd: %p\n", 1509 current->comm, 1510 scmd)); 1511 scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY); 1512 } else { 1513 /* 1514 * If just we got sense for the device (called 1515 * scsi_eh_get_sense), scmd->result is already 1516 * set, do not set DRIVER_TIMEOUT. 1517 */ 1518 if (!scmd->result) 1519 scmd->result |= (DRIVER_TIMEOUT << 24); 1520 SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish" 1521 " cmd: %p\n", 1522 current->comm, scmd)); 1523 scsi_finish_command(scmd); 1524 } 1525 } 1526 } 1527 1528 /** 1529 * scsi_unjam_host - Attempt to fix a host which has a cmd that failed. 1530 * @shost: Host to unjam. 1531 * 1532 * Notes: 1533 * When we come in here, we *know* that all commands on the bus have 1534 * either completed, failed or timed out. we also know that no further 1535 * commands are being sent to the host, so things are relatively quiet 1536 * and we have freedom to fiddle with things as we wish. 1537 * 1538 * This is only the *default* implementation. it is possible for 1539 * individual drivers to supply their own version of this function, and 1540 * if the maintainer wishes to do this, it is strongly suggested that 1541 * this function be taken as a template and modified. this function 1542 * was designed to correctly handle problems for about 95% of the 1543 * different cases out there, and it should always provide at least a 1544 * reasonable amount of error recovery. 1545 * 1546 * Any command marked 'failed' or 'timeout' must eventually have 1547 * scsi_finish_cmd() called for it. we do all of the retry stuff 1548 * here, so when we restart the host after we return it should have an 1549 * empty queue. 1550 **/ 1551 static void scsi_unjam_host(struct Scsi_Host *shost) 1552 { 1553 unsigned long flags; 1554 LIST_HEAD(eh_work_q); 1555 LIST_HEAD(eh_done_q); 1556 1557 spin_lock_irqsave(shost->host_lock, flags); 1558 list_splice_init(&shost->eh_cmd_q, &eh_work_q); 1559 spin_unlock_irqrestore(shost->host_lock, flags); 1560 1561 SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q)); 1562 1563 if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q)) 1564 if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q)) 1565 scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q); 1566 1567 scsi_eh_flush_done_q(&eh_done_q); 1568 } 1569 1570 /** 1571 * scsi_error_handler - Handle errors/timeouts of SCSI cmds. 1572 * @data: Host for which we are running. 1573 * 1574 * Notes: 1575 * This is always run in the context of a kernel thread. The idea is 1576 * that we start this thing up when the kernel starts up (one per host 1577 * that we detect), and it immediately goes to sleep and waits for some 1578 * event (i.e. failure). When this takes place, we have the job of 1579 * trying to unjam the bus and restarting things. 1580 **/ 1581 int scsi_error_handler(void *data) 1582 { 1583 struct Scsi_Host *shost = (struct Scsi_Host *) data; 1584 int rtn; 1585 DECLARE_MUTEX_LOCKED(sem); 1586 1587 current->flags |= PF_NOFREEZE; 1588 shost->eh_wait = &sem; 1589 1590 /* 1591 * Wake up the thread that created us. 1592 */ 1593 SCSI_LOG_ERROR_RECOVERY(3, printk("Wake up parent of" 1594 " scsi_eh_%d\n",shost->host_no)); 1595 1596 while (1) { 1597 /* 1598 * If we get a signal, it means we are supposed to go 1599 * away and die. This typically happens if the user is 1600 * trying to unload a module. 