1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 1999 Eric Youngdale 4 * Copyright (C) 2014 Christoph Hellwig 5 * 6 * SCSI queueing library. 7 * Initial versions: Eric Youngdale (eric@andante.org). 8 * Based upon conversations with large numbers 9 * of people at Linux Expo. 10 */ 11 12 #include <linux/bio.h> 13 #include <linux/bitops.h> 14 #include <linux/blkdev.h> 15 #include <linux/completion.h> 16 #include <linux/kernel.h> 17 #include <linux/export.h> 18 #include <linux/init.h> 19 #include <linux/pci.h> 20 #include <linux/delay.h> 21 #include <linux/hardirq.h> 22 #include <linux/scatterlist.h> 23 #include <linux/blk-mq.h> 24 #include <linux/blk-integrity.h> 25 #include <linux/ratelimit.h> 26 #include <asm/unaligned.h> 27 28 #include <scsi/scsi.h> 29 #include <scsi/scsi_cmnd.h> 30 #include <scsi/scsi_dbg.h> 31 #include <scsi/scsi_device.h> 32 #include <scsi/scsi_driver.h> 33 #include <scsi/scsi_eh.h> 34 #include <scsi/scsi_host.h> 35 #include <scsi/scsi_transport.h> /* __scsi_init_queue() */ 36 #include <scsi/scsi_dh.h> 37 38 #include <trace/events/scsi.h> 39 40 #include "scsi_debugfs.h" 41 #include "scsi_priv.h" 42 #include "scsi_logging.h" 43 44 /* 45 * Size of integrity metadata is usually small, 1 inline sg should 46 * cover normal cases. 47 */ 48 #ifdef CONFIG_ARCH_NO_SG_CHAIN 49 #define SCSI_INLINE_PROT_SG_CNT 0 50 #define SCSI_INLINE_SG_CNT 0 51 #else 52 #define SCSI_INLINE_PROT_SG_CNT 1 53 #define SCSI_INLINE_SG_CNT 2 54 #endif 55 56 static struct kmem_cache *scsi_sense_cache; 57 static DEFINE_MUTEX(scsi_sense_cache_mutex); 58 59 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd); 60 61 int scsi_init_sense_cache(struct Scsi_Host *shost) 62 { 63 int ret = 0; 64 65 mutex_lock(&scsi_sense_cache_mutex); 66 if (!scsi_sense_cache) { 67 scsi_sense_cache = 68 kmem_cache_create_usercopy("scsi_sense_cache", 69 SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN, 70 0, SCSI_SENSE_BUFFERSIZE, NULL); 71 if (!scsi_sense_cache) 72 ret = -ENOMEM; 73 } 74 mutex_unlock(&scsi_sense_cache_mutex); 75 return ret; 76 } 77 78 /* 79 * When to reinvoke queueing after a resource shortage. It's 3 msecs to 80 * not change behaviour from the previous unplug mechanism, experimentation 81 * may prove this needs changing. 82 */ 83 #define SCSI_QUEUE_DELAY 3 84 85 static void 86 scsi_set_blocked(struct scsi_cmnd *cmd, int reason) 87 { 88 struct Scsi_Host *host = cmd->device->host; 89 struct scsi_device *device = cmd->device; 90 struct scsi_target *starget = scsi_target(device); 91 92 /* 93 * Set the appropriate busy bit for the device/host. 94 * 95 * If the host/device isn't busy, assume that something actually 96 * completed, and that we should be able to queue a command now. 97 * 98 * Note that the prior mid-layer assumption that any host could 99 * always queue at least one command is now broken. The mid-layer 100 * will implement a user specifiable stall (see 101 * scsi_host.max_host_blocked and scsi_device.max_device_blocked) 102 * if a command is requeued with no other commands outstanding 103 * either for the device or for the host. 104 */ 105 switch (reason) { 106 case SCSI_MLQUEUE_HOST_BUSY: 107 atomic_set(&host->host_blocked, host->max_host_blocked); 108 break; 109 case SCSI_MLQUEUE_DEVICE_BUSY: 110 case SCSI_MLQUEUE_EH_RETRY: 111 atomic_set(&device->device_blocked, 112 device->max_device_blocked); 113 break; 114 case SCSI_MLQUEUE_TARGET_BUSY: 115 atomic_set(&starget->target_blocked, 116 starget->max_target_blocked); 117 break; 118 } 119 } 120 121 static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd) 122 { 123 struct request *rq = scsi_cmd_to_rq(cmd); 124 125 if (rq->rq_flags & RQF_DONTPREP) { 126 rq->rq_flags &= ~RQF_DONTPREP; 127 scsi_mq_uninit_cmd(cmd); 128 } else { 129 WARN_ON_ONCE(true); 130 } 131 blk_mq_requeue_request(rq, true); 132 } 133 134 /** 135 * __scsi_queue_insert - private queue insertion 136 * @cmd: The SCSI command being requeued 137 * @reason: The reason for the requeue 138 * @unbusy: Whether the queue should be unbusied 139 * 140 * This is a private queue insertion. The public interface 141 * scsi_queue_insert() always assumes the queue should be unbusied 142 * because it's always called before the completion. This function is 143 * for a requeue after completion, which should only occur in this 144 * file. 145 */ 146 static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy) 147 { 148 struct scsi_device *device = cmd->device; 149 150 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd, 151 "Inserting command %p into mlqueue\n", cmd)); 152 153 scsi_set_blocked(cmd, reason); 154 155 /* 156 * Decrement the counters, since these commands are no longer 157 * active on the host/device. 158 */ 159 if (unbusy) 160 scsi_device_unbusy(device, cmd); 161 162 /* 163 * Requeue this command. It will go before all other commands 164 * that are already in the queue. Schedule requeue work under 165 * lock such that the kblockd_schedule_work() call happens 166 * before blk_cleanup_queue() finishes. 167 */ 168 cmd->result = 0; 169 170 blk_mq_requeue_request(scsi_cmd_to_rq(cmd), true); 171 } 172 173 /** 174 * scsi_queue_insert - Reinsert a command in the queue. 175 * @cmd: command that we are adding to queue. 176 * @reason: why we are inserting command to queue. 177 * 178 * We do this for one of two cases. Either the host is busy and it cannot accept 179 * any more commands for the time being, or the device returned QUEUE_FULL and 180 * can accept no more commands. 181 * 182 * Context: This could be called either from an interrupt context or a normal 183 * process context. 184 */ 185 void scsi_queue_insert(struct scsi_cmnd *cmd, int reason) 186 { 187 __scsi_queue_insert(cmd, reason, true); 188 } 189 190 191 /** 192 * __scsi_execute - insert request and wait for the result 193 * @sdev: scsi device 194 * @cmd: scsi command 195 * @data_direction: data direction 196 * @buffer: data buffer 197 * @bufflen: len of buffer 198 * @sense: optional sense buffer 199 * @sshdr: optional decoded sense header 200 * @timeout: request timeout in HZ 201 * @retries: number of times to retry request 202 * @flags: flags for ->cmd_flags 203 * @rq_flags: flags for ->rq_flags 204 * @resid: optional residual length 205 * 206 * Returns the scsi_cmnd result field if a command was executed, or a negative 207 * Linux error code if we didn't get that far. 208 */ 209 int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, 210 int data_direction, void *buffer, unsigned bufflen, 211 unsigned char *sense, struct scsi_sense_hdr *sshdr, 212 int timeout, int retries, u64 flags, req_flags_t rq_flags, 213 int *resid) 214 { 215 struct request *req; 216 struct scsi_request *rq; 217 int ret; 218 219 req = scsi_alloc_request(sdev->request_queue, 220 data_direction == DMA_TO_DEVICE ? 221 REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 222 rq_flags & RQF_PM ? BLK_MQ_REQ_PM : 0); 223 if (IS_ERR(req)) 224 return PTR_ERR(req); 225 226 rq = scsi_req(req); 227 228 if (bufflen) { 229 ret = blk_rq_map_kern(sdev->request_queue, req, 230 buffer, bufflen, GFP_NOIO); 231 if (ret) 232 goto out; 233 } 234 rq->cmd_len = COMMAND_SIZE(cmd[0]); 235 memcpy(rq->cmd, cmd, rq->cmd_len); 236 rq->retries = retries; 237 req->timeout = timeout; 238 req->cmd_flags |= flags; 239 req->rq_flags |= rq_flags | RQF_QUIET; 240 241 /* 242 * head injection *required* here otherwise quiesce won't work 243 */ 244 blk_execute_rq(req, true); 245 246 /* 247 * Some devices (USB mass-storage in particular) may transfer 248 * garbage data together with a residue indicating that the data 249 * is invalid. Prevent the garbage from being misinterpreted 250 * and prevent security leaks by zeroing out the excess data. 251 */ 252 if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen)) 253 memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len); 254 255 if (resid) 256 *resid = rq->resid_len; 257 if (sense && rq->sense_len) 258 memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE); 259 if (sshdr) 260 scsi_normalize_sense(rq->sense, rq->sense_len, sshdr); 261 ret = rq->result; 262 out: 263 blk_mq_free_request(req); 264 265 return ret; 266 } 267 EXPORT_SYMBOL(__scsi_execute); 268 269 /* 270 * Wake up the error handler if necessary. Avoid as follows that the error 271 * handler is not woken up if host in-flight requests number == 272 * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination 273 * with an RCU read lock in this function to ensure that this function in 274 * its entirety either finishes before scsi_eh_scmd_add() increases the 275 * host_failed counter or that it notices the shost state change made by 276 * scsi_eh_scmd_add(). 277 */ 278 static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd) 279 { 280 unsigned long flags; 281 282 rcu_read_lock(); 283 __clear_bit(SCMD_STATE_INFLIGHT, &cmd->state); 284 if (unlikely(scsi_host_in_recovery(shost))) { 285 spin_lock_irqsave(shost->host_lock, flags); 286 if (shost->host_failed || shost->host_eh_scheduled) 287 scsi_eh_wakeup(shost); 288 spin_unlock_irqrestore(shost->host_lock, flags); 289 } 290 rcu_read_unlock(); 291 } 292 293 void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd) 294 { 295 struct Scsi_Host *shost = sdev->host; 296 struct scsi_target *starget = scsi_target(sdev); 297 298 scsi_dec_host_busy(shost, cmd); 299 300 if (starget->can_queue > 0) 301 atomic_dec(&starget->target_busy); 302 303 sbitmap_put(&sdev->budget_map, cmd->budget_token); 304 cmd->budget_token = -1; 305 } 306 307 static void scsi_kick_queue(struct request_queue *q) 308 { 309 blk_mq_run_hw_queues(q, false); 310 } 311 312 /* 313 * Called for single_lun devices on IO completion. Clear starget_sdev_user, 314 * and call blk_run_queue for all the scsi_devices on the target - 315 * including current_sdev first. 316 * 317 * Called with *no* scsi locks held. 318 */ 319 static void scsi_single_lun_run(struct scsi_device *current_sdev) 320 { 321 struct Scsi_Host *shost = current_sdev->host; 322 struct scsi_device *sdev, *tmp; 323 struct scsi_target *starget = scsi_target(current_sdev); 324 unsigned long flags; 325 326 spin_lock_irqsave(shost->host_lock, flags); 327 starget->starget_sdev_user = NULL; 328 spin_unlock_irqrestore(shost->host_lock, flags); 329 330 /* 331 * Call blk_run_queue for all LUNs on the target, starting with 332 * current_sdev. We race with others (to set starget_sdev_user), 333 * but in most cases, we will be first. Ideally, each LU on the 334 * target would get some limited time or requests on the target. 335 */ 336 scsi_kick_queue(current_sdev->request_queue); 337 338 spin_lock_irqsave(shost->host_lock, flags); 339 if (starget->starget_sdev_user) 340 goto out; 341 list_for_each_entry_safe(sdev, tmp, &starget->devices, 342 same_target_siblings) { 343 if (sdev == current_sdev) 344 continue; 345 if (scsi_device_get(sdev)) 346 continue; 347 348 spin_unlock_irqrestore(shost->host_lock, flags); 349 scsi_kick_queue(sdev->request_queue); 350 spin_lock_irqsave(shost->host_lock, flags); 351 352 scsi_device_put(sdev); 353 } 354 out: 355 spin_unlock_irqrestore(shost->host_lock, flags); 356 } 357 358 static inline bool scsi_device_is_busy(struct scsi_device *sdev) 359 { 360 if (scsi_device_busy(sdev) >= sdev->queue_depth) 361 return true; 362 if (atomic_read(&sdev->device_blocked) > 0) 363 return true; 364 return false; 365 } 366 367 static inline bool scsi_target_is_busy(struct scsi_target *starget) 368 { 369 if (starget->can_queue > 0) { 370 if (atomic_read(&starget->target_busy) >= starget->can_queue) 371 return true; 372 if (atomic_read(&starget->target_blocked) > 0) 373 return true; 374 } 375 return false; 376 } 377 378 static inline bool scsi_host_is_busy(struct Scsi_Host *shost) 379 { 380 if (atomic_read(&shost->host_blocked) > 0) 381 return true; 382 if (shost->host_self_blocked) 383 return true; 384 return false; 385 } 386 387 static void scsi_starved_list_run(struct Scsi_Host *shost) 388 { 389 LIST_HEAD(starved_list); 390 struct scsi_device *sdev; 391 unsigned long flags; 392 393 spin_lock_irqsave(shost->host_lock, flags); 394 list_splice_init(&shost->starved_list, &starved_list); 395 396 while (!list_empty(&starved_list)) { 397 struct request_queue *slq; 398 399 /* 400 * As long as shost is accepting commands and we have 401 * starved queues, call blk_run_queue. scsi_request_fn 402 * drops the queue_lock and can add us back to the 403 * starved_list. 404 * 405 * host_lock protects the starved_list and starved_entry. 