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