1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 1999 Eric Youngdale 4 * Copyright (C) 2014 Christoph Hellwig 5 * 6 * SCSI queueing library. 7 * Initial versions: Eric Youngdale (eric@andante.org). 8 * Based upon conversations with large numbers 9 * of people at Linux Expo. 10 */ 11 12 #include <linux/bio.h> 13 #include <linux/bitops.h> 14 #include <linux/blkdev.h> 15 #include <linux/completion.h> 16 #include <linux/kernel.h> 17 #include <linux/export.h> 18 #include <linux/init.h> 19 #include <linux/pci.h> 20 #include <linux/delay.h> 21 #include <linux/hardirq.h> 22 #include <linux/scatterlist.h> 23 #include <linux/blk-mq.h> 24 #include <linux/blk-integrity.h> 25 #include <linux/ratelimit.h> 26 #include <asm/unaligned.h> 27 28 #include <scsi/scsi.h> 29 #include <scsi/scsi_cmnd.h> 30 #include <scsi/scsi_dbg.h> 31 #include <scsi/scsi_device.h> 32 #include <scsi/scsi_driver.h> 33 #include <scsi/scsi_eh.h> 34 #include <scsi/scsi_host.h> 35 #include <scsi/scsi_transport.h> /* __scsi_init_queue() */ 36 #include <scsi/scsi_dh.h> 37 38 #include <trace/events/scsi.h> 39 40 #include "scsi_debugfs.h" 41 #include "scsi_priv.h" 42 #include "scsi_logging.h" 43 44 /* 45 * Size of integrity metadata is usually small, 1 inline sg should 46 * cover normal cases. 47 */ 48 #ifdef CONFIG_ARCH_NO_SG_CHAIN 49 #define SCSI_INLINE_PROT_SG_CNT 0 50 #define SCSI_INLINE_SG_CNT 0 51 #else 52 #define SCSI_INLINE_PROT_SG_CNT 1 53 #define SCSI_INLINE_SG_CNT 2 54 #endif 55 56 static struct kmem_cache *scsi_sense_cache; 57 static DEFINE_MUTEX(scsi_sense_cache_mutex); 58 59 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd); 60 61 int scsi_init_sense_cache(struct Scsi_Host *shost) 62 { 63 int ret = 0; 64 65 mutex_lock(&scsi_sense_cache_mutex); 66 if (!scsi_sense_cache) { 67 scsi_sense_cache = 68 kmem_cache_create_usercopy("scsi_sense_cache", 69 SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN, 70 0, SCSI_SENSE_BUFFERSIZE, NULL); 71 if (!scsi_sense_cache) 72 ret = -ENOMEM; 73 } 74 mutex_unlock(&scsi_sense_cache_mutex); 75 return ret; 76 } 77 78 static void 79 scsi_set_blocked(struct scsi_cmnd *cmd, int reason) 80 { 81 struct Scsi_Host *host = cmd->device->host; 82 struct scsi_device *device = cmd->device; 83 struct scsi_target *starget = scsi_target(device); 84 85 /* 86 * Set the appropriate busy bit for the device/host. 87 * 88 * If the host/device isn't busy, assume that something actually 89 * completed, and that we should be able to queue a command now. 90 * 91 * Note that the prior mid-layer assumption that any host could 92 * always queue at least one command is now broken. The mid-layer 93 * will implement a user specifiable stall (see 94 * scsi_host.max_host_blocked and scsi_device.max_device_blocked) 95 * if a command is requeued with no other commands outstanding 96 * either for the device or for the host. 97 */ 98 switch (reason) { 99 case SCSI_MLQUEUE_HOST_BUSY: 100 atomic_set(&host->host_blocked, host->max_host_blocked); 101 break; 102 case SCSI_MLQUEUE_DEVICE_BUSY: 103 case SCSI_MLQUEUE_EH_RETRY: 104 atomic_set(&device->device_blocked, 105 device->max_device_blocked); 106 break; 107 case SCSI_MLQUEUE_TARGET_BUSY: 108 atomic_set(&starget->target_blocked, 109 starget->max_target_blocked); 110 break; 111 } 112 } 113 114 static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd, unsigned long msecs) 115 { 116 struct request *rq = scsi_cmd_to_rq(cmd); 117 118 if (rq->rq_flags & RQF_DONTPREP) { 119 rq->rq_flags &= ~RQF_DONTPREP; 120 scsi_mq_uninit_cmd(cmd); 121 } else { 122 WARN_ON_ONCE(true); 123 } 124 125 blk_mq_requeue_request(rq, false); 126 if (!scsi_host_in_recovery(cmd->device->host)) 127 blk_mq_delay_kick_requeue_list(rq->q, msecs); 128 } 129 130 /** 131 * __scsi_queue_insert - private queue insertion 132 * @cmd: The SCSI command being requeued 133 * @reason: The reason for the requeue 134 * @unbusy: Whether the queue should be unbusied 135 * 136 * This is a private queue insertion. The public interface 137 * scsi_queue_insert() always assumes the queue should be unbusied 138 * because it's always called before the completion. This function is 139 * for a requeue after completion, which should only occur in this 140 * file. 141 */ 142 static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy) 143 { 144 struct scsi_device *device = cmd->device; 145 146 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd, 147 "Inserting command %p into mlqueue\n", cmd)); 148 149 scsi_set_blocked(cmd, reason); 150 151 /* 152 * Decrement the counters, since these commands are no longer 153 * active on the host/device. 154 */ 155 if (unbusy) 156 scsi_device_unbusy(device, cmd); 157 158 /* 159 * Requeue this command. It will go before all other commands 160 * that are already in the queue. Schedule requeue work under 161 * lock such that the kblockd_schedule_work() call happens 162 * before blk_mq_destroy_queue() finishes. 163 */ 164 cmd->result = 0; 165 166 blk_mq_requeue_request(scsi_cmd_to_rq(cmd), 167 !scsi_host_in_recovery(cmd->device->host)); 168 } 169 170 /** 171 * scsi_queue_insert - Reinsert a command in the queue. 172 * @cmd: command that we are adding to queue. 173 * @reason: why we are inserting command to queue. 174 * 175 * We do this for one of two cases. Either the host is busy and it cannot accept 176 * any more commands for the time being, or the device returned QUEUE_FULL and 177 * can accept no more commands. 178 * 179 * Context: This could be called either from an interrupt context or a normal 180 * process context. 181 */ 182 void scsi_queue_insert(struct scsi_cmnd *cmd, int reason) 183 { 184 __scsi_queue_insert(cmd, reason, true); 185 } 186 187 /** 188 * scsi_execute_cmd - insert request and wait for the result 189 * @sdev: scsi_device 190 * @cmd: scsi command 191 * @opf: block layer request cmd_flags 192 * @buffer: data buffer 193 * @bufflen: len of buffer 194 * @timeout: request timeout in HZ 195 * @retries: number of times to retry request 196 * @args: Optional args. See struct definition for field descriptions 197 * 198 * Returns the scsi_cmnd result field if a command was executed, or a negative 199 * Linux error code if we didn't get that far. 200 */ 201 int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd, 202 blk_opf_t opf, void *buffer, unsigned int bufflen, 203 int timeout, int retries, 204 const struct scsi_exec_args *args) 205 { 206 static const struct scsi_exec_args default_args; 207 struct request *req; 208 struct scsi_cmnd *scmd; 209 int ret; 210 211 if (!args) 212 args = &default_args; 213 else if (WARN_ON_ONCE(args->sense && 214 args->sense_len != SCSI_SENSE_BUFFERSIZE)) 215 return -EINVAL; 216 217 req = scsi_alloc_request(sdev->request_queue, opf, args->req_flags); 218 if (IS_ERR(req)) 219 return PTR_ERR(req); 220 221 if (bufflen) { 222 ret = blk_rq_map_kern(sdev->request_queue, req, 223 buffer, bufflen, GFP_NOIO); 224 if (ret) 225 goto out; 226 } 227 scmd = blk_mq_rq_to_pdu(req); 228 scmd->cmd_len = COMMAND_SIZE(cmd[0]); 229 memcpy(scmd->cmnd, cmd, scmd->cmd_len); 230 scmd->allowed = retries; 231 scmd->flags |= args->scmd_flags; 232 req->timeout = timeout; 233 req->rq_flags |= RQF_QUIET; 234 235 /* 236 * head injection *required* here otherwise quiesce won't work 237 */ 238 blk_execute_rq(req, true); 239 240 /* 241 * Some devices (USB mass-storage in particular) may transfer 242 * garbage data together with a residue indicating that the data 243 * is invalid. Prevent the garbage from being misinterpreted 244 * and prevent security leaks by zeroing out the excess data. 245 */ 246 if (unlikely(scmd->resid_len > 0 && scmd->resid_len <= bufflen)) 247 memset(buffer + bufflen - scmd->resid_len, 0, scmd->resid_len); 248 249 if (args->resid) 250 *args->resid = scmd->resid_len; 251 if (args->sense) 252 memcpy(args->sense, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE); 253 if (args->sshdr) 254 scsi_normalize_sense(scmd->sense_buffer, scmd->sense_len, 255 args->sshdr); 256 257 ret = scmd->result; 258 out: 259 blk_mq_free_request(req); 260 261 return ret; 262 } 263 EXPORT_SYMBOL(scsi_execute_cmd); 264 265 /* 266 * Wake up the error handler if necessary. Avoid as follows that the error 267 * handler is not woken up if host in-flight requests number == 268 * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination 269 * with an RCU read lock in this function to ensure that this function in 270 * its entirety either finishes before scsi_eh_scmd_add() increases the 271 * host_failed counter or that it notices the shost state change made by 272 * scsi_eh_scmd_add(). 273 */ 274 static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd) 275 { 276 unsigned long flags; 277 278 rcu_read_lock(); 279 __clear_bit(SCMD_STATE_INFLIGHT, &cmd->state); 280 if (unlikely(scsi_host_in_recovery(shost))) { 281 spin_lock_irqsave(shost->host_lock, flags); 282 if (shost->host_failed || shost->host_eh_scheduled) 283 scsi_eh_wakeup(shost); 284 spin_unlock_irqrestore(shost->host_lock, flags); 285 } 286 rcu_read_unlock(); 287 } 288 289 void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd) 290 { 291 struct Scsi_Host *shost = sdev->host; 292 struct scsi_target *starget = scsi_target(sdev); 293 294 scsi_dec_host_busy(shost, cmd); 295 296 if (starget->can_queue > 0) 297 atomic_dec(&starget->target_busy); 298 299 sbitmap_put(&sdev->budget_map, cmd->budget_token); 300 cmd->budget_token = -1; 301 } 302 303 static void scsi_kick_queue(struct request_queue *q) 304 { 305 blk_mq_run_hw_queues(q, false); 306 } 307 308 /* 309 * Kick the queue of SCSI device @sdev if @sdev != current_sdev. Called with 310 * interrupts disabled. 311 */ 312 static void scsi_kick_sdev_queue(struct scsi_device *sdev, void *data) 313 { 314 struct scsi_device *current_sdev = data; 315 316 if (sdev != current_sdev) 317 blk_mq_run_hw_queues(sdev->request_queue, true); 318 } 319 320 /* 321 * Called for single_lun devices on IO completion. Clear starget_sdev_user, 322 * and call blk_run_queue for all the scsi_devices on the target - 323 * including current_sdev first. 324 * 325 * Called with *no* scsi locks held. 326 */ 327 static void scsi_single_lun_run(struct scsi_device *current_sdev) 328 { 329 struct Scsi_Host *shost = current_sdev->host; 330 struct scsi_target *starget = scsi_target(current_sdev); 331 unsigned long flags; 332 333 spin_lock_irqsave(shost->host_lock, flags); 334 starget->starget_sdev_user = NULL; 335 spin_unlock_irqrestore(shost->host_lock, flags); 336 337 /* 338 * Call blk_run_queue for all LUNs on the target, starting with 339 * current_sdev. We race with others (to set starget_sdev_user), 340 * but in most cases, we will be first. Ideally, each LU on the 341 * target would get some limited time or requests on the target. 