406 * scsi_request_fn must get the host_lock before checking 407 * or modifying starved_list or starved_entry. 408 */ 409 if (scsi_host_is_busy(shost)) 410 break; 411 412 sdev = list_entry(starved_list.next, 413 struct scsi_device, starved_entry); 414 list_del_init(&sdev->starved_entry); 415 if (scsi_target_is_busy(scsi_target(sdev))) { 416 list_move_tail(&sdev->starved_entry, 417 &shost->starved_list); 418 continue; 419 } 420 421 /* 422 * Once we drop the host lock, a racing scsi_remove_device() 423 * call may remove the sdev from the starved list and destroy 424 * it and the queue. Mitigate by taking a reference to the 425 * queue and never touching the sdev again after we drop the 426 * host lock. Note: if __scsi_remove_device() invokes 427 * blk_cleanup_queue() before the queue is run from this 428 * function then blk_run_queue() will return immediately since 429 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING. 430 */ 431 slq = sdev->request_queue; 432 if (!blk_get_queue(slq)) 433 continue; 434 spin_unlock_irqrestore(shost->host_lock, flags); 435 436 scsi_kick_queue(slq); 437 blk_put_queue(slq); 438 439 spin_lock_irqsave(shost->host_lock, flags); 440 } 441 /* put any unprocessed entries back */ 442 list_splice(&starved_list, &shost->starved_list); 443 spin_unlock_irqrestore(shost->host_lock, flags); 444 } 445 446 /** 447 * scsi_run_queue - Select a proper request queue to serve next. 448 * @q: last request's queue 449 * 450 * The previous command was completely finished, start a new one if possible. 451 */ 452 static void scsi_run_queue(struct request_queue *q) 453 { 454 struct scsi_device *sdev = q->queuedata; 455 456 if (scsi_target(sdev)->single_lun) 457 scsi_single_lun_run(sdev); 458 if (!list_empty(&sdev->host->starved_list)) 459 scsi_starved_list_run(sdev->host); 460 461 blk_mq_run_hw_queues(q, false); 462 } 463 464 void scsi_requeue_run_queue(struct work_struct *work) 465 { 466 struct scsi_device *sdev; 467 struct request_queue *q; 468 469 sdev = container_of(work, struct scsi_device, requeue_work); 470 q = sdev->request_queue; 471 scsi_run_queue(q); 472 } 473 474 void scsi_run_host_queues(struct Scsi_Host *shost) 475 { 476 struct scsi_device *sdev; 477 478 shost_for_each_device(sdev, shost) 479 scsi_run_queue(sdev->request_queue); 480 } 481 482 static void scsi_uninit_cmd(struct scsi_cmnd *cmd) 483 { 484 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) { 485 struct scsi_driver *drv = scsi_cmd_to_driver(cmd); 486 487 if (drv->uninit_command) 488 drv->uninit_command(cmd); 489 } 490 } 491 492 void scsi_free_sgtables(struct scsi_cmnd *cmd) 493 { 494 if (cmd->sdb.table.nents) 495 sg_free_table_chained(&cmd->sdb.table, 496 SCSI_INLINE_SG_CNT); 497 if (scsi_prot_sg_count(cmd)) 498 sg_free_table_chained(&cmd->prot_sdb->table, 499 SCSI_INLINE_PROT_SG_CNT); 500 } 501 EXPORT_SYMBOL_GPL(scsi_free_sgtables); 502 503 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd) 504 { 505 scsi_free_sgtables(cmd); 506 scsi_uninit_cmd(cmd); 507 } 508 509 static void scsi_run_queue_async(struct scsi_device *sdev) 510 { 511 if (scsi_target(sdev)->single_lun || 512 !list_empty(&sdev->host->starved_list)) { 513 kblockd_schedule_work(&sdev->requeue_work); 514 } else { 515 /* 516 * smp_mb() present in sbitmap_queue_clear() or implied in 517 * .end_io is for ordering writing .device_busy in 518 * scsi_device_unbusy() and reading sdev->restarts. 519 */ 520 int old = atomic_read(&sdev->restarts); 521 522 /* 523 * ->restarts has to be kept as non-zero if new budget 524 * contention occurs. 525 * 526 * No need to run queue when either another re-run 527 * queue wins in updating ->restarts or a new budget 528 * contention occurs. 529 */ 530 if (old && atomic_cmpxchg(&sdev->restarts, old, 0) == old) 531 blk_mq_run_hw_queues(sdev->request_queue, true); 532 } 533 } 534 535 /* Returns false when no more bytes to process, true if there are more */ 536 static bool scsi_end_request(struct request *req, blk_status_t error, 537 unsigned int bytes) 538 { 539 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 540 struct scsi_device *sdev = cmd->device; 541 struct request_queue *q = sdev->request_queue; 542 543 if (blk_update_request(req, error, bytes)) 544 return true; 545 546 // XXX: 547 if (blk_queue_add_random(q)) 548 add_disk_randomness(req->q->disk); 549 550 if (!blk_rq_is_passthrough(req)) { 551 WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED)); 552 cmd->flags &= ~SCMD_INITIALIZED; 553 } 554 555 /* 556 * Calling rcu_barrier() is not necessary here because the 557 * SCSI error handler guarantees that the function called by 558 * call_rcu() has been called before scsi_end_request() is 559 * called. 560 */ 561 destroy_rcu_head(&cmd->rcu); 562 563 /* 564 * In the MQ case the command gets freed by __blk_mq_end_request, 565 * so we have to do all cleanup that depends on it earlier. 566 * 567 * We also can't kick the queues from irq context, so we 568 * will have to defer it to a workqueue. 569 */ 570 scsi_mq_uninit_cmd(cmd); 571 572 /* 573 * queue is still alive, so grab the ref for preventing it 574 * from being cleaned up during running queue. 575 */ 576 percpu_ref_get(&q->q_usage_counter); 577 578 __blk_mq_end_request(req, error); 579 580 scsi_run_queue_async(sdev); 581 582 percpu_ref_put(&q->q_usage_counter); 583 return false; 584 } 585 586 /** 587 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t 588 * @cmd: SCSI command 589 * @result: scsi error code 590 * 591 * Translate a SCSI result code into a blk_status_t value. May reset the host 592 * byte of @cmd->result. 593 */ 594 static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result) 595 { 596 switch (host_byte(result)) { 597 case DID_OK: 598 if (scsi_status_is_good(result)) 599 return BLK_STS_OK; 600 return BLK_STS_IOERR; 601 case DID_TRANSPORT_FAILFAST: 602 case DID_TRANSPORT_MARGINAL: 603 return BLK_STS_TRANSPORT; 604 case DID_TARGET_FAILURE: 605 set_host_byte(cmd, DID_OK); 606 return BLK_STS_TARGET; 607 case DID_NEXUS_FAILURE: 608 set_host_byte(cmd, DID_OK); 609 return BLK_STS_NEXUS; 610 case DID_ALLOC_FAILURE: 611 set_host_byte(cmd, DID_OK); 612 return BLK_STS_NOSPC; 613 case DID_MEDIUM_ERROR: 614 set_host_byte(cmd, DID_OK); 615 return BLK_STS_MEDIUM; 616 default: 617 return BLK_STS_IOERR; 618 } 619 } 620 621 /** 622 * scsi_rq_err_bytes - determine number of bytes till the next failure boundary 623 * @rq: request to examine 624 * 625 * Description: 626 * A request could be merge of IOs which require different failure 627 * handling. This function determines the number of bytes which 628 * can be failed from the beginning of the request without 629 * crossing into area which need to be retried further. 630 * 631 * Return: 632 * The number of bytes to fail. 633 */ 634 static unsigned int scsi_rq_err_bytes(const struct request *rq) 635 { 636 unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; 637 unsigned int bytes = 0; 638 struct bio *bio; 639 640 if (!(rq->rq_flags & RQF_MIXED_MERGE)) 641 return blk_rq_bytes(rq); 642 643 /* 644 * Currently the only 'mixing' which can happen is between 645 * different fastfail types. We can safely fail portions 646 * which have all the failfast bits that the first one has - 647 * the ones which are at least as eager to fail as the first 648 * one. 649 */ 650 for (bio = rq->bio; bio; bio = bio->bi_next) { 651 if ((bio->bi_opf & ff) != ff) 652 break; 653 bytes += bio->bi_iter.bi_size; 654 } 655 656 /* this could lead to infinite loop */ 657 BUG_ON(blk_rq_bytes(rq) && !bytes); 658 return bytes; 659 } 660 661 /* Helper for scsi_io_completion() when "reprep" action required. */ 662 static void scsi_io_completion_reprep(struct scsi_cmnd *cmd, 663 struct request_queue *q) 664 { 665 /* A new command will be prepared and issued. */ 666 scsi_mq_requeue_cmd(cmd); 667 } 668 669 static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd) 670 { 671 struct request *req = scsi_cmd_to_rq(cmd); 672 unsigned long wait_for; 673 674 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT) 675 return false; 676 677 wait_for = (cmd->allowed + 1) * req->timeout; 678 if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { 679 scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n", 680 wait_for/HZ); 681 return true; 682 } 683 return false; 684 } 685 686 /* Helper for scsi_io_completion() when special action required. */ 687 static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result) 688 { 689 struct request_queue *q = cmd->device->request_queue; 690 struct request *req = scsi_cmd_to_rq(cmd); 691 int level = 0; 692 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY, 693 ACTION_DELAYED_RETRY} action; 694 struct scsi_sense_hdr sshdr; 695 bool sense_valid; 696 bool sense_current = true; /* false implies "deferred sense" */ 697 blk_status_t blk_stat; 698 699 sense_valid = scsi_command_normalize_sense(cmd, &sshdr); 700 if (sense_valid) 701 sense_current = !scsi_sense_is_deferred(&sshdr); 702 703 blk_stat = scsi_result_to_blk_status(cmd, result); 704 705 if (host_byte(result) == DID_RESET) { 706 /* Third party bus reset or reset for error recovery 707 * reasons. Just retry the command and see what 708 * happens. 709 */ 710 action = ACTION_RETRY; 711 } else if (sense_valid && sense_current) { 712 switch (sshdr.sense_key) { 713 case UNIT_ATTENTION: 714 if (cmd->device->removable) { 715 /* Detected disc change. Set a bit 716 * and quietly refuse further access. 717 */ 718 cmd->device->changed = 1; 719 action = ACTION_FAIL; 720 } else { 721 /* Must have been a power glitch, or a 722 * bus reset. Could not have been a 723 * media change, so we just retry the 724 * command and see what happens. 725 */ 726 action = ACTION_RETRY; 727 } 728 break; 729 case ILLEGAL_REQUEST: 730 /* If we had an ILLEGAL REQUEST returned, then 731 * we may have performed an unsupported 732 * command. The only thing this should be 733 * would be a ten byte read where only a six 734 * byte read was supported. Also, on a system 735 * where READ CAPACITY failed, we may have 736 * read past the end of the disk. 737 */ 738 if ((cmd->device->use_10_for_rw && 739 sshdr.asc == 0x20 && sshdr.ascq == 0x00) && 740 (cmd->cmnd[0] == READ_10 || 741 cmd->cmnd[0] == WRITE_10)) { 742 /* This will issue a new 6-byte command. */ 743 cmd->device->use_10_for_rw = 0; 744 action = ACTION_REPREP; 745 } else if (sshdr.asc == 0x10) /* DIX */ { 746 action = ACTION_FAIL; 747 blk_stat = BLK_STS_PROTECTION; 748 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */ 749 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) { 750 action = ACTION_FAIL; 751 blk_stat = BLK_STS_TARGET; 752 } else 753 action = ACTION_FAIL; 754 break; 755 case ABORTED_COMMAND: 756 action = ACTION_FAIL; 757 if (sshdr.asc == 0x10) /* DIF */ 758 blk_stat = BLK_STS_PROTECTION; 759 break; 760 case NOT_READY: 761 /* If the device is in the process of becoming 762 * ready, or has a temporary blockage, retry. 763 */ 764 if (sshdr.asc == 0x04) { 765 switch (sshdr.ascq) { 766 case 0x01: /* becoming ready */ 767 case 0x04: /* format in progress */ 768 case 0x05: /* rebuild in progress */ 769 case 0x06: /* recalculation in progress */ 770 case 0x07: /* operation in progress */ 771 case 0x08: /* Long write in progress */ 772 case 0x09: /* self test in progress */ 773 case 0x11: /* notify (enable spinup) required */ 774 case 0x14: /* space allocation in progress */ 775 case 0x1a: /* start stop unit in progress */ 776 case 0x1b: /* sanitize in progress */ 777 case 0x1d: /* configuration in progress */ 778 case 0x24: /* depopulation in progress */ 779 action = ACTION_DELAYED_RETRY; 780 break; 781 case 0x0a: /* ALUA state transition */ 782 blk_stat = BLK_STS_AGAIN; 783 fallthrough; 784 default: 785 action = ACTION_FAIL; 786 break; 787 } 788 } else 789 action = ACTION_FAIL; 790 break; 791 case VOLUME_OVERFLOW: 792 /* See SSC3rXX or current. */ 793 action = ACTION_FAIL; 794 break; 795 case DATA_PROTECT: 796 action = ACTION_FAIL; 797 if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) || 798 (sshdr.asc == 0x55 && 799 (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) { 800 /* Insufficient zone resources */ 801 blk_stat = BLK_STS_ZONE_OPEN_RESOURCE; 802 } 803 break; 804 default: 805 action = ACTION_FAIL; 806 break; 807 } 808 } else 809 action = ACTION_FAIL; 810 811 if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd)) 812 action = ACTION_FAIL; 813 814 switch (action) { 815 case ACTION_FAIL: 816 /* Give up and fail the remainder of the request */ 817 if (!