1 /* 2 * scsi_lib.c Copyright (C) 1999 Eric Youngdale 3 * 4 * SCSI queueing library. 5 * Initial versions: Eric Youngdale (eric@andante.org). 6 * Based upon conversations with large numbers 7 * of people at Linux Expo. 8 */ 9 10 #include <linux/bio.h> 11 #include <linux/bitops.h> 12 #include <linux/blkdev.h> 13 #include <linux/completion.h> 14 #include <linux/kernel.h> 15 #include <linux/mempool.h> 16 #include <linux/slab.h> 17 #include <linux/init.h> 18 #include <linux/pci.h> 19 #include <linux/delay.h> 20 #include <linux/hardirq.h> 21 #include <linux/scatterlist.h> 22 23 #include <scsi/scsi.h> 24 #include <scsi/scsi_cmnd.h> 25 #include <scsi/scsi_dbg.h> 26 #include <scsi/scsi_device.h> 27 #include <scsi/scsi_driver.h> 28 #include <scsi/scsi_eh.h> 29 #include <scsi/scsi_host.h> 30 31 #include "scsi_priv.h" 32 #include "scsi_logging.h" 33 34 35 #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools) 36 #define SG_MEMPOOL_SIZE 2 37 38 struct scsi_host_sg_pool { 39 size_t size; 40 char *name; 41 struct kmem_cache *slab; 42 mempool_t *pool; 43 }; 44 45 #define SP(x) { x, "sgpool-" __stringify(x) } 46 #if (SCSI_MAX_SG_SEGMENTS < 32) 47 #error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater) 48 #endif 49 static struct scsi_host_sg_pool scsi_sg_pools[] = { 50 SP(8), 51 SP(16), 52 #if (SCSI_MAX_SG_SEGMENTS > 32) 53 SP(32), 54 #if (SCSI_MAX_SG_SEGMENTS > 64) 55 SP(64), 56 #if (SCSI_MAX_SG_SEGMENTS > 128) 57 SP(128), 58 #if (SCSI_MAX_SG_SEGMENTS > 256) 59 #error SCSI_MAX_SG_SEGMENTS is too large (256 MAX) 60 #endif 61 #endif 62 #endif 63 #endif 64 SP(SCSI_MAX_SG_SEGMENTS) 65 }; 66 #undef SP 67 68 struct kmem_cache *scsi_sdb_cache; 69 70 static void scsi_run_queue(struct request_queue *q); 71 72 /* 73 * Function: scsi_unprep_request() 74 * 75 * Purpose: Remove all preparation done for a request, including its 76 * associated scsi_cmnd, so that it can be requeued. 77 * 78 * Arguments: req - request to unprepare 79 * 80 * Lock status: Assumed that no locks are held upon entry. 81 * 82 * Returns: Nothing. 83 */ 84 static void scsi_unprep_request(struct request *req) 85 { 86 struct scsi_cmnd *cmd = req->special; 87 88 req->cmd_flags &= ~REQ_DONTPREP; 89 req->special = NULL; 90 91 scsi_put_command(cmd); 92 } 93 94 /** 95 * __scsi_queue_insert - private queue insertion 96 * @cmd: The SCSI command being requeued 97 * @reason: The reason for the requeue 98 * @unbusy: Whether the queue should be unbusied 99 * 100 * This is a private queue insertion. The public interface 101 * scsi_queue_insert() always assumes the queue should be unbusied 102 * because it's always called before the completion. This function is 103 * for a requeue after completion, which should only occur in this 104 * file. 105 */ 106 static int __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy) 107 { 108 struct Scsi_Host *host = cmd->device->host; 109 struct scsi_device *device = cmd->device; 110 struct scsi_target *starget = scsi_target(device); 111 struct request_queue *q = device->request_queue; 112 unsigned long flags; 113 114 SCSI_LOG_MLQUEUE(1, 115 printk("Inserting command %p into mlqueue\n", cmd)); 116 117 /* 118 * Set the appropriate busy bit for the device/host. 119 * 120 * If the host/device isn't busy, assume that something actually 121 * completed, and that we should be able to queue a command now. 122 * 123 * Note that the prior mid-layer assumption that any host could 124 * always queue at least one command is now broken. The mid-layer 125 * will implement a user specifiable stall (see 126 * scsi_host.max_host_blocked and scsi_device.max_device_blocked) 127 * if a command is requeued with no other commands outstanding 128 * either for the device or for the host. 129 */ 130 switch (reason) { 131 case SCSI_MLQUEUE_HOST_BUSY: 132 host->host_blocked = host->max_host_blocked; 133 break; 134 case SCSI_MLQUEUE_DEVICE_BUSY: 135 device->device_blocked = device->max_device_blocked; 136 break; 137 case SCSI_MLQUEUE_TARGET_BUSY: 138 starget->target_blocked = starget->max_target_blocked; 139 break; 140 } 141 142 /* 143 * Decrement the counters, since these commands are no longer 144 * active on the host/device. 145 */ 146 if (unbusy) 147 scsi_device_unbusy(device); 148 149 /* 150 * Requeue this command. It will go before all other commands 151 * that are already in the queue. 152 * 153 * NOTE: there is magic here about the way the queue is plugged if 154 * we have no outstanding commands. 155 * 156 * Although we *don't* plug the queue, we call the request 157 * function. The SCSI request function detects the blocked condition 158 * and plugs the queue appropriately. 159 */ 160 spin_lock_irqsave(q->queue_lock, flags); 161 blk_requeue_request(q, cmd->request); 162 spin_unlock_irqrestore(q->queue_lock, flags); 163 164 scsi_run_queue(q); 165 166 return 0; 167 } 168 169 /* 170 * Function: scsi_queue_insert() 171 * 172 * Purpose: Insert a command in the midlevel queue. 173 * 174 * Arguments: cmd - command that we are adding to queue. 175 * reason - why we are inserting command to queue. 176 * 177 * Lock status: Assumed that lock is not held upon entry. 178 * 179 * Returns: Nothing. 180 * 181 * Notes: We do this for one of two cases. Either the host is busy 182 * and it cannot accept any more commands for the time being, 183 * or the device returned QUEUE_FULL and can accept no more 184 * commands. 185 * Notes: This could be called either from an interrupt context or a 186 * normal process context. 187 */ 188 int scsi_queue_insert(struct scsi_cmnd *cmd, int reason) 189 { 190 return __scsi_queue_insert(cmd, reason, 1); 191 } 192 /** 193 * scsi_execute - insert request and wait for the result 194 * @sdev: scsi device 195 * @cmd: scsi command 196 * @data_direction: data direction 197 * @buffer: data buffer 198 * @bufflen: len of buffer 199 * @sense: optional sense buffer 200 * @timeout: request timeout in seconds 201 * @retries: number of times to retry request 202 * @flags: or into request flags; 203 * @resid: optional residual length 204 * 205 * returns the req->errors value which is the scsi_cmnd result 206 * field. 207 */ 208 int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, 209 int data_direction, void *buffer, unsigned bufflen, 210 unsigned char *sense, int timeout, int retries, int flags, 211 int *resid) 212 { 213 struct request *req; 214 int write = (data_direction == DMA_TO_DEVICE); 215 int ret = DRIVER_ERROR << 24; 216 217 req = blk_get_request(sdev->request_queue, write, __GFP_WAIT); 218 219 if (bufflen && blk_rq_map_kern(sdev->request_queue, req, 220 buffer, bufflen, __GFP_WAIT)) 221 goto out; 222 223 req->cmd_len = COMMAND_SIZE(cmd[0]); 224 memcpy(req->cmd, cmd, req->cmd_len); 225 req->sense = sense; 226 req->sense_len = 0; 227 req->retries = retries; 228 req->timeout = timeout; 229 req->cmd_type = REQ_TYPE_BLOCK_PC; 230 req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT; 231 232 /* 233 * head injection *required* here otherwise quiesce won't work 234 */ 235 blk_execute_rq(req->q, NULL, req, 1); 236 237 /* 238 * Some devices (USB mass-storage in particular) may transfer 239 * garbage data together with a residue indicating that the data 240 * is invalid. Prevent the garbage from being misinterpreted 241 * and prevent security leaks by zeroing out the excess data. 242 */ 243 if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen)) 244 memset(buffer + (bufflen - req->resid_len), 0, req->resid_len); 245 246 if (resid) 247 *resid = req->resid_len; 248 ret = req->errors; 249 out: 250 blk_put_request(req); 251 252 return ret; 253 } 254 EXPORT_SYMBOL(scsi_execute); 255 256 257 int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd, 258 int data_direction, void *buffer, unsigned bufflen, 259 struct scsi_sense_hdr *sshdr, int timeout, int retries, 260 int *resid) 261 { 262 char *sense = NULL; 263 int result; 264 265 if (sshdr) { 266 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO); 267 if (!sense) 268 return DRIVER_ERROR << 24; 269 } 270 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen, 271 sense, timeout, retries, 0, resid); 272 if (sshdr) 273 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr); 274 275 kfree(sense); 276 return result; 277 } 278 EXPORT_SYMBOL(scsi_execute_req); 279 280 /* 281 * Function: scsi_init_cmd_errh() 282 * 283 * Purpose: Initialize cmd fields related to error handling. 284 * 285 * Arguments: cmd - command that is ready to be queued. 286 * 287 * Notes: This function has the job of initializing a number of 288 * fields related to error handling. Typically this will 289 * be called once for each command, as required. 