342 */ 343 scsi_kick_queue(current_sdev->request_queue); 344 345 spin_lock_irqsave(shost->host_lock, flags); 346 if (!starget->starget_sdev_user) 347 __starget_for_each_device(starget, current_sdev, 348 scsi_kick_sdev_queue); 349 spin_unlock_irqrestore(shost->host_lock, flags); 350 } 351 352 static inline bool scsi_device_is_busy(struct scsi_device *sdev) 353 { 354 if (scsi_device_busy(sdev) >= sdev->queue_depth) 355 return true; 356 if (atomic_read(&sdev->device_blocked) > 0) 357 return true; 358 return false; 359 } 360 361 static inline bool scsi_target_is_busy(struct scsi_target *starget) 362 { 363 if (starget->can_queue > 0) { 364 if (atomic_read(&starget->target_busy) >= starget->can_queue) 365 return true; 366 if (atomic_read(&starget->target_blocked) > 0) 367 return true; 368 } 369 return false; 370 } 371 372 static inline bool scsi_host_is_busy(struct Scsi_Host *shost) 373 { 374 if (atomic_read(&shost->host_blocked) > 0) 375 return true; 376 if (shost->host_self_blocked) 377 return true; 378 return false; 379 } 380 381 static void scsi_starved_list_run(struct Scsi_Host *shost) 382 { 383 LIST_HEAD(starved_list); 384 struct scsi_device *sdev; 385 unsigned long flags; 386 387 spin_lock_irqsave(shost->host_lock, flags); 388 list_splice_init(&shost->starved_list, &starved_list); 389 390 while (!list_empty(&starved_list)) { 391 struct request_queue *slq; 392 393 /* 394 * As long as shost is accepting commands and we have 395 * starved queues, call blk_run_queue. scsi_request_fn 396 * drops the queue_lock and can add us back to the 397 * starved_list. 398 * 399 * host_lock protects the starved_list and starved_entry. 400 * scsi_request_fn must get the host_lock before checking 401 * or modifying starved_list or starved_entry. 402 */ 403 if (scsi_host_is_busy(shost)) 404 break; 405 406 sdev = list_entry(starved_list.next, 407 struct scsi_device, starved_entry); 408 list_del_init(&sdev->starved_entry); 409 if (scsi_target_is_busy(scsi_target(sdev))) { 410 list_move_tail(&sdev->starved_entry, 411 &shost->starved_list); 412 continue; 413 } 414 415 /* 416 * Once we drop the host lock, a racing scsi_remove_device() 417 * call may remove the sdev from the starved list and destroy 418 * it and the queue. Mitigate by taking a reference to the 419 * queue and never touching the sdev again after we drop the 420 * host lock. Note: if __scsi_remove_device() invokes 421 * blk_mq_destroy_queue() before the queue is run from this 422 * function then blk_run_queue() will return immediately since 423 * blk_mq_destroy_queue() marks the queue with QUEUE_FLAG_DYING. 424 */ 425 slq = sdev->request_queue; 426 if (!blk_get_queue(slq)) 427 continue; 428 spin_unlock_irqrestore(shost->host_lock, flags); 429 430 scsi_kick_queue(slq); 431 blk_put_queue(slq); 432 433 spin_lock_irqsave(shost->host_lock, flags); 434 } 435 /* put any unprocessed entries back */ 436 list_splice(&starved_list, &shost->starved_list); 437 spin_unlock_irqrestore(shost->host_lock, flags); 438 } 439 440 /** 441 * scsi_run_queue - Select a proper request queue to serve next. 442 * @q: last request's queue 443 * 444 * The previous command was completely finished, start a new one if possible. 445 */ 446 static void scsi_run_queue(struct request_queue *q) 447 { 448 struct scsi_device *sdev = q->queuedata; 449 450 if (scsi_target(sdev)->single_lun) 451 scsi_single_lun_run(sdev); 452 if (!list_empty(&sdev->host->starved_list)) 453 scsi_starved_list_run(sdev->host); 454 455 blk_mq_kick_requeue_list(q); 456 blk_mq_run_hw_queues(q, false); 457 } 458 459 void scsi_requeue_run_queue(struct work_struct *work) 460 { 461 struct scsi_device *sdev; 462 struct request_queue *q; 463 464 sdev = container_of(work, struct scsi_device, requeue_work); 465 q = sdev->request_queue; 466 scsi_run_queue(q); 467 } 468 469 void scsi_run_host_queues(struct Scsi_Host *shost) 470 { 471 struct scsi_device *sdev; 472 473 shost_for_each_device(sdev, shost) 474 scsi_run_queue(sdev->request_queue); 475 } 476 477 static void scsi_uninit_cmd(struct scsi_cmnd *cmd) 478 { 479 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) { 480 struct scsi_driver *drv = scsi_cmd_to_driver(cmd); 481 482 if (drv->uninit_command) 483 drv->uninit_command(cmd); 484 } 485 } 486 487 void scsi_free_sgtables(struct scsi_cmnd *cmd) 488 { 489 if (cmd->sdb.table.nents) 490 sg_free_table_chained(&cmd->sdb.table, 491 SCSI_INLINE_SG_CNT); 492 if (scsi_prot_sg_count(cmd)) 493 sg_free_table_chained(&cmd->prot_sdb->table, 494 SCSI_INLINE_PROT_SG_CNT); 495 } 496 EXPORT_SYMBOL_GPL(scsi_free_sgtables); 497 498 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd) 499 { 500 scsi_free_sgtables(cmd); 501 scsi_uninit_cmd(cmd); 502 } 503 504 static void scsi_run_queue_async(struct scsi_device *sdev) 505 { 506 if (scsi_host_in_recovery(sdev->host)) 507 return; 508 509 if (scsi_target(sdev)->single_lun || 510 !list_empty(&sdev->host->starved_list)) { 511 kblockd_schedule_work(&sdev->requeue_work); 512 } else { 513 /* 514 * smp_mb() present in sbitmap_queue_clear() or implied in 515 * .end_io is for ordering writing .device_busy in 516 * scsi_device_unbusy() and reading sdev->restarts. 517 */ 518 int old = atomic_read(&sdev->restarts); 519 520 /* 521 * ->restarts has to be kept as non-zero if new budget 522 * contention occurs. 523 * 524 * No need to run queue when either another re-run 525 * queue wins in updating ->restarts or a new budget 526 * contention occurs. 527 */ 528 if (old && atomic_cmpxchg(&sdev->restarts, old, 0) == old) 529 blk_mq_run_hw_queues(sdev->request_queue, true); 530 } 531 } 532 533 /* Returns false when no more bytes to process, true if there are more */ 534 static bool scsi_end_request(struct request *req, blk_status_t error, 535 unsigned int bytes) 536 { 537 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 538 struct scsi_device *sdev = cmd->device; 539 struct request_queue *q = sdev->request_queue; 540 541 if (blk_update_request(req, error, bytes)) 542 return true; 543 544 // XXX: 545 if (blk_queue_add_random(q)) 546 add_disk_randomness(req->q->disk); 547 548 if (!blk_rq_is_passthrough(req)) { 549 WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED)); 550 cmd->flags &= ~SCMD_INITIALIZED; 551 } 552 553 /* 554 * Calling rcu_barrier() is not necessary here because the 555 * SCSI error handler guarantees that the function called by 556 * call_rcu() has been called before scsi_end_request() is 557 * called. 558 */ 559 destroy_rcu_head(&cmd->rcu); 560 561 /* 562 * In the MQ case the command gets freed by __blk_mq_end_request, 563 * so we have to do all cleanup that depends on it earlier. 564 * 565 * We also can't kick the queues from irq context, so we 566 * will have to defer it to a workqueue. 567 */ 568 scsi_mq_uninit_cmd(cmd); 569 570 /* 571 * queue is still alive, so grab the ref for preventing it 572 * from being cleaned up during running queue. 573 */ 574 percpu_ref_get(&q->q_usage_counter); 575 576 __blk_mq_end_request(req, error); 577 578 scsi_run_queue_async(sdev); 579 580 percpu_ref_put(&q->q_usage_counter); 581 return false; 582 } 583 584 /** 585 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t 586 * @result: scsi error code 587 * 588 * Translate a SCSI result code into a blk_status_t value. 589 */ 590 static blk_status_t scsi_result_to_blk_status(int result) 591 { 592 /* 593 * Check the scsi-ml byte first in case we converted a host or status 594 * byte. 595 */ 596 switch (scsi_ml_byte(result)) { 597 case SCSIML_STAT_OK: 598 break; 599 case SCSIML_STAT_RESV_CONFLICT: 600 return BLK_STS_RESV_CONFLICT; 601 case SCSIML_STAT_NOSPC: 602 return BLK_STS_NOSPC; 603 case SCSIML_STAT_MED_ERROR: 604 return BLK_STS_MEDIUM; 605 case SCSIML_STAT_TGT_FAILURE: 606 return BLK_STS_TARGET; 607 case SCSIML_STAT_DL_TIMEOUT: 608 return BLK_STS_DURATION_LIMIT; 609 } 610 611 switch (host_byte(result)) { 612 case DID_OK: 613 if (scsi_status_is_good(result)) 614 return BLK_STS_OK; 615 return BLK_STS_IOERR; 616 case DID_TRANSPORT_FAILFAST: 617 case DID_TRANSPORT_MARGINAL: 618 return BLK_STS_TRANSPORT; 619 default: 620 return BLK_STS_IOERR; 621 } 622 } 623 624 /** 625 * scsi_rq_err_bytes - determine number of bytes till the next failure boundary 626 * @rq: request to examine 627 * 628 * Description: 629 * A request could be merge of IOs which require different failure 630 * handling. This function determines the number of bytes which 631 * can be failed from the beginning of the request without 632 * crossing into area which need to be retried further. 633 * 634 * Return: 635 * The number of bytes to fail. 636 */ 637 static unsigned int scsi_rq_err_bytes(const struct request *rq) 638 { 639 blk_opf_t ff = rq->cmd_flags & REQ_FAILFAST_MASK; 640 unsigned int bytes = 0; 641 struct bio *bio; 642 643 if (!(rq->rq_flags & RQF_MIXED_MERGE)) 644 return blk_rq_bytes(rq); 645 646 /* 647 * Currently the only 'mixing' which can happen is between 648 * different fastfail types. We can safely fail portions 649 * which have all the failfast bits that the first one has - 650 * the ones which are at least as eager to fail as the first 651 * one. 652 */ 653 for (bio = rq->bio; bio; bio = bio->bi_next) { 654 if ((bio->bi_opf & ff) != ff) 655 break; 656 bytes += bio->bi_iter.bi_size; 657 } 658 659 /* this could lead to infinite loop */ 660 BUG_ON(blk_rq_bytes(rq) && !bytes); 661 return bytes; 662 } 663 664 static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd) 665 { 666 struct request *req = scsi_cmd_to_rq(cmd); 667 unsigned long wait_for; 668 669 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT) 670 return false; 671 672 wait_for = (cmd->allowed + 1) * req->timeout; 673 if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { 674 scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n", 675 wait_for/HZ); 676 return true; 677 } 678 return false; 679 } 680 681 /* 682 * When ALUA transition state is returned, reprep the cmd to 683 * use the ALUA handler's transition timeout. Delay the reprep 684 * 1 sec to avoid aggressive retries of the target in that 685 * state. 686 */ 687 #define ALUA_TRANSITION_REPREP_DELAY 1000 688 689 /* Helper for scsi_io_completion() when special action required. */ 690 static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result) 691 { 692 struct request *req = scsi_cmd_to_rq(cmd); 693 int level = 0; 694 enum {ACTION_FAIL, ACTION_REPREP, ACTION_DELAYED_REPREP, 695 ACTION_RETRY, ACTION_DELAYED_RETRY} action; 696 struct scsi_sense_hdr sshdr; 697 bool sense_valid; 698 bool sense_current = true; /* false implies "deferred sense" */ 699 blk_status_t blk_stat; 700 701 sense_valid = scsi_command_normalize_sense(cmd, &sshdr); 702 if (sense_valid) 703 sense_current = !scsi_sense_is_deferred(&sshdr); 704 705 blk_stat = scsi_result_to_blk_status(result); 706 707 if (host_byte(result) == DID_RESET) { 708 /* Third party bus reset or reset for error recovery 709 * reasons. Just retry the command and see what 710 * happens. 