(req->rq_flags & RQF_QUIET)) { 818 static DEFINE_RATELIMIT_STATE(_rs, 819 DEFAULT_RATELIMIT_INTERVAL, 820 DEFAULT_RATELIMIT_BURST); 821 822 if (unlikely(scsi_logging_level)) 823 level = 824 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT, 825 SCSI_LOG_MLCOMPLETE_BITS); 826 827 /* 828 * if logging is enabled the failure will be printed 829 * in scsi_log_completion(), so avoid duplicate messages 830 */ 831 if (!level && __ratelimit(&_rs)) { 832 scsi_print_result(cmd, NULL, FAILED); 833 if (sense_valid) 834 scsi_print_sense(cmd); 835 scsi_print_command(cmd); 836 } 837 } 838 if (!scsi_end_request(req, blk_stat, scsi_rq_err_bytes(req))) 839 return; 840 fallthrough; 841 case ACTION_REPREP: 842 scsi_io_completion_reprep(cmd, q); 843 break; 844 case ACTION_RETRY: 845 /* Retry the same command immediately */ 846 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false); 847 break; 848 case ACTION_DELAYED_RETRY: 849 /* Retry the same command after a delay */ 850 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false); 851 break; 852 } 853 } 854 855 /* 856 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a 857 * new result that may suppress further error checking. Also modifies 858 * *blk_statp in some cases. 859 */ 860 static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result, 861 blk_status_t *blk_statp) 862 { 863 bool sense_valid; 864 bool sense_current = true; /* false implies "deferred sense" */ 865 struct request *req = scsi_cmd_to_rq(cmd); 866 struct scsi_sense_hdr sshdr; 867 868 sense_valid = scsi_command_normalize_sense(cmd, &sshdr); 869 if (sense_valid) 870 sense_current = !scsi_sense_is_deferred(&sshdr); 871 872 if (blk_rq_is_passthrough(req)) { 873 if (sense_valid) { 874 /* 875 * SG_IO wants current and deferred errors 876 */ 877 scsi_req(req)->sense_len = 878 min(8 + cmd->sense_buffer[7], 879 SCSI_SENSE_BUFFERSIZE); 880 } 881 if (sense_current) 882 *blk_statp = scsi_result_to_blk_status(cmd, result); 883 } else if (blk_rq_bytes(req) == 0 && sense_current) { 884 /* 885 * Flush commands do not transfers any data, and thus cannot use 886 * good_bytes != blk_rq_bytes(req) as the signal for an error. 887 * This sets *blk_statp explicitly for the problem case. 888 */ 889 *blk_statp = scsi_result_to_blk_status(cmd, result); 890 } 891 /* 892 * Recovered errors need reporting, but they're always treated as 893 * success, so fiddle the result code here. For passthrough requests 894 * we already took a copy of the original into sreq->result which 895 * is what gets returned to the user 896 */ 897 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) { 898 bool do_print = true; 899 /* 900 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d] 901 * skip print since caller wants ATA registers. Only occurs 902 * on SCSI ATA PASS_THROUGH commands when CK_COND=1 903 */ 904 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d)) 905 do_print = false; 906 else if (req->rq_flags & RQF_QUIET) 907 do_print = false; 908 if (do_print) 909 scsi_print_sense(cmd); 910 result = 0; 911 /* for passthrough, *blk_statp may be set */ 912 *blk_statp = BLK_STS_OK; 913 } 914 /* 915 * Another corner case: the SCSI status byte is non-zero but 'good'. 916 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when 917 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD 918 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related 919 * intermediate statuses (both obsolete in SAM-4) as good. 920 */ 921 if ((result & 0xff) && scsi_status_is_good(result)) { 922 result = 0; 923 *blk_statp = BLK_STS_OK; 924 } 925 return result; 926 } 927 928 /** 929 * scsi_io_completion - Completion processing for SCSI commands. 930 * @cmd: command that is finished. 931 * @good_bytes: number of processed bytes. 932 * 933 * We will finish off the specified number of sectors. If we are done, the 934 * command block will be released and the queue function will be goosed. If we 935 * are not done then we have to figure out what to do next: 936 * 937 * a) We can call scsi_io_completion_reprep(). The request will be 938 * unprepared and put back on the queue. Then a new command will 939 * be created for it. This should be used if we made forward 940 * progress, or if we want to switch from READ(10) to READ(6) for 941 * example. 942 * 943 * b) We can call scsi_io_completion_action(). The request will be 944 * put back on the queue and retried using the same command as 945 * before, possibly after a delay. 946 * 947 * c) We can call scsi_end_request() with blk_stat other than 948 * BLK_STS_OK, to fail the remainder of the request. 949 */ 950 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) 951 { 952 int result = cmd->result; 953 struct request_queue *q = cmd->device->request_queue; 954 struct request *req = scsi_cmd_to_rq(cmd); 955 blk_status_t blk_stat = BLK_STS_OK; 956 957 if (unlikely(result)) /* a nz result may or may not be an error */ 958 result = scsi_io_completion_nz_result(cmd, result, &blk_stat); 959 960 if (unlikely(blk_rq_is_passthrough(req))) { 961 /* 962 * scsi_result_to_blk_status may have reset the host_byte 963 */ 964 scsi_req(req)->result = cmd->result; 965 } 966 967 /* 968 * Next deal with any sectors which we were able to correctly 969 * handle. 970 */ 971 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd, 972 "%u sectors total, %d bytes done.\n", 973 blk_rq_sectors(req), good_bytes)); 974 975 /* 976 * Failed, zero length commands always need to drop down 977 * to retry code. Fast path should return in this block. 978 */ 979 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) { 980 if (likely(!scsi_end_request(req, blk_stat, good_bytes))) 981 return; /* no bytes remaining */ 982 } 983 984 /* Kill remainder if no retries. */ 985 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) { 986 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req))) 987 WARN_ONCE(true, 988 "Bytes remaining after failed, no-retry command"); 989 return; 990 } 991 992 /* 993 * If there had been no error, but we have leftover bytes in the 994 * request just queue the command up again. 995 */ 996 if (likely(result == 0)) 997 scsi_io_completion_reprep(cmd, q); 998 else 999 scsi_io_completion_action(cmd, result); 1000 } 1001 1002 static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev, 1003 struct request *rq) 1004 { 1005 return sdev->dma_drain_len && blk_rq_is_passthrough(rq) && 1006 !op_is_write(req_op(rq)) && 1007 sdev->host->hostt->dma_need_drain(rq); 1008 } 1009 1010 /** 1011 * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists 1012 * @cmd: SCSI command data structure to initialize. 1013 * 1014 * Initializes @cmd->sdb and also @cmd->prot_sdb if data integrity is enabled 1015 * for @cmd. 1016 * 1017 * Returns: 1018 * * BLK_STS_OK - on success 1019 * * BLK_STS_RESOURCE - if the failure is retryable 1020 * * BLK_STS_IOERR - if the failure is fatal 1021 */ 1022 blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd) 1023 { 1024 struct scsi_device *sdev = cmd->device; 1025 struct request *rq = scsi_cmd_to_rq(cmd); 1026 unsigned short nr_segs = blk_rq_nr_phys_segments(rq); 1027 struct scatterlist *last_sg = NULL; 1028 blk_status_t ret; 1029 bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq); 1030 int count; 1031 1032 if (WARN_ON_ONCE(!nr_segs)) 1033 return BLK_STS_IOERR; 1034 1035 /* 1036 * Make sure there is space for the drain. The driver must adjust 1037 * max_hw_segments to be prepared for this. 1038 */ 1039 if (need_drain) 1040 nr_segs++; 1041 1042 /* 1043 * If sg table allocation fails, requeue request later. 1044 */ 1045 if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs, 1046 cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT))) 1047 return BLK_STS_RESOURCE; 1048 1049 /* 1050 * Next, walk the list, and fill in the addresses and sizes of 1051 * each segment. 1052 */ 1053 count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg); 1054 1055 if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) { 1056 unsigned int pad_len = 1057 (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1; 1058 1059 last_sg->length += pad_len; 1060 cmd->extra_len += pad_len; 1061 } 1062 1063 if (need_drain) { 1064 sg_unmark_end(last_sg); 1065 last_sg = sg_next(last_sg); 1066 sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len); 1067 sg_mark_end(last_sg); 1068 1069 cmd->extra_len += sdev->dma_drain_len; 1070 count++; 1071 } 1072 1073 BUG_ON(count > cmd->sdb.table.nents); 1074 cmd->sdb.table.nents = count; 1075 cmd->sdb.length = blk_rq_payload_bytes(rq); 1076 1077 if (blk_integrity_rq(rq)) { 1078 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb; 1079 int ivecs; 1080 1081 if (WARN_ON_ONCE(!prot_sdb)) { 1082 /* 1083 * This can happen if someone (e.g. multipath) 1084 * queues a command to a device on an adapter 1085 * that does not support DIX. 1086 */ 1087 ret = BLK_STS_IOERR; 1088 goto out_free_sgtables; 1089 } 1090 1091 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio); 1092 1093 if (sg_alloc_table_chained(&prot_sdb->table, ivecs, 1094 prot_sdb->table.sgl, 1095 SCSI_INLINE_PROT_SG_CNT)) { 1096 ret = BLK_STS_RESOURCE; 1097 goto out_free_sgtables; 1098 } 1099 1100 count = blk_rq_map_integrity_sg(rq->q, rq->bio, 1101 prot_sdb->table.sgl); 1102 BUG_ON(count > ivecs); 1103 BUG_ON(count > queue_max_integrity_segments(rq->q)); 1104 1105 cmd->prot_sdb = prot_sdb; 1106 cmd->prot_sdb->table.nents = count; 1107 } 1108 1109 return BLK_STS_OK; 1110 out_free_sgtables: 1111 scsi_free_sgtables(cmd); 1112 return ret; 1113 } 1114 EXPORT_SYMBOL(scsi_alloc_sgtables); 1115 1116 /** 1117 * scsi_initialize_rq - initialize struct scsi_cmnd partially 1118 * @rq: Request associated with the SCSI command to be initialized. 1119 * 1120 * This function initializes the members of struct scsi_cmnd that must be 1121 * initialized before request processing starts and that won't be 1122 * reinitialized if a SCSI command is requeued. 1123 */ 1124 static void scsi_initialize_rq(struct request *rq) 1125 { 1126 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); 1127 struct scsi_request *req = &cmd->req; 1128 1129 memset(req->__cmd, 0, sizeof(req->__cmd)); 1130 req->cmd = req->__cmd; 1131 req->cmd_len = BLK_MAX_CDB; 1132 req->sense_len = 0; 1133 1134 init_rcu_head(&cmd->rcu); 1135 cmd->jiffies_at_alloc = jiffies; 1136 cmd->retries = 0; 1137 } 1138 1139 struct request *scsi_alloc_request(struct request_queue *q, 1140 unsigned int op, blk_mq_req_flags_t flags) 1141 { 1142 struct request *rq; 1143 1144 rq = blk_mq_alloc_request(q, op, flags); 1145 if (!IS_ERR(rq)) 1146 scsi_initialize_rq(rq); 1147 return rq; 1148 } 1149 EXPORT_SYMBOL_GPL(scsi_alloc_request); 1150 1151 /* 1152 * Only called when the request isn't completed by SCSI, and not freed by 1153 * SCSI 1154 */ 1155 static void scsi_cleanup_rq(struct request *rq) 1156 { 1157 if (rq->rq_flags & RQF_DONTPREP) { 1158 scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq)); 1159 rq->rq_flags &= ~RQF_DONTPREP; 1160 } 1161 } 1162 1163 /* Called before a request is prepared. See also scsi_mq_prep_fn(). */ 1164 void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd) 1165 { 1166 void *buf = cmd->sense_buffer; 1167 void *prot = cmd->prot_sdb; 1168 struct request *rq = scsi_cmd_to_rq(cmd); 1169 unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS; 1170 unsigned long jiffies_at_alloc; 1171 int retries, to_clear; 1172 bool in_flight; 1173 int budget_token = cmd->budget_token; 1174 1175 if (!blk_rq_is_passthrough(rq) && !