290 */ 291 static void scsi_init_cmd_errh(struct scsi_cmnd *cmd) 292 { 293 cmd->serial_number = 0; 294 scsi_set_resid(cmd, 0); 295 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE); 296 if (cmd->cmd_len == 0) 297 cmd->cmd_len = scsi_command_size(cmd->cmnd); 298 } 299 300 void scsi_device_unbusy(struct scsi_device *sdev) 301 { 302 struct Scsi_Host *shost = sdev->host; 303 struct scsi_target *starget = scsi_target(sdev); 304 unsigned long flags; 305 306 spin_lock_irqsave(shost->host_lock, flags); 307 shost->host_busy--; 308 starget->target_busy--; 309 if (unlikely(scsi_host_in_recovery(shost) && 310 (shost->host_failed || shost->host_eh_scheduled))) 311 scsi_eh_wakeup(shost); 312 spin_unlock(shost->host_lock); 313 spin_lock(sdev->request_queue->queue_lock); 314 sdev->device_busy--; 315 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); 316 } 317 318 /* 319 * Called for single_lun devices on IO completion. Clear starget_sdev_user, 320 * and call blk_run_queue for all the scsi_devices on the target - 321 * including current_sdev first. 322 * 323 * Called with *no* scsi locks held. 324 */ 325 static void scsi_single_lun_run(struct scsi_device *current_sdev) 326 { 327 struct Scsi_Host *shost = current_sdev->host; 328 struct scsi_device *sdev, *tmp; 329 struct scsi_target *starget = scsi_target(current_sdev); 330 unsigned long flags; 331 332 spin_lock_irqsave(shost->host_lock, flags); 333 starget->starget_sdev_user = NULL; 334 spin_unlock_irqrestore(shost->host_lock, flags); 335 336 /* 337 * Call blk_run_queue for all LUNs on the target, starting with 338 * current_sdev. We race with others (to set starget_sdev_user), 339 * but in most cases, we will be first. Ideally, each LU on the 340 * target would get some limited time or requests on the target. 341 */ 342 blk_run_queue(current_sdev->request_queue); 343 344 spin_lock_irqsave(shost->host_lock, flags); 345 if (starget->starget_sdev_user) 346 goto out; 347 list_for_each_entry_safe(sdev, tmp, &starget->devices, 348 same_target_siblings) { 349 if (sdev == current_sdev) 350 continue; 351 if (scsi_device_get(sdev)) 352 continue; 353 354 spin_unlock_irqrestore(shost->host_lock, flags); 355 blk_run_queue(sdev->request_queue); 356 spin_lock_irqsave(shost->host_lock, flags); 357 358 scsi_device_put(sdev); 359 } 360 out: 361 spin_unlock_irqrestore(shost->host_lock, flags); 362 } 363 364 static inline int scsi_device_is_busy(struct scsi_device *sdev) 365 { 366 if (sdev->device_busy >= sdev->queue_depth || sdev->device_blocked) 367 return 1; 368 369 return 0; 370 } 371 372 static inline int scsi_target_is_busy(struct scsi_target *starget) 373 { 374 return ((starget->can_queue > 0 && 375 starget->target_busy >= starget->can_queue) || 376 starget->target_blocked); 377 } 378 379 static inline int scsi_host_is_busy(struct Scsi_Host *shost) 380 { 381 if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) || 382 shost->host_blocked || shost->host_self_blocked) 383 return 1; 384 385 return 0; 386 } 387 388 /* 389 * Function: scsi_run_queue() 390 * 391 * Purpose: Select a proper request queue to serve next 392 * 393 * Arguments: q - last request's queue 394 * 395 * Returns: Nothing 396 * 397 * Notes: The previous command was completely finished, start 398 * a new one if possible. 399 */ 400 static void scsi_run_queue(struct request_queue *q) 401 { 402 struct scsi_device *sdev = q->queuedata; 403 struct Scsi_Host *shost = sdev->host; 404 LIST_HEAD(starved_list); 405 unsigned long flags; 406 407 if (scsi_target(sdev)->single_lun) 408 scsi_single_lun_run(sdev); 409 410 spin_lock_irqsave(shost->host_lock, flags); 411 list_splice_init(&shost->starved_list, &starved_list); 412 413 while (!list_empty(&starved_list)) { 414 int flagset; 415 416 /* 417 * As long as shost is accepting commands and we have 418 * starved queues, call blk_run_queue. scsi_request_fn 419 * drops the queue_lock and can add us back to the 420 * starved_list. 421 * 422 * host_lock protects the starved_list and starved_entry. 423 * scsi_request_fn must get the host_lock before checking 424 * or modifying starved_list or starved_entry. 425 */ 426 if (scsi_host_is_busy(shost)) 427 break; 428 429 sdev = list_entry(starved_list.next, 430 struct scsi_device, starved_entry); 431 list_del_init(&sdev->starved_entry); 432 if (scsi_target_is_busy(scsi_target(sdev))) { 433 list_move_tail(&sdev->starved_entry, 434 &shost->starved_list); 435 continue; 436 } 437 438 spin_unlock(shost->host_lock); 439 440 spin_lock(sdev->request_queue->queue_lock); 441 flagset = test_bit(QUEUE_FLAG_REENTER, &q->queue_flags) && 442 !test_bit(QUEUE_FLAG_REENTER, 443 &sdev->request_queue->queue_flags); 444 if (flagset) 445 queue_flag_set(QUEUE_FLAG_REENTER, sdev->request_queue); 446 __blk_run_queue(sdev->request_queue); 447 if (flagset) 448 queue_flag_clear(QUEUE_FLAG_REENTER, sdev->request_queue); 449 spin_unlock(sdev->request_queue->queue_lock); 450 451 spin_lock(shost->host_lock); 452 } 453 /* put any unprocessed entries back */ 454 list_splice(&starved_list, &shost->starved_list); 455 spin_unlock_irqrestore(shost->host_lock, flags); 456 457 blk_run_queue(q); 458 } 459 460 /* 461 * Function: scsi_requeue_command() 462 * 463 * Purpose: Handle post-processing of completed commands. 464 * 465 * Arguments: q - queue to operate on 466 * cmd - command that may need to be requeued. 467 * 468 * Returns: Nothing 469 * 470 * Notes: After command completion, there may be blocks left 471 * over which weren't finished by the previous command 472 * this can be for a number of reasons - the main one is 473 * I/O errors in the middle of the request, in which case 474 * we need to request the blocks that come after the bad 475 * sector. 476 * Notes: Upon return, cmd is a stale pointer. 477 */ 478 static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) 479 { 480 struct request *req = cmd->request; 481 unsigned long flags; 482 483 spin_lock_irqsave(q->queue_lock, flags); 484 scsi_unprep_request(req); 485 blk_requeue_request(q, req); 486 spin_unlock_irqrestore(q->queue_lock, flags); 487 488 scsi_run_queue(q); 489 } 490 491 void scsi_next_command(struct scsi_cmnd *cmd) 492 { 493 struct scsi_device *sdev = cmd->device; 494 struct request_queue *q = sdev->request_queue; 495 496 /* need to hold a reference on the device before we let go of the cmd */ 497 get_device(&sdev->sdev_gendev); 498 499 scsi_put_command(cmd); 500 scsi_run_queue(q); 501 502 /* ok to remove device now */ 503 put_device(&sdev->sdev_gendev); 504 } 505 506 void scsi_run_host_queues(struct Scsi_Host *shost) 507 { 508 struct scsi_device *sdev; 509 510 shost_for_each_device(sdev, shost) 511 scsi_run_queue(sdev->request_queue); 512 } 513 514 static void __scsi_release_buffers(struct scsi_cmnd *, int); 515 516 /* 517 * Function: scsi_end_request() 518 * 519 * Purpose: Post-processing of completed commands (usually invoked at end 520 * of upper level post-processing and scsi_io_completion). 521 * 522 * Arguments: cmd - command that is complete. 523 * error - 0 if I/O indicates success, < 0 for I/O error. 524 * bytes - number of bytes of completed I/O 525 * requeue - indicates whether we should requeue leftovers. 526 * 527 * Lock status: Assumed that lock is not held upon entry. 528 * 529 * Returns: cmd if requeue required, NULL otherwise. 530 * 531 * Notes: This is called for block device requests in order to 532 * mark some number of sectors as complete. 533 * 534 * We are guaranteeing that the request queue will be goosed 535 * at some point during this call. 536 * Notes: If cmd was requeued, upon return it will be a stale pointer. 537 */ 538 static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error, 539 int bytes, int requeue) 540 { 541 struct request_queue *q = cmd->device->request_queue; 542 struct request *req = cmd->request; 543 544 /* 545 * If there are blocks left over at the end, set up the command 546 * to queue the remainder of them. 547 */ 548 if (blk_end_request(req, error, bytes)) { 549 /* kill remainder if no retrys */ 550 if (error && scsi_noretry_cmd(cmd)) 551 blk_end_request_all(req, error); 552 else { 553 if (requeue) { 554 /* 555 * Bleah. Leftovers again. Stick the 556 * leftovers in the front of the 557 * queue, and goose the queue again. 558 */ 559 scsi_release_buffers(cmd); 560 scsi_requeue_command(q, cmd); 561 cmd = NULL; 562 } 563 return cmd; 564 } 565 } 566 567 /* 568 * This will goose the queue request function at the end, so we don't 569 * need to worry about launching another command. 570 */ 571 __scsi_release_buffers(cmd, 0); 572 scsi_next_command(cmd); 573 return NULL; 574 } 575 576 static inline unsigned int scsi_sgtable_index(unsigned short nents) 577 { 578 unsigned int index; 579 580 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS); 581 582 if (nents <= 8) 583 index = 0; 584 else 585 index = get_count_order(nents) - 3; 586 587 return index; 588 } 589 590 static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents) 591 { 592 struct scsi_host_sg_pool *sgp; 593 594 sgp = scsi_sg_pools + scsi_sgtable_index(nents); 595 mempool_free(sgl, sgp->pool); 596 } 597 598 static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask) 599 { 600 struct scsi_host_sg_pool *sgp; 601 602 sgp = scsi_sg_pools + scsi_sgtable_index(nents); 603 return mempool_alloc(sgp->pool, gfp_mask); 604 } 605 606 static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, 607 gfp_t gfp_mask) 608 { 609 int ret; 610 611 BUG_ON(!nents); 612 613 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS, 614 gfp_mask, scsi_sg_alloc); 615 if (unlikely(ret)) 616 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, 617 scsi_sg_free); 618 619 return ret; 620 } 621 622 static void scsi_free_sgtable(struct scsi_data_buffer *sdb) 623 { 624 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free); 625 } 626 627 static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check) 628 { 629 630 if (cmd->sdb.table.nents) 631 scsi_free_sgtable(&cmd->sdb); 632 633 memset(&cmd->sdb, 0, sizeof(cmd->sdb)); 634 635 if (do_bidi_check && scsi_bidi_cmnd(cmd)) { 636 struct scsi_data_buffer *bidi_sdb = 637 cmd->request->next_rq->special; 638 scsi_free_sgtable(bidi_sdb); 639 kmem_cache_free(scsi_sdb_cache, bidi_sdb); 640 cmd->request->next_rq->special = NULL; 641 } 642 643 if (scsi_prot_sg_count(cmd)) 644 scsi_free_sgtable(cmd->prot_sdb); 645 } 646 647 /* 648 * Function: scsi_release_buffers() 649 * 650 * Purpose: Completion processing for block device I/O requests. 