1601 */ 1602 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler" 1603 " scsi_eh_%d" 1604 " sleeping\n",shost->host_no)); 1605 1606 /* 1607 * Note - we always use down_interruptible with the semaphore 1608 * even if the module was loaded as part of the kernel. The 1609 * reason is that down() will cause this thread to be counted 1610 * in the load average as a running process, and down 1611 * interruptible doesn't. Given that we need to allow this 1612 * thread to die if the driver was loaded as a module, using 1613 * semaphores isn't unreasonable. 1614 */ 1615 down_interruptible(&sem); 1616 if (kthread_should_stop()) 1617 break; 1618 1619 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler" 1620 " scsi_eh_%d waking" 1621 " up\n",shost->host_no)); 1622 1623 shost->eh_active = 1; 1624 1625 /* 1626 * We have a host that is failing for some reason. Figure out 1627 * what we need to do to get it up and online again (if we can). 1628 * If we fail, we end up taking the thing offline. 1629 */ 1630 if (shost->hostt->eh_strategy_handler) 1631 rtn = shost->hostt->eh_strategy_handler(shost); 1632 else 1633 scsi_unjam_host(shost); 1634 1635 shost->eh_active = 0; 1636 1637 /* 1638 * Note - if the above fails completely, the action is to take 1639 * individual devices offline and flush the queue of any 1640 * outstanding requests that may have been pending. When we 1641 * restart, we restart any I/O to any other devices on the bus 1642 * which are still online. 1643 */ 1644 scsi_restart_operations(shost); 1645 1646 } 1647 1648 SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler scsi_eh_%d" 1649 " exiting\n",shost->host_no)); 1650 1651 /* 1652 * Make sure that nobody tries to wake us up again. 1653 */ 1654 shost->eh_wait = NULL; 1655 return 0; 1656 } 1657 1658 /* 1659 * Function: scsi_report_bus_reset() 1660 * 1661 * Purpose: Utility function used by low-level drivers to report that 1662 * they have observed a bus reset on the bus being handled. 1663 * 1664 * Arguments: shost - Host in question 1665 * channel - channel on which reset was observed. 1666 * 1667 * Returns: Nothing 1668 * 1669 * Lock status: Host lock must be held. 1670 * 1671 * Notes: This only needs to be called if the reset is one which 1672 * originates from an unknown location. Resets originated 1673 * by the mid-level itself don't need to call this, but there 1674 * should be no harm. 1675 * 1676 * The main purpose of this is to make sure that a CHECK_CONDITION 1677 * is properly treated. 1678 */ 1679 void scsi_report_bus_reset(struct Scsi_Host *shost, int channel) 1680 { 1681 struct scsi_device *sdev; 1682 1683 __shost_for_each_device(sdev, shost) { 1684 if (channel == sdev->channel) { 1685 sdev->was_reset = 1; 1686 sdev->expecting_cc_ua = 1; 1687 } 1688 } 1689 } 1690 EXPORT_SYMBOL(scsi_report_bus_reset); 1691 1692 /* 1693 * Function: scsi_report_device_reset() 1694 * 1695 * Purpose: Utility function used by low-level drivers to report that 1696 * they have observed a device reset on the device being handled. 1697 * 1698 * Arguments: shost - Host in question 1699 * channel - channel on which reset was observed 1700 * target - target on which reset was observed 1701 * 1702 * Returns: Nothing 1703 * 1704 * Lock status: Host lock must be held 1705 * 1706 * Notes: This only needs to be called if the reset is one which 1707 * originates from an unknown location. Resets originated 1708 * by the mid-level itself don't need to call this, but there 1709 * should be no harm. 1710 * 1711 * The main purpose of this is to make sure that a CHECK_CONDITION 1712 * is properly treated. 