711 */ 712 action = ACTION_RETRY; 713 } else if (sense_valid && sense_current) { 714 switch (sshdr.sense_key) { 715 case UNIT_ATTENTION: 716 if (cmd->device->removable) { 717 /* Detected disc change. Set a bit 718 * and quietly refuse further access. 719 */ 720 cmd->device->changed = 1; 721 action = ACTION_FAIL; 722 } else { 723 /* Must have been a power glitch, or a 724 * bus reset. Could not have been a 725 * media change, so we just retry the 726 * command and see what happens. 727 */ 728 action = ACTION_RETRY; 729 } 730 break; 731 case ILLEGAL_REQUEST: 732 /* If we had an ILLEGAL REQUEST returned, then 733 * we may have performed an unsupported 734 * command. The only thing this should be 735 * would be a ten byte read where only a six 736 * byte read was supported. Also, on a system 737 * where READ CAPACITY failed, we may have 738 * read past the end of the disk. 739 */ 740 if ((cmd->device->use_10_for_rw && 741 sshdr.asc == 0x20 && sshdr.ascq == 0x00) && 742 (cmd->cmnd[0] == READ_10 || 743 cmd->cmnd[0] == WRITE_10)) { 744 /* This will issue a new 6-byte command. */ 745 cmd->device->use_10_for_rw = 0; 746 action = ACTION_REPREP; 747 } else if (sshdr.asc == 0x10) /* DIX */ { 748 action = ACTION_FAIL; 749 blk_stat = BLK_STS_PROTECTION; 750 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */ 751 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) { 752 action = ACTION_FAIL; 753 blk_stat = BLK_STS_TARGET; 754 } else 755 action = ACTION_FAIL; 756 break; 757 case ABORTED_COMMAND: 758 action = ACTION_FAIL; 759 if (sshdr.asc == 0x10) /* DIF */ 760 blk_stat = BLK_STS_PROTECTION; 761 break; 762 case NOT_READY: 763 /* If the device is in the process of becoming 764 * ready, or has a temporary blockage, retry. 765 */ 766 if (sshdr.asc == 0x04) { 767 switch (sshdr.ascq) { 768 case 0x01: /* becoming ready */ 769 case 0x04: /* format in progress */ 770 case 0x05: /* rebuild in progress */ 771 case 0x06: /* recalculation in progress */ 772 case 0x07: /* operation in progress */ 773 case 0x08: /* Long write in progress */ 774 case 0x09: /* self test in progress */ 775 case 0x11: /* notify (enable spinup) required */ 776 case 0x14: /* space allocation in progress */ 777 case 0x1a: /* start stop unit in progress */ 778 case 0x1b: /* sanitize in progress */ 779 case 0x1d: /* configuration in progress */ 780 case 0x24: /* depopulation in progress */ 781 action = ACTION_DELAYED_RETRY; 782 break; 783 case 0x0a: /* ALUA state transition */ 784 action = ACTION_DELAYED_REPREP; 785 break; 786 default: 787 action = ACTION_FAIL; 788 break; 789 } 790 } else 791 action = ACTION_FAIL; 792 break; 793 case VOLUME_OVERFLOW: 794 /* See SSC3rXX or current. */ 795 action = ACTION_FAIL; 796 break; 797 case DATA_PROTECT: 798 action = ACTION_FAIL; 799 if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) || 800 (sshdr.asc == 0x55 && 801 (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) { 802 /* Insufficient zone resources */ 803 blk_stat = BLK_STS_ZONE_OPEN_RESOURCE; 804 } 805 break; 806 case COMPLETED: 807 fallthrough; 808 default: 809 action = ACTION_FAIL; 810 break; 811 } 812 } else 813 action = ACTION_FAIL; 814 815 if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd)) 816 action = ACTION_FAIL; 817 818 switch (action) { 819 case ACTION_FAIL: 820 /* Give up and fail the remainder of the request */ 821 if (!(req->rq_flags & RQF_QUIET)) { 822 static DEFINE_RATELIMIT_STATE(_rs, 823 DEFAULT_RATELIMIT_INTERVAL, 824 DEFAULT_RATELIMIT_BURST); 825 826 if (unlikely(scsi_logging_level)) 827 level = 828 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT, 829 SCSI_LOG_MLCOMPLETE_BITS); 830 831 /* 832 * if logging is enabled the failure will be printed 833 * in scsi_log_completion(), so avoid duplicate messages 834 */ 835 if (!level && __ratelimit(&_rs)) { 836 scsi_print_result(cmd, NULL, FAILED); 837 if (sense_valid) 838 scsi_print_sense(cmd); 839 scsi_print_command(cmd); 840 } 841 } 842 if (!scsi_end_request(req, blk_stat, scsi_rq_err_bytes(req))) 843 return; 844 fallthrough; 845 case ACTION_REPREP: 846 scsi_mq_requeue_cmd(cmd, 0); 847 break; 848 case ACTION_DELAYED_REPREP: 849 scsi_mq_requeue_cmd(cmd, ALUA_TRANSITION_REPREP_DELAY); 850 break; 851 case ACTION_RETRY: 852 /* Retry the same command immediately */ 853 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false); 854 break; 855 case ACTION_DELAYED_RETRY: 856 /* Retry the same command after a delay */ 857 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false); 858 break; 859 } 860 } 861 862 /* 863 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a 864 * new result that may suppress further error checking. Also modifies 865 * *blk_statp in some cases. 866 */ 867 static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result, 868 blk_status_t *blk_statp) 869 { 870 bool sense_valid; 871 bool sense_current = true; /* false implies "deferred sense" */ 872 struct request *req = scsi_cmd_to_rq(cmd); 873 struct scsi_sense_hdr sshdr; 874 875 sense_valid = scsi_command_normalize_sense(cmd, &sshdr); 876 if (sense_valid) 877 sense_current = !scsi_sense_is_deferred(&sshdr); 878 879 if (blk_rq_is_passthrough(req)) { 880 if (sense_valid) { 881 /* 882 * SG_IO wants current and deferred errors 883 */ 884 cmd->sense_len = min(8 + cmd->sense_buffer[7], 885 SCSI_SENSE_BUFFERSIZE); 886 } 887 if (sense_current) 888 *blk_statp = scsi_result_to_blk_status(result); 889 } else if (blk_rq_bytes(req) == 0 && sense_current) { 890 /* 891 * Flush commands do not transfers any data, and thus cannot use 892 * good_bytes != blk_rq_bytes(req) as the signal for an error. 893 * This sets *blk_statp explicitly for the problem case. 894 */ 895 *blk_statp = scsi_result_to_blk_status(result); 896 } 897 /* 898 * Recovered errors need reporting, but they're always treated as 899 * success, so fiddle the result code here. For passthrough requests 900 * we already took a copy of the original into sreq->result which 901 * is what gets returned to the user 902 */ 903 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) { 904 bool do_print = true; 905 /* 906 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d] 907 * skip print since caller wants ATA registers. Only occurs 908 * on SCSI ATA PASS_THROUGH commands when CK_COND=1 909 */ 910 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d)) 911 do_print = false; 912 else if (req->rq_flags & RQF_QUIET) 913 do_print = false; 914 if (do_print) 915 scsi_print_sense(cmd); 916 result = 0; 917 /* for passthrough, *blk_statp may be set */ 918 *blk_statp = BLK_STS_OK; 919 } 920 /* 921 * Another corner case: the SCSI status byte is non-zero but 'good'. 922 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when 923 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD 924 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related 925 * intermediate statuses (both obsolete in SAM-4) as good. 926 */ 927 if ((result & 0xff) && scsi_status_is_good(result)) { 928 result = 0; 929 *blk_statp = BLK_STS_OK; 930 } 931 return result; 932 } 933 934 /** 935 * scsi_io_completion - Completion processing for SCSI commands. 936 * @cmd: command that is finished. 937 * @good_bytes: number of processed bytes. 938 * 939 * We will finish off the specified number of sectors. If we are done, the 940 * command block will be released and the queue function will be goosed. If we 941 * are not done then we have to figure out what to do next: 942 * 943 * a) We can call scsi_mq_requeue_cmd(). The request will be 944 * unprepared and put back on the queue. Then a new command will 945 * be created for it. This should be used if we made forward 946 * progress, or if we want to switch from READ(10) to READ(6) for 947 * example. 948 * 949 * b) We can call scsi_io_completion_action(). The request will be 950 * put back on the queue and retried using the same command as 951 * before, possibly after a delay. 952 * 953 * c) We can call scsi_end_request() with blk_stat other than 954 * BLK_STS_OK, to fail the remainder of the request. 955 */ 956 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) 957 { 958 int result = cmd->result; 959 struct request *req = scsi_cmd_to_rq(cmd); 960 blk_status_t blk_stat = BLK_STS_OK; 961 962 if (unlikely(result)) /* a nz result may or may not be an error */ 963 result = scsi_io_completion_nz_result(cmd, result, &blk_stat); 964 965 /* 966 * Next deal with any sectors which we were able to correctly 967 * handle. 968 */ 969 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd, 970 "%u sectors total, %d bytes done.\n", 971 blk_rq_sectors(req), good_bytes)); 972 973 /* 974 * Failed, zero length commands always need to drop down 975 * to retry code. Fast path should return in this block. 976 */ 977 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) { 978 if (likely(!scsi_end_request(req, blk_stat, good_bytes))) 979 return; /* no bytes remaining */ 980 } 981 982 /* Kill remainder if no retries. */ 983 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) { 984 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req))) 985 WARN_ONCE(true, 986 "Bytes remaining after failed, no-retry command"); 987 return; 988 } 989 990 /* 991 * If there had been no error, but we have leftover bytes in the 992 * request just queue the command up again. 993 */ 994 if (likely(result == 0)) 995 scsi_mq_requeue_cmd(cmd, 0); 996 else 997 scsi_io_completion_action(cmd, result); 998 } 999 1000 static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev, 1001 struct request *rq) 1002 { 1003 return sdev->dma_drain_len && blk_rq_is_passthrough(rq) && 1004 !op_is_write(req_op(rq)) && 1005 sdev->host->hostt->dma_need_drain(rq); 1006 } 1007 1008 /** 1009 * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists 1010 * @cmd: SCSI command data structure to initialize. 1011 * 1012 * Initializes @cmd->sdb and also @cmd->prot_sdb if data integrity is enabled 1013 * for @cmd. 1014 * 1015 * Returns: 1016 * * BLK_STS_OK - on success 1017 * * BLK_STS_RESOURCE - if the failure is retryable 1018 * * BLK_STS_IOERR - if the failure is fatal 1019 */ 1020 blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd) 1021 { 1022 struct scsi_device *sdev = cmd->device; 1023 struct request *rq = scsi_cmd_to_rq(cmd); 1024 unsigned short nr_segs = blk_rq_nr_phys_segments(rq); 1025 struct scatterlist *last_sg = NULL; 1026 blk_status_t ret; 1027 bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq); 1028 int count; 1029 1030 if (WARN_ON_ONCE(!nr_segs)) 1031 return BLK_STS_IOERR; 1032 1033 /* 1034 * Make sure there is space for the drain. The driver must adjust 1035 * max_hw_segments to be prepared for this. 1036 */ 1037 if (need_drain) 1038 nr_segs++; 1039 1040 /* 1041 * If sg table allocation fails, requeue request later. 