651 * 652 * Arguments: cmd - command that we are bailing. 653 * 654 * Lock status: Assumed that no lock is held upon entry. 655 * 656 * Returns: Nothing 657 * 658 * Notes: In the event that an upper level driver rejects a 659 * command, we must release resources allocated during 660 * the __init_io() function. Primarily this would involve 661 * the scatter-gather table, and potentially any bounce 662 * buffers. 663 */ 664 void scsi_release_buffers(struct scsi_cmnd *cmd) 665 { 666 __scsi_release_buffers(cmd, 1); 667 } 668 EXPORT_SYMBOL(scsi_release_buffers); 669 670 /* 671 * Function: scsi_io_completion() 672 * 673 * Purpose: Completion processing for block device I/O requests. 674 * 675 * Arguments: cmd - command that is finished. 676 * 677 * Lock status: Assumed that no lock is held upon entry. 678 * 679 * Returns: Nothing 680 * 681 * Notes: This function is matched in terms of capabilities to 682 * the function that created the scatter-gather list. 683 * In other words, if there are no bounce buffers 684 * (the normal case for most drivers), we don't need 685 * the logic to deal with cleaning up afterwards. 686 * 687 * We must call scsi_end_request(). This will finish off 688 * the specified number of sectors. If we are done, the 689 * command block will be released and the queue function 690 * will be goosed. If we are not done then we have to 691 * figure out what to do next: 692 * 693 * a) We can call scsi_requeue_command(). The request 694 * will be unprepared and put back on the queue. Then 695 * a new command will be created for it. This should 696 * be used if we made forward progress, or if we want 697 * to switch from READ(10) to READ(6) for example. 698 * 699 * b) We can call scsi_queue_insert(). The request will 700 * be put back on the queue and retried using the same 701 * command as before, possibly after a delay. 702 * 703 * c) We can call blk_end_request() with -EIO to fail 704 * the remainder of the request. 705 */ 706 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) 707 { 708 int result = cmd->result; 709 struct request_queue *q = cmd->device->request_queue; 710 struct request *req = cmd->request; 711 int error = 0; 712 struct scsi_sense_hdr sshdr; 713 int sense_valid = 0; 714 int sense_deferred = 0; 715 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY, 716 ACTION_DELAYED_RETRY} action; 717 char *description = NULL; 718 719 if (result) { 720 sense_valid = scsi_command_normalize_sense(cmd, &sshdr); 721 if (sense_valid) 722 sense_deferred = scsi_sense_is_deferred(&sshdr); 723 } 724 725 if (blk_pc_request(req)) { /* SG_IO ioctl from block level */ 726 req->errors = result; 727 if (result) { 728 if (sense_valid && req->sense) { 729 /* 730 * SG_IO wants current and deferred errors 731 */ 732 int len = 8 + cmd->sense_buffer[7]; 733 734 if (len > SCSI_SENSE_BUFFERSIZE) 735 len = SCSI_SENSE_BUFFERSIZE; 736 memcpy(req->sense, cmd->sense_buffer, len); 737 req->sense_len = len; 738 } 739 if (!sense_deferred) 740 error = -EIO; 741 } 742 743 req->resid_len = scsi_get_resid(cmd); 744 745 if (scsi_bidi_cmnd(cmd)) { 746 /* 747 * Bidi commands Must be complete as a whole, 748 * both sides at once. 749 */ 750 req->next_rq->resid_len = scsi_in(cmd)->resid; 751 752 scsi_release_buffers(cmd); 753 blk_end_request_all(req, 0); 754 755 scsi_next_command(cmd); 756 return; 757 } 758 } 759 760 BUG_ON(blk_bidi_rq(req)); /* bidi not support for !blk_pc_request yet */ 761 762 /* 763 * Next deal with any sectors which we were able to correctly 764 * handle. 765 */ 766 SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, " 767 "%d bytes done.\n", 768 blk_rq_sectors(req), good_bytes)); 769 770 /* 771 * Recovered errors need reporting, but they're always treated 772 * as success, so fiddle the result code here. For BLOCK_PC 773 * we already took a copy of the original into rq->errors which 774 * is what gets returned to the user 775 */ 776 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) { 777 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip 778 * print since caller wants ATA registers. Only occurs on 779 * SCSI ATA PASS_THROUGH commands when CK_COND=1 780 */ 781 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d)) 782 ; 783 else if (!(req->cmd_flags & REQ_QUIET)) 784 scsi_print_sense("", cmd); 785 result = 0; 786 /* BLOCK_PC may have set error */ 787 error = 0; 788 } 789 790 /* 791 * A number of bytes were successfully read. If there 792 * are leftovers and there is some kind of error 793 * (result != 0), retry the rest. 794 */ 795 if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL) 796 return; 797 798 error = -EIO; 799 800 if (host_byte(result) == DID_RESET) { 801 /* Third party bus reset or reset for error recovery 802 * reasons. Just retry the command and see what 803 * happens. 804 */ 805 action = ACTION_RETRY; 806 } else if (sense_valid && !sense_deferred) { 807 switch (sshdr.sense_key) { 808 case UNIT_ATTENTION: 809 if (cmd->device->removable) { 810 /* Detected disc change. Set a bit 811 * and quietly refuse further access. 812 */ 813 cmd->device->changed = 1; 814 description = "Media Changed"; 815 action = ACTION_FAIL; 816 } else { 817 /* Must have been a power glitch, or a 818 * bus reset. Could not have been a 819 * media change, so we just retry the 820 * command and see what happens. 821 */ 822 action = ACTION_RETRY; 823 } 824 break; 825 case ILLEGAL_REQUEST: 826 /* If we had an ILLEGAL REQUEST returned, then 827 * we may have performed an unsupported 828 * command. The only thing this should be 829 * would be a ten byte read where only a six 830 * byte read was supported. Also, on a system 831 * where READ CAPACITY failed, we may have 832 * read past the end of the disk. 833 */ 834 if ((cmd->device->use_10_for_rw && 835 sshdr.asc == 0x20 && sshdr.ascq == 0x00) && 836 (cmd->cmnd[0] == READ_10 || 837 cmd->cmnd[0] == WRITE_10)) { 838 /* This will issue a new 6-byte command. */ 839 cmd->device->use_10_for_rw = 0; 840 action = ACTION_REPREP; 841 } else if (sshdr.asc == 0x10) /* DIX */ { 842 description = "Host Data Integrity Failure"; 843 action = ACTION_FAIL; 844 error = -EILSEQ; 845 } else 846 action = ACTION_FAIL; 847 break; 848 case ABORTED_COMMAND: 849 action = ACTION_FAIL; 850 if (sshdr.asc == 0x10) { /* DIF */ 851 description = "Target Data Integrity Failure"; 852 error = -EILSEQ; 853 } 854 break; 855 case NOT_READY: 856 /* If the device is in the process of becoming 857 * ready, or has a temporary blockage, retry. 858 */ 859 if (sshdr.asc == 0x04) { 860 switch (sshdr.ascq) { 861 case 0x01: /* becoming ready */ 862 case 0x04: /* format in progress */ 863 case 0x05: /* rebuild in progress */ 864 case 0x06: /* recalculation in progress */ 865 case 0x07: /* operation in progress */ 866 case 0x08: /* Long write in progress */ 867 case 0x09: /* self test in progress */ 868 case 0x14: /* space allocation in progress */ 869 action = ACTION_DELAYED_RETRY; 870 break; 871 default: 872 description = "Device not ready"; 873 action = ACTION_FAIL; 874 break; 875 } 876 } else { 877 description = "Device not ready"; 878 action = ACTION_FAIL; 879 } 880 break; 881 case VOLUME_OVERFLOW: 882 /* See SSC3rXX or current. */ 883 action = ACTION_FAIL; 884 break; 885 default: 886 description = "Unhandled sense code"; 887 action = ACTION_FAIL; 888 break; 889 } 890 } else { 891 description = "Unhandled error code"; 892 action = ACTION_FAIL; 893 } 894 895 switch (action) { 896 case ACTION_FAIL: 897 /* Give up and fail the remainder of the request */ 898 scsi_release_buffers(cmd); 899 if (!(req->cmd_flags & REQ_QUIET)) { 900 if (description) 901 scmd_printk(KERN_INFO, cmd, "%s\n", 902 description); 903 scsi_print_result(cmd); 904 if (driver_byte(result) & DRIVER_SENSE) 905 scsi_print_sense("", cmd); 906 scsi_print_command(cmd); 907 } 908 if (blk_end_request_err(req, error)) 909 scsi_requeue_command(q, cmd); 910 else 911 scsi_next_command(cmd); 912 break; 913 case ACTION_REPREP: 914 /* Unprep the request and put it back at the head of the queue. 915 * A new command will be prepared and issued. 