scsi_lib.c revision da6c5c720c52cc717124f8f0830b710ea6a092fd
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 38struct 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 49static 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 68struct kmem_cache *scsi_sdb_cache; 69 70static 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 */ 84static 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 */ 106static 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 */ 188int 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 */ 208int 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} 254EXPORT_SYMBOL(scsi_execute); 255 256 257int 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} 278EXPORT_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 */ 291static 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 300void 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 */ 325static 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 364static 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 372static 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 379static 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 */ 400static 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 */ 478static 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 491void 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 506void 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 514static 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 */ 538static 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 576static 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 590static 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 598static 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 606static 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 622static 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 627static 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 */ 664void scsi_release_buffers(struct scsi_cmnd *cmd) 665{ 666 __scsi_release_buffers(cmd, 1); 667} 668EXPORT_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 */ 706void 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 blk_end_request_all(req, 0); 753 754 scsi_release_buffers(cmd); 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 (!(req->cmd_flags & REQ_QUIET)) 778 scsi_print_sense("", cmd); 779 result = 0; 780 /* BLOCK_PC may have set error */ 781 error = 0; 782 } 783 784 /* 785 * A number of bytes were successfully read. If there 786 * are leftovers and there is some kind of error 787 * (result != 0), retry the rest. 788 */ 789 if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL) 790 return; 791 792 error = -EIO; 793 794 if (host_byte(result) == DID_RESET) { 795 /* Third party bus reset or reset for error recovery 796 * reasons. Just retry the command and see what 797 * happens. 798 */ 799 action = ACTION_RETRY; 800 } else if (sense_valid && !sense_deferred) { 801 switch (sshdr.sense_key) { 802 case UNIT_ATTENTION: 803 if (cmd->device->removable) { 804 /* Detected disc change. Set a bit 805 * and quietly refuse further access. 806 */ 807 cmd->device->changed = 1; 808 description = "Media Changed"; 809 action = ACTION_FAIL; 810 } else { 811 /* Must have been a power glitch, or a 812 * bus reset. Could not have been a 813 * media change, so we just retry the 814 * command and see what happens. 815 */ 816 action = ACTION_RETRY; 817 } 818 break; 819 case ILLEGAL_REQUEST: 820 /* If we had an ILLEGAL REQUEST returned, then 821 * we may have performed an unsupported 822 * command. The only thing this should be 823 * would be a ten byte read where only a six 824 * byte read was supported. Also, on a system 825 * where READ CAPACITY failed, we may have 826 * read past the end of the disk. 827 */ 828 if ((cmd->device->use_10_for_rw && 829 sshdr.asc == 0x20 && sshdr.ascq == 0x00) && 830 (cmd->cmnd[0] == READ_10 || 831 cmd->cmnd[0] == WRITE_10)) { 832 /* This will issue a new 6-byte command. */ 833 cmd->device->use_10_for_rw = 0; 834 action = ACTION_REPREP; 835 } else if (sshdr.asc == 0x10) /* DIX */ { 836 description = "Host Data Integrity Failure"; 837 action = ACTION_FAIL; 838 error = -EILSEQ; 839 } else 840 action = ACTION_FAIL; 841 break; 842 case ABORTED_COMMAND: 843 action = ACTION_FAIL; 844 if (sshdr.asc == 0x10) { /* DIF */ 845 description = "Target Data Integrity Failure"; 846 error = -EILSEQ; 847 } 848 break; 849 case NOT_READY: 850 /* If the device is in the process of becoming 851 * ready, or has a temporary blockage, retry. 852 */ 853 if (sshdr.asc == 0x04) { 854 switch (sshdr.ascq) { 855 case 0x01: /* becoming ready */ 856 case 0x04: /* format in progress */ 857 case 0x05: /* rebuild in progress */ 858 case 0x06: /* recalculation in progress */ 859 case 0x07: /* operation in progress */ 860 case 0x08: /* Long write in progress */ 861 case 0x09: /* self test in progress */ 862 action = ACTION_DELAYED_RETRY; 863 break; 864 default: 865 description = "Device not ready"; 866 action = ACTION_FAIL; 867 break; 868 } 869 } else { 870 description = "Device not ready"; 871 action = ACTION_FAIL; 872 } 873 break; 874 case VOLUME_OVERFLOW: 875 /* See SSC3rXX or current. */ 876 action = ACTION_FAIL; 877 break; 878 default: 879 description = "Unhandled sense code"; 880 action = ACTION_FAIL; 881 break; 882 } 883 } else { 884 description = "Unhandled error code"; 885 action = ACTION_FAIL; 886 } 887 888 switch (action) { 889 case ACTION_FAIL: 890 /* Give up and fail the remainder of the request */ 891 scsi_release_buffers(cmd); 892 if (!(req->cmd_flags & REQ_QUIET)) { 893 if (description) 894 scmd_printk(KERN_INFO, cmd, "%s\n", 895 description); 896 scsi_print_result(cmd); 897 if (driver_byte(result) & DRIVER_SENSE) 898 scsi_print_sense("", cmd); 899 } 900 if (blk_end_request_err(req, -EIO)) 901 scsi_requeue_command(q, cmd); 902 else 903 scsi_next_command(cmd); 904 break; 905 case ACTION_REPREP: 906 /* Unprep the request and put it back at the head of the queue. 907 * A new command will be prepared and issued. 908 */ 909 scsi_release_buffers(cmd); 910 scsi_requeue_command(q, cmd); 911 break; 912 case ACTION_RETRY: 913 /* Retry the same command immediately */ 914 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0); 915 break; 916 case ACTION_DELAYED_RETRY: 917 /* Retry the same command after a delay */ 918 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0); 919 break; 920 } 921} 922 923static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb, 924 gfp_t gfp_mask) 925{ 926 int count; 927 928 /* 929 * If sg table allocation fails, requeue request later. 