1042 */ 1043 if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs, 1044 cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT))) 1045 return BLK_STS_RESOURCE; 1046 1047 /* 1048 * Next, walk the list, and fill in the addresses and sizes of 1049 * each segment. 1050 */ 1051 count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg); 1052 1053 if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) { 1054 unsigned int pad_len = 1055 (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1; 1056 1057 last_sg->length += pad_len; 1058 cmd->extra_len += pad_len; 1059 } 1060 1061 if (need_drain) { 1062 sg_unmark_end(last_sg); 1063 last_sg = sg_next(last_sg); 1064 sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len); 1065 sg_mark_end(last_sg); 1066 1067 cmd->extra_len += sdev->dma_drain_len; 1068 count++; 1069 } 1070 1071 BUG_ON(count > cmd->sdb.table.nents); 1072 cmd->sdb.table.nents = count; 1073 cmd->sdb.length = blk_rq_payload_bytes(rq); 1074 1075 if (blk_integrity_rq(rq)) { 1076 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb; 1077 int ivecs; 1078 1079 if (WARN_ON_ONCE(!prot_sdb)) { 1080 /* 1081 * This can happen if someone (e.g. multipath) 1082 * queues a command to a device on an adapter 1083 * that does not support DIX. 1084 */ 1085 ret = BLK_STS_IOERR; 1086 goto out_free_sgtables; 1087 } 1088 1089 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio); 1090 1091 if (sg_alloc_table_chained(&prot_sdb->table, ivecs, 1092 prot_sdb->table.sgl, 1093 SCSI_INLINE_PROT_SG_CNT)) { 1094 ret = BLK_STS_RESOURCE; 1095 goto out_free_sgtables; 1096 } 1097 1098 count = blk_rq_map_integrity_sg(rq->q, rq->bio, 1099 prot_sdb->table.sgl); 1100 BUG_ON(count > ivecs); 1101 BUG_ON(count > queue_max_integrity_segments(rq->q)); 1102 1103 cmd->prot_sdb = prot_sdb; 1104 cmd->prot_sdb->table.nents = count; 1105 } 1106 1107 return BLK_STS_OK; 1108 out_free_sgtables: 1109 scsi_free_sgtables(cmd); 1110 return ret; 1111 } 1112 EXPORT_SYMBOL(scsi_alloc_sgtables); 1113 1114 /** 1115 * scsi_initialize_rq - initialize struct scsi_cmnd partially 1116 * @rq: Request associated with the SCSI command to be initialized. 1117 * 1118 * This function initializes the members of struct scsi_cmnd that must be 1119 * initialized before request processing starts and that won't be 1120 * reinitialized if a SCSI command is requeued. 1121 */ 1122 static void scsi_initialize_rq(struct request *rq) 1123 { 1124 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); 1125 1126 memset(cmd->cmnd, 0, sizeof(cmd->cmnd)); 1127 cmd->cmd_len = MAX_COMMAND_SIZE; 1128 cmd->sense_len = 0; 1129 init_rcu_head(&cmd->rcu); 1130 cmd->jiffies_at_alloc = jiffies; 1131 cmd->retries = 0; 1132 } 1133 1134 struct request *scsi_alloc_request(struct request_queue *q, blk_opf_t opf, 1135 blk_mq_req_flags_t flags) 1136 { 1137 struct request *rq; 1138 1139 rq = blk_mq_alloc_request(q, opf, flags); 1140 if (!IS_ERR(rq)) 1141 scsi_initialize_rq(rq); 1142 return rq; 1143 } 1144 EXPORT_SYMBOL_GPL(scsi_alloc_request); 1145 1146 /* 1147 * Only called when the request isn't completed by SCSI, and not freed by 1148 * SCSI 1149 */ 1150 static void scsi_cleanup_rq(struct request *rq) 1151 { 1152 if (rq->rq_flags & RQF_DONTPREP) { 1153 scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq)); 1154 rq->rq_flags &= ~RQF_DONTPREP; 1155 } 1156 } 1157 1158 /* Called before a request is prepared. See also scsi_mq_prep_fn(). */ 1159 void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd) 1160 { 1161 struct request *rq = scsi_cmd_to_rq(cmd); 1162 1163 if (!blk_rq_is_passthrough(rq) && !(cmd->flags & SCMD_INITIALIZED)) { 1164 cmd->flags |= SCMD_INITIALIZED; 1165 scsi_initialize_rq(rq); 1166 } 1167 1168 cmd->device = dev; 1169 INIT_LIST_HEAD(&cmd->eh_entry); 1170 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler); 1171 } 1172 1173 static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev, 1174 struct request *req) 1175 { 1176 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 1177 1178 /* 1179 * Passthrough requests may transfer data, in which case they must 1180 * a bio attached to them. Or they might contain a SCSI command 1181 * that does not transfer data, in which case they may optionally 1182 * submit a request without an attached bio. 1183 */ 1184 if (req->bio) { 1185 blk_status_t ret = scsi_alloc_sgtables(cmd); 1186 if (unlikely(ret != BLK_STS_OK)) 1187 return ret; 1188 } else { 1189 BUG_ON(blk_rq_bytes(req)); 1190 1191 memset(&cmd->sdb, 0, sizeof(cmd->sdb)); 1192 } 1193 1194 cmd->transfersize = blk_rq_bytes(req); 1195 return BLK_STS_OK; 1196 } 1197 1198 static blk_status_t 1199 scsi_device_state_check(struct scsi_device *sdev, struct request *req) 1200 { 1201 switch (sdev->sdev_state) { 1202 case SDEV_CREATED: 1203 return BLK_STS_OK; 1204 case SDEV_OFFLINE: 1205 case SDEV_TRANSPORT_OFFLINE: 1206 /* 1207 * If the device is offline we refuse to process any 1208 * commands. The device must be brought online 1209 * before trying any recovery commands. 1210 */ 1211 if (!sdev->offline_already) { 1212 sdev->offline_already = true; 1213 sdev_printk(KERN_ERR, sdev, 1214 "rejecting I/O to offline device\n"); 1215 } 1216 return BLK_STS_IOERR; 1217 case SDEV_DEL: 1218 /* 1219 * If the device is fully deleted, we refuse to 1220 * process any commands as well. 1221 */ 1222 sdev_printk(KERN_ERR, sdev, 1223 "rejecting I/O to dead device\n"); 1224 return BLK_STS_IOERR; 1225 case SDEV_BLOCK: 1226 case SDEV_CREATED_BLOCK: 1227 return BLK_STS_RESOURCE; 1228 case SDEV_QUIESCE: 1229 /* 1230 * If the device is blocked we only accept power management 1231 * commands. 1232 */ 1233 if (req && WARN_ON_ONCE(!(req->rq_flags & RQF_PM))) 1234 return BLK_STS_RESOURCE; 1235 return BLK_STS_OK; 1236 default: 1237 /* 1238 * For any other not fully online state we only allow 1239 * power management commands. 1240 */ 1241 if (req && !(req->rq_flags & RQF_PM)) 1242 return BLK_STS_OFFLINE; 1243 return BLK_STS_OK; 1244 } 1245 } 1246 1247 /* 1248 * scsi_dev_queue_ready: if we can send requests to sdev, assign one token 1249 * and return the token else return -1. 1250 */ 1251 static inline int scsi_dev_queue_ready(struct request_queue *q, 1252 struct scsi_device *sdev) 1253 { 1254 int token; 1255 1256 token = sbitmap_get(&sdev->budget_map); 1257 if (atomic_read(&sdev->device_blocked)) { 1258 if (token < 0) 1259 goto out; 1260 1261 if (scsi_device_busy(sdev) > 1) 1262 goto out_dec; 1263 1264 /* 1265 * unblock after device_blocked iterates to zero 1266 */ 1267 if (atomic_dec_return(&sdev->device_blocked) > 0) 1268 goto out_dec; 1269 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev, 1270 "unblocking device at zero depth\n")); 1271 } 1272 1273 return token; 1274 out_dec: 1275 if (token >= 0) 1276 sbitmap_put(&sdev->budget_map, token); 1277 out: 1278 return -1; 1279 } 1280 1281 /* 1282 * scsi_target_queue_ready: checks if there we can send commands to target 1283 * @sdev: scsi device on starget to check. 1284 */ 1285 static inline int scsi_target_queue_ready(struct Scsi_Host *shost, 1286 struct scsi_device *sdev) 1287 { 1288 struct scsi_target *starget = scsi_target(sdev); 1289 unsigned int busy; 1290 1291 if (starget->single_lun) { 1292 spin_lock_irq(shost->host_lock); 1293 if (starget->starget_sdev_user && 1294 starget->starget_sdev_user != sdev) { 1295 spin_unlock_irq(shost->host_lock); 1296 return 0; 1297 } 1298 starget->starget_sdev_user = sdev; 1299 spin_unlock_irq(shost->host_lock); 1300 } 1301 1302 if (starget->can_queue <= 0) 1303 return 1; 1304 1305 busy = atomic_inc_return(&starget->target_busy) - 1; 1306 if (atomic_read(&starget->target_blocked) > 0) { 1307 if (busy) 1308 goto starved; 1309 1310 /* 1311 * unblock after target_blocked iterates to zero 1312 */ 1313 if (atomic_dec_return(&starget->target_blocked) > 0) 1314 goto out_dec; 1315 1316 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget, 1317 "unblocking target at zero depth\n")); 1318 } 1319 1320 if (busy >= starget->can_queue) 1321 goto starved; 1322 1323 return 1; 1324 1325 starved: 1326 spin_lock_irq(shost->host_lock); 1327 list_move_tail(&sdev->starved_entry, &shost->starved_list); 1328 spin_unlock_irq(shost->host_lock); 1329 out_dec: 1330 if (starget->can_queue > 0) 1331 atomic_dec(&starget->target_busy); 1332 return 0; 1333 } 1334 1335 /* 1336 * scsi_host_queue_ready: if we can send requests to shost, return 1 else 1337 * return 0. We must end up running the queue again whenever 0 is 1338 * returned, else IO can hang. 1339 */ 1340 static inline int scsi_host_queue_ready(struct request_queue *q, 1341 struct Scsi_Host *shost, 1342 struct scsi_device *sdev, 1343 struct scsi_cmnd *cmd) 1344 { 1345 if (atomic_read(&shost->host_blocked) > 0) { 1346 if (scsi_host_busy(shost) > 0) 1347 goto starved; 1348 1349 /* 1350 * unblock after host_blocked iterates to zero 1351 */ 1352 if (atomic_dec_return(&shost->host_blocked) > 0) 1353 goto out_dec; 1354 1355 SCSI_LOG_MLQUEUE(3, 1356 shost_printk(KERN_INFO, shost, 1357 "unblocking host at zero depth\n")); 1358 } 1359 1360 if (shost->host_self_blocked) 1361 goto starved; 1362 1363 /* We're OK to process the command, so we can't be starved */ 1364 if (!list_empty(&sdev->starved_entry)) { 1365 spin_lock_irq(shost->host_lock); 1366 if (!list_empty(&sdev->starved_entry)) 1367 list_del_init(&sdev->starved_entry); 1368 spin_unlock_irq(shost->host_lock); 1369 } 1370 1371 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state); 1372 1373 return 1; 1374 1375 starved: 1376 spin_lock_irq(shost->host_lock); 1377 if (list_empty(&sdev->starved_entry)) 1378 list_add_tail(&sdev->starved_entry, &shost->starved_list); 1379 spin_unlock_irq(shost->host_lock); 1380 out_dec: 1381 scsi_dec_host_busy(shost, cmd); 1382 return 0; 1383 } 1384 1385 /* 1386 * Busy state exporting function for request stacking drivers. 1387 * 1388 * For efficiency, no lock is taken to check the busy state of 1389 * shost/starget/sdev, since the returned value is not guaranteed and 1390 * may be changed after request stacking drivers call the function, 1391 * regardless of taking lock or not. 1392 * 1393 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi 1394 * needs to return 'not busy'. Otherwise, request stacking drivers 1395 * may hold requests forever. 