916 */ 917 scsi_release_buffers(cmd); 918 scsi_requeue_command(q, cmd); 919 break; 920 case ACTION_RETRY: 921 /* Retry the same command immediately */ 922 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0); 923 break; 924 case ACTION_DELAYED_RETRY: 925 /* Retry the same command after a delay */ 926 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0); 927 break; 928 } 929 } 930 931 static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb, 932 gfp_t gfp_mask) 933 { 934 int count; 935 936 /* 937 * If sg table allocation fails, requeue request later. 938 */ 939 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments, 940 gfp_mask))) { 941 return BLKPREP_DEFER; 942 } 943 944 req->buffer = NULL; 945 946 /* 947 * Next, walk the list, and fill in the addresses and sizes of 948 * each segment. 949 */ 950 count = blk_rq_map_sg(req->q, req, sdb->table.sgl); 951 BUG_ON(count > sdb->table.nents); 952 sdb->table.nents = count; 953 sdb->length = blk_rq_bytes(req); 954 return BLKPREP_OK; 955 } 956 957 /* 958 * Function: scsi_init_io() 959 * 960 * Purpose: SCSI I/O initialize function. 961 * 962 * Arguments: cmd - Command descriptor we wish to initialize 963 * 964 * Returns: 0 on success 965 * BLKPREP_DEFER if the failure is retryable 966 * BLKPREP_KILL if the failure is fatal 967 */ 968 int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask) 969 { 970 int error = scsi_init_sgtable(cmd->request, &cmd->sdb, gfp_mask); 971 if (error) 972 goto err_exit; 973 974 if (blk_bidi_rq(cmd->request)) { 975 struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc( 976 scsi_sdb_cache, GFP_ATOMIC); 977 if (!bidi_sdb) { 978 error = BLKPREP_DEFER; 979 goto err_exit; 980 } 981 982 cmd->request->next_rq->special = bidi_sdb; 983 error = scsi_init_sgtable(cmd->request->next_rq, bidi_sdb, 984 GFP_ATOMIC); 985 if (error) 986 goto err_exit; 987 } 988 989 if (blk_integrity_rq(cmd->request)) { 990 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb; 991 int ivecs, count; 992 993 BUG_ON(prot_sdb == NULL); 994 ivecs = blk_rq_count_integrity_sg(cmd->request); 995 996 if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) { 997 error = BLKPREP_DEFER; 998 goto err_exit; 999 } 1000 1001 count = blk_rq_map_integrity_sg(cmd->request, 1002 prot_sdb->table.sgl); 1003 BUG_ON(unlikely(count > ivecs)); 1004 1005 cmd->prot_sdb = prot_sdb; 1006 cmd->prot_sdb->table.nents = count; 1007 } 1008 1009 return BLKPREP_OK ; 1010 1011 err_exit: 1012 scsi_release_buffers(cmd); 1013 if (error == BLKPREP_KILL) 1014 scsi_put_command(cmd); 1015 else /* BLKPREP_DEFER */ 1016 scsi_unprep_request(cmd->request); 1017 1018 return error; 1019 } 1020 EXPORT_SYMBOL(scsi_init_io); 1021 1022 static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev, 1023 struct request *req) 1024 { 1025 struct scsi_cmnd *cmd; 1026 1027 if (!req->special) { 1028 cmd = scsi_get_command(sdev, GFP_ATOMIC); 1029 if (unlikely(!cmd)) 1030 return NULL; 1031 req->special = cmd; 1032 } else { 1033 cmd = req->special; 1034 } 1035 1036 /* pull a tag out of the request if we have one */ 1037 cmd->tag = req->tag; 1038 cmd->request = req; 1039 1040 cmd->cmnd = req->cmd; 1041 1042 return cmd; 1043 } 1044 1045 int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req) 1046 { 1047 struct scsi_cmnd *cmd; 1048 int ret = scsi_prep_state_check(sdev, req); 1049 1050 if (ret != BLKPREP_OK) 1051 return ret; 1052 1053 cmd = scsi_get_cmd_from_req(sdev, req); 1054 if (unlikely(!cmd)) 1055 return BLKPREP_DEFER; 1056 1057 /* 1058 * BLOCK_PC requests may transfer data, in which case they must 1059 * a bio attached to them. Or they might contain a SCSI command 1060 * that does not transfer data, in which case they may optionally 1061 * submit a request without an attached bio. 1062 */ 1063 if (req->bio) { 1064 int ret; 1065 1066 BUG_ON(!req->nr_phys_segments); 1067 1068 ret = scsi_init_io(cmd, GFP_ATOMIC); 1069 if (unlikely(ret)) 1070 return ret; 1071 } else { 1072 BUG_ON(blk_rq_bytes(req)); 1073 1074 memset(&cmd->sdb, 0, sizeof(cmd->sdb)); 1075 req->buffer = NULL; 1076 } 1077 1078 cmd->cmd_len = req->cmd_len; 1079 if (!blk_rq_bytes(req)) 1080 cmd->sc_data_direction = DMA_NONE; 1081 else if (rq_data_dir(req) == WRITE) 1082 cmd->sc_data_direction = DMA_TO_DEVICE; 1083 else 1084 cmd->sc_data_direction = DMA_FROM_DEVICE; 1085 1086 cmd->transfersize = blk_rq_bytes(req); 1087 cmd->allowed = req->retries; 1088 return BLKPREP_OK; 1089 } 1090 EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd); 1091 1092 /* 1093 * Setup a REQ_TYPE_FS command. These are simple read/write request 1094 * from filesystems that still need to be translated to SCSI CDBs from 1095 * the ULD. 1096 */ 1097 int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req) 1098 { 1099 struct scsi_cmnd *cmd; 1100 int ret = scsi_prep_state_check(sdev, req); 1101 1102 if (ret != BLKPREP_OK) 1103 return ret; 1104 1105 if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh 1106 && sdev->scsi_dh_data->scsi_dh->prep_fn)) { 1107 ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req); 1108 if (ret != BLKPREP_OK) 1109 return ret; 1110 } 1111 1112 /* 1113 * Filesystem requests must transfer data. 1114 */ 1115 BUG_ON(!req->nr_phys_segments); 1116 1117 cmd = scsi_get_cmd_from_req(sdev, req); 1118 if (unlikely(!cmd)) 1119 return BLKPREP_DEFER; 1120 1121 memset(cmd->cmnd, 0, BLK_MAX_CDB); 1122 return scsi_init_io(cmd, GFP_ATOMIC); 1123 } 1124 EXPORT_SYMBOL(scsi_setup_fs_cmnd); 1125 1126 int scsi_prep_state_check(struct scsi_device *sdev, struct request *req) 1127 { 1128 int ret = BLKPREP_OK; 1129 1130 /* 1131 * If the device is not in running state we will reject some 1132 * or all commands. 1133 */ 1134 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { 1135 switch (sdev->sdev_state) { 1136 case SDEV_OFFLINE: 1137 /* 1138 * If the device is offline we refuse to process any 1139 * commands. The device must be brought online 1140 * before trying any recovery commands. 1141 */ 1142 sdev_printk(KERN_ERR, sdev, 1143 "rejecting I/O to offline device\n"); 1144 ret = BLKPREP_KILL; 1145 break; 1146 case SDEV_DEL: 1147 /* 1148 * If the device is fully deleted, we refuse to 1149 * process any commands as well. 1150 */ 1151 sdev_printk(KERN_ERR, sdev, 1152 "rejecting I/O to dead device\n"); 1153 ret = BLKPREP_KILL; 1154 break; 1155 case SDEV_QUIESCE: 1156 case SDEV_BLOCK: 1157 case SDEV_CREATED_BLOCK: 1158 /* 1159 * If the devices is blocked we defer normal commands. 1160 */ 1161 if (!(req->cmd_flags & REQ_PREEMPT)) 1162 ret = BLKPREP_DEFER; 1163 break; 1164 default: 1165 /* 1166 * For any other not fully online state we only allow 1167 * special commands. In particular any user initiated 1168 * command is not allowed. 1169 */ 1170 if (!(req->cmd_flags & REQ_PREEMPT)) 1171 ret = BLKPREP_KILL; 1172 break; 1173 } 1174 } 1175 return ret; 1176 } 1177 EXPORT_SYMBOL(scsi_prep_state_check); 1178 1179 int scsi_prep_return(struct request_queue *q, struct request *req, int ret) 1180 { 1181 struct scsi_device *sdev = q->queuedata; 1182 1183 switch (ret) { 1184 case BLKPREP_KILL: 1185 req->errors = DID_NO_CONNECT << 16; 1186 /* release the command and kill it */ 1187 if (req->special) { 1188 struct scsi_cmnd *cmd = req->special; 1189 scsi_release_buffers(cmd); 1190 scsi_put_command(cmd); 1191 req->special = NULL; 1192 } 1193 break; 1194 case BLKPREP_DEFER: 1195 /* 1196 * If we defer, the blk_peek_request() returns NULL, but the 1197 * queue must be restarted, so we plug here if no returning 1198 * command will automatically do that. 1199 */ 1200 if (sdev->device_busy == 0) 1201 blk_plug_device(q); 1202 break; 1203 default: 1204 req->cmd_flags |= REQ_DONTPREP; 1205 } 1206 1207 return ret; 1208 } 1209 EXPORT_SYMBOL(scsi_prep_return); 1210 1211 int scsi_prep_fn(struct request_queue *q, struct request *req) 1212 { 1213 struct scsi_device *sdev = q->queuedata; 1214 int ret = BLKPREP_KILL; 1215 1216 if (req->cmd_type == REQ_TYPE_BLOCK_PC) 1217 ret = scsi_setup_blk_pc_cmnd(sdev, req); 1218 return scsi_prep_return(q, req, ret); 1219 } 1220 EXPORT_SYMBOL(scsi_prep_fn); 1221 1222 /* 1223 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else 1224 * return 0. 1225 * 1226 * Called with the queue_lock held. 1227 */ 1228 static inline int scsi_dev_queue_ready(struct request_queue *q, 1229 struct scsi_device *sdev) 1230 { 1231 if (sdev->device_busy == 0 && sdev->device_blocked) { 1232 /* 1233 * unblock after device_blocked iterates to zero 1234 */ 1235 if (--sdev->device_blocked == 0) { 1236 SCSI_LOG_MLQUEUE(3, 1237 sdev_printk(KERN_INFO, sdev, 1238 "unblocking device at zero depth\n")); 1239 } else { 1240 blk_plug_device(q); 1241 return 0; 1242 } 1243 } 1244 if (scsi_device_is_busy(sdev)) 1245 return 0; 1246 1247 return 1; 1248 } 1249 1250 1251 /* 1252 * scsi_target_queue_ready: checks if there we can send commands to target 1253 * @sdev: scsi device on starget to check. 