930 */ 931 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments, 932 gfp_mask))) { 933 return BLKPREP_DEFER; 934 } 935 936 req->buffer = NULL; 937 938 /* 939 * Next, walk the list, and fill in the addresses and sizes of 940 * each segment. 941 */ 942 count = blk_rq_map_sg(req->q, req, sdb->table.sgl); 943 BUG_ON(count > sdb->table.nents); 944 sdb->table.nents = count; 945 sdb->length = blk_rq_bytes(req); 946 return BLKPREP_OK; 947} 948 949/* 950 * Function: scsi_init_io() 951 * 952 * Purpose: SCSI I/O initialize function. 953 * 954 * Arguments: cmd - Command descriptor we wish to initialize 955 * 956 * Returns: 0 on success 957 * BLKPREP_DEFER if the failure is retryable 958 * BLKPREP_KILL if the failure is fatal 959 */ 960int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask) 961{ 962 int error = scsi_init_sgtable(cmd->request, &cmd->sdb, gfp_mask); 963 if (error) 964 goto err_exit; 965 966 if (blk_bidi_rq(cmd->request)) { 967 struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc( 968 scsi_sdb_cache, GFP_ATOMIC); 969 if (!bidi_sdb) { 970 error = BLKPREP_DEFER; 971 goto err_exit; 972 } 973 974 cmd->request->next_rq->special = bidi_sdb; 975 error = scsi_init_sgtable(cmd->request->next_rq, bidi_sdb, 976 GFP_ATOMIC); 977 if (error) 978 goto err_exit; 979 } 980 981 if (blk_integrity_rq(cmd->request)) { 982 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb; 983 int ivecs, count; 984 985 BUG_ON(prot_sdb == NULL); 986 ivecs = blk_rq_count_integrity_sg(cmd->request); 987 988 if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) { 989 error = BLKPREP_DEFER; 990 goto err_exit; 991 } 992 993 count = blk_rq_map_integrity_sg(cmd->request, 994 prot_sdb->table.sgl); 995 BUG_ON(unlikely(count > ivecs)); 996 997 cmd->prot_sdb = prot_sdb; 998 cmd->prot_sdb->table.nents = count; 999 } 1000 1001 return BLKPREP_OK ; 1002 1003err_exit: 1004 scsi_release_buffers(cmd); 1005 if (error == BLKPREP_KILL) 1006 scsi_put_command(cmd); 1007 else /* BLKPREP_DEFER */ 1008 scsi_unprep_request(cmd->request); 1009 1010 return error; 1011} 1012EXPORT_SYMBOL(scsi_init_io); 1013 1014static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev, 1015 struct request *req) 1016{ 1017 struct scsi_cmnd *cmd; 1018 1019 if (!req->special) { 1020 cmd = scsi_get_command(sdev, GFP_ATOMIC); 1021 if (unlikely(!cmd)) 1022 return NULL; 1023 req->special = cmd; 1024 } else { 1025 cmd = req->special; 1026 } 1027 1028 /* pull a tag out of the request if we have one */ 1029 cmd->tag = req->tag; 1030 cmd->request = req; 1031 1032 cmd->cmnd = req->cmd; 1033 1034 return cmd; 1035} 1036 1037int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req) 1038{ 1039 struct scsi_cmnd *cmd; 1040 int ret = scsi_prep_state_check(sdev, req); 1041 1042 if (ret != BLKPREP_OK) 1043 return ret; 1044 1045 cmd = scsi_get_cmd_from_req(sdev, req); 1046 if (unlikely(!cmd)) 1047 return BLKPREP_DEFER; 1048 1049 /* 1050 * BLOCK_PC requests may transfer data, in which case they must 1051 * a bio attached to them. Or they might contain a SCSI command 1052 * that does not transfer data, in which case they may optionally 1053 * submit a request without an attached bio. 1054 */ 1055 if (req->bio) { 1056 int ret; 1057 1058 BUG_ON(!req->nr_phys_segments); 1059 1060 ret = scsi_init_io(cmd, GFP_ATOMIC); 1061 if (unlikely(ret)) 1062 return ret; 1063 } else { 1064 BUG_ON(blk_rq_bytes(req)); 1065 1066 memset(&cmd->sdb, 0, sizeof(cmd->sdb)); 1067 req->buffer = NULL; 1068 } 1069 1070 cmd->cmd_len = req->cmd_len; 1071 if (!blk_rq_bytes(req)) 1072 cmd->sc_data_direction = DMA_NONE; 1073 else if (rq_data_dir(req) == WRITE) 1074 cmd->sc_data_direction = DMA_TO_DEVICE; 1075 else 1076 cmd->sc_data_direction = DMA_FROM_DEVICE; 1077 1078 cmd->transfersize = blk_rq_bytes(req); 1079 cmd->allowed = req->retries; 1080 return BLKPREP_OK; 1081} 1082EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd); 1083 1084/* 1085 * Setup a REQ_TYPE_FS command. These are simple read/write request 1086 * from filesystems that still need to be translated to SCSI CDBs from 1087 * the ULD. 1088 */ 1089int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req) 1090{ 1091 struct scsi_cmnd *cmd; 1092 int ret = scsi_prep_state_check(sdev, req); 1093 1094 if (ret != BLKPREP_OK) 1095 return ret; 1096 1097 if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh 1098 && sdev->scsi_dh_data->scsi_dh->prep_fn)) { 1099 ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req); 1100 if (ret != BLKPREP_OK) 1101 return ret; 1102 } 1103 1104 /* 1105 * Filesystem requests must transfer data. 1106 */ 1107 BUG_ON(!req->nr_phys_segments); 1108 1109 cmd = scsi_get_cmd_from_req(sdev, req); 1110 if (unlikely(!cmd)) 1111 return BLKPREP_DEFER; 1112 1113 memset(cmd->cmnd, 0, BLK_MAX_CDB); 1114 return scsi_init_io(cmd, GFP_ATOMIC); 1115} 1116EXPORT_SYMBOL(scsi_setup_fs_cmnd); 1117 1118int scsi_prep_state_check(struct scsi_device *sdev, struct request *req) 1119{ 1120 int ret = BLKPREP_OK; 1121 1122 /* 1123 * If the device is not in running state we will reject some 1124 * or all commands. 1125 */ 1126 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { 1127 switch (sdev->sdev_state) { 1128 case SDEV_OFFLINE: 1129 /* 1130 * If the device is offline we refuse to process any 1131 * commands. The device must be brought online 1132 * before trying any recovery commands. 1133 */ 1134 sdev_printk(KERN_ERR, sdev, 1135 "rejecting I/O to offline device\n"); 1136 ret = BLKPREP_KILL; 1137 break; 1138 case SDEV_DEL: 1139 /* 1140 * If the device is fully deleted, we refuse to 1141 * process any commands as well. 1142 */ 1143 sdev_printk(KERN_ERR, sdev, 1144 "rejecting I/O to dead device\n"); 1145 ret = BLKPREP_KILL; 1146 break; 1147 case SDEV_QUIESCE: 1148 case SDEV_BLOCK: 1149 case SDEV_CREATED_BLOCK: 1150 /* 1151 * If the devices is blocked we defer normal commands. 1152 */ 1153 if (!(req->cmd_flags & REQ_PREEMPT)) 1154 ret = BLKPREP_DEFER; 1155 break; 1156 default: 1157 /* 1158 * For any other not fully online state we only allow 1159 * special commands. In particular any user initiated 1160 * command is not allowed. 1161 */ 1162 if (!