1396 */ 1397 static bool scsi_mq_lld_busy(struct request_queue *q) 1398 { 1399 struct scsi_device *sdev = q->queuedata; 1400 struct Scsi_Host *shost; 1401 1402 if (blk_queue_dying(q)) 1403 return false; 1404 1405 shost = sdev->host; 1406 1407 /* 1408 * Ignore host/starget busy state. 1409 * Since block layer does not have a concept of fairness across 1410 * multiple queues, congestion of host/starget needs to be handled 1411 * in SCSI layer. 1412 */ 1413 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev)) 1414 return true; 1415 1416 return false; 1417 } 1418 1419 /* 1420 * Block layer request completion callback. May be called from interrupt 1421 * context. 1422 */ 1423 static void scsi_complete(struct request *rq) 1424 { 1425 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); 1426 enum scsi_disposition disposition; 1427 1428 INIT_LIST_HEAD(&cmd->eh_entry); 1429 1430 atomic_inc(&cmd->device->iodone_cnt); 1431 if (cmd->result) 1432 atomic_inc(&cmd->device->ioerr_cnt); 1433 1434 disposition = scsi_decide_disposition(cmd); 1435 if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd)) 1436 disposition = SUCCESS; 1437 1438 scsi_log_completion(cmd, disposition); 1439 1440 switch (disposition) { 1441 case SUCCESS: 1442 scsi_finish_command(cmd); 1443 break; 1444 case NEEDS_RETRY: 1445 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY); 1446 break; 1447 case ADD_TO_MLQUEUE: 1448 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); 1449 break; 1450 default: 1451 scsi_eh_scmd_add(cmd); 1452 break; 1453 } 1454 } 1455 1456 /** 1457 * scsi_dispatch_cmd - Dispatch a command to the low-level driver. 1458 * @cmd: command block we are dispatching. 1459 * 1460 * Return: nonzero return request was rejected and device's queue needs to be 1461 * plugged. 1462 */ 1463 static int scsi_dispatch_cmd(struct scsi_cmnd *cmd) 1464 { 1465 struct Scsi_Host *host = cmd->device->host; 1466 int rtn = 0; 1467 1468 atomic_inc(&cmd->device->iorequest_cnt); 1469 1470 /* check if the device is still usable */ 1471 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) { 1472 /* in SDEV_DEL we error all commands. DID_NO_CONNECT 1473 * returns an immediate error upwards, and signals 1474 * that the device is no longer present */ 1475 cmd->result = DID_NO_CONNECT << 16; 1476 goto done; 1477 } 1478 1479 /* Check to see if the scsi lld made this device blocked. */ 1480 if (unlikely(scsi_device_blocked(cmd->device))) { 1481 /* 1482 * in blocked state, the command is just put back on 1483 * the device queue. The suspend state has already 1484 * blocked the queue so future requests should not 1485 * occur until the device transitions out of the 1486 * suspend state. 1487 */ 1488 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, 1489 "queuecommand : device blocked\n")); 1490 atomic_dec(&cmd->device->iorequest_cnt); 1491 return SCSI_MLQUEUE_DEVICE_BUSY; 1492 } 1493 1494 /* Store the LUN value in cmnd, if needed. */ 1495 if (cmd->device->lun_in_cdb) 1496 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) | 1497 (cmd->device->lun << 5 & 0xe0); 1498 1499 scsi_log_send(cmd); 1500 1501 /* 1502 * Before we queue this command, check if the command 1503 * length exceeds what the host adapter can handle. 1504 */ 1505 if (cmd->cmd_len > cmd->device->host->max_cmd_len) { 1506 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, 1507 "queuecommand : command too long. " 1508 "cdb_size=%d host->max_cmd_len=%d\n", 1509 cmd->cmd_len, cmd->device->host->max_cmd_len)); 1510 cmd->result = (DID_ABORT << 16); 1511 goto done; 1512 } 1513 1514 if (unlikely(host->shost_state == SHOST_DEL)) { 1515 cmd->result = (DID_NO_CONNECT << 16); 1516 goto done; 1517 1518 } 1519 1520 trace_scsi_dispatch_cmd_start(cmd); 1521 rtn = host->hostt->queuecommand(host, cmd); 1522 if (rtn) { 1523 atomic_dec(&cmd->device->iorequest_cnt); 1524 trace_scsi_dispatch_cmd_error(cmd, rtn); 1525 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY && 1526 rtn != SCSI_MLQUEUE_TARGET_BUSY) 1527 rtn = SCSI_MLQUEUE_HOST_BUSY; 1528 1529 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, 1530 "queuecommand : request rejected\n")); 1531 } 1532 1533 return rtn; 1534 done: 1535 scsi_done(cmd); 1536 return 0; 1537 } 1538 1539 /* Size in bytes of the sg-list stored in the scsi-mq command-private data. */ 1540 static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost) 1541 { 1542 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) * 1543 sizeof(struct scatterlist); 1544 } 1545 1546 static blk_status_t scsi_prepare_cmd(struct request *req) 1547 { 1548 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 1549 struct scsi_device *sdev = req->q->queuedata; 1550 struct Scsi_Host *shost = sdev->host; 1551 bool in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state); 1552 struct scatterlist *sg; 1553 1554 scsi_init_command(sdev, cmd); 1555 1556 cmd->eh_eflags = 0; 1557 cmd->prot_type = 0; 1558 cmd->prot_flags = 0; 1559 cmd->submitter = 0; 1560 memset(&cmd->sdb, 0, sizeof(cmd->sdb)); 1561 cmd->underflow = 0; 1562 cmd->transfersize = 0; 1563 cmd->host_scribble = NULL; 1564 cmd->result = 0; 1565 cmd->extra_len = 0; 1566 cmd->state = 0; 1567 if (in_flight) 1568 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state); 1569 1570 /* 1571 * Only clear the driver-private command data if the LLD does not supply 1572 * a function to initialize that data. 1573 */ 1574 if (!shost->hostt->init_cmd_priv) 1575 memset(cmd + 1, 0, shost->hostt->cmd_size); 1576 1577 cmd->prot_op = SCSI_PROT_NORMAL; 1578 if (blk_rq_bytes(req)) 1579 cmd->sc_data_direction = rq_dma_dir(req); 1580 else 1581 cmd->sc_data_direction = DMA_NONE; 1582 1583 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size; 1584 cmd->sdb.table.sgl = sg; 1585 1586 if (scsi_host_get_prot(shost)) { 1587 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer)); 1588 1589 cmd->prot_sdb->table.sgl = 1590 (struct scatterlist *)(cmd->prot_sdb + 1); 1591 } 1592 1593 /* 1594 * Special handling for passthrough commands, which don't go to the ULP 1595 * at all: 1596 */ 1597 if (blk_rq_is_passthrough(req)) 1598 return scsi_setup_scsi_cmnd(sdev, req); 1599 1600 if (sdev->handler && sdev->handler->prep_fn) { 1601 blk_status_t ret = sdev->handler->prep_fn(sdev, req); 1602 1603 if (ret != BLK_STS_OK) 1604 return ret; 1605 } 1606 1607 /* Usually overridden by the ULP */ 1608 cmd->allowed = 0; 1609 memset(cmd->cmnd, 0, sizeof(cmd->cmnd)); 1610 return scsi_cmd_to_driver(cmd)->init_command(cmd); 1611 } 1612 1613 static void scsi_done_internal(struct scsi_cmnd *cmd, bool complete_directly) 1614 { 1615 struct request *req = scsi_cmd_to_rq(cmd); 1616 1617 switch (cmd->submitter) { 1618 case SUBMITTED_BY_BLOCK_LAYER: 1619 break; 1620 case SUBMITTED_BY_SCSI_ERROR_HANDLER: 1621 return scsi_eh_done(cmd); 1622 case SUBMITTED_BY_SCSI_RESET_IOCTL: 1623 return; 1624 } 1625 1626 if (unlikely(blk_should_fake_timeout(scsi_cmd_to_rq(cmd)->q))) 1627 return; 1628 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state))) 1629 return; 1630 trace_scsi_dispatch_cmd_done(cmd); 1631 1632 if (complete_directly) 1633 blk_mq_complete_request_direct(req, scsi_complete); 1634 else 1635 blk_mq_complete_request(req); 1636 } 1637 1638 void scsi_done(struct scsi_cmnd *cmd) 1639 { 1640 scsi_done_internal(cmd, false); 1641 } 1642 EXPORT_SYMBOL(scsi_done); 1643 1644 void scsi_done_direct(struct scsi_cmnd *cmd) 1645 { 1646 scsi_done_internal(cmd, true); 1647 } 1648 EXPORT_SYMBOL(scsi_done_direct); 1649 1650 static void scsi_mq_put_budget(struct request_queue *q, int budget_token) 1651 { 1652 struct scsi_device *sdev = q->queuedata; 1653 1654 sbitmap_put(&sdev->budget_map, budget_token); 1655 } 1656 1657 /* 1658 * When to reinvoke queueing after a resource shortage. It's 3 msecs to 1659 * not change behaviour from the previous unplug mechanism, experimentation 1660 * may prove this needs changing. 1661 */ 1662 #define SCSI_QUEUE_DELAY 3 1663 1664 static int scsi_mq_get_budget(struct request_queue *q) 1665 { 1666 struct scsi_device *sdev = q->queuedata; 1667 int token = scsi_dev_queue_ready(q, sdev); 1668 1669 if (token >= 0) 1670 return token; 1671 1672 atomic_inc(&sdev->restarts); 1673 1674 /* 1675 * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy). 1676 * .restarts must be incremented before .device_busy is read because the 1677 * code in scsi_run_queue_async() depends on the order of these operations. 1678 */ 1679 smp_mb__after_atomic(); 1680 1681 /* 1682 * If all in-flight requests originated from this LUN are completed 1683 * before reading .device_busy, sdev->device_busy will be observed as 1684 * zero, then blk_mq_delay_run_hw_queues() will dispatch this request 1685 * soon. Otherwise, completion of one of these requests will observe 1686 * the .restarts flag, and the request queue will be run for handling 1687 * this request, see scsi_end_request(). 1688 */ 1689 if (unlikely(scsi_device_busy(sdev) == 0 && 1690 !scsi_device_blocked(sdev))) 1691 blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY); 1692 return -1; 1693 } 1694 1695 static void scsi_mq_set_rq_budget_token(struct request *req, int token) 1696 { 1697 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 1698 1699 cmd->budget_token = token; 1700 } 1701 1702 static int scsi_mq_get_rq_budget_token(struct request *req) 1703 { 1704 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 1705 1706 return cmd->budget_token; 1707 } 1708 1709 static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx, 1710 const struct blk_mq_queue_data *bd) 1711 { 1712 struct request *req = bd->rq; 1713 struct request_queue *q = req->q; 1714 struct scsi_device *sdev = q->queuedata; 1715 struct Scsi_Host *shost = sdev->host; 1716 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 1717 blk_status_t ret; 1718 int reason; 1719 1720 WARN_ON_ONCE(cmd->budget_token < 0); 1721 1722 /* 1723 * If the device is not in running state we will reject some or all 1724 * commands. 1725 */ 1726 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { 1727 ret = scsi_device_state_check(sdev, req); 1728 if (ret != BLK_STS_OK) 1729 goto out_put_budget; 1730 } 1731 1732 ret = BLK_STS_RESOURCE; 1733 if (!scsi_target_queue_ready(shost, sdev)) 1734 goto out_put_budget; 1735 if (unlikely(scsi_host_in_recovery(shost))) { 1736 if (cmd->flags & SCMD_FAIL_IF_RECOVERING) 1737 ret = BLK_STS_OFFLINE; 1738 goto out_dec_target_busy; 1739 } 1740 if (!scsi_host_queue_ready(q, shost, sdev, cmd)) 1741 goto out_dec_target_busy; 1742 1743 if (!