1254 * 1255 * Called with the host lock held. 1256 */ 1257 static inline int scsi_target_queue_ready(struct Scsi_Host *shost, 1258 struct scsi_device *sdev) 1259 { 1260 struct scsi_target *starget = scsi_target(sdev); 1261 1262 if (starget->single_lun) { 1263 if (starget->starget_sdev_user && 1264 starget->starget_sdev_user != sdev) 1265 return 0; 1266 starget->starget_sdev_user = sdev; 1267 } 1268 1269 if (starget->target_busy == 0 && starget->target_blocked) { 1270 /* 1271 * unblock after target_blocked iterates to zero 1272 */ 1273 if (--starget->target_blocked == 0) { 1274 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget, 1275 "unblocking target at zero depth\n")); 1276 } else 1277 return 0; 1278 } 1279 1280 if (scsi_target_is_busy(starget)) { 1281 if (list_empty(&sdev->starved_entry)) { 1282 list_add_tail(&sdev->starved_entry, 1283 &shost->starved_list); 1284 return 0; 1285 } 1286 } 1287 1288 /* We're OK to process the command, so we can't be starved */ 1289 if (!list_empty(&sdev->starved_entry)) 1290 list_del_init(&sdev->starved_entry); 1291 return 1; 1292 } 1293 1294 /* 1295 * scsi_host_queue_ready: if we can send requests to shost, return 1 else 1296 * return 0. We must end up running the queue again whenever 0 is 1297 * returned, else IO can hang. 1298 * 1299 * Called with host_lock held. 1300 */ 1301 static inline int scsi_host_queue_ready(struct request_queue *q, 1302 struct Scsi_Host *shost, 1303 struct scsi_device *sdev) 1304 { 1305 if (scsi_host_in_recovery(shost)) 1306 return 0; 1307 if (shost->host_busy == 0 && shost->host_blocked) { 1308 /* 1309 * unblock after host_blocked iterates to zero 1310 */ 1311 if (--shost->host_blocked == 0) { 1312 SCSI_LOG_MLQUEUE(3, 1313 printk("scsi%d unblocking host at zero depth\n", 1314 shost->host_no)); 1315 } else { 1316 return 0; 1317 } 1318 } 1319 if (scsi_host_is_busy(shost)) { 1320 if (list_empty(&sdev->starved_entry)) 1321 list_add_tail(&sdev->starved_entry, &shost->starved_list); 1322 return 0; 1323 } 1324 1325 /* We're OK to process the command, so we can't be starved */ 1326 if (!list_empty(&sdev->starved_entry)) 1327 list_del_init(&sdev->starved_entry); 1328 1329 return 1; 1330 } 1331 1332 /* 1333 * Busy state exporting function for request stacking drivers. 1334 * 1335 * For efficiency, no lock is taken to check the busy state of 1336 * shost/starget/sdev, since the returned value is not guaranteed and 1337 * may be changed after request stacking drivers call the function, 1338 * regardless of taking lock or not. 1339 * 1340 * When scsi can't dispatch I/Os anymore and needs to kill I/Os 1341 * (e.g. !sdev), scsi needs to return 'not busy'. 1342 * Otherwise, request stacking drivers may hold requests forever. 1343 */ 1344 static int scsi_lld_busy(struct request_queue *q) 1345 { 1346 struct scsi_device *sdev = q->queuedata; 1347 struct Scsi_Host *shost; 1348 struct scsi_target *starget; 1349 1350 if (!sdev) 1351 return 0; 1352 1353 shost = sdev->host; 1354 starget = scsi_target(sdev); 1355 1356 if (scsi_host_in_recovery(shost) || scsi_host_is_busy(shost) || 1357 scsi_target_is_busy(starget) || scsi_device_is_busy(sdev)) 1358 return 1; 1359 1360 return 0; 1361 } 1362 1363 /* 1364 * Kill a request for a dead device 1365 */ 1366 static void scsi_kill_request(struct request *req, struct request_queue *q) 1367 { 1368 struct scsi_cmnd *cmd = req->special; 1369 struct scsi_device *sdev; 1370 struct scsi_target *starget; 1371 struct Scsi_Host *shost; 1372 1373 blk_start_request(req); 1374 1375 if (unlikely(cmd == NULL)) { 1376 printk(KERN_CRIT "impossible request in %s.\n", 1377 __func__); 1378 BUG(); 1379 } 1380 1381 sdev = cmd->device; 1382 starget = scsi_target(sdev); 1383 shost = sdev->host; 1384 scsi_init_cmd_errh(cmd); 1385 cmd->result = DID_NO_CONNECT << 16; 1386 atomic_inc(&cmd->device->iorequest_cnt); 1387 1388 /* 1389 * SCSI request completion path will do scsi_device_unbusy(), 1390 * bump busy counts. To bump the counters, we need to dance 1391 * with the locks as normal issue path does. 1392 */ 1393 sdev->device_busy++; 1394 spin_unlock(sdev->request_queue->queue_lock); 1395 spin_lock(shost->host_lock); 1396 shost->host_busy++; 1397 starget->target_busy++; 1398 spin_unlock(shost->host_lock); 1399 spin_lock(sdev->request_queue->queue_lock); 1400 1401 blk_complete_request(req); 1402 } 1403 1404 static void scsi_softirq_done(struct request *rq) 1405 { 1406 struct scsi_cmnd *cmd = rq->special; 1407 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout; 1408 int disposition; 1409 1410 INIT_LIST_HEAD(&cmd->eh_entry); 1411 1412 /* 1413 * Set the serial numbers back to zero 1414 */ 1415 cmd->serial_number = 0; 1416 1417 atomic_inc(&cmd->device->iodone_cnt); 1418 if (cmd->result) 1419 atomic_inc(&cmd->device->ioerr_cnt); 1420 1421 disposition = scsi_decide_disposition(cmd); 1422 if (disposition != SUCCESS && 1423 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { 1424 sdev_printk(KERN_ERR, cmd->device, 1425 "timing out command, waited %lus\n", 1426 wait_for/HZ); 1427 disposition = SUCCESS; 1428 } 1429 1430 scsi_log_completion(cmd, disposition); 1431 1432 switch (disposition) { 1433 case SUCCESS: 1434 scsi_finish_command(cmd); 1435 break; 1436 case NEEDS_RETRY: 1437 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY); 1438 break; 1439 case ADD_TO_MLQUEUE: 1440 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); 1441 break; 1442 default: 1443 if (!scsi_eh_scmd_add(cmd, 0)) 1444 scsi_finish_command(cmd); 1445 } 1446 } 1447 1448 /* 1449 * Function: scsi_request_fn() 1450 * 1451 * Purpose: Main strategy routine for SCSI. 1452 * 1453 * Arguments: q - Pointer to actual queue. 1454 * 1455 * Returns: Nothing 1456 * 1457 * Lock status: IO request lock assumed to be held when called. 1458 */ 1459 static void scsi_request_fn(struct request_queue *q) 1460 { 1461 struct scsi_device *sdev = q->queuedata; 1462 struct Scsi_Host *shost; 1463 struct scsi_cmnd *cmd; 1464 struct request *req; 1465 1466 if (!sdev) { 1467 printk("scsi: killing requests for dead queue\n"); 1468 while ((req = blk_peek_request(q)) != NULL) 1469 scsi_kill_request(req, q); 1470 return; 1471 } 1472 1473 if(!get_device(&sdev->sdev_gendev)) 1474 /* We must be tearing the block queue down already */ 1475 return; 1476 1477 /* 1478 * To start with, we keep looping until the queue is empty, or until 1479 * the host is no longer able to accept any more requests. 1480 */ 1481 shost = sdev->host; 1482 while (!blk_queue_plugged(q)) { 1483 int rtn; 1484 /* 1485 * get next queueable request. We do this early to make sure 1486 * that the request is fully prepared even if we cannot 1487 * accept it. 1488 */ 1489 req = blk_peek_request(q); 1490 if (!req || !scsi_dev_queue_ready(q, sdev)) 1491 break; 1492 1493 if (unlikely(!scsi_device_online(sdev))) { 1494 sdev_printk(KERN_ERR, sdev, 1495 "rejecting I/O to offline device\n"); 1496 scsi_kill_request(req, q); 1497 continue; 1498 } 1499 1500 1501 /* 1502 * Remove the request from the request list. 1503 */ 1504 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) 1505 blk_start_request(req); 1506 sdev->device_busy++; 1507 1508 spin_unlock(q->queue_lock); 1509 cmd = req->special; 1510 if (unlikely(cmd == NULL)) { 1511 printk(KERN_CRIT "impossible request in %s.\n" 1512 "please mail a stack trace to " 1513 "linux-scsi@vger.kernel.org\n", 1514 __func__); 1515 blk_dump_rq_flags(req, "foo"); 1516 BUG(); 1517 } 1518 spin_lock(shost->host_lock); 1519 1520 /* 1521 * We hit this when the driver is using a host wide 1522 * tag map. For device level tag maps the queue_depth check 1523 * in the device ready fn would prevent us from trying 1524 * to allocate a tag. Since the map is a shared host resource 1525 * we add the dev to the starved list so it eventually gets 1526 * a run when a tag is freed. 1527 */ 1528 if (blk_queue_tagged(q) && !blk_rq_tagged(req)) { 1529 if (list_empty(&sdev->starved_entry)) 1530 list_add_tail(&sdev->starved_entry, 1531 &shost->starved_list); 1532 goto not_ready; 1533 } 1534 1535 if (!scsi_target_queue_ready(shost, sdev)) 1536 goto not_ready; 1537 1538 if (!scsi_host_queue_ready(q, shost, sdev)) 1539 goto not_ready; 1540 1541 scsi_target(sdev)->target_busy++; 1542 shost->host_busy++; 1543 1544 /* 1545 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will 1546 * take the lock again. 1547 */ 1548 spin_unlock_irq(shost->host_lock); 1549 1550 /* 1551 * Finally, initialize any error handling parameters, and set up 1552 * the timers for timeouts. 1553 */ 1554 scsi_init_cmd_errh(cmd); 1555 1556 /* 1557 * Dispatch the command to the low-level driver. 1558 */ 1559 rtn = scsi_dispatch_cmd(cmd); 1560 spin_lock_irq(q->queue_lock); 1561 if(rtn) { 1562 /* we're refusing the command; because of 1563 * the way locks get dropped, we need to 1564 * check here if plugging is required */ 1565 if(sdev->device_busy == 0) 1566 blk_plug_device(q); 1567 1568 break; 1569 } 1570 } 1571 1572 goto out; 1573 1574 not_ready: 1575 spin_unlock_irq(shost->host_lock); 1576 1577 /* 1578 * lock q, handle tag, requeue req, and decrement device_busy. We 1579 * must return with queue_lock held. 1580 * 1581 * Decrementing device_busy without checking it is OK, as all such 1582 * cases (host limits or settings) should run the queue at some 1583 * later time. 1584 */ 1585 spin_lock_irq(q->queue_lock); 1586 blk_requeue_request(q, req); 1587 sdev->device_busy--; 1588 if(sdev->device_busy == 0) 1589 blk_plug_device(q); 1590 out: 1591 /* must be careful here...if we trigger the ->remove() function 1592 * we cannot be holding the q lock */ 1593 spin_unlock_irq(q->queue_lock); 1594 put_device(&sdev->sdev_gendev); 1595 spin_lock_irq(q->queue_lock); 1596 } 1597 1598 u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) 1599 { 1600 struct device *host_dev; 1601 u64 bounce_limit = 0xffffffff; 1602 1603 if (shost->unchecked_isa_dma) 1604 return BLK_BOUNCE_ISA; 1605 /* 1606 * Platforms with virtual-DMA translation 1607 * hardware have no practical limit. 