1713 */ 1714 void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target) 1715 { 1716 struct scsi_device *sdev; 1717 1718 __shost_for_each_device(sdev, shost) { 1719 if (channel == sdev->channel && 1720 target == sdev->id) { 1721 sdev->was_reset = 1; 1722 sdev->expecting_cc_ua = 1; 1723 } 1724 } 1725 } 1726 EXPORT_SYMBOL(scsi_report_device_reset); 1727 1728 static void 1729 scsi_reset_provider_done_command(struct scsi_cmnd *scmd) 1730 { 1731 } 1732 1733 /* 1734 * Function: scsi_reset_provider 1735 * 1736 * Purpose: Send requested reset to a bus or device at any phase. 1737 * 1738 * Arguments: device - device to send reset to 1739 * flag - reset type (see scsi.h) 1740 * 1741 * Returns: SUCCESS/FAILURE. 1742 * 1743 * Notes: This is used by the SCSI Generic driver to provide 1744 * Bus/Device reset capability. 1745 */ 1746 int 1747 scsi_reset_provider(struct scsi_device *dev, int flag) 1748 { 1749 struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL); 1750 struct request req; 1751 int rtn; 1752 1753 scmd->request = &req; 1754 memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout)); 1755 scmd->request->rq_status = RQ_SCSI_BUSY; 1756 1757 memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd)); 1758 1759 scmd->scsi_done = scsi_reset_provider_done_command; 1760 scmd->done = NULL; 1761 scmd->buffer = NULL; 1762 scmd->bufflen = 0; 1763 scmd->request_buffer = NULL; 1764 scmd->request_bufflen = 0; 1765 1766 scmd->cmd_len = 0; 1767 1768 scmd->sc_data_direction = DMA_BIDIRECTIONAL; 1769 scmd->sc_request = NULL; 1770 scmd->sc_magic = SCSI_CMND_MAGIC; 1771 1772 init_timer(&scmd->eh_timeout); 1773 1774 /* 1775 * Sometimes the command can get back into the timer chain, 1776 * so use the pid as an identifier. 1777 */ 1778 scmd->pid = 0; 1779 1780 switch (flag) { 1781 case SCSI_TRY_RESET_DEVICE: 1782 rtn = scsi_try_bus_device_reset(scmd); 1783 if (rtn == SUCCESS) 1784 break; 1785 /* FALLTHROUGH */ 1786 case SCSI_TRY_RESET_BUS: 1787 rtn = scsi_try_bus_reset(scmd); 1788 if (rtn == SUCCESS) 1789 break; 1790 /* FALLTHROUGH */ 1791 case SCSI_TRY_RESET_HOST: 1792 rtn = scsi_try_host_reset(scmd); 1793 break; 1794 default: 1795 rtn = FAILED; 1796 } 1797 1798 scsi_next_command(scmd); 1799 return rtn; 1800 } 1801 EXPORT_SYMBOL(scsi_reset_provider); 1802 1803 /** 1804 * scsi_normalize_sense - normalize main elements from either fixed or 1805 * descriptor sense data format into a common format. 1806 * 1807 * @sense_buffer: byte array containing sense data returned by device 1808 * @sb_len: number of valid bytes in sense_buffer 1809 * @sshdr: pointer to instance of structure that common 1810 * elements are written to. 1811 * 1812 * Notes: 1813 * The "main elements" from sense data are: response_code, sense_key, 1814 * asc, ascq and additional_length (only for descriptor format). 1815 * 1816 * Typically this function can be called after a device has 1817 * responded to a SCSI command with the CHECK_CONDITION status. 1818 * 1819 * Return value: 1820 * 1 if valid sense data information found, else 0; 1821 **/ 1822 int scsi_normalize_sense(const u8 *sense_buffer, int sb_len, 1823 struct scsi_sense_hdr *sshdr) 1824 { 1825 if (!sense_buffer || !sb_len) 1826 return 0; 1827 1828 memset(sshdr, 0, sizeof(struct scsi_sense_hdr)); 1829 1830 sshdr->response_code = (sense_buffer[0] & 0x7f); 1831 1832 if (!scsi_sense_valid(sshdr)) 1833 return 0; 1834 1835 if (sshdr->response_code >= 0x72) { 1836 /* 1837 * descriptor format 1838 */ 1839 if (sb_len > 1) 1840 sshdr->sense_key = (sense_buffer[1] & 0xf); 1841 if (sb_len > 2) 1842 sshdr->asc = sense_buffer[2]; 1843 if (sb_len > 3) 1844 sshdr->ascq = sense_buffer[3]; 1845 if (sb_len > 7) 1846 sshdr->additional_length = sense_buffer[7]; 1847 } else { 1848 /* 1849 * fixed format 1850 */ 1851 if (sb_len > 2) 1852 sshdr->sense_key = (sense_buffer[2] & 0xf); 1853 if (sb_len > 7) { 1854 sb_len = (sb_len < (sense_buffer[7] + 8)) ? 