(req->rq_flags & RQF_DONTPREP)) { 1744 ret = scsi_prepare_cmd(req); 1745 if (ret != BLK_STS_OK) 1746 goto out_dec_host_busy; 1747 req->rq_flags |= RQF_DONTPREP; 1748 } else { 1749 clear_bit(SCMD_STATE_COMPLETE, &cmd->state); 1750 } 1751 1752 cmd->flags &= SCMD_PRESERVED_FLAGS; 1753 if (sdev->simple_tags) 1754 cmd->flags |= SCMD_TAGGED; 1755 if (bd->last) 1756 cmd->flags |= SCMD_LAST; 1757 1758 scsi_set_resid(cmd, 0); 1759 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE); 1760 cmd->submitter = SUBMITTED_BY_BLOCK_LAYER; 1761 1762 blk_mq_start_request(req); 1763 reason = scsi_dispatch_cmd(cmd); 1764 if (reason) { 1765 scsi_set_blocked(cmd, reason); 1766 ret = BLK_STS_RESOURCE; 1767 goto out_dec_host_busy; 1768 } 1769 1770 return BLK_STS_OK; 1771 1772 out_dec_host_busy: 1773 scsi_dec_host_busy(shost, cmd); 1774 out_dec_target_busy: 1775 if (scsi_target(sdev)->can_queue > 0) 1776 atomic_dec(&scsi_target(sdev)->target_busy); 1777 out_put_budget: 1778 scsi_mq_put_budget(q, cmd->budget_token); 1779 cmd->budget_token = -1; 1780 switch (ret) { 1781 case BLK_STS_OK: 1782 break; 1783 case BLK_STS_RESOURCE: 1784 case BLK_STS_ZONE_RESOURCE: 1785 if (scsi_device_blocked(sdev)) 1786 ret = BLK_STS_DEV_RESOURCE; 1787 break; 1788 case BLK_STS_AGAIN: 1789 cmd->result = DID_BUS_BUSY << 16; 1790 if (req->rq_flags & RQF_DONTPREP) 1791 scsi_mq_uninit_cmd(cmd); 1792 break; 1793 default: 1794 if (unlikely(!scsi_device_online(sdev))) 1795 cmd->result = DID_NO_CONNECT << 16; 1796 else 1797 cmd->result = DID_ERROR << 16; 1798 /* 1799 * Make sure to release all allocated resources when 1800 * we hit an error, as we will never see this command 1801 * again. 1802 */ 1803 if (req->rq_flags & RQF_DONTPREP) 1804 scsi_mq_uninit_cmd(cmd); 1805 scsi_run_queue_async(sdev); 1806 break; 1807 } 1808 return ret; 1809 } 1810 1811 static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq, 1812 unsigned int hctx_idx, unsigned int numa_node) 1813 { 1814 struct Scsi_Host *shost = set->driver_data; 1815 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); 1816 struct scatterlist *sg; 1817 int ret = 0; 1818 1819 cmd->sense_buffer = 1820 kmem_cache_alloc_node(scsi_sense_cache, GFP_KERNEL, numa_node); 1821 if (!cmd->sense_buffer) 1822 return -ENOMEM; 1823 1824 if (scsi_host_get_prot(shost)) { 1825 sg = (void *)cmd + sizeof(struct scsi_cmnd) + 1826 shost->hostt->cmd_size; 1827 cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost); 1828 } 1829 1830 if (shost->hostt->init_cmd_priv) { 1831 ret = shost->hostt->init_cmd_priv(shost, cmd); 1832 if (ret < 0) 1833 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer); 1834 } 1835 1836 return ret; 1837 } 1838 1839 static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq, 1840 unsigned int hctx_idx) 1841 { 1842 struct Scsi_Host *shost = set->driver_data; 1843 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); 1844 1845 if (shost->hostt->exit_cmd_priv) 1846 shost->hostt->exit_cmd_priv(shost, cmd); 1847 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer); 1848 } 1849 1850 1851 static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob) 1852 { 1853 struct Scsi_Host *shost = hctx->driver_data; 1854 1855 if (shost->hostt->mq_poll) 1856 return shost->hostt->mq_poll(shost, hctx->queue_num); 1857 1858 return 0; 1859 } 1860 1861 static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data, 1862 unsigned int hctx_idx) 1863 { 1864 struct Scsi_Host *shost = data; 1865 1866 hctx->driver_data = shost; 1867 return 0; 1868 } 1869 1870 static void scsi_map_queues(struct blk_mq_tag_set *set) 1871 { 1872 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set); 1873 1874 if (shost->hostt->map_queues) 1875 return shost->hostt->map_queues(shost); 1876 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]); 1877 } 1878 1879 void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q) 1880 { 1881 struct device *dev = shost->dma_dev; 1882 1883 /* 1884 * this limit is imposed by hardware restrictions 1885 */ 1886 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize, 1887 SG_MAX_SEGMENTS)); 1888 1889 if (scsi_host_prot_dma(shost)) { 1890 shost->sg_prot_tablesize = 1891 min_not_zero(shost->sg_prot_tablesize, 1892 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS); 1893 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize); 1894 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize); 1895 } 1896 1897 blk_queue_max_hw_sectors(q, shost->max_sectors); 1898 blk_queue_segment_boundary(q, shost->dma_boundary); 1899 dma_set_seg_boundary(dev, shost->dma_boundary); 1900 1901 blk_queue_max_segment_size(q, shost->max_segment_size); 1902 blk_queue_virt_boundary(q, shost->virt_boundary_mask); 1903 dma_set_max_seg_size(dev, queue_max_segment_size(q)); 1904 1905 /* 1906 * Set a reasonable default alignment: The larger of 32-byte (dword), 1907 * which is a common minimum for HBAs, and the minimum DMA alignment, 1908 * which is set by the platform. 1909 * 1910 * Devices that require a bigger alignment can increase it later. 1911 */ 1912 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1); 1913 } 1914 EXPORT_SYMBOL_GPL(__scsi_init_queue); 1915 1916 static const struct blk_mq_ops scsi_mq_ops_no_commit = { 1917 .get_budget = scsi_mq_get_budget, 1918 .put_budget = scsi_mq_put_budget, 1919 .queue_rq = scsi_queue_rq, 1920 .complete = scsi_complete, 1921 .timeout = scsi_timeout, 1922 #ifdef CONFIG_BLK_DEBUG_FS 1923 .show_rq = scsi_show_rq, 1924 #endif 1925 .init_request = scsi_mq_init_request, 1926 .exit_request = scsi_mq_exit_request, 1927 .cleanup_rq = scsi_cleanup_rq, 1928 .busy = scsi_mq_lld_busy, 1929 .map_queues = scsi_map_queues, 1930 .init_hctx = scsi_init_hctx, 1931 .poll = scsi_mq_poll, 1932 .set_rq_budget_token = scsi_mq_set_rq_budget_token, 1933 .get_rq_budget_token = scsi_mq_get_rq_budget_token, 1934 }; 1935 1936 1937 static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx) 1938 { 1939 struct Scsi_Host *shost = hctx->driver_data; 1940 1941 shost->hostt->commit_rqs(shost, hctx->queue_num); 1942 } 1943 1944 static const struct blk_mq_ops scsi_mq_ops = { 1945 .get_budget = scsi_mq_get_budget, 1946 .put_budget = scsi_mq_put_budget, 1947 .queue_rq = scsi_queue_rq, 1948 .commit_rqs = scsi_commit_rqs, 1949 .complete = scsi_complete, 1950 .timeout = scsi_timeout, 1951 #ifdef CONFIG_BLK_DEBUG_FS 1952 .show_rq = scsi_show_rq, 1953 #endif 1954 .init_request = scsi_mq_init_request, 1955 .exit_request = scsi_mq_exit_request, 1956 .cleanup_rq = scsi_cleanup_rq, 1957 .busy = scsi_mq_lld_busy, 1958 .map_queues = scsi_map_queues, 1959 .init_hctx = scsi_init_hctx, 1960 .poll = scsi_mq_poll, 1961 .set_rq_budget_token = scsi_mq_set_rq_budget_token, 1962 .get_rq_budget_token = scsi_mq_get_rq_budget_token, 1963 }; 1964 1965 int scsi_mq_setup_tags(struct Scsi_Host *shost) 1966 { 1967 unsigned int cmd_size, sgl_size; 1968 struct blk_mq_tag_set *tag_set = &shost->tag_set; 1969 1970 sgl_size = max_t(unsigned int, sizeof(struct scatterlist), 1971 scsi_mq_inline_sgl_size(shost)); 1972 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size; 1973 if (scsi_host_get_prot(shost)) 1974 cmd_size += sizeof(struct scsi_data_buffer) + 1975 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT; 1976 1977 memset(tag_set, 0, sizeof(*tag_set)); 1978 if (shost->hostt->commit_rqs) 1979 tag_set->ops = &scsi_mq_ops; 1980 else 1981 tag_set->ops = &scsi_mq_ops_no_commit; 1982 tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1; 1983 tag_set->nr_maps = shost->nr_maps ? : 1; 1984 tag_set->queue_depth = shost->can_queue; 1985 tag_set->cmd_size = cmd_size; 1986 tag_set->numa_node = dev_to_node(shost->dma_dev); 1987 tag_set->flags = BLK_MQ_F_SHOULD_MERGE; 1988 tag_set->flags |= 1989 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy); 1990 if (shost->queuecommand_may_block) 1991 tag_set->flags |= BLK_MQ_F_BLOCKING; 1992 tag_set->driver_data = shost; 1993 if (shost->host_tagset) 1994 tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED; 1995 1996 return blk_mq_alloc_tag_set(tag_set); 1997 } 1998 1999 void scsi_mq_free_tags(struct kref *kref) 2000 { 2001 struct Scsi_Host *shost = container_of(kref, typeof(*shost), 2002 tagset_refcnt); 2003 2004 blk_mq_free_tag_set(&shost->tag_set); 2005 complete(&shost->tagset_freed); 2006 } 2007 2008 /** 2009 * scsi_device_from_queue - return sdev associated with a request_queue 2010 * @q: The request queue to return the sdev from 2011 * 2012 * Return the sdev associated with a request queue or NULL if the 2013 * request_queue does not reference a SCSI device. 2014 */ 2015 struct scsi_device *scsi_device_from_queue(struct request_queue *q) 2016 { 2017 struct scsi_device *sdev = NULL; 2018 2019 if (q->mq_ops == &scsi_mq_ops_no_commit || 2020 q->mq_ops == &scsi_mq_ops) 2021 sdev = q->queuedata; 2022 if (!sdev || !get_device(&sdev->sdev_gendev)) 2023 sdev = NULL; 2024 2025 return sdev; 2026 } 2027 /* 2028 * pktcdvd should have been integrated into the SCSI layers, but for historical 2029 * reasons like the old IDE driver it isn't. This export allows it to safely 2030 * probe if a given device is a SCSI one and only attach to that. 2031 */ 2032 #ifdef CONFIG_CDROM_PKTCDVD_MODULE 2033 EXPORT_SYMBOL_GPL(scsi_device_from_queue); 2034 #endif 2035 2036 /** 2037 * scsi_block_requests - Utility function used by low-level drivers to prevent 2038 * further commands from being queued to the device. 2039 * @shost: host in question 2040 * 2041 * There is no timer nor any other means by which the requests get unblocked 2042 * other than the low-level driver calling scsi_unblock_requests(). 2043 */ 2044 void scsi_block_requests(struct Scsi_Host *shost) 2045 { 2046 shost->host_self_blocked = 1; 2047 } 2048 EXPORT_SYMBOL(scsi_block_requests); 2049 2050 /** 2051 * scsi_unblock_requests - Utility function used by low-level drivers to allow 2052 * further commands to be queued to the device. 2053 * @shost: host in question 2054 * 2055 * There is no timer nor any other means by which the requests get unblocked 2056 * other than the low-level driver calling scsi_unblock_requests(). This is done 2057 * as an API function so that changes to the internals of the scsi mid-layer 2058 * won't require wholesale changes to drivers that use this feature. 2059 */ 2060 void scsi_unblock_requests(struct Scsi_Host *shost) 2061 { 2062 shost->host_self_blocked = 0; 2063 scsi_run_host_queues(shost); 2064 } 2065 EXPORT_SYMBOL(scsi_unblock_requests); 2066 2067 void scsi_exit_queue(void) 2068 { 2069 kmem_cache_destroy(scsi_sense_cache); 2070 } 2071 2072 /** 2073 * scsi_mode_select - issue a mode select 2074 * @sdev: SCSI device to be queried 2075 * @pf: Page format bit (1 == standard, 0 == vendor specific) 2076 * @sp: Save page bit (0 == don't save, 1 == save) 2077 * @buffer: request buffer (may not be smaller than eight bytes) 2078 * @len: length of request buffer. 