(flags & SCMD_INITIALIZED)) { 1176 flags |= SCMD_INITIALIZED; 1177 scsi_initialize_rq(rq); 1178 } 1179 1180 jiffies_at_alloc = cmd->jiffies_at_alloc; 1181 retries = cmd->retries; 1182 in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state); 1183 /* 1184 * Zero out the cmd, except for the embedded scsi_request. Only clear 1185 * the driver-private command data if the LLD does not supply a 1186 * function to initialize that data. 1187 */ 1188 to_clear = sizeof(*cmd) - sizeof(cmd->req); 1189 if (!dev->host->hostt->init_cmd_priv) 1190 to_clear += dev->host->hostt->cmd_size; 1191 memset((char *)cmd + sizeof(cmd->req), 0, to_clear); 1192 1193 cmd->device = dev; 1194 cmd->sense_buffer = buf; 1195 cmd->prot_sdb = prot; 1196 cmd->flags = flags; 1197 INIT_LIST_HEAD(&cmd->eh_entry); 1198 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler); 1199 cmd->jiffies_at_alloc = jiffies_at_alloc; 1200 cmd->retries = retries; 1201 if (in_flight) 1202 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state); 1203 cmd->budget_token = budget_token; 1204 1205 } 1206 1207 static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev, 1208 struct request *req) 1209 { 1210 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 1211 1212 /* 1213 * Passthrough requests may transfer data, in which case they must 1214 * a bio attached to them. Or they might contain a SCSI command 1215 * that does not transfer data, in which case they may optionally 1216 * submit a request without an attached bio. 1217 */ 1218 if (req->bio) { 1219 blk_status_t ret = scsi_alloc_sgtables(cmd); 1220 if (unlikely(ret != BLK_STS_OK)) 1221 return ret; 1222 } else { 1223 BUG_ON(blk_rq_bytes(req)); 1224 1225 memset(&cmd->sdb, 0, sizeof(cmd->sdb)); 1226 } 1227 1228 cmd->cmd_len = scsi_req(req)->cmd_len; 1229 cmd->cmnd = scsi_req(req)->cmd; 1230 cmd->transfersize = blk_rq_bytes(req); 1231 cmd->allowed = scsi_req(req)->retries; 1232 return BLK_STS_OK; 1233 } 1234 1235 static blk_status_t 1236 scsi_device_state_check(struct scsi_device *sdev, struct request *req) 1237 { 1238 switch (sdev->sdev_state) { 1239 case SDEV_CREATED: 1240 return BLK_STS_OK; 1241 case SDEV_OFFLINE: 1242 case SDEV_TRANSPORT_OFFLINE: 1243 /* 1244 * If the device is offline we refuse to process any 1245 * commands. The device must be brought online 1246 * before trying any recovery commands. 1247 */ 1248 if (!sdev->offline_already) { 1249 sdev->offline_already = true; 1250 sdev_printk(KERN_ERR, sdev, 1251 "rejecting I/O to offline device\n"); 1252 } 1253 return BLK_STS_IOERR; 1254 case SDEV_DEL: 1255 /* 1256 * If the device is fully deleted, we refuse to 1257 * process any commands as well. 1258 */ 1259 sdev_printk(KERN_ERR, sdev, 1260 "rejecting I/O to dead device\n"); 1261 return BLK_STS_IOERR; 1262 case SDEV_BLOCK: 1263 case SDEV_CREATED_BLOCK: 1264 return BLK_STS_RESOURCE; 1265 case SDEV_QUIESCE: 1266 /* 1267 * If the device is blocked we only accept power management 1268 * commands. 1269 */ 1270 if (req && WARN_ON_ONCE(!(req->rq_flags & RQF_PM))) 1271 return BLK_STS_RESOURCE; 1272 return BLK_STS_OK; 1273 default: 1274 /* 1275 * For any other not fully online state we only allow 1276 * power management commands. 1277 */ 1278 if (req && !(req->rq_flags & RQF_PM)) 1279 return BLK_STS_IOERR; 1280 return BLK_STS_OK; 1281 } 1282 } 1283 1284 /* 1285 * scsi_dev_queue_ready: if we can send requests to sdev, assign one token 1286 * and return the token else return -1. 1287 */ 1288 static inline int scsi_dev_queue_ready(struct request_queue *q, 1289 struct scsi_device *sdev) 1290 { 1291 int token; 1292 1293 token = sbitmap_get(&sdev->budget_map); 1294 if (atomic_read(&sdev->device_blocked)) { 1295 if (token < 0) 1296 goto out; 1297 1298 if (scsi_device_busy(sdev) > 1) 1299 goto out_dec; 1300 1301 /* 1302 * unblock after device_blocked iterates to zero 1303 */ 1304 if (atomic_dec_return(&sdev->device_blocked) > 0) 1305 goto out_dec; 1306 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev, 1307 "unblocking device at zero depth\n")); 1308 } 1309 1310 return token; 1311 out_dec: 1312 if (token >= 0) 1313 sbitmap_put(&sdev->budget_map, token); 1314 out: 1315 return -1; 1316 } 1317 1318 /* 1319 * scsi_target_queue_ready: checks if there we can send commands to target 1320 * @sdev: scsi device on starget to check. 1321 */ 1322 static inline int scsi_target_queue_ready(struct Scsi_Host *shost, 1323 struct scsi_device *sdev) 1324 { 1325 struct scsi_target *starget = scsi_target(sdev); 1326 unsigned int busy; 1327 1328 if (starget->single_lun) { 1329 spin_lock_irq(shost->host_lock); 1330 if (starget->starget_sdev_user && 1331 starget->starget_sdev_user != sdev) { 1332 spin_unlock_irq(shost->host_lock); 1333 return 0; 1334 } 1335 starget->starget_sdev_user = sdev; 1336 spin_unlock_irq(shost->host_lock); 1337 } 1338 1339 if (starget->can_queue <= 0) 1340 return 1; 1341 1342 busy = atomic_inc_return(&starget->target_busy) - 1; 1343 if (atomic_read(&starget->target_blocked) > 0) { 1344 if (busy) 1345 goto starved; 1346 1347 /* 1348 * unblock after target_blocked iterates to zero 1349 */ 1350 if (atomic_dec_return(&starget->target_blocked) > 0) 1351 goto out_dec; 1352 1353 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget, 1354 "unblocking target at zero depth\n")); 1355 } 1356 1357 if (busy >= starget->can_queue) 1358 goto starved; 1359 1360 return 1; 1361 1362 starved: 1363 spin_lock_irq(shost->host_lock); 1364 list_move_tail(&sdev->starved_entry, &shost->starved_list); 1365 spin_unlock_irq(shost->host_lock); 1366 out_dec: 1367 if (starget->can_queue > 0) 1368 atomic_dec(&starget->target_busy); 1369 return 0; 1370 } 1371 1372 /* 1373 * scsi_host_queue_ready: if we can send requests to shost, return 1 else 1374 * return 0. We must end up running the queue again whenever 0 is 1375 * returned, else IO can hang. 1376 */ 1377 static inline int scsi_host_queue_ready(struct request_queue *q, 1378 struct Scsi_Host *shost, 1379 struct scsi_device *sdev, 1380 struct scsi_cmnd *cmd) 1381 { 1382 if (scsi_host_in_recovery(shost)) 1383 return 0; 1384 1385 if (atomic_read(&shost->host_blocked) > 0) { 1386 if (scsi_host_busy(shost) > 0) 1387 goto starved; 1388 1389 /* 1390 * unblock after host_blocked iterates to zero 1391 */ 1392 if (atomic_dec_return(&shost->host_blocked) > 0) 1393 goto out_dec; 1394 1395 SCSI_LOG_MLQUEUE(3, 1396 shost_printk(KERN_INFO, shost, 1397 "unblocking host at zero depth\n")); 1398 } 1399 1400 if (shost->host_self_blocked) 1401 goto starved; 1402 1403 /* We're OK to process the command, so we can't be starved */ 1404 if (!list_empty(&sdev->starved_entry)) { 1405 spin_lock_irq(shost->host_lock); 1406 if (!list_empty(&sdev->starved_entry)) 1407 list_del_init(&sdev->starved_entry); 1408 spin_unlock_irq(shost->host_lock); 1409 } 1410 1411 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state); 1412 1413 return 1; 1414 1415 starved: 1416 spin_lock_irq(shost->host_lock); 1417 if (list_empty(&sdev->starved_entry)) 1418 list_add_tail(&sdev->starved_entry, &shost->starved_list); 1419 spin_unlock_irq(shost->host_lock); 1420 out_dec: 1421 scsi_dec_host_busy(shost, cmd); 1422 return 0; 1423 } 1424 1425 /* 1426 * Busy state exporting function for request stacking drivers. 1427 * 1428 * For efficiency, no lock is taken to check the busy state of 1429 * shost/starget/sdev, since the returned value is not guaranteed and 1430 * may be changed after request stacking drivers call the function, 1431 * regardless of taking lock or not. 1432 * 1433 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi 1434 * needs to return 'not busy'. Otherwise, request stacking drivers 1435 * may hold requests forever. 1436 */ 1437 static bool scsi_mq_lld_busy(struct request_queue *q) 1438 { 1439 struct scsi_device *sdev = q->queuedata; 1440 struct Scsi_Host *shost; 1441 1442 if (blk_queue_dying(q)) 1443 return false; 1444 1445 shost = sdev->host; 1446 1447 /* 1448 * Ignore host/starget busy state. 1449 * Since block layer does not have a concept of fairness across 1450 * multiple queues, congestion of host/starget needs to be handled 1451 * in SCSI layer. 1452 */ 1453 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev)) 1454 return true; 1455 1456 return false; 1457 } 1458 1459 /* 1460 * Block layer request completion callback. May be called from interrupt 1461 * context. 1462 */ 1463 static void scsi_complete(struct request *rq) 1464 { 1465 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); 1466 enum scsi_disposition disposition; 1467 1468 INIT_LIST_HEAD(&cmd->eh_entry); 1469 1470 atomic_inc(&cmd->device->iodone_cnt); 1471 if (cmd->result) 1472 atomic_inc(&cmd->device->ioerr_cnt); 1473 1474 disposition = scsi_decide_disposition(cmd); 1475 if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd)) 1476 disposition = SUCCESS; 1477 1478 scsi_log_completion(cmd, disposition); 1479 1480 switch (disposition) { 1481 case SUCCESS: 1482 scsi_finish_command(cmd); 1483 break; 1484 case NEEDS_RETRY: 1485 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY); 1486 break; 1487 case ADD_TO_MLQUEUE: 1488 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); 1489 break; 1490 default: 1491 scsi_eh_scmd_add(cmd); 1492 break; 1493 } 1494 } 1495 1496 /** 1497 * scsi_dispatch_cmd - Dispatch a command to the low-level driver. 1498 * @cmd: command block we are dispatching. 1499 * 1500 * Return: nonzero return request was rejected and device's queue needs to be 1501 * plugged. 1502 */ 1503 static int scsi_dispatch_cmd(struct scsi_cmnd *cmd) 1504 { 1505 struct Scsi_Host *host = cmd->device->host; 1506 int rtn = 0; 1507 1508 atomic_inc(&cmd->device->iorequest_cnt); 1509 1510 /* check if the device is still usable */ 1511 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) { 1512 /* in SDEV_DEL we error all commands. DID_NO_CONNECT 1513 * returns an immediate error upwards, and signals 1514 * that the device is no longer present */ 1515 cmd->result = DID_NO_CONNECT << 16; 1516 goto done; 1517 } 1518 1519 /* Check to see if the scsi lld made this device blocked. */ 1520 if (unlikely(scsi_device_blocked(cmd->device))) { 1521 /* 1522 * in blocked state, the command is just put back on 1523 * the device queue. The suspend state has already 1524 * blocked the queue so future requests should not 1525 * occur until the device transitions out of the 1526 * suspend state. 1527 */ 1528 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, 1529 "queuecommand : device blocked\n")); 1530 return SCSI_MLQUEUE_DEVICE_BUSY; 1531 } 1532 1533 /* Store the LUN value in cmnd, if needed. */ 1534 if (cmd->device->lun_in_cdb) 1535 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) | 1536 (cmd->device->lun << 5 & 0xe0); 1537 1538 scsi_log_send(cmd); 1539 1540 /* 1541 * Before we queue this command, check if the command 1542 * length exceeds what the host adapter can handle. 1543 */ 1544 if (cmd->cmd_len > cmd->device->host->max_cmd_len) { 1545 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, 1546 "queuecommand : command too long. " 1547 "cdb_size=%d host->max_cmd_len=%d\n", 1548 cmd->cmd_len, cmd->device->host->max_cmd_len)); 1549 cmd->result = (DID_ABORT << 16); 1550 goto done; 1551 } 1552 1553 if (unlikely(host->shost_state == SHOST_DEL)) { 1554 cmd->result = (DID_NO_CONNECT << 16); 1555 goto done; 1556 1557 } 1558 1559 trace_scsi_dispatch_cmd_start(cmd); 1560 rtn = host->hostt->queuecommand(host, cmd); 1561 if (rtn) { 1562 trace_scsi_dispatch_cmd_error(cmd, rtn); 1563 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY && 1564 rtn != SCSI_MLQUEUE_TARGET_BUSY) 1565 rtn = SCSI_MLQUEUE_HOST_BUSY; 1566 1567 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, 1568 "queuecommand : request rejected\n")); 1569 } 1570 1571 return rtn; 1572 done: 1573 scsi_done(cmd); 1574 return 0; 1575 } 1576 1577 /* Size in bytes of the sg-list stored in the scsi-mq command-private data. */ 1578 static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost) 1579 { 1580 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) * 1581 sizeof(struct scatterlist); 1582 } 1583 1584 static blk_status_t scsi_prepare_cmd(struct request *req) 1585 { 1586 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 1587 struct scsi_device *sdev = req->q->queuedata; 1588 struct Scsi_Host *shost = sdev->host; 1589 struct scatterlist *sg; 1590 1591 scsi_init_command(sdev, cmd); 1592 1593 cmd->prot_op = SCSI_PROT_NORMAL; 1594 if (blk_rq_bytes(req)) 1595 cmd->sc_data_direction = rq_dma_dir(req); 1596 else 1597 cmd->sc_data_direction = DMA_NONE; 1598 1599 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size; 1600 cmd->sdb.table.sgl = sg; 1601 1602 if (scsi_host_get_prot(shost)) { 1603 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer)); 1604 1605 cmd->prot_sdb->table.sgl = 1606 (struct scatterlist *)(cmd->prot_sdb + 1); 1607 } 1608 1609 /* 1610 * Special handling for passthrough commands, which don't go to the ULP 1611 * at all: 1612 */ 1613 if (blk_rq_is_passthrough(req)) 1614 return scsi_setup_scsi_cmnd(sdev, req); 1615 1616 if (sdev->handler && sdev->handler->prep_fn) { 1617 blk_status_t ret = sdev->handler->prep_fn(sdev, req); 1618 1619 if (ret != BLK_STS_OK) 1620 return ret; 1621 } 1622 1623 cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd; 1624 memset(cmd->cmnd, 0, BLK_MAX_CDB); 1625 return scsi_cmd_to_driver(cmd)->init_command(cmd); 1626 } 1627 1628 void scsi_done(struct scsi_cmnd *cmd) 1629 { 1630 switch (cmd->submitter) { 1631 case SUBMITTED_BY_BLOCK_LAYER: 1632 break; 1633 case SUBMITTED_BY_SCSI_ERROR_HANDLER: 1634 return scsi_eh_done(cmd); 1635 case SUBMITTED_BY_SCSI_RESET_IOCTL: 1636 return; 1637 } 1638 1639 if (unlikely(blk_should_fake_timeout(scsi_cmd_to_rq(cmd)->q))) 1640 return; 1641 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state))) 1642 return; 1643 trace_scsi_dispatch_cmd_done(cmd); 1644 blk_mq_complete_request(scsi_cmd_to_rq(cmd)); 1645 } 1646 EXPORT_SYMBOL(scsi_done); 1647 1648 static void scsi_mq_put_budget(struct request_queue *q, int budget_token) 1649 { 1650 struct scsi_device *sdev = q->queuedata; 1651 1652 sbitmap_put(&sdev->budget_map, budget_token); 1653 } 1654 1655 static int scsi_mq_get_budget(struct request_queue *q) 1656 { 1657 struct scsi_device *sdev = q->queuedata; 1658 int token = scsi_dev_queue_ready(q, sdev); 1659 1660 if (token >= 0) 1661 return token; 1662 1663 atomic_inc(&sdev->restarts); 1664 1665 /* 1666 * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy). 