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