1608 */ 1609 if (!PCI_DMA_BUS_IS_PHYS) 1610 return BLK_BOUNCE_ANY; 1611 1612 host_dev = scsi_get_device(shost); 1613 if (host_dev && host_dev->dma_mask) 1614 bounce_limit = *host_dev->dma_mask; 1615 1616 return bounce_limit; 1617 } 1618 EXPORT_SYMBOL(scsi_calculate_bounce_limit); 1619 1620 struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost, 1621 request_fn_proc *request_fn) 1622 { 1623 struct request_queue *q; 1624 struct device *dev = shost->shost_gendev.parent; 1625 1626 q = blk_init_queue(request_fn, NULL); 1627 if (!q) 1628 return NULL; 1629 1630 /* 1631 * this limit is imposed by hardware restrictions 1632 */ 1633 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize, 1634 SCSI_MAX_SG_CHAIN_SEGMENTS)); 1635 1636 blk_queue_max_hw_sectors(q, shost->max_sectors); 1637 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost)); 1638 blk_queue_segment_boundary(q, shost->dma_boundary); 1639 dma_set_seg_boundary(dev, shost->dma_boundary); 1640 1641 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev)); 1642 1643 /* New queue, no concurrency on queue_flags */ 1644 if (!shost->use_clustering) 1645 queue_flag_clear_unlocked(QUEUE_FLAG_CLUSTER, q); 1646 1647 /* 1648 * set a reasonable default alignment on word boundaries: the 1649 * host and device may alter it using 1650 * blk_queue_update_dma_alignment() later. 1651 */ 1652 blk_queue_dma_alignment(q, 0x03); 1653 1654 return q; 1655 } 1656 EXPORT_SYMBOL(__scsi_alloc_queue); 1657 1658 struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) 1659 { 1660 struct request_queue *q; 1661 1662 q = __scsi_alloc_queue(sdev->host, scsi_request_fn); 1663 if (!q) 1664 return NULL; 1665 1666 blk_queue_prep_rq(q, scsi_prep_fn); 1667 blk_queue_softirq_done(q, scsi_softirq_done); 1668 blk_queue_rq_timed_out(q, scsi_times_out); 1669 blk_queue_lld_busy(q, scsi_lld_busy); 1670 return q; 1671 } 1672 1673 void scsi_free_queue(struct request_queue *q) 1674 { 1675 blk_cleanup_queue(q); 1676 } 1677 1678 /* 1679 * Function: scsi_block_requests() 1680 * 1681 * Purpose: Utility function used by low-level drivers to prevent further 1682 * commands from being queued to the device. 1683 * 1684 * Arguments: shost - Host in question 1685 * 1686 * Returns: Nothing 1687 * 1688 * Lock status: No locks are assumed held. 1689 * 1690 * Notes: There is no timer nor any other means by which the requests 1691 * get unblocked other than the low-level driver calling 1692 * scsi_unblock_requests(). 1693 */ 1694 void scsi_block_requests(struct Scsi_Host *shost) 1695 { 1696 shost->host_self_blocked = 1; 1697 } 1698 EXPORT_SYMBOL(scsi_block_requests); 1699 1700 /* 1701 * Function: scsi_unblock_requests() 1702 * 1703 * Purpose: Utility function used by low-level drivers to allow further 1704 * commands from being queued to the device. 1705 * 1706 * Arguments: shost - Host in question 1707 * 1708 * Returns: Nothing 1709 * 1710 * Lock status: No locks are assumed held. 1711 * 1712 * Notes: There is no timer nor any other means by which the requests 1713 * get unblocked other than the low-level driver calling 1714 * scsi_unblock_requests(). 1715 * 1716 * This is done as an API function so that changes to the 1717 * internals of the scsi mid-layer won't require wholesale 1718 * changes to drivers that use this feature. 1719 */ 1720 void scsi_unblock_requests(struct Scsi_Host *shost) 1721 { 1722 shost->host_self_blocked = 0; 1723 scsi_run_host_queues(shost); 1724 } 1725 EXPORT_SYMBOL(scsi_unblock_requests); 1726 1727 int __init scsi_init_queue(void) 1728 { 1729 int i; 1730 1731 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer", 1732 sizeof(struct scsi_data_buffer), 1733 0, 0, NULL); 1734 if (!scsi_sdb_cache) { 1735 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n"); 1736 return -ENOMEM; 1737 } 1738 1739 for (i = 0; i < SG_MEMPOOL_NR; i++) { 1740 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; 1741 int size = sgp->size * sizeof(struct scatterlist); 1742 1743 sgp->slab = kmem_cache_create(sgp->name, size, 0, 1744 SLAB_HWCACHE_ALIGN, NULL); 1745 if (!sgp->slab) { 1746 printk(KERN_ERR "SCSI: can't init sg slab %s\n", 1747 sgp->name); 1748 goto cleanup_sdb; 1749 } 1750 1751 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE, 1752 sgp->slab); 1753 if (!sgp->pool) { 1754 printk(KERN_ERR "SCSI: can't init sg mempool %s\n", 1755 sgp->name); 1756 goto cleanup_sdb; 1757 } 1758 } 1759 1760 return 0; 1761 1762 cleanup_sdb: 1763 for (i = 0; i < SG_MEMPOOL_NR; i++) { 1764 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; 1765 if (sgp->pool) 1766 mempool_destroy(sgp->pool); 1767 if (sgp->slab) 1768 kmem_cache_destroy(sgp->slab); 1769 } 1770 kmem_cache_destroy(scsi_sdb_cache); 1771 1772 return -ENOMEM; 1773 } 1774 1775 void scsi_exit_queue(void) 1776 { 1777 int i; 1778 1779 kmem_cache_destroy(scsi_sdb_cache); 1780 1781 for (i = 0; i < SG_MEMPOOL_NR; i++) { 1782 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; 1783 mempool_destroy(sgp->pool); 1784 kmem_cache_destroy(sgp->slab); 1785 } 1786 } 1787 1788 /** 1789 * scsi_mode_select - issue a mode select 1790 * @sdev: SCSI device to be queried 1791 * @pf: Page format bit (1 == standard, 0 == vendor specific) 1792 * @sp: Save page bit (0 == don't save, 1 == save) 1793 * @modepage: mode page being requested 1794 * @buffer: request buffer (may not be smaller than eight bytes) 1795 * @len: length of request buffer. 1796 * @timeout: command timeout 1797 * @retries: number of retries before failing 1798 * @data: returns a structure abstracting the mode header data 1799 * @sshdr: place to put sense data (or NULL if no sense to be collected). 1800 * must be SCSI_SENSE_BUFFERSIZE big. 1801 * 1802 * Returns zero if successful; negative error number or scsi 1803 * status on error 1804 * 1805 */ 1806 int 1807 scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage, 1808 unsigned char *buffer, int len, int timeout, int retries, 1809 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) 1810 { 1811 unsigned char cmd[10]; 1812 unsigned char *real_buffer; 1813 int ret; 1814 1815 memset(cmd, 0, sizeof(cmd)); 1816 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); 1817 1818 if (sdev->use_10_for_ms) { 1819 if (len > 65535) 1820 return -EINVAL; 1821 real_buffer = kmalloc(8 + len, GFP_KERNEL); 1822 if (!real_buffer) 1823 return -ENOMEM; 1824 memcpy(real_buffer + 8, buffer, len); 1825 len += 8; 1826 real_buffer[0] = 0; 1827 real_buffer[1] = 0; 1828 real_buffer[2] = data->medium_type; 1829 real_buffer[3] = data->device_specific; 1830 real_buffer[4] = data->longlba ? 0x01 : 0; 1831 real_buffer[5] = 0; 1832 real_buffer[6] = data->block_descriptor_length >> 8; 1833 real_buffer[7] = data->block_descriptor_length; 1834 1835 cmd[0] = MODE_SELECT_10; 1836 cmd[7] = len >> 8; 1837 cmd[8] = len; 1838 } else { 1839 if (len > 255 || data->block_descriptor_length > 255 || 1840 data->longlba) 1841 return -EINVAL; 1842 1843 real_buffer = kmalloc(4 + len, GFP_KERNEL); 1844 if (!real_buffer) 1845 return -ENOMEM; 1846 memcpy(real_buffer + 4, buffer, len); 1847 len += 4; 1848 real_buffer[0] = 0; 1849 real_buffer[1] = data->medium_type; 1850 real_buffer[2] = data->device_specific; 1851 real_buffer[3] = data->block_descriptor_length; 1852 1853 1854 cmd[0] = MODE_SELECT; 1855 cmd[4] = len; 1856 } 1857 1858 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, 1859 sshdr, timeout, retries, NULL); 1860 kfree(real_buffer); 1861 return ret; 1862 } 1863 EXPORT_SYMBOL_GPL(scsi_mode_select); 1864 1865 /** 1866 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary. 1867 * @sdev: SCSI device to be queried 1868 * @dbd: set if mode sense will allow block descriptors to be returned 1869 * @modepage: mode page being requested 1870 * @buffer: request buffer (may not be smaller than eight bytes) 1871 * @len: length of request buffer. 1872 * @timeout: command timeout 1873 * @retries: number of retries before failing 1874 * @data: returns a structure abstracting the mode header data 1875 * @sshdr: place to put sense data (or NULL if no sense to be collected). 1876 * must be SCSI_SENSE_BUFFERSIZE big. 1877 * 1878 * Returns zero if unsuccessful, or the header offset (either 4 1879 * or 8 depending on whether a six or ten byte command was 1880 * issued) if successful. 