(req->cmd_flags & REQ_PREEMPT)) 1163 ret = BLKPREP_KILL; 1164 break; 1165 } 1166 } 1167 return ret; 1168} 1169EXPORT_SYMBOL(scsi_prep_state_check); 1170 1171int scsi_prep_return(struct request_queue *q, struct request *req, int ret) 1172{ 1173 struct scsi_device *sdev = q->queuedata; 1174 1175 switch (ret) { 1176 case BLKPREP_KILL: 1177 req->errors = DID_NO_CONNECT << 16; 1178 /* release the command and kill it */ 1179 if (req->special) { 1180 struct scsi_cmnd *cmd = req->special; 1181 scsi_release_buffers(cmd); 1182 scsi_put_command(cmd); 1183 req->special = NULL; 1184 } 1185 break; 1186 case BLKPREP_DEFER: 1187 /* 1188 * If we defer, the blk_peek_request() returns NULL, but the 1189 * queue must be restarted, so we plug here if no returning 1190 * command will automatically do that. 1191 */ 1192 if (sdev->device_busy == 0) 1193 blk_plug_device(q); 1194 break; 1195 default: 1196 req->cmd_flags |= REQ_DONTPREP; 1197 } 1198 1199 return ret; 1200} 1201EXPORT_SYMBOL(scsi_prep_return); 1202 1203int scsi_prep_fn(struct request_queue *q, struct request *req) 1204{ 1205 struct scsi_device *sdev = q->queuedata; 1206 int ret = BLKPREP_KILL; 1207 1208 if (req->cmd_type == REQ_TYPE_BLOCK_PC) 1209 ret = scsi_setup_blk_pc_cmnd(sdev, req); 1210 return scsi_prep_return(q, req, ret); 1211} 1212EXPORT_SYMBOL(scsi_prep_fn); 1213 1214/* 1215 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else 1216 * return 0. 1217 * 1218 * Called with the queue_lock held. 1219 */ 1220static inline int scsi_dev_queue_ready(struct request_queue *q, 1221 struct scsi_device *sdev) 1222{ 1223 if (sdev->device_busy == 0 && sdev->device_blocked) { 1224 /* 1225 * unblock after device_blocked iterates to zero 1226 */ 1227 if (--sdev->device_blocked == 0) { 1228 SCSI_LOG_MLQUEUE(3, 1229 sdev_printk(KERN_INFO, sdev, 1230 "unblocking device at zero depth\n")); 1231 } else { 1232 blk_plug_device(q); 1233 return 0; 1234 } 1235 } 1236 if (scsi_device_is_busy(sdev)) 1237 return 0; 1238 1239 return 1; 1240} 1241 1242 1243/* 1244 * scsi_target_queue_ready: checks if there we can send commands to target 1245 * @sdev: scsi device on starget to check. 1246 * 1247 * Called with the host lock held. 1248 */ 1249static inline int scsi_target_queue_ready(struct Scsi_Host *shost, 1250 struct scsi_device *sdev) 1251{ 1252 struct scsi_target *starget = scsi_target(sdev); 1253 1254 if (starget->single_lun) { 1255 if (starget->starget_sdev_user && 1256 starget->starget_sdev_user != sdev) 1257 return 0; 1258 starget->starget_sdev_user = sdev; 1259 } 1260 1261 if (starget->target_busy == 0 && starget->target_blocked) { 1262 /* 1263 * unblock after target_blocked iterates to zero 1264 */ 1265 if (--starget->target_blocked == 0) { 1266 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget, 1267 "unblocking target at zero depth\n")); 1268 } else 1269 return 0; 1270 } 1271 1272 if (scsi_target_is_busy(starget)) { 1273 if (list_empty(&sdev->starved_entry)) { 1274 list_add_tail(&sdev->starved_entry, 1275 &shost->starved_list); 1276 return 0; 1277 } 1278 } 1279 1280 /* We're OK to process the command, so we can't be starved */ 1281 if (!list_empty(&sdev->starved_entry)) 1282 list_del_init(&sdev->starved_entry); 1283 return 1; 1284} 1285 1286/* 1287 * scsi_host_queue_ready: if we can send requests to shost, return 1 else 1288 * return 0. We must end up running the queue again whenever 0 is 1289 * returned, else IO can hang. 1290 * 1291 * Called with host_lock held. 1292 */ 1293static inline int scsi_host_queue_ready(struct request_queue *q, 1294 struct Scsi_Host *shost, 1295 struct scsi_device *sdev) 1296{ 1297 if (scsi_host_in_recovery(shost)) 1298 return 0; 1299 if (shost->host_busy == 0 && shost->host_blocked) { 1300 /* 1301 * unblock after host_blocked iterates to zero 1302 */ 1303 if (--shost->host_blocked == 0) { 1304 SCSI_LOG_MLQUEUE(3, 1305 printk("scsi%d unblocking host at zero depth\n", 1306 shost->host_no)); 1307 } else { 1308 return 0; 1309 } 1310 } 1311 if (scsi_host_is_busy(shost)) { 1312 if (list_empty(&sdev->starved_entry)) 1313 list_add_tail(&sdev->starved_entry, &shost->starved_list); 1314 return 0; 1315 } 1316 1317 /* We're OK to process the command, so we can't be starved */ 1318 if (!list_empty(&sdev->starved_entry)) 1319 list_del_init(&sdev->starved_entry); 1320 1321 return 1; 1322} 1323 1324/* 1325 * Busy state exporting function for request stacking drivers. 1326 * 1327 * For efficiency, no lock is taken to check the busy state of 1328 * shost/starget/sdev, since the returned value is not guaranteed and 1329 * may be changed after request stacking drivers call the function, 1330 * regardless of taking lock or not. 1331 * 1332 * When scsi can't dispatch I/Os anymore and needs to kill I/Os 1333 * (e.g. !sdev), scsi needs to return 'not busy'. 1334 * Otherwise, request stacking drivers may hold requests forever. 1335 */ 1336static int scsi_lld_busy(struct request_queue *q) 1337{ 1338 struct scsi_device *sdev = q->queuedata; 1339 struct Scsi_Host *shost; 1340 struct scsi_target *starget; 1341 1342 if (!sdev) 1343 return 0; 1344 1345 shost = sdev->host; 1346 starget = scsi_target(sdev); 1347 1348 if (scsi_host_in_recovery(shost) || scsi_host_is_busy(shost) || 1349 scsi_target_is_busy(starget) || scsi_device_is_busy(sdev)) 1350 return 1; 1351 1352 return 0; 1353} 1354 1355/* 1356 * Kill a request for a dead device 1357 */ 1358static void scsi_kill_request(struct request *req, struct request_queue *q) 1359{ 1360 struct scsi_cmnd *cmd = req->special; 1361 struct scsi_device *sdev = cmd->device; 1362 struct scsi_target *starget = scsi_target(sdev); 1363 struct Scsi_Host *shost = sdev->host; 1364 1365 blk_start_request(req); 1366 1367 if (unlikely(cmd == NULL)) { 1368 printk(KERN_CRIT "impossible request in %s.