1855 sb_len : (sense_buffer[7] + 8); 1856 if (sb_len > 12) 1857 sshdr->asc = sense_buffer[12]; 1858 if (sb_len > 13) 1859 sshdr->ascq = sense_buffer[13]; 1860 } 1861 } 1862 1863 return 1; 1864 } 1865 EXPORT_SYMBOL(scsi_normalize_sense); 1866 1867 int scsi_request_normalize_sense(struct scsi_request *sreq, 1868 struct scsi_sense_hdr *sshdr) 1869 { 1870 return scsi_normalize_sense(sreq->sr_sense_buffer, 1871 sizeof(sreq->sr_sense_buffer), sshdr); 1872 } 1873 EXPORT_SYMBOL(scsi_request_normalize_sense); 1874 1875 int scsi_command_normalize_sense(struct scsi_cmnd *cmd, 1876 struct scsi_sense_hdr *sshdr) 1877 { 1878 return scsi_normalize_sense(cmd->sense_buffer, 1879 sizeof(cmd->sense_buffer), sshdr); 1880 } 1881 EXPORT_SYMBOL(scsi_command_normalize_sense); 1882 1883 /** 1884 * scsi_sense_desc_find - search for a given descriptor type in 1885 * descriptor sense data format. 1886 * 1887 * @sense_buffer: byte array of descriptor format sense data 1888 * @sb_len: number of valid bytes in sense_buffer 1889 * @desc_type: value of descriptor type to find 1890 * (e.g. 0 -> information) 1891 * 1892 * Notes: 1893 * only valid when sense data is in descriptor format 1894 * 1895 * Return value: 1896 * pointer to start of (first) descriptor if found else NULL 1897 **/ 1898 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len, 1899 int desc_type) 1900 { 1901 int add_sen_len, add_len, desc_len, k; 1902 const u8 * descp; 1903 1904 if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7]))) 1905 return NULL; 1906 if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73)) 1907 return NULL; 1908 add_sen_len = (add_sen_len < (sb_len - 8)) ? 1909 add_sen_len : (sb_len - 8); 1910 descp = &sense_buffer[8]; 1911 for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) { 1912 descp += desc_len; 1913 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1; 1914 desc_len = add_len + 2; 1915 if (descp[0] == desc_type) 1916 return descp; 1917 if (add_len < 0) // short descriptor ?? 1918 break; 1919 } 1920 return NULL; 1921 } 1922 EXPORT_SYMBOL(scsi_sense_desc_find); 1923 1924 /** 1925 * scsi_get_sense_info_fld - attempts to get information field from 1926 * sense data (either fixed or descriptor format) 1927 * 1928 * @sense_buffer: byte array of sense data 1929 * @sb_len: number of valid bytes in sense_buffer 1930 * @info_out: pointer to 64 integer where 8 or 4 byte information 1931 * field will be placed if found. 1932 * 1933 * Return value: 1934 * 1 if information field found, 0 if not found. 1935 **/ 1936 int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len, 1937 u64 * info_out) 1938 { 1939 int j; 1940 const u8 * ucp; 1941 u64 ull; 1942 1943 if (sb_len < 7) 1944 return 0; 1945 switch (sense_buffer[0] & 0x7f) { 1946 case 0x70: 1947 case 0x71: 1948 if (sense_buffer[0] & 0x80) { 1949 *info_out = (sense_buffer[3] << 24) + 1950 (sense_buffer[4] << 16) + 1951 (sense_buffer[5] << 8) + sense_buffer[6]; 1952 return 1; 1953 } else 1954 return 0; 1955 case 0x72: 1956 case 0x73: 1957 ucp = scsi_sense_desc_find(sense_buffer, sb_len, 1958 0 /* info desc */); 1959 if (ucp && (0xa == ucp[1])) { 1960 ull = 0; 1961 for (j = 0; j < 8; ++j) { 1962 if (j > 0) 1963 ull <<= 8; 1964 ull |= ucp[4 + j]; 1965 } 1966 *info_out = ull; 1967 return 1; 1968 } else 1969 return 0; 1970 default: 1971 return 0; 1972 } 1973 } 1974 EXPORT_SYMBOL(scsi_get_sense_info_fld); 1975