1881 */ 1882 int 1883 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, 1884 unsigned char *buffer, int len, int timeout, int retries, 1885 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) 1886 { 1887 unsigned char cmd[12]; 1888 int use_10_for_ms; 1889 int header_length; 1890 int result; 1891 struct scsi_sense_hdr my_sshdr; 1892 1893 memset(data, 0, sizeof(*data)); 1894 memset(&cmd[0], 0, 12); 1895 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ 1896 cmd[2] = modepage; 1897 1898 /* caller might not be interested in sense, but we need it */ 1899 if (!sshdr) 1900 sshdr = &my_sshdr; 1901 1902 retry: 1903 use_10_for_ms = sdev->use_10_for_ms; 1904 1905 if (use_10_for_ms) { 1906 if (len < 8) 1907 len = 8; 1908 1909 cmd[0] = MODE_SENSE_10; 1910 cmd[8] = len; 1911 header_length = 8; 1912 } else { 1913 if (len < 4) 1914 len = 4; 1915 1916 cmd[0] = MODE_SENSE; 1917 cmd[4] = len; 1918 header_length = 4; 1919 } 1920 1921 memset(buffer, 0, len); 1922 1923 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, 1924 sshdr, timeout, retries, NULL); 1925 1926 /* This code looks awful: what it's doing is making sure an 1927 * ILLEGAL REQUEST sense return identifies the actual command 1928 * byte as the problem. MODE_SENSE commands can return 1929 * ILLEGAL REQUEST if the code page isn't supported */ 1930 1931 if (use_10_for_ms && !scsi_status_is_good(result) && 1932 (driver_byte(result) & DRIVER_SENSE)) { 1933 if (scsi_sense_valid(sshdr)) { 1934 if ((sshdr->sense_key == ILLEGAL_REQUEST) && 1935 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { 1936 /* 1937 * Invalid command operation code 1938 */ 1939 sdev->use_10_for_ms = 0; 1940 goto retry; 1941 } 1942 } 1943 } 1944 1945 if(scsi_status_is_good(result)) { 1946 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && 1947 (modepage == 6 || modepage == 8))) { 1948 /* Initio breakage? */ 1949 header_length = 0; 1950 data->length = 13; 1951 data->medium_type = 0; 1952 data->device_specific = 0; 1953 data->longlba = 0; 1954 data->block_descriptor_length = 0; 1955 } else if(use_10_for_ms) { 1956 data->length = buffer[0]*256 + buffer[1] + 2; 1957 data->medium_type = buffer[2]; 1958 data->device_specific = buffer[3]; 1959 data->longlba = buffer[4] & 0x01; 1960 data->block_descriptor_length = buffer[6]*256 1961 + buffer[7]; 1962 } else { 1963 data->length = buffer[0] + 1; 1964 data->medium_type = buffer[1]; 1965 data->device_specific = buffer[2]; 1966 data->block_descriptor_length = buffer[3]; 1967 } 1968 data->header_length = header_length; 1969 } 1970 1971 return result; 1972 } 1973 EXPORT_SYMBOL(scsi_mode_sense); 1974 1975 /** 1976 * scsi_test_unit_ready - test if unit is ready 1977 * @sdev: scsi device to change the state of. 1978 * @timeout: command timeout 1979 * @retries: number of retries before failing 1980 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for 1981 * returning sense. Make sure that this is cleared before passing 1982 * in. 1983 * 1984 * Returns zero if unsuccessful or an error if TUR failed. For 1985 * removable media, a return of NOT_READY or UNIT_ATTENTION is 1986 * translated to success, with the ->changed flag updated. 1987 **/ 1988 int 1989 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, 1990 struct scsi_sense_hdr *sshdr_external) 1991 { 1992 char cmd[] = { 1993 TEST_UNIT_READY, 0, 0, 0, 0, 0, 1994 }; 1995 struct scsi_sense_hdr *sshdr; 1996 int result; 1997 1998 if (!sshdr_external) 1999 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL); 2000 else 2001 sshdr = sshdr_external; 2002 2003 /* try to eat the UNIT_ATTENTION if there are enough retries */ 2004 do { 2005 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr, 2006 timeout, retries, NULL); 2007 if (sdev->removable && scsi_sense_valid(sshdr) && 2008 sshdr->sense_key == UNIT_ATTENTION) 2009 sdev->changed = 1; 2010 } while (scsi_sense_valid(sshdr) && 2011 sshdr->sense_key == UNIT_ATTENTION && --retries); 2012 2013 if (!sshdr) 2014 /* could not allocate sense buffer, so can't process it */ 2015 return result; 2016 2017 if (sdev->removable && scsi_sense_valid(sshdr) && 2018 (sshdr->sense_key == UNIT_ATTENTION || 2019 sshdr->sense_key == NOT_READY)) { 2020 sdev->changed = 1; 2021 result = 0; 2022 } 2023 if (!sshdr_external) 2024 kfree(sshdr); 2025 return result; 2026 } 2027 EXPORT_SYMBOL(scsi_test_unit_ready); 2028 2029 /** 2030 * scsi_device_set_state - Take the given device through the device state model. 2031 * @sdev: scsi device to change the state of. 2032 * @state: state to change to. 2033 * 2034 * Returns zero if unsuccessful or an error if the requested 2035 * transition is illegal. 2036 */ 2037 int 2038 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) 2039 { 2040 enum scsi_device_state oldstate = sdev->sdev_state; 2041 2042 if (state == oldstate) 2043 return 0; 2044 2045 switch (state) { 2046 case SDEV_CREATED: 2047 switch (oldstate) { 2048 case SDEV_CREATED_BLOCK: 2049 break; 2050 default: 2051 goto illegal; 2052 } 2053 break; 2054 2055 case SDEV_RUNNING: 2056 switch (oldstate) { 2057 case SDEV_CREATED: 2058 case SDEV_OFFLINE: 2059 case SDEV_QUIESCE: 2060 case SDEV_BLOCK: 2061 break; 2062 default: 2063 goto illegal; 2064 } 2065 break; 2066 2067 case SDEV_QUIESCE: 2068 switch (oldstate) { 2069 case SDEV_RUNNING: 2070 case SDEV_OFFLINE: 2071 break; 2072 default: 2073 goto illegal; 2074 } 2075 break; 2076 2077 case SDEV_OFFLINE: 2078 switch (oldstate) { 2079 case SDEV_CREATED: 2080 case SDEV_RUNNING: 2081 case SDEV_QUIESCE: 2082 case SDEV_BLOCK: 2083 break; 2084 default: 2085 goto illegal; 2086 } 2087 break; 2088 2089 case SDEV_BLOCK: 2090 switch (oldstate) { 2091 case SDEV_RUNNING: 2092 case SDEV_CREATED_BLOCK: 2093 break; 2094 default: 2095 goto illegal; 2096 } 2097 break; 2098 2099 case SDEV_CREATED_BLOCK: 2100 switch (oldstate) { 2101 case SDEV_CREATED: 2102 break; 2103 default: 2104 goto illegal; 2105 } 2106 break; 2107 2108 case SDEV_CANCEL: 2109 switch (oldstate) { 2110 case SDEV_CREATED: 2111 case SDEV_RUNNING: 2112 case SDEV_QUIESCE: 2113 case SDEV_OFFLINE: 2114 case SDEV_BLOCK: 2115 break; 2116 default: 2117 goto illegal; 2118 } 2119 break; 2120 2121 case SDEV_DEL: 2122 switch (oldstate) { 2123 case SDEV_CREATED: 2124 case SDEV_RUNNING: 2125 case SDEV_OFFLINE: 2126 case SDEV_CANCEL: 2127 break; 2128 default: 2129 goto illegal; 2130 } 2131 break; 2132 2133 } 2134 sdev->sdev_state = state; 2135 return 0; 2136 2137 illegal: 2138 SCSI_LOG_ERROR_RECOVERY(1, 2139 sdev_printk(KERN_ERR, sdev, 2140 "Illegal state transition %s->%s\n", 2141 scsi_device_state_name(oldstate), 2142 scsi_device_state_name(state)) 2143 ); 2144 return -EINVAL; 2145 } 2146 EXPORT_SYMBOL(scsi_device_set_state); 2147 2148 /** 2149 * sdev_evt_emit - emit a single SCSI device uevent 2150 * @sdev: associated SCSI device 2151 * @evt: event to emit 2152 * 2153 * Send a single uevent (scsi_event) to the associated scsi_device. 2154 */ 2155 static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt) 2156 { 2157 int idx = 0; 2158 char *envp[3]; 2159 2160 switch (evt->evt_type) { 2161 case SDEV_EVT_MEDIA_CHANGE: 2162 envp[idx++] = "SDEV_MEDIA_CHANGE=1"; 2163 break; 2164 2165 default: 2166 /* do nothing */ 2167 break; 2168 } 2169 2170 envp[idx++] = NULL; 2171 2172 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp); 2173 } 2174 2175 /** 2176 * sdev_evt_thread - send a uevent for each scsi event 2177 * @work: work struct for scsi_device 2178 * 2179 * Dispatch queued events to their associated scsi_device kobjects 2180 * as uevents. 2181 */ 2182 void scsi_evt_thread(struct work_struct *work) 2183 { 2184 struct scsi_device *sdev; 2185 LIST_HEAD(event_list); 2186 2187 sdev = container_of(work, struct scsi_device, event_work); 2188 2189 while (1) { 2190 struct scsi_event *evt; 2191 struct list_head *this, *tmp; 2192 unsigned long flags; 2193 2194 spin_lock_irqsave(&sdev->list_lock, flags); 2195 list_splice_init(&sdev->event_list, &event_list); 2196 spin_unlock_irqrestore(&sdev->list_lock, flags); 2197 2198 if (list_empty(&event_list)) 2199 break; 2200 2201 list_for_each_safe(this, tmp, &event_list) { 2202 evt = list_entry(this, struct scsi_event, node); 2203 list_del(&evt->node); 2204 scsi_evt_emit(sdev, evt); 2205 kfree(evt); 2206 } 2207 } 2208 } 2209 2210 /** 2211 * sdev_evt_send - send asserted event to uevent thread 2212 * @sdev: scsi_device event occurred on 2213 * @evt: event to send 2214 * 2215 * Assert scsi device event asynchronously. 2216 */ 2217 void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt) 2218 { 2219 unsigned long flags; 2220 2221 #if 0 2222 /* FIXME: currently this check eliminates all media change events 2223 * for polled devices. Need to update to discriminate between AN 2224 * and polled events */ 2225 if (!test_bit(evt->evt_type, sdev->supported_events)) { 2226 kfree(evt); 2227 return; 2228 } 2229 #endif 2230 2231 spin_lock_irqsave(&sdev->list_lock, flags); 2232 list_add_tail(&evt->node, &sdev->event_list); 2233 schedule_work(&sdev->event_work); 2234 spin_unlock_irqrestore(&sdev->list_lock, flags); 2235 } 2236 EXPORT_SYMBOL_GPL(sdev_evt_send); 2237 2238 /** 2239 * sdev_evt_alloc - allocate a new scsi event 2240 * @evt_type: type of event to allocate 2241 * @gfpflags: GFP flags for allocation 2242 * 2243 * Allocates and returns a new scsi_event. 