\n", 1369 __func__); 1370 BUG(); 1371 } 1372 1373 scsi_init_cmd_errh(cmd); 1374 cmd->result = DID_NO_CONNECT << 16; 1375 atomic_inc(&cmd->device->iorequest_cnt); 1376 1377 /* 1378 * SCSI request completion path will do scsi_device_unbusy(), 1379 * bump busy counts. To bump the counters, we need to dance 1380 * with the locks as normal issue path does. 1381 */ 1382 sdev->device_busy++; 1383 spin_unlock(sdev->request_queue->queue_lock); 1384 spin_lock(shost->host_lock); 1385 shost->host_busy++; 1386 starget->target_busy++; 1387 spin_unlock(shost->host_lock); 1388 spin_lock(sdev->request_queue->queue_lock); 1389 1390 blk_complete_request(req); 1391} 1392 1393static void scsi_softirq_done(struct request *rq) 1394{ 1395 struct scsi_cmnd *cmd = rq->special; 1396 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout; 1397 int disposition; 1398 1399 INIT_LIST_HEAD(&cmd->eh_entry); 1400 1401 /* 1402 * Set the serial numbers back to zero 1403 */ 1404 cmd->serial_number = 0; 1405 1406 atomic_inc(&cmd->device->iodone_cnt); 1407 if (cmd->result) 1408 atomic_inc(&cmd->device->ioerr_cnt); 1409 1410 disposition = scsi_decide_disposition(cmd); 1411 if (disposition != SUCCESS && 1412 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { 1413 sdev_printk(KERN_ERR, cmd->device, 1414 "timing out command, waited %lus\n", 1415 wait_for/HZ); 1416 disposition = SUCCESS; 1417 } 1418 1419 scsi_log_completion(cmd, disposition); 1420 1421 switch (disposition) { 1422 case SUCCESS: 1423 scsi_finish_command(cmd); 1424 break; 1425 case NEEDS_RETRY: 1426 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY); 1427 break; 1428 case ADD_TO_MLQUEUE: 1429 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); 1430 break; 1431 default: 1432 if (!scsi_eh_scmd_add(cmd, 0)) 1433 scsi_finish_command(cmd); 1434 } 1435} 1436 1437/* 1438 * Function: scsi_request_fn() 1439 * 1440 * Purpose: Main strategy routine for SCSI. 1441 * 1442 * Arguments: q - Pointer to actual queue. 1443 * 1444 * Returns: Nothing 1445 * 1446 * Lock status: IO request lock assumed to be held when called. 1447 */ 1448static void scsi_request_fn(struct request_queue *q) 1449{ 1450 struct scsi_device *sdev = q->queuedata; 1451 struct Scsi_Host *shost; 1452 struct scsi_cmnd *cmd; 1453 struct request *req; 1454 1455 if (!sdev) { 1456 printk("scsi: killing requests for dead queue\n"); 1457 while ((req = blk_peek_request(q)) != NULL) 1458 scsi_kill_request(req, q); 1459 return; 1460 } 1461 1462 if(!get_device(&sdev->sdev_gendev)) 1463 /* We must be tearing the block queue down already */ 1464 return; 1465 1466 /* 1467 * To start with, we keep looping until the queue is empty, or until 1468 * the host is no longer able to accept any more requests. 1469 */ 1470 shost = sdev->host; 1471 while (!blk_queue_plugged(q)) { 1472 int rtn; 1473 /* 1474 * get next queueable request. We do this early to make sure 1475 * that the request is fully prepared even if we cannot 1476 * accept it. 1477 */ 1478 req = blk_peek_request(q); 1479 if (!req || !scsi_dev_queue_ready(q, sdev)) 1480 break; 1481 1482 if (unlikely(!scsi_device_online(sdev))) { 1483 sdev_printk(KERN_ERR, sdev, 1484 "rejecting I/O to offline device\n"); 1485 scsi_kill_request(req, q); 1486 continue; 1487 } 1488 1489 1490 /* 1491 * Remove the request from the request list. 1492 */ 1493 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) 1494 blk_start_request(req); 1495 sdev->device_busy++; 1496 1497 spin_unlock(q->queue_lock); 1498 cmd = req->special; 1499 if (unlikely(cmd == NULL)) { 1500 printk(KERN_CRIT "impossible request in %s.\n" 1501 "please mail a stack trace to " 1502 "linux-scsi@vger.kernel.org\n", 1503 __func__); 1504 blk_dump_rq_flags(req, "foo"); 1505 BUG(); 1506 } 1507 spin_lock(shost->host_lock); 1508 1509 /* 1510 * We hit this when the driver is using a host wide 1511 * tag map. For device level tag maps the queue_depth check 1512 * in the device ready fn would prevent us from trying 1513 * to allocate a tag. Since the map is a shared host resource 1514 * we add the dev to the starved list so it eventually gets 1515 * a run when a tag is freed. 1516 */ 1517 if (blk_queue_tagged(q) && !blk_rq_tagged(req)) { 1518 if (list_empty(&sdev->starved_entry)) 1519 list_add_tail(&sdev->starved_entry, 1520 &shost->starved_list); 1521 goto not_ready; 1522 } 1523 1524 if (!scsi_target_queue_ready(shost, sdev)) 1525 goto not_ready; 1526 1527 if (!scsi_host_queue_ready(q, shost, sdev)) 1528 goto not_ready; 1529 1530 scsi_target(sdev)->target_busy++; 1531 shost->host_busy++; 1532 1533 /* 1534 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will 1535 * take the lock again. 1536 */ 1537 spin_unlock_irq(shost->host_lock); 1538 1539 /* 1540 * Finally, initialize any error handling parameters, and set up 1541 * the timers for timeouts. 1542 */ 1543 scsi_init_cmd_errh(cmd); 1544 1545 /* 1546 * Dispatch the command to the low-level driver. 1547 */ 1548 rtn = scsi_dispatch_cmd(cmd); 1549 spin_lock_irq(q->queue_lock); 1550 if(rtn) { 1551 /* we're refusing the command; because of 1552 * the way locks get dropped, we need to 1553 * check here if plugging is required */ 1554 if(sdev->device_busy == 0) 1555 blk_plug_device(q); 1556 1557 break; 1558 } 1559 } 1560 1561 goto out; 1562 1563 not_ready: 1564 spin_unlock_irq(shost->host_lock); 1565 1566 /* 1567 * lock q, handle tag, requeue req, and decrement device_busy. We 1568 * must return with queue_lock held. 1569 * 1570 * Decrementing device_busy without checking it is OK, as all such 1571 * cases (host limits or settings) should run the queue at some 1572 * later time. 1573 */ 1574 spin_lock_irq(q->queue_lock); 1575 blk_requeue_request(q, req); 1576 sdev->device_busy--; 1577 if(sdev->device_busy == 0) 1578 blk_plug_device(q); 1579 out: 1580 /* must be careful here...if we trigger the ->remove() function 1581 * we cannot be holding the q lock */ 1582 spin_unlock_irq(q->queue_lock); 1583 put_device(&sdev->sdev_gendev); 1584 spin_lock_irq(q->queue_lock); 1585} 1586 1587u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) 1588{ 1589 struct device *host_dev; 1590 u64 bounce_limit = 0xffffffff; 1591 1592 if (shost->unchecked_isa_dma) 1593 return BLK_BOUNCE_ISA; 1594 /* 1595 * Platforms with virtual-DMA translation 1596 * hardware have no practical limit. 1597 */ 1598 if (!PCI_DMA_BUS_IS_PHYS) 1599 return BLK_BOUNCE_ANY; 1600 1601 host_dev = scsi_get_device(shost); 1602 if (host_dev && host_dev->dma_mask) 1603 bounce_limit = *host_dev->dma_mask; 1604 1605 return bounce_limit; 1606} 1607EXPORT_SYMBOL(scsi_calculate_bounce_limit); 1608 1609struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost, 1610 request_fn_proc *request_fn) 1611{ 1612 struct request_queue *q; 1613 struct device *dev = shost->shost_gendev.parent; 1614 1615 q = blk_init_queue(request_fn, NULL); 1616 if (!q) 1617 return NULL; 1618 1619 /* 1620 * this limit is imposed by hardware restrictions 1621 */ 1622 blk_queue_max_hw_segments(q, shost->sg_tablesize); 1623 blk_queue_max_phys_segments(q, SCSI_MAX_SG_CHAIN_SEGMENTS); 1624 1625 blk_queue_max_sectors(q, shost->max_sectors); 1626 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost)); 1627 blk_queue_segment_boundary(q, shost->dma_boundary); 1628 dma_set_seg_boundary(dev, shost->dma_boundary); 1629 1630 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev)); 1631 1632 /* New queue, no concurrency on queue_flags */ 1633 if (!shost->use_clustering) 1634 queue_flag_clear_unlocked(QUEUE_FLAG_CLUSTER, q); 1635 1636 /* 1637 * set a reasonable default alignment on word boundaries: the 1638 * host and device may alter it using 1639 * blk_queue_update_dma_alignment() later. 