1667 * .restarts must be incremented before .device_busy is read because the 1668 * code in scsi_run_queue_async() depends on the order of these operations. 1669 */ 1670 smp_mb__after_atomic(); 1671 1672 /* 1673 * If all in-flight requests originated from this LUN are completed 1674 * before reading .device_busy, sdev->device_busy will be observed as 1675 * zero, then blk_mq_delay_run_hw_queues() will dispatch this request 1676 * soon. Otherwise, completion of one of these requests will observe 1677 * the .restarts flag, and the request queue will be run for handling 1678 * this request, see scsi_end_request(). 1679 */ 1680 if (unlikely(scsi_device_busy(sdev) == 0 && 1681 !scsi_device_blocked(sdev))) 1682 blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY); 1683 return -1; 1684 } 1685 1686 static void scsi_mq_set_rq_budget_token(struct request *req, int token) 1687 { 1688 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 1689 1690 cmd->budget_token = token; 1691 } 1692 1693 static int scsi_mq_get_rq_budget_token(struct request *req) 1694 { 1695 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 1696 1697 return cmd->budget_token; 1698 } 1699 1700 static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx, 1701 const struct blk_mq_queue_data *bd) 1702 { 1703 struct request *req = bd->rq; 1704 struct request_queue *q = req->q; 1705 struct scsi_device *sdev = q->queuedata; 1706 struct Scsi_Host *shost = sdev->host; 1707 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 1708 blk_status_t ret; 1709 int reason; 1710 1711 WARN_ON_ONCE(cmd->budget_token < 0); 1712 1713 /* 1714 * If the device is not in running state we will reject some or all 1715 * commands. 1716 */ 1717 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { 1718 ret = scsi_device_state_check(sdev, req); 1719 if (ret != BLK_STS_OK) 1720 goto out_put_budget; 1721 } 1722 1723 ret = BLK_STS_RESOURCE; 1724 if (!scsi_target_queue_ready(shost, sdev)) 1725 goto out_put_budget; 1726 if (!scsi_host_queue_ready(q, shost, sdev, cmd)) 1727 goto out_dec_target_busy; 1728 1729 if (!(req->rq_flags & RQF_DONTPREP)) { 1730 ret = scsi_prepare_cmd(req); 1731 if (ret != BLK_STS_OK) 1732 goto out_dec_host_busy; 1733 req->rq_flags |= RQF_DONTPREP; 1734 } else { 1735 clear_bit(SCMD_STATE_COMPLETE, &cmd->state); 1736 } 1737 1738 cmd->flags &= SCMD_PRESERVED_FLAGS; 1739 if (sdev->simple_tags) 1740 cmd->flags |= SCMD_TAGGED; 1741 if (bd->last) 1742 cmd->flags |= SCMD_LAST; 1743 1744 scsi_set_resid(cmd, 0); 1745 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE); 1746 cmd->submitter = SUBMITTED_BY_BLOCK_LAYER; 1747 1748 blk_mq_start_request(req); 1749 reason = scsi_dispatch_cmd(cmd); 1750 if (reason) { 1751 scsi_set_blocked(cmd, reason); 1752 ret = BLK_STS_RESOURCE; 1753 goto out_dec_host_busy; 1754 } 1755 1756 return BLK_STS_OK; 1757 1758 out_dec_host_busy: 1759 scsi_dec_host_busy(shost, cmd); 1760 out_dec_target_busy: 1761 if (scsi_target(sdev)->can_queue > 0) 1762 atomic_dec(&scsi_target(sdev)->target_busy); 1763 out_put_budget: 1764 scsi_mq_put_budget(q, cmd->budget_token); 1765 cmd->budget_token = -1; 1766 switch (ret) { 1767 case BLK_STS_OK: 1768 break; 1769 case BLK_STS_RESOURCE: 1770 case BLK_STS_ZONE_RESOURCE: 1771 if (scsi_device_blocked(sdev)) 1772 ret = BLK_STS_DEV_RESOURCE; 1773 break; 1774 case BLK_STS_AGAIN: 1775 scsi_req(req)->result = DID_BUS_BUSY << 16; 1776 if (req->rq_flags & RQF_DONTPREP) 1777 scsi_mq_uninit_cmd(cmd); 1778 break; 1779 default: 1780 if (unlikely(!scsi_device_online(sdev))) 1781 scsi_req(req)->result = DID_NO_CONNECT << 16; 1782 else 1783 scsi_req(req)->result = DID_ERROR << 16; 1784 /* 1785 * Make sure to release all allocated resources when 1786 * we hit an error, as we will never see this command 1787 * again. 1788 */ 1789 if (req->rq_flags & RQF_DONTPREP) 1790 scsi_mq_uninit_cmd(cmd); 1791 scsi_run_queue_async(sdev); 1792 break; 1793 } 1794 return ret; 1795 } 1796 1797 static enum blk_eh_timer_return scsi_timeout(struct request *req, 1798 bool reserved) 1799 { 1800 if (reserved) 1801 return BLK_EH_RESET_TIMER; 1802 return scsi_times_out(req); 1803 } 1804 1805 static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq, 1806 unsigned int hctx_idx, unsigned int numa_node) 1807 { 1808 struct Scsi_Host *shost = set->driver_data; 1809 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); 1810 struct scatterlist *sg; 1811 int ret = 0; 1812 1813 cmd->sense_buffer = 1814 kmem_cache_alloc_node(scsi_sense_cache, GFP_KERNEL, numa_node); 1815 if (!cmd->sense_buffer) 1816 return -ENOMEM; 1817 cmd->req.sense = cmd->sense_buffer; 1818 1819 if (scsi_host_get_prot(shost)) { 1820 sg = (void *)cmd + sizeof(struct scsi_cmnd) + 1821 shost->hostt->cmd_size; 1822 cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost); 1823 } 1824 1825 if (shost->hostt->init_cmd_priv) { 1826 ret = shost->hostt->init_cmd_priv(shost, cmd); 1827 if (ret < 0) 1828 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer); 1829 } 1830 1831 return ret; 1832 } 1833 1834 static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq, 1835 unsigned int hctx_idx) 1836 { 1837 struct Scsi_Host *shost = set->driver_data; 1838 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); 1839 1840 if (shost->hostt->exit_cmd_priv) 1841 shost->hostt->exit_cmd_priv(shost, cmd); 1842 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer); 1843 } 1844 1845 1846 static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob) 1847 { 1848 struct Scsi_Host *shost = hctx->driver_data; 1849 1850 if (shost->hostt->mq_poll) 1851 return shost->hostt->mq_poll(shost, hctx->queue_num); 1852 1853 return 0; 1854 } 1855 1856 static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data, 1857 unsigned int hctx_idx) 1858 { 1859 struct Scsi_Host *shost = data; 1860 1861 hctx->driver_data = shost; 1862 return 0; 1863 } 1864 1865 static int scsi_map_queues(struct blk_mq_tag_set *set) 1866 { 1867 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set); 1868 1869 if (shost->hostt->map_queues) 1870 return shost->hostt->map_queues(shost); 1871 return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]); 1872 } 1873 1874 void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q) 1875 { 1876 struct device *dev = shost->dma_dev; 1877 1878 /* 1879 * this limit is imposed by hardware restrictions 1880 */ 1881 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize, 1882 SG_MAX_SEGMENTS)); 1883 1884 if (scsi_host_prot_dma(shost)) { 1885 shost->sg_prot_tablesize = 1886 min_not_zero(shost->sg_prot_tablesize, 1887 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS); 1888 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize); 1889 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize); 1890 } 1891 1892 if (dev->dma_mask) { 1893 shost->max_sectors = min_t(unsigned int, shost->max_sectors, 1894 dma_max_mapping_size(dev) >> SECTOR_SHIFT); 1895 } 1896 blk_queue_max_hw_sectors(q, shost->max_sectors); 1897 blk_queue_segment_boundary(q, shost->dma_boundary); 1898 dma_set_seg_boundary(dev, shost->dma_boundary); 1899 1900 blk_queue_max_segment_size(q, shost->max_segment_size); 1901 blk_queue_virt_boundary(q, shost->virt_boundary_mask); 1902 dma_set_max_seg_size(dev, queue_max_segment_size(q)); 1903 1904 /* 1905 * Set a reasonable default alignment: The larger of 32-byte (dword), 1906 * which is a common minimum for HBAs, and the minimum DMA alignment, 1907 * which is set by the platform. 1908 * 1909 * Devices that require a bigger alignment can increase it later. 1910 */ 1911 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1); 1912 } 1913 EXPORT_SYMBOL_GPL(__scsi_init_queue); 1914 1915 static const struct blk_mq_ops scsi_mq_ops_no_commit = { 1916 .get_budget = scsi_mq_get_budget, 1917 .put_budget = scsi_mq_put_budget, 1918 .queue_rq = scsi_queue_rq, 1919 .complete = scsi_complete, 1920 .timeout = scsi_timeout, 1921 #ifdef CONFIG_BLK_DEBUG_FS 1922 .show_rq = scsi_show_rq, 1923 #endif 1924 .init_request = scsi_mq_init_request, 1925 .exit_request = scsi_mq_exit_request, 1926 .cleanup_rq = scsi_cleanup_rq, 1927 .busy = scsi_mq_lld_busy, 1928 .map_queues = scsi_map_queues, 1929 .init_hctx = scsi_init_hctx, 1930 .poll = scsi_mq_poll, 1931 .set_rq_budget_token = scsi_mq_set_rq_budget_token, 1932 .get_rq_budget_token = scsi_mq_get_rq_budget_token, 1933 }; 1934 1935 1936 static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx) 1937 { 1938 struct Scsi_Host *shost = hctx->driver_data; 1939 1940 shost->hostt->commit_rqs(shost, hctx->queue_num); 1941 } 1942 1943 static const struct blk_mq_ops scsi_mq_ops = { 1944 .get_budget = scsi_mq_get_budget, 1945 .put_budget = scsi_mq_put_budget, 1946 .queue_rq = scsi_queue_rq, 1947 .commit_rqs = scsi_commit_rqs, 1948 .complete = scsi_complete, 1949 .timeout = scsi_timeout, 1950 #ifdef CONFIG_BLK_DEBUG_FS 1951 .show_rq = scsi_show_rq, 1952 #endif 1953 .init_request = scsi_mq_init_request, 1954 .exit_request = scsi_mq_exit_request, 1955 .cleanup_rq = scsi_cleanup_rq, 1956 .busy = scsi_mq_lld_busy, 1957 .map_queues = scsi_map_queues, 1958 .init_hctx = scsi_init_hctx, 1959 .poll = scsi_mq_poll, 1960 .set_rq_budget_token = scsi_mq_set_rq_budget_token, 1961 .get_rq_budget_token = scsi_mq_get_rq_budget_token, 1962 }; 1963 1964 int scsi_mq_setup_tags(struct Scsi_Host *shost) 1965 { 1966 unsigned int cmd_size, sgl_size; 1967 struct blk_mq_tag_set *tag_set = &shost->tag_set; 1968 1969 sgl_size = max_t(unsigned int, sizeof(struct scatterlist), 1970 scsi_mq_inline_sgl_size(shost)); 1971 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size; 1972 if (scsi_host_get_prot(shost)) 1973 cmd_size += sizeof(struct scsi_data_buffer) + 1974 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT; 1975 1976 memset(tag_set, 0, sizeof(*tag_set)); 1977 if (shost->hostt->commit_rqs) 1978 tag_set->ops = &scsi_mq_ops; 1979 else 1980 tag_set->ops = &scsi_mq_ops_no_commit; 1981 tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1; 1982 tag_set->nr_maps = shost->nr_maps ? : 1; 1983 tag_set->queue_depth = shost->can_queue; 1984 tag_set->cmd_size = cmd_size; 1985 tag_set->numa_node = NUMA_NO_NODE; 1986 tag_set->flags = BLK_MQ_F_SHOULD_MERGE; 1987 tag_set->flags |= 1988 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy); 1989 tag_set->driver_data = shost; 1990 if (shost->host_tagset) 1991 tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED; 1992 1993 return blk_mq_alloc_tag_set(tag_set); 1994 } 1995 1996 void scsi_mq_destroy_tags(struct Scsi_Host *shost) 1997 { 1998 blk_mq_free_tag_set(&shost->tag_set); 1999 } 2000 2001 /** 2002 * scsi_device_from_queue - return sdev associated with a request_queue 2003 * @q: The request queue to return the sdev from 2004 * 2005 * Return the sdev associated with a request queue or NULL if the 2006 * request_queue does not reference a SCSI device. 