2079 * @timeout: command timeout 2080 * @retries: number of retries before failing 2081 * @data: returns a structure abstracting the mode header data 2082 * @sshdr: place to put sense data (or NULL if no sense to be collected). 2083 * must be SCSI_SENSE_BUFFERSIZE big. 2084 * 2085 * Returns zero if successful; negative error number or scsi 2086 * status on error 2087 * 2088 */ 2089 int scsi_mode_select(struct scsi_device *sdev, int pf, int sp, 2090 unsigned char *buffer, int len, int timeout, int retries, 2091 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) 2092 { 2093 unsigned char cmd[10]; 2094 unsigned char *real_buffer; 2095 const struct scsi_exec_args exec_args = { 2096 .sshdr = sshdr, 2097 }; 2098 int ret; 2099 2100 memset(cmd, 0, sizeof(cmd)); 2101 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); 2102 2103 /* 2104 * Use MODE SELECT(10) if the device asked for it or if the mode page 2105 * and the mode select header cannot fit within the maximumm 255 bytes 2106 * of the MODE SELECT(6) command. 2107 */ 2108 if (sdev->use_10_for_ms || 2109 len + 4 > 255 || 2110 data->block_descriptor_length > 255) { 2111 if (len > 65535 - 8) 2112 return -EINVAL; 2113 real_buffer = kmalloc(8 + len, GFP_KERNEL); 2114 if (!real_buffer) 2115 return -ENOMEM; 2116 memcpy(real_buffer + 8, buffer, len); 2117 len += 8; 2118 real_buffer[0] = 0; 2119 real_buffer[1] = 0; 2120 real_buffer[2] = data->medium_type; 2121 real_buffer[3] = data->device_specific; 2122 real_buffer[4] = data->longlba ? 0x01 : 0; 2123 real_buffer[5] = 0; 2124 put_unaligned_be16(data->block_descriptor_length, 2125 &real_buffer[6]); 2126 2127 cmd[0] = MODE_SELECT_10; 2128 put_unaligned_be16(len, &cmd[7]); 2129 } else { 2130 if (data->longlba) 2131 return -EINVAL; 2132 2133 real_buffer = kmalloc(4 + len, GFP_KERNEL); 2134 if (!real_buffer) 2135 return -ENOMEM; 2136 memcpy(real_buffer + 4, buffer, len); 2137 len += 4; 2138 real_buffer[0] = 0; 2139 real_buffer[1] = data->medium_type; 2140 real_buffer[2] = data->device_specific; 2141 real_buffer[3] = data->block_descriptor_length; 2142 2143 cmd[0] = MODE_SELECT; 2144 cmd[4] = len; 2145 } 2146 2147 ret = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_OUT, real_buffer, len, 2148 timeout, retries, &exec_args); 2149 kfree(real_buffer); 2150 return ret; 2151 } 2152 EXPORT_SYMBOL_GPL(scsi_mode_select); 2153 2154 /** 2155 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary. 2156 * @sdev: SCSI device to be queried 2157 * @dbd: set to prevent mode sense from returning block descriptors 2158 * @modepage: mode page being requested 2159 * @subpage: sub-page of the mode page being requested 2160 * @buffer: request buffer (may not be smaller than eight bytes) 2161 * @len: length of request buffer. 2162 * @timeout: command timeout 2163 * @retries: number of retries before failing 2164 * @data: returns a structure abstracting the mode header data 2165 * @sshdr: place to put sense data (or NULL if no sense to be collected). 2166 * must be SCSI_SENSE_BUFFERSIZE big. 2167 * 2168 * Returns zero if successful, or a negative error number on failure 2169 */ 2170 int 2171 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, int subpage, 2172 unsigned char *buffer, int len, int timeout, int retries, 2173 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) 2174 { 2175 unsigned char cmd[12]; 2176 int use_10_for_ms; 2177 int header_length; 2178 int result, retry_count = retries; 2179 struct scsi_sense_hdr my_sshdr; 2180 const struct scsi_exec_args exec_args = { 2181 /* caller might not be interested in sense, but we need it */ 2182 .sshdr = sshdr ? : &my_sshdr, 2183 }; 2184 2185 memset(data, 0, sizeof(*data)); 2186 memset(&cmd[0], 0, 12); 2187 2188 dbd = sdev->set_dbd_for_ms ? 8 : dbd; 2189 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ 2190 cmd[2] = modepage; 2191 cmd[3] = subpage; 2192 2193 sshdr = exec_args.sshdr; 2194 2195 retry: 2196 use_10_for_ms = sdev->use_10_for_ms || len > 255; 2197 2198 if (use_10_for_ms) { 2199 if (len < 8 || len > 65535) 2200 return -EINVAL; 2201 2202 cmd[0] = MODE_SENSE_10; 2203 put_unaligned_be16(len, &cmd[7]); 2204 header_length = 8; 2205 } else { 2206 if (len < 4) 2207 return -EINVAL; 2208 2209 cmd[0] = MODE_SENSE; 2210 cmd[4] = len; 2211 header_length = 4; 2212 } 2213 2214 memset(buffer, 0, len); 2215 2216 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer, len, 2217 timeout, retries, &exec_args); 2218 if (result < 0) 2219 return result; 2220 2221 /* This code looks awful: what it's doing is making sure an 2222 * ILLEGAL REQUEST sense return identifies the actual command 2223 * byte as the problem. MODE_SENSE commands can return 2224 * ILLEGAL REQUEST if the code page isn't supported */ 2225 2226 if (!scsi_status_is_good(result)) { 2227 if (scsi_sense_valid(sshdr)) { 2228 if ((sshdr->sense_key == ILLEGAL_REQUEST) && 2229 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { 2230 /* 2231 * Invalid command operation code: retry using 2232 * MODE SENSE(6) if this was a MODE SENSE(10) 2233 * request, except if the request mode page is 2234 * too large for MODE SENSE single byte 2235 * allocation length field. 2236 */ 2237 if (use_10_for_ms) { 2238 if (len > 255) 2239 return -EIO; 2240 sdev->use_10_for_ms = 0; 2241 goto retry; 2242 } 2243 } 2244 if (scsi_status_is_check_condition(result) && 2245 sshdr->sense_key == UNIT_ATTENTION && 2246 retry_count) { 2247 retry_count--; 2248 goto retry; 2249 } 2250 } 2251 return -EIO; 2252 } 2253 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && 2254 (modepage == 6 || modepage == 8))) { 2255 /* Initio breakage? */ 2256 header_length = 0; 2257 data->length = 13; 2258 data->medium_type = 0; 2259 data->device_specific = 0; 2260 data->longlba = 0; 2261 data->block_descriptor_length = 0; 2262 } else if (use_10_for_ms) { 2263 data->length = get_unaligned_be16(&buffer[0]) + 2; 2264 data->medium_type = buffer[2]; 2265 data->device_specific = buffer[3]; 2266 data->longlba = buffer[4] & 0x01; 2267 data->block_descriptor_length = get_unaligned_be16(&buffer[6]); 2268 } else { 2269 data->length = buffer[0] + 1; 2270 data->medium_type = buffer[1]; 2271 data->device_specific = buffer[2]; 2272 data->block_descriptor_length = buffer[3]; 2273 } 2274 data->header_length = header_length; 2275 2276 return 0; 2277 } 2278 EXPORT_SYMBOL(scsi_mode_sense); 2279 2280 /** 2281 * scsi_test_unit_ready - test if unit is ready 2282 * @sdev: scsi device to change the state of. 2283 * @timeout: command timeout 2284 * @retries: number of retries before failing 2285 * @sshdr: outpout pointer for decoded sense information. 2286 * 2287 * Returns zero if unsuccessful or an error if TUR failed. For 2288 * removable media, UNIT_ATTENTION sets ->changed flag. 2289 **/ 2290 int 2291 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, 2292 struct scsi_sense_hdr *sshdr) 2293 { 2294 char cmd[] = { 2295 TEST_UNIT_READY, 0, 0, 0, 0, 0, 2296 }; 2297 const struct scsi_exec_args exec_args = { 2298 .sshdr = sshdr, 2299 }; 2300 int result; 2301 2302 /* try to eat the UNIT_ATTENTION if there are enough retries */ 2303 do { 2304 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, NULL, 0, 2305 timeout, 1, &exec_args); 2306 if (sdev->removable && scsi_sense_valid(sshdr) && 2307 sshdr->sense_key == UNIT_ATTENTION) 2308 sdev->changed = 1; 2309 } while (scsi_sense_valid(sshdr) && 2310 sshdr->sense_key == UNIT_ATTENTION && --retries); 2311 2312 return result; 2313 } 2314 EXPORT_SYMBOL(scsi_test_unit_ready); 2315 2316 /** 2317 * scsi_device_set_state - Take the given device through the device state model. 2318 * @sdev: scsi device to change the state of. 2319 * @state: state to change to. 2320 * 2321 * Returns zero if successful or an error if the requested 2322 * transition is illegal. 2323 */ 2324 int 2325 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) 2326 { 2327 enum scsi_device_state oldstate = sdev->sdev_state; 2328 2329 if (state == oldstate) 2330 return 0; 2331 2332 switch (state) { 2333 case SDEV_CREATED: 2334 switch (oldstate) { 2335 case SDEV_CREATED_BLOCK: 2336 break; 2337 default: 2338 goto illegal; 2339 } 2340 break; 2341 2342 case SDEV_RUNNING: 2343 switch (oldstate) { 2344 case SDEV_CREATED: 2345 case SDEV_OFFLINE: 2346 case SDEV_TRANSPORT_OFFLINE: 2347 case SDEV_QUIESCE: 2348 case SDEV_BLOCK: 2349 break; 2350 default: 2351 goto illegal; 2352 } 2353 break; 2354 2355 case SDEV_QUIESCE: 2356 switch (oldstate) { 2357 case SDEV_RUNNING: 2358 case SDEV_OFFLINE: 2359 case SDEV_TRANSPORT_OFFLINE: 2360 break; 2361 default: 2362 goto illegal; 2363 } 2364 break; 2365 2366 case SDEV_OFFLINE: 2367 case SDEV_TRANSPORT_OFFLINE: 2368 switch (oldstate) { 2369 case SDEV_CREATED: 2370 case SDEV_RUNNING: 2371 case SDEV_QUIESCE: 2372 case SDEV_BLOCK: 2373 break; 2374 default: 2375 goto illegal; 2376 } 2377 break; 2378 2379 case SDEV_BLOCK: 2380 switch (oldstate) { 2381 case SDEV_RUNNING: 2382 case SDEV_CREATED_BLOCK: 2383 case SDEV_QUIESCE: 2384 case SDEV_OFFLINE: 2385 break; 2386 default: 2387 goto illegal; 2388 } 2389 break; 2390 2391 case SDEV_CREATED_BLOCK: 2392 switch (oldstate) { 2393 case SDEV_CREATED: 2394 break; 2395 default: 2396 goto illegal; 2397 } 2398 break; 2399 2400 case SDEV_CANCEL: 2401 switch (oldstate) { 2402 case SDEV_CREATED: 2403 case SDEV_RUNNING: 2404 case SDEV_QUIESCE: 2405 case SDEV_OFFLINE: 2406 case SDEV_TRANSPORT_OFFLINE: 2407 break; 2408 default: 2409 goto illegal; 2410 } 2411 break; 2412 2413 case SDEV_DEL: 2414 switch (oldstate) { 2415 case SDEV_CREATED: 2416 case SDEV_RUNNING: 2417 case SDEV_OFFLINE: 2418 case SDEV_TRANSPORT_OFFLINE: 2419 case SDEV_CANCEL: 2420 case SDEV_BLOCK: 2421 case SDEV_CREATED_BLOCK: 2422 break; 2423 default: 2424 goto illegal; 2425 } 2426 break; 2427 2428 } 2429 sdev->offline_already = false; 2430 sdev->sdev_state = state; 2431 return 0; 2432 2433 illegal: 2434 SCSI_LOG_ERROR_RECOVERY(1, 2435 sdev_printk(KERN_ERR, sdev, 2436 "Illegal state transition %s->%s", 2437 scsi_device_state_name(oldstate), 2438 scsi_device_state_name(state)) 2439 ); 2440 return -EINVAL; 2441 } 2442 EXPORT_SYMBOL(scsi_device_set_state); 2443 2444 /** 2445 * scsi_evt_emit - emit a single SCSI device uevent 2446 * @sdev: associated SCSI device 2447 * @evt: event to emit 2448 * 2449 * Send a single uevent (scsi_event) to the associated scsi_device. 