1640 */ 1641 blk_queue_dma_alignment(q, 0x03); 1642 1643 return q; 1644} 1645EXPORT_SYMBOL(__scsi_alloc_queue); 1646 1647struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) 1648{ 1649 struct request_queue *q; 1650 1651 q = __scsi_alloc_queue(sdev->host, scsi_request_fn); 1652 if (!q) 1653 return NULL; 1654 1655 blk_queue_prep_rq(q, scsi_prep_fn); 1656 blk_queue_softirq_done(q, scsi_softirq_done); 1657 blk_queue_rq_timed_out(q, scsi_times_out); 1658 blk_queue_lld_busy(q, scsi_lld_busy); 1659 return q; 1660} 1661 1662void scsi_free_queue(struct request_queue *q) 1663{ 1664 blk_cleanup_queue(q); 1665} 1666 1667/* 1668 * Function: scsi_block_requests() 1669 * 1670 * Purpose: Utility function used by low-level drivers to prevent further 1671 * commands from being queued to the device. 1672 * 1673 * Arguments: shost - Host in question 1674 * 1675 * Returns: Nothing 1676 * 1677 * Lock status: No locks are assumed held. 1678 * 1679 * Notes: There is no timer nor any other means by which the requests 1680 * get unblocked other than the low-level driver calling 1681 * scsi_unblock_requests(). 1682 */ 1683void scsi_block_requests(struct Scsi_Host *shost) 1684{ 1685 shost->host_self_blocked = 1; 1686} 1687EXPORT_SYMBOL(scsi_block_requests); 1688 1689/* 1690 * Function: scsi_unblock_requests() 1691 * 1692 * Purpose: Utility function used by low-level drivers to allow further 1693 * commands from being queued to the device. 1694 * 1695 * Arguments: shost - Host in question 1696 * 1697 * Returns: Nothing 1698 * 1699 * Lock status: No locks are assumed held. 1700 * 1701 * Notes: There is no timer nor any other means by which the requests 1702 * get unblocked other than the low-level driver calling 1703 * scsi_unblock_requests(). 1704 * 1705 * This is done as an API function so that changes to the 1706 * internals of the scsi mid-layer won't require wholesale 1707 * changes to drivers that use this feature. 1708 */ 1709void scsi_unblock_requests(struct Scsi_Host *shost) 1710{ 1711 shost->host_self_blocked = 0; 1712 scsi_run_host_queues(shost); 1713} 1714EXPORT_SYMBOL(scsi_unblock_requests); 1715 1716int __init scsi_init_queue(void) 1717{ 1718 int i; 1719 1720 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer", 1721 sizeof(struct scsi_data_buffer), 1722 0, 0, NULL); 1723 if (!scsi_sdb_cache) { 1724 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n"); 1725 return -ENOMEM; 1726 } 1727 1728 for (i = 0; i < SG_MEMPOOL_NR; i++) { 1729 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; 1730 int size = sgp->size * sizeof(struct scatterlist); 1731 1732 sgp->slab = kmem_cache_create(sgp->name, size, 0, 1733 SLAB_HWCACHE_ALIGN, NULL); 1734 if (!sgp->slab) { 1735 printk(KERN_ERR "SCSI: can't init sg slab %s\n", 1736 sgp->name); 1737 goto cleanup_sdb; 1738 } 1739 1740 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE, 1741 sgp->slab); 1742 if (!sgp->pool) { 1743 printk(KERN_ERR "SCSI: can't init sg mempool %s\n", 1744 sgp->name); 1745 goto cleanup_sdb; 1746 } 1747 } 1748 1749 return 0; 1750 1751cleanup_sdb: 1752 for (i = 0; i < SG_MEMPOOL_NR; i++) { 1753 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; 1754 if (sgp->pool) 1755 mempool_destroy(sgp->pool); 1756 if (sgp->slab) 1757 kmem_cache_destroy(sgp->slab); 1758 } 1759 kmem_cache_destroy(scsi_sdb_cache); 1760 1761 return -ENOMEM; 1762} 1763 1764void scsi_exit_queue(void) 1765{ 1766 int i; 1767 1768 kmem_cache_destroy(scsi_sdb_cache); 1769 1770 for (i = 0; i < SG_MEMPOOL_NR; i++) { 1771 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; 1772 mempool_destroy(sgp->pool); 1773 kmem_cache_destroy(sgp->slab); 1774 } 1775} 1776 1777/** 1778 * scsi_mode_select - issue a mode select 1779 * @sdev: SCSI device to be queried 1780 * @pf: Page format bit (1 == standard, 0 == vendor specific) 1781 * @sp: Save page bit (0 == don't save, 1 == save) 1782 * @modepage: mode page being requested 1783 * @buffer: request buffer (may not be smaller than eight bytes) 1784 * @len: length of request buffer. 1785 * @timeout: command timeout 1786 * @retries: number of retries before failing 1787 * @data: returns a structure abstracting the mode header data 1788 * @sshdr: place to put sense data (or NULL if no sense to be collected). 1789 * must be SCSI_SENSE_BUFFERSIZE big. 1790 * 1791 * Returns zero if successful; negative error number or scsi 1792 * status on error 1793 * 1794 */ 1795int 1796scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage, 1797 unsigned char *buffer, int len, int timeout, int retries, 1798 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) 1799{ 1800 unsigned char cmd[10]; 1801 unsigned char *real_buffer; 1802 int ret; 1803 1804 memset(cmd, 0, sizeof(cmd)); 1805 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); 1806 1807 if (sdev->use_10_for_ms) { 1808 if (len > 65535) 1809 return -EINVAL; 1810 real_buffer = kmalloc(8 + len, GFP_KERNEL); 1811 if (!real_buffer) 1812 return -ENOMEM; 1813 memcpy(real_buffer + 8, buffer, len); 1814 len += 8; 1815 real_buffer[0] = 0; 1816 real_buffer[1] = 0; 1817 real_buffer[2] = data->medium_type; 1818 real_buffer[3] = data->device_specific; 1819 real_buffer[4] = data->longlba ? 0x01 : 0; 1820 real_buffer[5] = 0; 1821 real_buffer[6] = data->block_descriptor_length >> 8; 1822 real_buffer[7] = data->block_descriptor_length; 1823 1824 cmd[0] = MODE_SELECT_10; 1825 cmd[7] = len >> 8; 1826 cmd[8] = len; 1827 } else { 1828 if (len > 255 || data->block_descriptor_length > 255 || 1829 data->longlba) 1830 return -EINVAL; 1831 1832 real_buffer = kmalloc(4 + len, GFP_KERNEL); 1833 if (!real_buffer) 1834 return -ENOMEM; 1835 memcpy(real_buffer + 4, buffer, len); 1836 len += 4; 1837 real_buffer[0] = 0; 1838 real_buffer[1] = data->medium_type; 1839 real_buffer[2] = data->device_specific; 1840 real_buffer[3] = data->block_descriptor_length; 1841 1842 1843 cmd[0] = MODE_SELECT; 1844 cmd[4] = len; 1845 } 1846 1847 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, 1848 sshdr, timeout, retries, NULL); 1849 kfree(real_buffer); 1850 return ret; 1851} 1852EXPORT_SYMBOL_GPL(scsi_mode_select); 1853 1854/** 1855 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary. 1856 * @sdev: SCSI device to be queried 1857 * @dbd: set if mode sense will allow block descriptors to be returned 1858 * @modepage: mode page being requested 1859 * @buffer: request buffer (may not be smaller than eight bytes) 1860 * @len: length of request buffer. 