2244 */ 2245 struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type, 2246 gfp_t gfpflags) 2247 { 2248 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags); 2249 if (!evt) 2250 return NULL; 2251 2252 evt->evt_type = evt_type; 2253 INIT_LIST_HEAD(&evt->node); 2254 2255 /* evt_type-specific initialization, if any */ 2256 switch (evt_type) { 2257 case SDEV_EVT_MEDIA_CHANGE: 2258 default: 2259 /* do nothing */ 2260 break; 2261 } 2262 2263 return evt; 2264 } 2265 EXPORT_SYMBOL_GPL(sdev_evt_alloc); 2266 2267 /** 2268 * sdev_evt_send_simple - send asserted event to uevent thread 2269 * @sdev: scsi_device event occurred on 2270 * @evt_type: type of event to send 2271 * @gfpflags: GFP flags for allocation 2272 * 2273 * Assert scsi device event asynchronously, given an event type. 2274 */ 2275 void sdev_evt_send_simple(struct scsi_device *sdev, 2276 enum scsi_device_event evt_type, gfp_t gfpflags) 2277 { 2278 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags); 2279 if (!evt) { 2280 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n", 2281 evt_type); 2282 return; 2283 } 2284 2285 sdev_evt_send(sdev, evt); 2286 } 2287 EXPORT_SYMBOL_GPL(sdev_evt_send_simple); 2288 2289 /** 2290 * scsi_device_quiesce - Block user issued commands. 2291 * @sdev: scsi device to quiesce. 2292 * 2293 * This works by trying to transition to the SDEV_QUIESCE state 2294 * (which must be a legal transition). When the device is in this 2295 * state, only special requests will be accepted, all others will 2296 * be deferred. Since special requests may also be requeued requests, 2297 * a successful return doesn't guarantee the device will be 2298 * totally quiescent. 2299 * 2300 * Must be called with user context, may sleep. 2301 * 2302 * Returns zero if unsuccessful or an error if not. 2303 */ 2304 int 2305 scsi_device_quiesce(struct scsi_device *sdev) 2306 { 2307 int err = scsi_device_set_state(sdev, SDEV_QUIESCE); 2308 if (err) 2309 return err; 2310 2311 scsi_run_queue(sdev->request_queue); 2312 while (sdev->device_busy) { 2313 msleep_interruptible(200); 2314 scsi_run_queue(sdev->request_queue); 2315 } 2316 return 0; 2317 } 2318 EXPORT_SYMBOL(scsi_device_quiesce); 2319 2320 /** 2321 * scsi_device_resume - Restart user issued commands to a quiesced device. 2322 * @sdev: scsi device to resume. 2323 * 2324 * Moves the device from quiesced back to running and restarts the 2325 * queues. 2326 * 2327 * Must be called with user context, may sleep. 2328 */ 2329 void 2330 scsi_device_resume(struct scsi_device *sdev) 2331 { 2332 if(scsi_device_set_state(sdev, SDEV_RUNNING)) 2333 return; 2334 scsi_run_queue(sdev->request_queue); 2335 } 2336 EXPORT_SYMBOL(scsi_device_resume); 2337 2338 static void 2339 device_quiesce_fn(struct scsi_device *sdev, void *data) 2340 { 2341 scsi_device_quiesce(sdev); 2342 } 2343 2344 void 2345 scsi_target_quiesce(struct scsi_target *starget) 2346 { 2347 starget_for_each_device(starget, NULL, device_quiesce_fn); 2348 } 2349 EXPORT_SYMBOL(scsi_target_quiesce); 2350 2351 static void 2352 device_resume_fn(struct scsi_device *sdev, void *data) 2353 { 2354 scsi_device_resume(sdev); 2355 } 2356 2357 void 2358 scsi_target_resume(struct scsi_target *starget) 2359 { 2360 starget_for_each_device(starget, NULL, device_resume_fn); 2361 } 2362 EXPORT_SYMBOL(scsi_target_resume); 2363 2364 /** 2365 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state 2366 * @sdev: device to block 2367 * 2368 * Block request made by scsi lld's to temporarily stop all 2369 * scsi commands on the specified device. Called from interrupt 2370 * or normal process context. 2371 * 2372 * Returns zero if successful or error if not 2373 * 2374 * Notes: 2375 * This routine transitions the device to the SDEV_BLOCK state 2376 * (which must be a legal transition). When the device is in this 2377 * state, all commands are deferred until the scsi lld reenables 2378 * the device with scsi_device_unblock or device_block_tmo fires. 2379 * This routine assumes the host_lock is held on entry. 2380 */ 2381 int 2382 scsi_internal_device_block(struct scsi_device *sdev) 2383 { 2384 struct request_queue *q = sdev->request_queue; 2385 unsigned long flags; 2386 int err = 0; 2387 2388 err = scsi_device_set_state(sdev, SDEV_BLOCK); 2389 if (err) { 2390 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK); 2391 2392 if (err) 2393 return err; 2394 } 2395 2396 /* 2397 * The device has transitioned to SDEV_BLOCK. Stop the 2398 * block layer from calling the midlayer with this device's 2399 * request queue. 2400 */ 2401 spin_lock_irqsave(q->queue_lock, flags); 2402 blk_stop_queue(q); 2403 spin_unlock_irqrestore(q->queue_lock, flags); 2404 2405 return 0; 2406 } 2407 EXPORT_SYMBOL_GPL(scsi_internal_device_block); 2408 2409 /** 2410 * scsi_internal_device_unblock - resume a device after a block request 2411 * @sdev: device to resume 2412 * 2413 * Called by scsi lld's or the midlayer to restart the device queue 2414 * for the previously suspended scsi device. Called from interrupt or 2415 * normal process context. 2416 * 2417 * Returns zero if successful or error if not. 2418 * 2419 * Notes: 2420 * This routine transitions the device to the SDEV_RUNNING state 2421 * (which must be a legal transition) allowing the midlayer to 2422 * goose the queue for this device. This routine assumes the 2423 * host_lock is held upon entry. 2424 */ 2425 int 2426 scsi_internal_device_unblock(struct scsi_device *sdev) 2427 { 2428 struct request_queue *q = sdev->request_queue; 2429 unsigned long flags; 2430 2431 /* 2432 * Try to transition the scsi device to SDEV_RUNNING 2433 * and goose the device queue if successful. 2434 */ 2435 if (sdev->sdev_state == SDEV_BLOCK) 2436 sdev->sdev_state = SDEV_RUNNING; 2437 else if (sdev->sdev_state == SDEV_CREATED_BLOCK) 2438 sdev->sdev_state = SDEV_CREATED; 2439 else 2440 return -EINVAL; 2441 2442 spin_lock_irqsave(q->queue_lock, flags); 2443 blk_start_queue(q); 2444 spin_unlock_irqrestore(q->queue_lock, flags); 2445 2446 return 0; 2447 } 2448 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); 2449 2450 static void 2451 device_block(struct scsi_device *sdev, void *data) 2452 { 2453 scsi_internal_device_block(sdev); 2454 } 2455 2456 static int 2457 target_block(struct device *dev, void *data) 2458 { 2459 if (scsi_is_target_device(dev)) 2460 starget_for_each_device(to_scsi_target(dev), NULL, 2461 device_block); 2462 return 0; 2463 } 2464 2465 void 2466 scsi_target_block(struct device *dev) 2467 { 2468 if (scsi_is_target_device(dev)) 2469 starget_for_each_device(to_scsi_target(dev), NULL, 2470 device_block); 2471 else 2472 device_for_each_child(dev, NULL, target_block); 2473 } 2474 EXPORT_SYMBOL_GPL(scsi_target_block); 2475 2476 static void 2477 device_unblock(struct scsi_device *sdev, void *data) 2478 { 2479 scsi_internal_device_unblock(sdev); 2480 } 2481 2482 static int 2483 target_unblock(struct device *dev, void *data) 2484 { 2485 if (scsi_is_target_device(dev)) 2486 starget_for_each_device(to_scsi_target(dev), NULL, 2487 device_unblock); 2488 return 0; 2489 } 2490 2491 void 2492 scsi_target_unblock(struct device *dev) 2493 { 2494 if (scsi_is_target_device(dev)) 2495 starget_for_each_device(to_scsi_target(dev), NULL, 2496 device_unblock); 2497 else 2498 device_for_each_child(dev, NULL, target_unblock); 2499 } 2500 EXPORT_SYMBOL_GPL(scsi_target_unblock); 2501 2502 /** 2503 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt 2504 * @sgl: scatter-gather list 2505 * @sg_count: number of segments in sg 2506 * @offset: offset in bytes into sg, on return offset into the mapped area 2507 * @len: bytes to map, on return number of bytes mapped 2508 * 2509 * Returns virtual address of the start of the mapped page 2510 */ 2511 void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count, 2512 size_t *offset, size_t *len) 2513 { 2514 int i; 2515 size_t sg_len = 0, len_complete = 0; 2516 struct scatterlist *sg; 2517 struct page *page; 2518 2519 WARN_ON(!irqs_disabled()); 2520 2521 for_each_sg(sgl, sg, sg_count, i) { 2522 len_complete = sg_len; /* Complete sg-entries */ 2523 sg_len += sg->length; 2524 if (sg_len > *offset) 2525 break; 2526 } 2527 2528 if (unlikely(i == sg_count)) { 2529 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " 2530 "elements %d\n", 2531 __func__, sg_len, *offset, sg_count); 2532 WARN_ON(1); 2533 return NULL; 2534 } 2535 2536 /* Offset starting from the beginning of first page in this sg-entry */ 2537 *offset = *offset - len_complete + sg->offset; 2538 2539 /* Assumption: contiguous pages can be accessed as "page + i" */ 2540 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT)); 2541 *offset &= ~PAGE_MASK; 2542 2543 /* Bytes in this sg-entry from *offset to the end of the page */ 2544 sg_len = PAGE_SIZE - *offset; 2545 if (*len > sg_len) 2546 *len = sg_len; 2547 2548 return kmap_atomic(page, KM_BIO_SRC_IRQ); 2549 } 2550 EXPORT_SYMBOL(scsi_kmap_atomic_sg); 2551 2552 /** 2553 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg 2554 * @virt: virtual address to be unmapped 2555 */ 2556 void scsi_kunmap_atomic_sg(void *virt) 2557 { 2558 kunmap_atomic(virt, KM_BIO_SRC_IRQ); 2559 } 2560 EXPORT_SYMBOL(scsi_kunmap_atomic_sg); 2561