2007 */ 2008 struct scsi_device *scsi_device_from_queue(struct request_queue *q) 2009 { 2010 struct scsi_device *sdev = NULL; 2011 2012 if (q->mq_ops == &scsi_mq_ops_no_commit || 2013 q->mq_ops == &scsi_mq_ops) 2014 sdev = q->queuedata; 2015 if (!sdev || !get_device(&sdev->sdev_gendev)) 2016 sdev = NULL; 2017 2018 return sdev; 2019 } 2020 /* 2021 * pktcdvd should have been integrated into the SCSI layers, but for historical 2022 * reasons like the old IDE driver it isn't. This export allows it to safely 2023 * probe if a given device is a SCSI one and only attach to that. 2024 */ 2025 #ifdef CONFIG_CDROM_PKTCDVD_MODULE 2026 EXPORT_SYMBOL_GPL(scsi_device_from_queue); 2027 #endif 2028 2029 /** 2030 * scsi_block_requests - Utility function used by low-level drivers to prevent 2031 * further commands from being queued to the device. 2032 * @shost: host in question 2033 * 2034 * There is no timer nor any other means by which the requests get unblocked 2035 * other than the low-level driver calling scsi_unblock_requests(). 2036 */ 2037 void scsi_block_requests(struct Scsi_Host *shost) 2038 { 2039 shost->host_self_blocked = 1; 2040 } 2041 EXPORT_SYMBOL(scsi_block_requests); 2042 2043 /** 2044 * scsi_unblock_requests - Utility function used by low-level drivers to allow 2045 * further commands to be queued to the device. 2046 * @shost: host in question 2047 * 2048 * There is no timer nor any other means by which the requests get unblocked 2049 * other than the low-level driver calling scsi_unblock_requests(). This is done 2050 * as an API function so that changes to the internals of the scsi mid-layer 2051 * won't require wholesale changes to drivers that use this feature. 2052 */ 2053 void scsi_unblock_requests(struct Scsi_Host *shost) 2054 { 2055 shost->host_self_blocked = 0; 2056 scsi_run_host_queues(shost); 2057 } 2058 EXPORT_SYMBOL(scsi_unblock_requests); 2059 2060 void scsi_exit_queue(void) 2061 { 2062 kmem_cache_destroy(scsi_sense_cache); 2063 } 2064 2065 /** 2066 * scsi_mode_select - issue a mode select 2067 * @sdev: SCSI device to be queried 2068 * @pf: Page format bit (1 == standard, 0 == vendor specific) 2069 * @sp: Save page bit (0 == don't save, 1 == save) 2070 * @buffer: request buffer (may not be smaller than eight bytes) 2071 * @len: length of request buffer. 2072 * @timeout: command timeout 2073 * @retries: number of retries before failing 2074 * @data: returns a structure abstracting the mode header data 2075 * @sshdr: place to put sense data (or NULL if no sense to be collected). 2076 * must be SCSI_SENSE_BUFFERSIZE big. 2077 * 2078 * Returns zero if successful; negative error number or scsi 2079 * status on error 2080 * 2081 */ 2082 int scsi_mode_select(struct scsi_device *sdev, int pf, int sp, 2083 unsigned char *buffer, int len, int timeout, int retries, 2084 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) 2085 { 2086 unsigned char cmd[10]; 2087 unsigned char *real_buffer; 2088 int ret; 2089 2090 memset(cmd, 0, sizeof(cmd)); 2091 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); 2092 2093 /* 2094 * Use MODE SELECT(10) if the device asked for it or if the mode page 2095 * and the mode select header cannot fit within the maximumm 255 bytes 2096 * of the MODE SELECT(6) command. 2097 */ 2098 if (sdev->use_10_for_ms || 2099 len + 4 > 255 || 2100 data->block_descriptor_length > 255) { 2101 if (len > 65535 - 8) 2102 return -EINVAL; 2103 real_buffer = kmalloc(8 + len, GFP_KERNEL); 2104 if (!real_buffer) 2105 return -ENOMEM; 2106 memcpy(real_buffer + 8, buffer, len); 2107 len += 8; 2108 real_buffer[0] = 0; 2109 real_buffer[1] = 0; 2110 real_buffer[2] = data->medium_type; 2111 real_buffer[3] = data->device_specific; 2112 real_buffer[4] = data->longlba ? 0x01 : 0; 2113 real_buffer[5] = 0; 2114 put_unaligned_be16(data->block_descriptor_length, 2115 &real_buffer[6]); 2116 2117 cmd[0] = MODE_SELECT_10; 2118 put_unaligned_be16(len, &cmd[7]); 2119 } else { 2120 if (data->longlba) 2121 return -EINVAL; 2122 2123 real_buffer = kmalloc(4 + len, GFP_KERNEL); 2124 if (!real_buffer) 2125 return -ENOMEM; 2126 memcpy(real_buffer + 4, buffer, len); 2127 len += 4; 2128 real_buffer[0] = 0; 2129 real_buffer[1] = data->medium_type; 2130 real_buffer[2] = data->device_specific; 2131 real_buffer[3] = data->block_descriptor_length; 2132 2133 cmd[0] = MODE_SELECT; 2134 cmd[4] = len; 2135 } 2136 2137 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, 2138 sshdr, timeout, retries, NULL); 2139 kfree(real_buffer); 2140 return ret; 2141 } 2142 EXPORT_SYMBOL_GPL(scsi_mode_select); 2143 2144 /** 2145 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary. 2146 * @sdev: SCSI device to be queried 2147 * @dbd: set to prevent mode sense from returning block descriptors 2148 * @modepage: mode page being requested 2149 * @buffer: request buffer (may not be smaller than eight bytes) 2150 * @len: length of request buffer. 2151 * @timeout: command timeout 2152 * @retries: number of retries before failing 2153 * @data: returns a structure abstracting the mode header data 2154 * @sshdr: place to put sense data (or NULL if no sense to be collected). 2155 * must be SCSI_SENSE_BUFFERSIZE big. 2156 * 2157 * Returns zero if successful, or a negative error number on failure 2158 */ 2159 int 2160 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, 2161 unsigned char *buffer, int len, int timeout, int retries, 2162 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) 2163 { 2164 unsigned char cmd[12]; 2165 int use_10_for_ms; 2166 int header_length; 2167 int result, retry_count = retries; 2168 struct scsi_sense_hdr my_sshdr; 2169 2170 memset(data, 0, sizeof(*data)); 2171 memset(&cmd[0], 0, 12); 2172 2173 dbd = sdev->set_dbd_for_ms ? 8 : dbd; 2174 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ 2175 cmd[2] = modepage; 2176 2177 /* caller might not be interested in sense, but we need it */ 2178 if (!sshdr) 2179 sshdr = &my_sshdr; 2180 2181 retry: 2182 use_10_for_ms = sdev->use_10_for_ms || len > 255; 2183 2184 if (use_10_for_ms) { 2185 if (len < 8 || len > 65535) 2186 return -EINVAL; 2187 2188 cmd[0] = MODE_SENSE_10; 2189 put_unaligned_be16(len, &cmd[7]); 2190 header_length = 8; 2191 } else { 2192 if (len < 4) 2193 return -EINVAL; 2194 2195 cmd[0] = MODE_SENSE; 2196 cmd[4] = len; 2197 header_length = 4; 2198 } 2199 2200 memset(buffer, 0, len); 2201 2202 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, 2203 sshdr, timeout, retries, NULL); 2204 if (result < 0) 2205 return result; 2206 2207 /* This code looks awful: what it's doing is making sure an 2208 * ILLEGAL REQUEST sense return identifies the actual command 2209 * byte as the problem. MODE_SENSE commands can return 2210 * ILLEGAL REQUEST if the code page isn't supported */ 2211 2212 if (!scsi_status_is_good(result)) { 2213 if (scsi_sense_valid(sshdr)) { 2214 if ((sshdr->sense_key == ILLEGAL_REQUEST) && 2215 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { 2216 /* 2217 * Invalid command operation code: retry using 2218 * MODE SENSE(6) if this was a MODE SENSE(10) 2219 * request, except if the request mode page is 2220 * too large for MODE SENSE single byte 2221 * allocation length field. 2222 */ 2223 if (use_10_for_ms) { 2224 if (len > 255) 2225 return -EIO; 2226 sdev->use_10_for_ms = 0; 2227 goto retry; 2228 } 2229 } 2230 if (scsi_status_is_check_condition(result) && 2231 sshdr->sense_key == UNIT_ATTENTION && 2232 retry_count) { 2233 retry_count--; 2234 goto retry; 2235 } 2236 } 2237 return -EIO; 2238 } 2239 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && 2240 (modepage == 6 || modepage == 8))) { 2241 /* Initio breakage? */ 2242 header_length = 0; 2243 data->length = 13; 2244 data->medium_type = 0; 2245 data->device_specific = 0; 2246 data->longlba = 0; 2247 data->block_descriptor_length = 0; 2248 } else if (use_10_for_ms) { 2249 data->length = get_unaligned_be16(&buffer[0]) + 2; 2250 data->medium_type = buffer[2]; 2251 data->device_specific = buffer[3]; 2252 data->longlba = buffer[4] & 0x01; 2253 data->block_descriptor_length = get_unaligned_be16(&buffer[6]); 2254 } else { 2255 data->length = buffer[0] + 1; 2256 data->medium_type = buffer[1]; 2257 data->device_specific = buffer[2]; 2258 data->block_descriptor_length = buffer[3]; 2259 } 2260 data->header_length = header_length; 2261 2262 return 0; 2263 } 2264 EXPORT_SYMBOL(scsi_mode_sense); 2265 2266 /** 2267 * scsi_test_unit_ready - test if unit is ready 2268 * @sdev: scsi device to change the state of. 2269 * @timeout: command timeout 2270 * @retries: number of retries before failing 2271 * @sshdr: outpout pointer for decoded sense information. 2272 * 2273 * Returns zero if unsuccessful or an error if TUR failed. For 2274 * removable media, UNIT_ATTENTION sets ->changed flag. 2275 **/ 2276 int 2277 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, 2278 struct scsi_sense_hdr *sshdr) 2279 { 2280 char cmd[] = { 2281 TEST_UNIT_READY, 0, 0, 0, 0, 0, 2282 }; 2283 int result; 2284 2285 /* try to eat the UNIT_ATTENTION if there are enough retries */ 2286 do { 2287 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr, 2288 timeout, 1, NULL); 2289 if (sdev->removable && scsi_sense_valid(sshdr) && 2290 sshdr->sense_key == UNIT_ATTENTION) 2291 sdev->changed = 1; 2292 } while (scsi_sense_valid(sshdr) && 2293 sshdr->sense_key == UNIT_ATTENTION && --retries); 2294 2295 return result; 2296 } 2297 EXPORT_SYMBOL(scsi_test_unit_ready); 2298 2299 /** 2300 * scsi_device_set_state - Take the given device through the device state model. 2301 * @sdev: scsi device to change the state of. 2302 * @state: state to change to. 2303 * 2304 * Returns zero if successful or an error if the requested 2305 * transition is illegal. 2306 */ 2307 int 2308 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) 2309 { 2310 enum scsi_device_state oldstate = sdev->sdev_state; 2311 2312 if (state == oldstate) 2313 return 0; 2314 2315 switch (state) { 2316 case SDEV_CREATED: 2317 switch (oldstate) { 2318 case SDEV_CREATED_BLOCK: 2319 break; 2320 default: 2321 goto illegal; 2322 } 2323 break; 2324 2325 case SDEV_RUNNING: 2326 switch (oldstate) { 2327 case SDEV_CREATED: 2328 case SDEV_OFFLINE: 2329 case SDEV_TRANSPORT_OFFLINE: 2330 case SDEV_QUIESCE: 2331 case SDEV_BLOCK: 2332 break; 2333 default: 2334 goto illegal; 2335 } 2336 break; 2337 2338 case SDEV_QUIESCE: 2339 switch (oldstate) { 2340 case SDEV_RUNNING: 2341 case SDEV_OFFLINE: 2342 case SDEV_TRANSPORT_OFFLINE: 2343 break; 2344 default: 2345 goto illegal; 2346 } 2347 break; 2348 2349 case SDEV_OFFLINE: 2350 case SDEV_TRANSPORT_OFFLINE: 2351 switch (oldstate) { 2352 case SDEV_CREATED: 2353 case SDEV_RUNNING: 2354 case SDEV_QUIESCE: 2355 case SDEV_BLOCK: 2356 break; 2357 default: 2358 goto illegal; 2359 } 2360 break; 2361 2362 case SDEV_BLOCK: 2363 switch (oldstate) { 2364 case SDEV_RUNNING: 2365 case SDEV_CREATED_BLOCK: 2366 case SDEV_QUIESCE: 2367 case SDEV_OFFLINE: 2368 break; 2369 default: 2370 goto illegal; 2371 } 2372 break; 2373 2374 case SDEV_CREATED_BLOCK: 2375 switch (oldstate) { 2376 case SDEV_CREATED: 2377 break; 2378 default: 2379 goto illegal; 2380 } 2381 break; 2382 2383 case SDEV_CANCEL: 2384 switch (oldstate) { 2385 case SDEV_CREATED: 2386 case SDEV_RUNNING: 2387 case SDEV_QUIESCE: 2388 case SDEV_OFFLINE: 2389 case SDEV_TRANSPORT_OFFLINE: 2390 break; 2391 default: 2392 goto illegal; 2393 } 2394 break; 2395 2396 case SDEV_DEL: 2397 switch (oldstate) { 2398 case SDEV_CREATED: 2399 case SDEV_RUNNING: 2400 case SDEV_OFFLINE: 2401 case SDEV_TRANSPORT_OFFLINE: 2402 case SDEV_CANCEL: 2403 case SDEV_BLOCK: 2404 case SDEV_CREATED_BLOCK: 2405 break; 2406 default: 2407 goto illegal; 2408 } 2409 break; 2410 2411 } 2412 sdev->offline_already = false; 2413 sdev->sdev_state = state; 2414 return 0; 2415 2416 illegal: 2417 SCSI_LOG_ERROR_RECOVERY(1, 2418 sdev_printk(KERN_ERR, sdev, 2419 "Illegal state transition %s->%s", 2420 scsi_device_state_name(oldstate), 2421 scsi_device_state_name(state)) 2422 ); 2423 return -EINVAL; 2424 } 2425 EXPORT_SYMBOL(scsi_device_set_state); 2426 2427 /** 2428 * scsi_evt_emit - emit a single SCSI device uevent 2429 * @sdev: associated SCSI device 2430 * @evt: event to emit 2431 * 2432 * Send a single uevent (scsi_event) to the associated scsi_device. 