1861 * @timeout: command timeout 1862 * @retries: number of retries before failing 1863 * @data: returns a structure abstracting the mode header data 1864 * @sshdr: place to put sense data (or NULL if no sense to be collected). 1865 * must be SCSI_SENSE_BUFFERSIZE big. 1866 * 1867 * Returns zero if unsuccessful, or the header offset (either 4 1868 * or 8 depending on whether a six or ten byte command was 1869 * issued) if successful. 1870 */ 1871int 1872scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, 1873 unsigned char *buffer, int len, int timeout, int retries, 1874 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) 1875{ 1876 unsigned char cmd[12]; 1877 int use_10_for_ms; 1878 int header_length; 1879 int result; 1880 struct scsi_sense_hdr my_sshdr; 1881 1882 memset(data, 0, sizeof(*data)); 1883 memset(&cmd[0], 0, 12); 1884 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ 1885 cmd[2] = modepage; 1886 1887 /* caller might not be interested in sense, but we need it */ 1888 if (!sshdr) 1889 sshdr = &my_sshdr; 1890 1891 retry: 1892 use_10_for_ms = sdev->use_10_for_ms; 1893 1894 if (use_10_for_ms) { 1895 if (len < 8) 1896 len = 8; 1897 1898 cmd[0] = MODE_SENSE_10; 1899 cmd[8] = len; 1900 header_length = 8; 1901 } else { 1902 if (len < 4) 1903 len = 4; 1904 1905 cmd[0] = MODE_SENSE; 1906 cmd[4] = len; 1907 header_length = 4; 1908 } 1909 1910 memset(buffer, 0, len); 1911 1912 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, 1913 sshdr, timeout, retries, NULL); 1914 1915 /* This code looks awful: what it's doing is making sure an 1916 * ILLEGAL REQUEST sense return identifies the actual command 1917 * byte as the problem. MODE_SENSE commands can return 1918 * ILLEGAL REQUEST if the code page isn't supported */ 1919 1920 if (use_10_for_ms && !scsi_status_is_good(result) && 1921 (driver_byte(result) & DRIVER_SENSE)) { 1922 if (scsi_sense_valid(sshdr)) { 1923 if ((sshdr->sense_key == ILLEGAL_REQUEST) && 1924 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { 1925 /* 1926 * Invalid command operation code 1927 */ 1928 sdev->use_10_for_ms = 0; 1929 goto retry; 1930 } 1931 } 1932 } 1933 1934 if(scsi_status_is_good(result)) { 1935 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && 1936 (modepage == 6 || modepage == 8))) { 1937 /* Initio breakage? */ 1938 header_length = 0; 1939 data->length = 13; 1940 data->medium_type = 0; 1941 data->device_specific = 0; 1942 data->longlba = 0; 1943 data->block_descriptor_length = 0; 1944 } else if(use_10_for_ms) { 1945 data->length = buffer[0]*256 + buffer[1] + 2; 1946 data->medium_type = buffer[2]; 1947 data->device_specific = buffer[3]; 1948 data->longlba = buffer[4] & 0x01; 1949 data->block_descriptor_length = buffer[6]*256 1950 + buffer[7]; 1951 } else { 1952 data->length = buffer[0] + 1; 1953 data->medium_type = buffer[1]; 1954 data->device_specific = buffer[2]; 1955 data->block_descriptor_length = buffer[3]; 1956 } 1957 data->header_length = header_length; 1958 } 1959 1960 return result; 1961} 1962EXPORT_SYMBOL(scsi_mode_sense); 1963 1964/** 1965 * scsi_test_unit_ready - test if unit is ready 1966 * @sdev: scsi device to change the state of. 1967 * @timeout: command timeout 1968 * @retries: number of retries before failing 1969 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for 1970 * returning sense. Make sure that this is cleared before passing 1971 * in. 1972 * 1973 * Returns zero if unsuccessful or an error if TUR failed. For 1974 * removable media, a return of NOT_READY or UNIT_ATTENTION is 1975 * translated to success, with the ->changed flag updated. 1976 **/ 1977int 1978scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, 1979 struct scsi_sense_hdr *sshdr_external) 1980{ 1981 char cmd[] = { 1982 TEST_UNIT_READY, 0, 0, 0, 0, 0, 1983 }; 1984 struct scsi_sense_hdr *sshdr; 1985 int result; 1986 1987 if (!sshdr_external) 1988 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL); 1989 else 1990 sshdr = sshdr_external; 1991 1992 /* try to eat the UNIT_ATTENTION if there are enough retries */ 1993 do { 1994 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr, 1995 timeout, retries, NULL); 1996 if (sdev->removable && scsi_sense_valid(sshdr) && 1997 sshdr->sense_key == UNIT_ATTENTION) 1998 sdev->changed = 1; 1999 } while (scsi_sense_valid(sshdr) && 2000 sshdr->sense_key == UNIT_ATTENTION && --retries); 2001 2002 if (!sshdr) 2003 /* could not allocate sense buffer, so can't process it */ 2004 return result; 2005 2006 if (sdev->removable && scsi_sense_valid(sshdr) && 2007 (sshdr->sense_key == UNIT_ATTENTION || 2008 sshdr->sense_key == NOT_READY)) { 2009 sdev->changed = 1; 2010 result = 0; 2011 } 2012 if (!sshdr_external) 2013 kfree(sshdr); 2014 return result; 2015} 2016EXPORT_SYMBOL(scsi_test_unit_ready); 2017 2018/** 2019 * scsi_device_set_state - Take the given device through the device state model. 2020 * @sdev: scsi device to change the state of. 2021 * @state: state to change to. 2022 * 2023 * Returns zero if unsuccessful or an error if the requested 2024 * transition is illegal. 2025 */ 2026int 2027scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) 2028{ 2029 enum scsi_device_state oldstate = sdev->sdev_state; 2030 2031 if (state == oldstate) 2032 return 0; 2033 2034 switch (state) { 2035 case SDEV_CREATED: 2036 switch (oldstate) { 2037 case SDEV_CREATED_BLOCK: 2038 break; 2039 default: 2040 goto illegal; 2041 } 2042 break; 2043 2044 case SDEV_RUNNING: 2045 switch (oldstate) { 2046 case SDEV_CREATED: 2047 case SDEV_OFFLINE: 2048 case SDEV_QUIESCE: 2049 case SDEV_BLOCK: 2050 break; 2051 default: 2052 goto illegal; 2053 } 2054 break; 2055 2056 case SDEV_QUIESCE: 2057 switch (oldstate) { 2058 case SDEV_RUNNING: 2059 case SDEV_OFFLINE: 2060 break; 2061 default: 2062 goto illegal; 2063 } 2064 break; 2065 2066 case SDEV_OFFLINE: 2067 switch (oldstate) { 2068 case SDEV_CREATED: 2069 case SDEV_RUNNING: 2070 case SDEV_QUIESCE: 2071 case SDEV_BLOCK: 2072 break; 2073 default: 2074 goto illegal; 2075 } 2076 break; 2077 2078 case SDEV_BLOCK: 2079 switch (oldstate) { 2080 case SDEV_RUNNING: 2081 case SDEV_CREATED_BLOCK: 2082 break; 2083 default: 2084 goto illegal; 2085 } 2086 break; 2087 2088 case SDEV_CREATED_BLOCK: 2089 switch (oldstate) { 2090 case SDEV_CREATED: 2091 break; 2092 default: 2093 goto illegal; 2094 } 2095 break; 2096 2097 case SDEV_CANCEL: 2098 switch (oldstate) { 2099 case SDEV_CREATED: 2100 case SDEV_RUNNING: 2101 case SDEV_QUIESCE: 2102 case SDEV_OFFLINE: 2103 case SDEV_BLOCK: 2104 break; 2105 default: 2106 goto illegal; 2107 } 2108 break; 2109 2110 case SDEV_DEL: 2111 switch (oldstate) { 2112 case SDEV_CREATED: 2113 case SDEV_RUNNING: 2114 case SDEV_OFFLINE: 2115 case SDEV_CANCEL: 2116 break; 2117 default: 2118 goto illegal; 2119 } 2120 break; 2121 2122 } 2123 sdev->sdev_state = state; 2124 return 0; 2125 2126 illegal: 2127 SCSI_LOG_ERROR_RECOVERY(1, 2128 sdev_printk(KERN_ERR, sdev, 2129 "Illegal state transition %s->%s\n", 2130 scsi_device_state_name(oldstate), 2131 scsi_device_state_name(state)) 2132 ); 2133 return -EINVAL; 2134} 2135EXPORT_SYMBOL(scsi_device_set_state); 2136 2137/** 2138 * sdev_evt_emit - emit a single SCSI device uevent 2139 * @sdev: associated SCSI device 2140 * @evt: event to emit 2141 * 2142 * Send a single uevent (scsi_event) to the associated scsi_device. 2143 */ 2144static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt) 2145{ 2146 int idx = 0; 2147 char *envp[3]; 2148 2149 switch (evt->evt_type) { 2150 case SDEV_EVT_MEDIA_CHANGE: 2151 envp[idx++] = "SDEV_MEDIA_CHANGE=1"; 2152 break; 2153 2154 default: 2155 /* do nothing */ 2156 break; 2157 } 2158 2159 envp[idx++] = NULL; 2160 2161 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp); 2162} 2163 2164/** 2165 * sdev_evt_thread - send a uevent for each scsi event 2166 * @work: work struct for scsi_device 2167 * 2168 * Dispatch queued events to their associated scsi_device kobjects 2169 * as uevents. 2170 */ 2171void scsi_evt_thread(struct work_struct *work) 2172{ 2173 struct scsi_device *sdev; 2174 LIST_HEAD(event_list); 2175 2176 sdev = container_of(work, struct scsi_device, event_work); 2177 2178 while (1) { 2179 struct scsi_event *evt; 2180 struct list_head *this, *tmp; 2181 unsigned long flags; 2182 2183 spin_lock_irqsave(&sdev->list_lock, flags); 2184 list_splice_init(&sdev->event_list, &event_list); 2185 spin_unlock_irqrestore(&sdev->list_lock, flags); 2186 2187 if (list_empty(&event_list)) 2188 break; 2189 2190 list_for_each_safe(this, tmp, &event_list) { 2191 evt = list_entry(this, struct scsi_event, node); 2192 list_del(&evt->node); 2193 scsi_evt_emit(sdev, evt); 2194 kfree(evt); 2195 } 2196 } 2197} 2198 2199/** 2200 * sdev_evt_send - send asserted event to uevent thread 2201 * @sdev: scsi_device event occurred on 2202 * @evt: event to send 2203 * 2204 * Assert scsi device event asynchronously. 2205 */ 2206void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt) 2207{ 2208 unsigned long flags; 2209 2210#if 0 2211 /* FIXME: currently this check eliminates all media change events 2212 * for polled devices. Need to update to discriminate between AN 2213 * and polled events */ 2214 if (!test_bit(evt->evt_type, sdev->supported_events)) { 2215 kfree(evt); 2216 return; 2217 } 2218#endif 2219 2220 spin_lock_irqsave(&sdev->list_lock, flags); 2221 list_add_tail(&evt->node, &sdev->event_list); 2222 schedule_work(&sdev->event_work); 2223 spin_unlock_irqrestore(&sdev->list_lock, flags); 2224} 2225EXPORT_SYMBOL_GPL(sdev_evt_send); 2226 2227/** 2228 * sdev_evt_alloc - allocate a new scsi event 2229 * @evt_type: type of event to allocate 2230 * @gfpflags: GFP flags for allocation 2231 * 2232 * Allocates and returns a new scsi_event. 2233 */ 2234struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type, 2235 gfp_t gfpflags) 2236{ 2237 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags); 2238 if (!evt) 2239 return NULL; 2240 2241 evt->evt_type = evt_type; 2242 INIT_LIST_HEAD(&evt->node); 2243 2244 /* evt_type-specific initialization, if any */ 2245 switch (evt_type) { 2246 case SDEV_EVT_MEDIA_CHANGE: 2247 default: 2248 /* do nothing */ 2249 break; 2250 } 2251 2252 return evt; 2253} 2254EXPORT_SYMBOL_GPL(sdev_evt_alloc); 2255 2256/** 2257 * sdev_evt_send_simple - send asserted event to uevent thread 2258 * @sdev: scsi_device event occurred on 2259 * @evt_type: type of event to send 2260 * @gfpflags: GFP flags for allocation 2261 * 2262 * Assert scsi device event asynchronously, given an event type. 2263 */ 2264void sdev_evt_send_simple(struct scsi_device *sdev, 2265 enum scsi_device_event evt_type, gfp_t gfpflags) 2266{ 2267 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags); 2268 if (!evt) { 2269 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n", 2270 evt_type); 2271 return; 2272 } 2273 2274 sdev_evt_send(sdev, evt); 2275} 2276EXPORT_SYMBOL_GPL(sdev_evt_send_simple); 2277 2278/** 2279 * scsi_device_quiesce - Block user issued commands. 2280 * @sdev: scsi device to quiesce. 2281 * 2282 * This works by trying to transition to the SDEV_QUIESCE state 2283 * (which must be a legal transition). When the device is in this 2284 * state, only special requests will be accepted, all others will 2285 * be deferred. Since special requests may also be requeued requests, 2286 * a successful return doesn't guarantee the device will be 2287 * totally quiescent. 2288 * 2289 * Must be called with user context, may sleep. 2290 * 2291 * Returns zero if unsuccessful or an error if not. 2292 */ 2293int 2294scsi_device_quiesce(struct scsi_device *sdev) 2295{ 2296 int err = scsi_device_set_state(sdev, SDEV_QUIESCE); 2297 if (err) 2298 return err; 2299 2300 scsi_run_queue(sdev->request_queue); 2301 while (sdev->device_busy) { 2302 msleep_interruptible(200); 2303 scsi_run_queue(sdev->request_queue); 2304 } 2305 return 0; 2306} 2307EXPORT_SYMBOL(scsi_device_quiesce); 2308 2309/** 2310 * scsi_device_resume - Restart user issued commands to a quiesced device. 2311 * @sdev: scsi device to resume. 2312 * 2313 * Moves the device from quiesced back to running and restarts the 2314 * queues. 2315 * 2316 * Must be called with user context, may sleep. 