2433 */ 2434 static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt) 2435 { 2436 int idx = 0; 2437 char *envp[3]; 2438 2439 switch (evt->evt_type) { 2440 case SDEV_EVT_MEDIA_CHANGE: 2441 envp[idx++] = "SDEV_MEDIA_CHANGE=1"; 2442 break; 2443 case SDEV_EVT_INQUIRY_CHANGE_REPORTED: 2444 scsi_rescan_device(&sdev->sdev_gendev); 2445 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED"; 2446 break; 2447 case SDEV_EVT_CAPACITY_CHANGE_REPORTED: 2448 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED"; 2449 break; 2450 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED: 2451 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED"; 2452 break; 2453 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED: 2454 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED"; 2455 break; 2456 case SDEV_EVT_LUN_CHANGE_REPORTED: 2457 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED"; 2458 break; 2459 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED: 2460 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED"; 2461 break; 2462 case SDEV_EVT_POWER_ON_RESET_OCCURRED: 2463 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED"; 2464 break; 2465 default: 2466 /* do nothing */ 2467 break; 2468 } 2469 2470 envp[idx++] = NULL; 2471 2472 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp); 2473 } 2474 2475 /** 2476 * scsi_evt_thread - send a uevent for each scsi event 2477 * @work: work struct for scsi_device 2478 * 2479 * Dispatch queued events to their associated scsi_device kobjects 2480 * as uevents. 2481 */ 2482 void scsi_evt_thread(struct work_struct *work) 2483 { 2484 struct scsi_device *sdev; 2485 enum scsi_device_event evt_type; 2486 LIST_HEAD(event_list); 2487 2488 sdev = container_of(work, struct scsi_device, event_work); 2489 2490 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++) 2491 if (test_and_clear_bit(evt_type, sdev->pending_events)) 2492 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL); 2493 2494 while (1) { 2495 struct scsi_event *evt; 2496 struct list_head *this, *tmp; 2497 unsigned long flags; 2498 2499 spin_lock_irqsave(&sdev->list_lock, flags); 2500 list_splice_init(&sdev->event_list, &event_list); 2501 spin_unlock_irqrestore(&sdev->list_lock, flags); 2502 2503 if (list_empty(&event_list)) 2504 break; 2505 2506 list_for_each_safe(this, tmp, &event_list) { 2507 evt = list_entry(this, struct scsi_event, node); 2508 list_del(&evt->node); 2509 scsi_evt_emit(sdev, evt); 2510 kfree(evt); 2511 } 2512 } 2513 } 2514 2515 /** 2516 * sdev_evt_send - send asserted event to uevent thread 2517 * @sdev: scsi_device event occurred on 2518 * @evt: event to send 2519 * 2520 * Assert scsi device event asynchronously. 2521 */ 2522 void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt) 2523 { 2524 unsigned long flags; 2525 2526 #if 0 2527 /* FIXME: currently this check eliminates all media change events 2528 * for polled devices. Need to update to discriminate between AN 2529 * and polled events */ 2530 if (!test_bit(evt->evt_type, sdev->supported_events)) { 2531 kfree(evt); 2532 return; 2533 } 2534 #endif 2535 2536 spin_lock_irqsave(&sdev->list_lock, flags); 2537 list_add_tail(&evt->node, &sdev->event_list); 2538 schedule_work(&sdev->event_work); 2539 spin_unlock_irqrestore(&sdev->list_lock, flags); 2540 } 2541 EXPORT_SYMBOL_GPL(sdev_evt_send); 2542 2543 /** 2544 * sdev_evt_alloc - allocate a new scsi event 2545 * @evt_type: type of event to allocate 2546 * @gfpflags: GFP flags for allocation 2547 * 2548 * Allocates and returns a new scsi_event. 2549 */ 2550 struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type, 2551 gfp_t gfpflags) 2552 { 2553 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags); 2554 if (!evt) 2555 return NULL; 2556 2557 evt->evt_type = evt_type; 2558 INIT_LIST_HEAD(&evt->node); 2559 2560 /* evt_type-specific initialization, if any */ 2561 switch (evt_type) { 2562 case SDEV_EVT_MEDIA_CHANGE: 2563 case SDEV_EVT_INQUIRY_CHANGE_REPORTED: 2564 case SDEV_EVT_CAPACITY_CHANGE_REPORTED: 2565 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED: 2566 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED: 2567 case SDEV_EVT_LUN_CHANGE_REPORTED: 2568 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED: 2569 case SDEV_EVT_POWER_ON_RESET_OCCURRED: 2570 default: 2571 /* do nothing */ 2572 break; 2573 } 2574 2575 return evt; 2576 } 2577 EXPORT_SYMBOL_GPL(sdev_evt_alloc); 2578 2579 /** 2580 * sdev_evt_send_simple - send asserted event to uevent thread 2581 * @sdev: scsi_device event occurred on 2582 * @evt_type: type of event to send 2583 * @gfpflags: GFP flags for allocation 2584 * 2585 * Assert scsi device event asynchronously, given an event type. 2586 */ 2587 void sdev_evt_send_simple(struct scsi_device *sdev, 2588 enum scsi_device_event evt_type, gfp_t gfpflags) 2589 { 2590 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags); 2591 if (!evt) { 2592 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n", 2593 evt_type); 2594 return; 2595 } 2596 2597 sdev_evt_send(sdev, evt); 2598 } 2599 EXPORT_SYMBOL_GPL(sdev_evt_send_simple); 2600 2601 /** 2602 * scsi_device_quiesce - Block all commands except power management. 2603 * @sdev: scsi device to quiesce. 2604 * 2605 * This works by trying to transition to the SDEV_QUIESCE state 2606 * (which must be a legal transition). When the device is in this 2607 * state, only power management requests will be accepted, all others will 2608 * be deferred. 2609 * 2610 * Must be called with user context, may sleep. 2611 * 2612 * Returns zero if unsuccessful or an error if not. 2613 */ 2614 int 2615 scsi_device_quiesce(struct scsi_device *sdev) 2616 { 2617 struct request_queue *q = sdev->request_queue; 2618 int err; 2619 2620 /* 2621 * It is allowed to call scsi_device_quiesce() multiple times from 2622 * the same context but concurrent scsi_device_quiesce() calls are 2623 * not allowed. 2624 */ 2625 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current); 2626 2627 if (sdev->quiesced_by == current) 2628 return 0; 2629 2630 blk_set_pm_only(q); 2631 2632 blk_mq_freeze_queue(q); 2633 /* 2634 * Ensure that the effect of blk_set_pm_only() will be visible 2635 * for percpu_ref_tryget() callers that occur after the queue 2636 * unfreeze even if the queue was already frozen before this function 2637 * was called. See also https://lwn.net/Articles/573497/. 2638 */ 2639 synchronize_rcu(); 2640 blk_mq_unfreeze_queue(q); 2641 2642 mutex_lock(&sdev->state_mutex); 2643 err = scsi_device_set_state(sdev, SDEV_QUIESCE); 2644 if (err == 0) 2645 sdev->quiesced_by = current; 2646 else 2647 blk_clear_pm_only(q); 2648 mutex_unlock(&sdev->state_mutex); 2649 2650 return err; 2651 } 2652 EXPORT_SYMBOL(scsi_device_quiesce); 2653 2654 /** 2655 * scsi_device_resume - Restart user issued commands to a quiesced device. 2656 * @sdev: scsi device to resume. 2657 * 2658 * Moves the device from quiesced back to running and restarts the 2659 * queues. 2660 * 2661 * Must be called with user context, may sleep. 2662 */ 2663 void scsi_device_resume(struct scsi_device *sdev) 2664 { 2665 /* check if the device state was mutated prior to resume, and if 2666 * so assume the state is being managed elsewhere (for example 2667 * device deleted during suspend) 2668 */ 2669 mutex_lock(&sdev->state_mutex); 2670 if (sdev->sdev_state == SDEV_QUIESCE) 2671 scsi_device_set_state(sdev, SDEV_RUNNING); 2672 if (sdev->quiesced_by) { 2673 sdev->quiesced_by = NULL; 2674 blk_clear_pm_only(sdev->request_queue); 2675 } 2676 mutex_unlock(&sdev->state_mutex); 2677 } 2678 EXPORT_SYMBOL(scsi_device_resume); 2679 2680 static void 2681 device_quiesce_fn(struct scsi_device *sdev, void *data) 2682 { 2683 scsi_device_quiesce(sdev); 2684 } 2685 2686 void 2687 scsi_target_quiesce(struct scsi_target *starget) 2688 { 2689 starget_for_each_device(starget, NULL, device_quiesce_fn); 2690 } 2691 EXPORT_SYMBOL(scsi_target_quiesce); 2692 2693 static void 2694 device_resume_fn(struct scsi_device *sdev, void *data) 2695 { 2696 scsi_device_resume(sdev); 2697 } 2698 2699 void 2700 scsi_target_resume(struct scsi_target *starget) 2701 { 2702 starget_for_each_device(starget, NULL, device_resume_fn); 2703 } 2704 EXPORT_SYMBOL(scsi_target_resume); 2705 2706 static int __scsi_internal_device_block_nowait(struct scsi_device *sdev) 2707 { 2708 if (scsi_device_set_state(sdev, SDEV_BLOCK)) 2709 return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK); 2710 2711 return 0; 2712 } 2713 2714 void scsi_start_queue(struct scsi_device *sdev) 2715 { 2716 if (cmpxchg(&sdev->queue_stopped, 1, 0)) 2717 blk_mq_unquiesce_queue(sdev->request_queue); 2718 } 2719 2720 static void scsi_stop_queue(struct scsi_device *sdev, bool nowait) 2721 { 2722 /* 2723 * The atomic variable of ->queue_stopped covers that 2724 * blk_mq_quiesce_queue* is balanced with blk_mq_unquiesce_queue. 2725 * 2726 * However, we still need to wait until quiesce is done 2727 * in case that queue has been stopped. 2728 */ 2729 if (!cmpxchg(&sdev->queue_stopped, 0, 1)) { 2730 if (nowait) 2731 blk_mq_quiesce_queue_nowait(sdev->request_queue); 2732 else 2733 blk_mq_quiesce_queue(sdev->request_queue); 2734 } else { 2735 if (!nowait) 2736 blk_mq_wait_quiesce_done(sdev->request_queue); 2737 } 2738 } 2739 2740 /** 2741 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state 2742 * @sdev: device to block 2743 * 2744 * Pause SCSI command processing on the specified device. Does not sleep. 2745 * 2746 * Returns zero if successful or a negative error code upon failure. 2747 * 2748 * Notes: 2749 * This routine transitions the device to the SDEV_BLOCK state (which must be 2750 * a legal transition). When the device is in this state, command processing 2751 * is paused until the device leaves the SDEV_BLOCK state. See also 2752 * scsi_internal_device_unblock_nowait(). 2753 */ 2754 int scsi_internal_device_block_nowait(struct scsi_device *sdev) 2755 { 2756 int ret = __scsi_internal_device_block_nowait(sdev); 2757 2758 /* 2759 * The device has transitioned to SDEV_BLOCK. Stop the 2760 * block layer from calling the midlayer with this device's 2761 * request queue. 2762 */ 2763 if (!ret) 2764 scsi_stop_queue(sdev, true); 2765 return ret; 2766 } 2767 EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait); 2768 2769 /** 2770 * scsi_internal_device_block - try to transition to the SDEV_BLOCK state 2771 * @sdev: device to block 2772 * 2773 * Pause SCSI command processing on the specified device and wait until all 2774 * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep. 2775 * 2776 * Returns zero if successful or a negative error code upon failure. 2777 * 2778 * Note: 2779 * This routine transitions the device to the SDEV_BLOCK state (which must be 2780 * a legal transition). When the device is in this state, command processing 2781 * is paused until the device leaves the SDEV_BLOCK state. See also 2782 * scsi_internal_device_unblock(). 2783 */ 2784 static int scsi_internal_device_block(struct scsi_device *sdev) 2785 { 2786 int err; 2787 2788 mutex_lock(&sdev->state_mutex); 2789 err = __scsi_internal_device_block_nowait(sdev); 2790 if (err == 0) 2791 scsi_stop_queue(sdev, false); 2792 mutex_unlock(&sdev->state_mutex); 2793 2794 return err; 2795 } 2796 2797 /** 2798 * scsi_internal_device_unblock_nowait - resume a device after a block request 2799 * @sdev: device to resume 2800 * @new_state: state to set the device to after unblocking 2801 * 2802 * Restart the device queue for a previously suspended SCSI device. Does not 2803 * sleep. 2804 * 2805 * Returns zero if successful or a negative error code upon failure. 2806 * 2807 * Notes: 2808 * This routine transitions the device to the SDEV_RUNNING state or to one of 2809 * the offline states (which must be a legal transition) allowing the midlayer 2810 * to goose the queue for this device. 2811 */ 2812 int scsi_internal_device_unblock_nowait(struct scsi_device *sdev, 2813 enum scsi_device_state new_state) 2814 { 2815 switch (new_state) { 2816 case SDEV_RUNNING: 2817 case SDEV_TRANSPORT_OFFLINE: 2818 break; 2819 default: 2820 return -EINVAL; 2821 } 2822 2823 /* 2824 * Try to transition the scsi device to SDEV_RUNNING or one of the 2825 * offlined states and goose the device queue if successful. 2826 */ 2827 switch (sdev->sdev_state) { 2828 case SDEV_BLOCK: 2829 case SDEV_TRANSPORT_OFFLINE: 2830 sdev->sdev_state = new_state; 2831 break; 2832 case SDEV_CREATED_BLOCK: 2833 if (new_state == SDEV_TRANSPORT_OFFLINE || 2834 new_state == SDEV_OFFLINE) 2835 sdev->sdev_state = new_state; 2836 else 2837 sdev->sdev_state = SDEV_CREATED; 2838 break; 2839 case SDEV_CANCEL: 2840 case SDEV_OFFLINE: 2841 break; 2842 default: 2843 return -EINVAL; 2844 } 2845 scsi_start_queue(sdev); 2846 2847 return 0; 2848 } 2849 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait); 2850 2851 /** 2852 * scsi_internal_device_unblock - resume a device after a block request 2853 * @sdev: device to resume 2854 * @new_state: state to set the device to after unblocking 2855 * 2856 * Restart the device queue for a previously suspended SCSI device. May sleep. 2857 * 2858 * Returns zero if successful or a negative error code upon failure. 2859 * 2860 * Notes: 2861 * This routine transitions the device to the SDEV_RUNNING state or to one of 2862 * the offline states (which must be a legal transition) allowing the midlayer 2863 * to goose the queue for this device. 2864 */ 2865 static int scsi_internal_device_unblock(struct scsi_device *sdev, 2866 enum scsi_device_state new_state) 2867 { 2868 int ret; 2869 2870 mutex_lock(&sdev->state_mutex); 2871 ret = scsi_internal_device_unblock_nowait(sdev, new_state); 2872 mutex_unlock(&sdev->state_mutex); 2873 2874 return ret; 2875 } 2876 2877 static void 2878 device_block(struct scsi_device *sdev, void *data) 2879 { 2880 int ret; 2881 2882 ret = scsi_internal_device_block(sdev); 2883 2884 WARN_ONCE(ret, "scsi_internal_device_block(%s) failed: ret = %d\n", 2885 dev_name(&sdev->sdev_gendev), ret); 2886 } 2887 2888 static int 2889 target_block(struct device *dev, void *data) 2890 { 2891 if (scsi_is_target_device(dev)) 2892 starget_for_each_device(to_scsi_target(dev), NULL, 2893 device_block); 2894 return 0; 2895 } 2896 2897 void 2898 scsi_target_block(struct device *dev) 2899 { 2900 if (scsi_is_target_device(dev)) 2901 starget_for_each_device(to_scsi_target(dev), NULL, 2902 device_block); 2903 else 2904 device_for_each_child(dev, NULL, target_block); 2905 } 2906 EXPORT_SYMBOL_GPL(scsi_target_block); 2907 2908 static void 2909 device_unblock(struct scsi_device *sdev, void *data) 2910 { 2911 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data); 2912 } 2913 2914 static int 2915 target_unblock(struct device *dev, void *data) 2916 { 2917 if (scsi_is_target_device(dev)) 2918 starget_for_each_device(to_scsi_target(dev), data, 2919 device_unblock); 2920 return 0; 2921 } 2922 2923 void 2924 scsi_target_unblock(struct device *dev, enum scsi_device_state new_state) 2925 { 2926 if (scsi_is_target_device(dev)) 2927 starget_for_each_device(to_scsi_target(dev), &new_state, 2928 device_unblock); 2929 else 2930 device_for_each_child(dev, &new_state, target_unblock); 2931 } 2932 EXPORT_SYMBOL_GPL(scsi_target_unblock); 2933 2934 int 2935 scsi_host_block(struct Scsi_Host *shost) 2936 { 2937 struct scsi_device *sdev; 2938 int ret = 0; 2939 2940 /* 2941 * Call scsi_internal_device_block_nowait so we can avoid 2942 * calling synchronize_rcu() for each LUN. 2943 */ 2944 shost_for_each_device(sdev, shost) { 2945 mutex_lock(&sdev->state_mutex); 2946 ret = scsi_internal_device_block_nowait(sdev); 2947 mutex_unlock(&sdev->state_mutex); 2948 if (ret) { 2949 scsi_device_put(sdev); 2950 break; 2951 } 2952 } 2953 2954 /* 2955 * SCSI never enables blk-mq's BLK_MQ_F_BLOCKING flag so 2956 * calling synchronize_rcu() once is enough. 2957 */ 2958 WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING); 2959 2960 if (!ret) 2961 synchronize_rcu(); 2962 2963 return ret; 2964 } 2965 EXPORT_SYMBOL_GPL(scsi_host_block); 2966 2967 int 2968 scsi_host_unblock(struct Scsi_Host *shost, int new_state) 2969 { 2970 struct scsi_device *sdev; 2971 int ret = 0; 2972 2973 shost_for_each_device(sdev, shost) { 2974 ret = scsi_internal_device_unblock(sdev, new_state); 2975 if (ret) { 2976 scsi_device_put(sdev); 2977 break; 2978 } 2979 } 2980 return ret; 2981 } 2982 EXPORT_SYMBOL_GPL(scsi_host_unblock); 2983 2984 /** 2985 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt 2986 * @sgl: scatter-gather list 2987 * @sg_count: number of segments in sg 2988 * @offset: offset in bytes into sg, on return offset into the mapped area 2989 * @len: bytes to map, on return number of bytes mapped 2990 * 2991 * Returns virtual address of the start of the mapped page 2992 */ 2993 void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count, 2994 size_t *offset, size_t *len) 2995 { 2996 int i; 2997 size_t sg_len = 0, len_complete = 0; 2998 struct scatterlist *sg; 2999 struct page *page; 3000 3001 WARN_ON(!irqs_disabled()); 3002 3003 for_each_sg(sgl, sg, sg_count, i) { 3004 len_complete = sg_len; /* Complete sg-entries */ 3005 sg_len += sg->length; 3006 if (sg_len > *offset) 3007 break; 3008 } 3009 3010 if (unlikely(i == sg_count)) { 3011 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " 3012 "elements %d\n", 3013 __func__, sg_len, *offset, sg_count); 3014 WARN_ON(1); 3015 return NULL; 3016 } 3017 3018 /* Offset starting from the beginning of first page in this sg-entry */ 3019 *offset = *offset - len_complete + sg->offset; 3020 3021 /* Assumption: contiguous pages can be accessed as "page + i" */ 3022 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT)); 3023 *offset &= ~PAGE_MASK; 3024 3025 /* Bytes in this sg-entry from *offset to the end of the page */ 3026 sg_len = PAGE_SIZE - *offset; 3027 if (*len > sg_len) 3028 *len = sg_len; 3029 3030 return kmap_atomic(page); 3031 } 3032 EXPORT_SYMBOL(scsi_kmap_atomic_sg); 3033 3034 /** 3035 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg 3036 * @virt: virtual address to be unmapped 3037 */ 3038 void scsi_kunmap_atomic_sg(void *virt) 3039 { 3040 kunmap_atomic(virt); 3041 } 3042 EXPORT_SYMBOL(scsi_kunmap_atomic_sg); 3043 3044 void sdev_disable_disk_events(struct scsi_device *sdev) 3045 { 3046 atomic_inc(&sdev->disk_events_disable_depth); 3047 } 3048 EXPORT_SYMBOL(sdev_disable_disk_events); 3049 3050 void sdev_enable_disk_events(struct scsi_device *sdev) 3051 { 3052 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0)) 3053 return; 3054 atomic_dec(&sdev->disk_events_disable_depth); 3055 } 3056 EXPORT_SYMBOL(sdev_enable_disk_events); 3057 3058 static unsigned char designator_prio(const unsigned char *d) 3059 { 3060 if (d[1] & 0x30) 3061 /* not associated with LUN */ 3062 return 0; 3063 3064 if (d[3] == 0) 3065 /* invalid length */ 3066 return 0; 3067 3068 /* 3069 * Order of preference for lun descriptor: 3070 * - SCSI name string 3071 * - NAA IEEE Registered Extended 3072 * - EUI-64 based 16-byte 3073 * - EUI-64 based 12-byte 3074 * - NAA IEEE Registered 3075 * - NAA IEEE Extended 3076 * - EUI-64 based 8-byte 3077 * - SCSI name string (truncated) 3078 * - T10 Vendor ID 3079 * as longer descriptors reduce the likelyhood 3080 * of identification clashes. 3081 */ 3082 3083 switch (d[1] & 0xf) { 3084 case 8: 3085 /* SCSI name string, variable-length UTF-8 */ 3086 return 9; 3087 case 3: 3088 switch (d[4] >> 4) { 3089 case 6: 3090 /* NAA registered extended */ 3091 return 8; 3092 case 5: 3093 /* NAA registered */ 3094 return 5; 3095 case 4: 3096 /* NAA extended */ 3097 return 4; 3098 case 3: 3099 /* NAA locally assigned */ 3100 return 1; 3101 default: 3102 break; 3103 } 3104 break; 3105 case 2: 3106 switch (d[3]) { 3107 case 16: 3108 /* EUI64-based, 16 byte */ 3109 return 7; 3110 case 12: 3111 /* EUI64-based, 12 byte */ 3112 return 6; 3113 case 8: 3114 /* EUI64-based, 8 byte */ 3115 return 3; 3116 default: 3117 break; 3118 } 3119 break; 3120 case 1: 3121 /* T10 vendor ID */ 3122 return 1; 3123 default: 3124 break; 3125 } 3126 3127 return 0; 3128 } 3129 3130 /** 3131 * scsi_vpd_lun_id - return a unique device identification 3132 * @sdev: SCSI device 3133 * @id: buffer for the identification 3134 * @id_len: length of the buffer 3135 * 3136 * Copies a unique device identification into @id based 3137 * on the information in the VPD page 0x83 of the device. 3138 * The string will be formatted as a SCSI name string. 3139 * 3140 * Returns the length of the identification or error on failure. 3141 * If the identifier is longer than the supplied buffer the actual 3142 * identifier length is returned and the buffer is not zero-padded. 3143 */ 3144 int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len) 3145 { 3146 u8 cur_id_prio = 0; 3147 u8 cur_id_size = 0; 3148 const unsigned char *d, *cur_id_str; 3149 const struct scsi_vpd *vpd_pg83; 3150 int id_size = -EINVAL; 3151 3152 rcu_read_lock(); 3153 vpd_pg83 = rcu_dereference(sdev->vpd_pg83); 3154 if (!vpd_pg83) { 3155 rcu_read_unlock(); 3156 return -ENXIO; 3157 } 3158 3159 /* The id string must be at least 20 bytes + terminating NULL byte */ 3160 if (id_len < 21) { 3161 rcu_read_unlock(); 3162 return -EINVAL; 3163 } 3164 3165 memset(id, 0, id_len); 3166 for (d = vpd_pg83->data + 4; 3167 d < vpd_pg83->data + vpd_pg83->len; 3168 d += d[3] + 4) { 3169 u8 prio = designator_prio(d); 3170 3171 if (prio == 0 || cur_id_prio > prio) 3172 continue; 3173 3174 switch (d[1] & 0xf) { 3175 case 0x1: 3176 /* T10 Vendor ID */ 3177 if (cur_id_size > d[3]) 3178 break; 3179 cur_id_prio = prio; 3180 cur_id_size = d[3]; 3181 if (cur_id_size + 4 > id_len) 3182 cur_id_size = id_len - 4; 3183 cur_id_str = d + 4; 3184 id_size = snprintf(id, id_len, "t10.%*pE", 3185 cur_id_size, cur_id_str); 3186 break; 3187 case 0x2: 3188 /* EUI-64 */ 3189 cur_id_prio = prio; 3190 cur_id_size = d[3]; 3191 cur_id_str = d + 4; 3192 switch (cur_id_size) { 3193 case 8: 3194 id_size = snprintf(id, id_len, 3195 "eui.%8phN", 3196 cur_id_str); 3197 break; 3198 case 12: 3199 id_size = snprintf(id, id_len, 3200 "eui.%12phN", 3201 cur_id_str); 3202 break; 3203 case 16: 3204 id_size = snprintf(id, id_len, 3205 "eui.%16phN", 3206 cur_id_str); 3207 break; 3208 default: 3209 break; 3210 } 3211 break; 3212 case 0x3: 3213 /* NAA */ 3214 cur_id_prio = prio; 3215 cur_id_size = d[3]; 3216 cur_id_str = d + 4; 3217 switch (cur_id_size) { 3218 case 8: 3219 id_size = snprintf(id, id_len, 3220 "naa.%8phN", 3221 cur_id_str); 3222 break; 3223 case 16: 3224 id_size = snprintf(id, id_len, 3225 "naa.%16phN", 3226 cur_id_str); 3227 break; 3228 default: 3229 break; 3230 } 3231 break; 3232 case 0x8: 3233 /* SCSI name string */ 3234 if (cur_id_size > d[3]) 3235 break; 3236 /* Prefer others for truncated descriptor */ 3237 if (d[3] > id_len) { 3238 prio = 2; 3239 if (cur_id_prio > prio) 3240 break; 3241 } 3242 cur_id_prio = prio; 3243 cur_id_size = id_size = d[3]; 3244 cur_id_str = d + 4; 3245 if (cur_id_size >= id_len) 3246 cur_id_size = id_len - 1; 3247 memcpy(id, cur_id_str, cur_id_size); 3248 break; 3249 default: 3250 break; 3251 } 3252 } 3253 rcu_read_unlock(); 3254 3255 return id_size; 3256 } 3257 EXPORT_SYMBOL(scsi_vpd_lun_id); 3258 3259 /* 3260 * scsi_vpd_tpg_id - return a target port group identifier 3261 * @sdev: SCSI device 3262 * 3263 * Returns the Target Port Group identifier from the information 3264 * froom VPD page 0x83 of the device. 3265 * 3266 * Returns the identifier or error on failure. 3267 */ 3268 int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id) 3269 { 3270 const unsigned char *d; 3271 const struct scsi_vpd *vpd_pg83; 3272 int group_id = -EAGAIN, rel_port = -1; 3273 3274 rcu_read_lock(); 3275 vpd_pg83 = rcu_dereference(sdev->vpd_pg83); 3276 if (!vpd_pg83) { 3277 rcu_read_unlock(); 3278 return -ENXIO; 3279 } 3280 3281 d = vpd_pg83->data + 4; 3282 while (d < vpd_pg83->data + vpd_pg83->len) { 3283 switch (d[1] & 0xf) { 3284 case 0x4: 3285 /* Relative target port */ 3286 rel_port = get_unaligned_be16(&d[6]); 3287 break; 3288 case 0x5: 3289 /* Target port group */ 3290 group_id = get_unaligned_be16(&d[6]); 3291 break; 3292 default: 3293 break; 3294 } 3295 d += d[3] + 4; 3296 } 3297 rcu_read_unlock(); 3298 3299 if (group_id >= 0 && rel_id && rel_port != -1) 3300 *rel_id = rel_port; 3301 3302 return group_id; 3303 } 3304 EXPORT_SYMBOL(scsi_vpd_tpg_id); 3305 3306 /** 3307 * scsi_build_sense - build sense data for a command 3308 * @scmd: scsi command for which the sense should be formatted 3309 * @desc: Sense format (non-zero == descriptor format, 3310 * 0 == fixed format) 3311 * @key: Sense key 3312 * @asc: Additional sense code 3313 * @ascq: Additional sense code qualifier 3314 * 3315 **/ 3316 void scsi_build_sense(struct scsi_cmnd *scmd, int desc, u8 key, u8 asc, u8 ascq) 3317 { 3318 scsi_build_sense_buffer(desc, scmd->sense_buffer, key, asc, ascq); 3319 scmd->result = SAM_STAT_CHECK_CONDITION; 3320 } 3321 EXPORT_SYMBOL_GPL(scsi_build_sense); 3322