2317 */ 2318void 2319scsi_device_resume(struct scsi_device *sdev) 2320{ 2321 if(scsi_device_set_state(sdev, SDEV_RUNNING)) 2322 return; 2323 scsi_run_queue(sdev->request_queue); 2324} 2325EXPORT_SYMBOL(scsi_device_resume); 2326 2327static void 2328device_quiesce_fn(struct scsi_device *sdev, void *data) 2329{ 2330 scsi_device_quiesce(sdev); 2331} 2332 2333void 2334scsi_target_quiesce(struct scsi_target *starget) 2335{ 2336 starget_for_each_device(starget, NULL, device_quiesce_fn); 2337} 2338EXPORT_SYMBOL(scsi_target_quiesce); 2339 2340static void 2341device_resume_fn(struct scsi_device *sdev, void *data) 2342{ 2343 scsi_device_resume(sdev); 2344} 2345 2346void 2347scsi_target_resume(struct scsi_target *starget) 2348{ 2349 starget_for_each_device(starget, NULL, device_resume_fn); 2350} 2351EXPORT_SYMBOL(scsi_target_resume); 2352 2353/** 2354 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state 2355 * @sdev: device to block 2356 * 2357 * Block request made by scsi lld's to temporarily stop all 2358 * scsi commands on the specified device. Called from interrupt 2359 * or normal process context. 2360 * 2361 * Returns zero if successful or error if not 2362 * 2363 * Notes: 2364 * This routine transitions the device to the SDEV_BLOCK state 2365 * (which must be a legal transition). When the device is in this 2366 * state, all commands are deferred until the scsi lld reenables 2367 * the device with scsi_device_unblock or device_block_tmo fires. 2368 * This routine assumes the host_lock is held on entry. 2369 */ 2370int 2371scsi_internal_device_block(struct scsi_device *sdev) 2372{ 2373 struct request_queue *q = sdev->request_queue; 2374 unsigned long flags; 2375 int err = 0; 2376 2377 err = scsi_device_set_state(sdev, SDEV_BLOCK); 2378 if (err) { 2379 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK); 2380 2381 if (err) 2382 return err; 2383 } 2384 2385 /* 2386 * The device has transitioned to SDEV_BLOCK. Stop the 2387 * block layer from calling the midlayer with this device's 2388 * request queue. 2389 */ 2390 spin_lock_irqsave(q->queue_lock, flags); 2391 blk_stop_queue(q); 2392 spin_unlock_irqrestore(q->queue_lock, flags); 2393 2394 return 0; 2395} 2396EXPORT_SYMBOL_GPL(scsi_internal_device_block); 2397 2398/** 2399 * scsi_internal_device_unblock - resume a device after a block request 2400 * @sdev: device to resume 2401 * 2402 * Called by scsi lld's or the midlayer to restart the device queue 2403 * for the previously suspended scsi device. Called from interrupt or 2404 * normal process context. 2405 * 2406 * Returns zero if successful or error if not. 2407 * 2408 * Notes: 2409 * This routine transitions the device to the SDEV_RUNNING state 2410 * (which must be a legal transition) allowing the midlayer to 2411 * goose the queue for this device. This routine assumes the 2412 * host_lock is held upon entry. 2413 */ 2414int 2415scsi_internal_device_unblock(struct scsi_device *sdev) 2416{ 2417 struct request_queue *q = sdev->request_queue; 2418 unsigned long flags; 2419 2420 /* 2421 * Try to transition the scsi device to SDEV_RUNNING 2422 * and goose the device queue if successful. 2423 */ 2424 if (sdev->sdev_state == SDEV_BLOCK) 2425 sdev->sdev_state = SDEV_RUNNING; 2426 else if (sdev->sdev_state == SDEV_CREATED_BLOCK) 2427 sdev->sdev_state = SDEV_CREATED; 2428 else 2429 return -EINVAL; 2430 2431 spin_lock_irqsave(q->queue_lock, flags); 2432 blk_start_queue(q); 2433 spin_unlock_irqrestore(q->queue_lock, flags); 2434 2435 return 0; 2436} 2437EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); 2438 2439static void 2440device_block(struct scsi_device *sdev, void *data) 2441{ 2442 scsi_internal_device_block(sdev); 2443} 2444 2445static int 2446target_block(struct device *dev, void *data) 2447{ 2448 if (scsi_is_target_device(dev)) 2449 starget_for_each_device(to_scsi_target(dev), NULL, 2450 device_block); 2451 return 0; 2452} 2453 2454void 2455scsi_target_block(struct device *dev) 2456{ 2457 if (scsi_is_target_device(dev)) 2458 starget_for_each_device(to_scsi_target(dev), NULL, 2459 device_block); 2460 else 2461 device_for_each_child(dev, NULL, target_block); 2462} 2463EXPORT_SYMBOL_GPL(scsi_target_block); 2464 2465static void 2466device_unblock(struct scsi_device *sdev, void *data) 2467{ 2468 scsi_internal_device_unblock(sdev); 2469} 2470 2471static int 2472target_unblock(struct device *dev, void *data) 2473{ 2474 if (scsi_is_target_device(dev)) 2475 starget_for_each_device(to_scsi_target(dev), NULL, 2476 device_unblock); 2477 return 0; 2478} 2479 2480void 2481scsi_target_unblock(struct device *dev) 2482{ 2483 if (scsi_is_target_device(dev)) 2484 starget_for_each_device(to_scsi_target(dev), NULL, 2485 device_unblock); 2486 else 2487 device_for_each_child(dev, NULL, target_unblock); 2488} 2489EXPORT_SYMBOL_GPL(scsi_target_unblock); 2490 2491/** 2492 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt 2493 * @sgl: scatter-gather list 2494 * @sg_count: number of segments in sg 2495 * @offset: offset in bytes into sg, on return offset into the mapped area 2496 * @len: bytes to map, on return number of bytes mapped 2497 * 2498 * Returns virtual address of the start of the mapped page 2499 */ 2500void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count, 2501 size_t *offset, size_t *len) 2502{ 2503 int i; 2504 size_t sg_len = 0, len_complete = 0; 2505 struct scatterlist *sg; 2506 struct page *page; 2507 2508 WARN_ON(!irqs_disabled()); 2509 2510 for_each_sg(sgl, sg, sg_count, i) { 2511 len_complete = sg_len; /* Complete sg-entries */ 2512 sg_len += sg->length; 2513 if (sg_len > *offset) 2514 break; 2515 } 2516 2517 if (unlikely(i == sg_count)) { 2518 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " 2519 "elements %d\n", 2520 __func__, sg_len, *offset, sg_count); 2521 WARN_ON(1); 2522 return NULL; 2523 } 2524 2525 /* Offset starting from the beginning of first page in this sg-entry */ 2526 *offset = *offset - len_complete + sg->offset; 2527 2528 /* Assumption: contiguous pages can be accessed as "page + i" */ 2529 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT)); 2530 *offset &= ~PAGE_MASK; 2531 2532 /* Bytes in this sg-entry from *offset to the end of the page */ 2533 sg_len = PAGE_SIZE - *offset; 2534 if (*len > sg_len) 2535 *len = sg_len; 2536 2537 return kmap_atomic(page, KM_BIO_SRC_IRQ); 2538} 2539EXPORT_SYMBOL(scsi_kmap_atomic_sg); 2540 2541/** 2542 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg 2543 * @virt: virtual address to be unmapped 2544 */ 2545void scsi_kunmap_atomic_sg(void *virt) 2546{ 2547 kunmap_atomic(virt, KM_BIO_SRC_IRQ); 2548} 2549EXPORT_SYMBOL(scsi_kunmap_atomic_sg); 2550