2450 */ 2451 static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt) 2452 { 2453 int idx = 0; 2454 char *envp[3]; 2455 2456 switch (evt->evt_type) { 2457 case SDEV_EVT_MEDIA_CHANGE: 2458 envp[idx++] = "SDEV_MEDIA_CHANGE=1"; 2459 break; 2460 case SDEV_EVT_INQUIRY_CHANGE_REPORTED: 2461 scsi_rescan_device(&sdev->sdev_gendev); 2462 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED"; 2463 break; 2464 case SDEV_EVT_CAPACITY_CHANGE_REPORTED: 2465 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED"; 2466 break; 2467 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED: 2468 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED"; 2469 break; 2470 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED: 2471 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED"; 2472 break; 2473 case SDEV_EVT_LUN_CHANGE_REPORTED: 2474 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED"; 2475 break; 2476 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED: 2477 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED"; 2478 break; 2479 case SDEV_EVT_POWER_ON_RESET_OCCURRED: 2480 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED"; 2481 break; 2482 default: 2483 /* do nothing */ 2484 break; 2485 } 2486 2487 envp[idx++] = NULL; 2488 2489 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp); 2490 } 2491 2492 /** 2493 * scsi_evt_thread - send a uevent for each scsi event 2494 * @work: work struct for scsi_device 2495 * 2496 * Dispatch queued events to their associated scsi_device kobjects 2497 * as uevents. 2498 */ 2499 void scsi_evt_thread(struct work_struct *work) 2500 { 2501 struct scsi_device *sdev; 2502 enum scsi_device_event evt_type; 2503 LIST_HEAD(event_list); 2504 2505 sdev = container_of(work, struct scsi_device, event_work); 2506 2507 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++) 2508 if (test_and_clear_bit(evt_type, sdev->pending_events)) 2509 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL); 2510 2511 while (1) { 2512 struct scsi_event *evt; 2513 struct list_head *this, *tmp; 2514 unsigned long flags; 2515 2516 spin_lock_irqsave(&sdev->list_lock, flags); 2517 list_splice_init(&sdev->event_list, &event_list); 2518 spin_unlock_irqrestore(&sdev->list_lock, flags); 2519 2520 if (list_empty(&event_list)) 2521 break; 2522 2523 list_for_each_safe(this, tmp, &event_list) { 2524 evt = list_entry(this, struct scsi_event, node); 2525 list_del(&evt->node); 2526 scsi_evt_emit(sdev, evt); 2527 kfree(evt); 2528 } 2529 } 2530 } 2531 2532 /** 2533 * sdev_evt_send - send asserted event to uevent thread 2534 * @sdev: scsi_device event occurred on 2535 * @evt: event to send 2536 * 2537 * Assert scsi device event asynchronously. 2538 */ 2539 void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt) 2540 { 2541 unsigned long flags; 2542 2543 #if 0 2544 /* FIXME: currently this check eliminates all media change events 2545 * for polled devices. Need to update to discriminate between AN 2546 * and polled events */ 2547 if (!test_bit(evt->evt_type, sdev->supported_events)) { 2548 kfree(evt); 2549 return; 2550 } 2551 #endif 2552 2553 spin_lock_irqsave(&sdev->list_lock, flags); 2554 list_add_tail(&evt->node, &sdev->event_list); 2555 schedule_work(&sdev->event_work); 2556 spin_unlock_irqrestore(&sdev->list_lock, flags); 2557 } 2558 EXPORT_SYMBOL_GPL(sdev_evt_send); 2559 2560 /** 2561 * sdev_evt_alloc - allocate a new scsi event 2562 * @evt_type: type of event to allocate 2563 * @gfpflags: GFP flags for allocation 2564 * 2565 * Allocates and returns a new scsi_event. 2566 */ 2567 struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type, 2568 gfp_t gfpflags) 2569 { 2570 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags); 2571 if (!evt) 2572 return NULL; 2573 2574 evt->evt_type = evt_type; 2575 INIT_LIST_HEAD(&evt->node); 2576 2577 /* evt_type-specific initialization, if any */ 2578 switch (evt_type) { 2579 case SDEV_EVT_MEDIA_CHANGE: 2580 case SDEV_EVT_INQUIRY_CHANGE_REPORTED: 2581 case SDEV_EVT_CAPACITY_CHANGE_REPORTED: 2582 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED: 2583 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED: 2584 case SDEV_EVT_LUN_CHANGE_REPORTED: 2585 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED: 2586 case SDEV_EVT_POWER_ON_RESET_OCCURRED: 2587 default: 2588 /* do nothing */ 2589 break; 2590 } 2591 2592 return evt; 2593 } 2594 EXPORT_SYMBOL_GPL(sdev_evt_alloc); 2595 2596 /** 2597 * sdev_evt_send_simple - send asserted event to uevent thread 2598 * @sdev: scsi_device event occurred on 2599 * @evt_type: type of event to send 2600 * @gfpflags: GFP flags for allocation 2601 * 2602 * Assert scsi device event asynchronously, given an event type. 2603 */ 2604 void sdev_evt_send_simple(struct scsi_device *sdev, 2605 enum scsi_device_event evt_type, gfp_t gfpflags) 2606 { 2607 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags); 2608 if (!evt) { 2609 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n", 2610 evt_type); 2611 return; 2612 } 2613 2614 sdev_evt_send(sdev, evt); 2615 } 2616 EXPORT_SYMBOL_GPL(sdev_evt_send_simple); 2617 2618 /** 2619 * scsi_device_quiesce - Block all commands except power management. 2620 * @sdev: scsi device to quiesce. 2621 * 2622 * This works by trying to transition to the SDEV_QUIESCE state 2623 * (which must be a legal transition). When the device is in this 2624 * state, only power management requests will be accepted, all others will 2625 * be deferred. 2626 * 2627 * Must be called with user context, may sleep. 2628 * 2629 * Returns zero if unsuccessful or an error if not. 2630 */ 2631 int 2632 scsi_device_quiesce(struct scsi_device *sdev) 2633 { 2634 struct request_queue *q = sdev->request_queue; 2635 int err; 2636 2637 /* 2638 * It is allowed to call scsi_device_quiesce() multiple times from 2639 * the same context but concurrent scsi_device_quiesce() calls are 2640 * not allowed. 2641 */ 2642 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current); 2643 2644 if (sdev->quiesced_by == current) 2645 return 0; 2646 2647 blk_set_pm_only(q); 2648 2649 blk_mq_freeze_queue(q); 2650 /* 2651 * Ensure that the effect of blk_set_pm_only() will be visible 2652 * for percpu_ref_tryget() callers that occur after the queue 2653 * unfreeze even if the queue was already frozen before this function 2654 * was called. See also https://lwn.net/Articles/573497/. 2655 */ 2656 synchronize_rcu(); 2657 blk_mq_unfreeze_queue(q); 2658 2659 mutex_lock(&sdev->state_mutex); 2660 err = scsi_device_set_state(sdev, SDEV_QUIESCE); 2661 if (err == 0) 2662 sdev->quiesced_by = current; 2663 else 2664 blk_clear_pm_only(q); 2665 mutex_unlock(&sdev->state_mutex); 2666 2667 return err; 2668 } 2669 EXPORT_SYMBOL(scsi_device_quiesce); 2670 2671 /** 2672 * scsi_device_resume - Restart user issued commands to a quiesced device. 2673 * @sdev: scsi device to resume. 2674 * 2675 * Moves the device from quiesced back to running and restarts the 2676 * queues. 2677 * 2678 * Must be called with user context, may sleep. 2679 */ 2680 void scsi_device_resume(struct scsi_device *sdev) 2681 { 2682 /* check if the device state was mutated prior to resume, and if 2683 * so assume the state is being managed elsewhere (for example 2684 * device deleted during suspend) 2685 */ 2686 mutex_lock(&sdev->state_mutex); 2687 if (sdev->sdev_state == SDEV_QUIESCE) 2688 scsi_device_set_state(sdev, SDEV_RUNNING); 2689 if (sdev->quiesced_by) { 2690 sdev->quiesced_by = NULL; 2691 blk_clear_pm_only(sdev->request_queue); 2692 } 2693 mutex_unlock(&sdev->state_mutex); 2694 } 2695 EXPORT_SYMBOL(scsi_device_resume); 2696 2697 static void 2698 device_quiesce_fn(struct scsi_device *sdev, void *data) 2699 { 2700 scsi_device_quiesce(sdev); 2701 } 2702 2703 void 2704 scsi_target_quiesce(struct scsi_target *starget) 2705 { 2706 starget_for_each_device(starget, NULL, device_quiesce_fn); 2707 } 2708 EXPORT_SYMBOL(scsi_target_quiesce); 2709 2710 static void 2711 device_resume_fn(struct scsi_device *sdev, void *data) 2712 { 2713 scsi_device_resume(sdev); 2714 } 2715 2716 void 2717 scsi_target_resume(struct scsi_target *starget) 2718 { 2719 starget_for_each_device(starget, NULL, device_resume_fn); 2720 } 2721 EXPORT_SYMBOL(scsi_target_resume); 2722 2723 static int __scsi_internal_device_block_nowait(struct scsi_device *sdev) 2724 { 2725 if (scsi_device_set_state(sdev, SDEV_BLOCK)) 2726 return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK); 2727 2728 return 0; 2729 } 2730 2731 void scsi_start_queue(struct scsi_device *sdev) 2732 { 2733 if (cmpxchg(&sdev->queue_stopped, 1, 0)) 2734 blk_mq_unquiesce_queue(sdev->request_queue); 2735 } 2736 2737 static void scsi_stop_queue(struct scsi_device *sdev) 2738 { 2739 /* 2740 * The atomic variable of ->queue_stopped covers that 2741 * blk_mq_quiesce_queue* is balanced with blk_mq_unquiesce_queue. 2742 * 2743 * The caller needs to wait until quiesce is done. 2744 */ 2745 if (!cmpxchg(&sdev->queue_stopped, 0, 1)) 2746 blk_mq_quiesce_queue_nowait(sdev->request_queue); 2747 } 2748 2749 /** 2750 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state 2751 * @sdev: device to block 2752 * 2753 * Pause SCSI command processing on the specified device. Does not sleep. 2754 * 2755 * Returns zero if successful or a negative error code upon failure. 2756 * 2757 * Notes: 2758 * This routine transitions the device to the SDEV_BLOCK state (which must be 2759 * a legal transition). When the device is in this state, command processing 2760 * is paused until the device leaves the SDEV_BLOCK state. See also 2761 * scsi_internal_device_unblock_nowait(). 2762 */ 2763 int scsi_internal_device_block_nowait(struct scsi_device *sdev) 2764 { 2765 int ret = __scsi_internal_device_block_nowait(sdev); 2766 2767 /* 2768 * The device has transitioned to SDEV_BLOCK. Stop the 2769 * block layer from calling the midlayer with this device's 2770 * request queue. 2771 */ 2772 if (!ret) 2773 scsi_stop_queue(sdev); 2774 return ret; 2775 } 2776 EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait); 2777 2778 /** 2779 * scsi_device_block - try to transition to the SDEV_BLOCK state 2780 * @sdev: device to block 2781 * @data: dummy argument, ignored 2782 * 2783 * Pause SCSI command processing on the specified device. Callers must wait 2784 * until all ongoing scsi_queue_rq() calls have finished after this function 2785 * returns. 2786 * 2787 * Note: 2788 * This routine transitions the device to the SDEV_BLOCK state (which must be 2789 * a legal transition). When the device is in this state, command processing 2790 * is paused until the device leaves the SDEV_BLOCK state. See also 2791 * scsi_internal_device_unblock(). 2792 */ 2793 static void scsi_device_block(struct scsi_device *sdev, void *data) 2794 { 2795 int err; 2796 enum scsi_device_state state; 2797 2798 mutex_lock(&sdev->state_mutex); 2799 err = __scsi_internal_device_block_nowait(sdev); 2800 state = sdev->sdev_state; 2801 if (err == 0) 2802 /* 2803 * scsi_stop_queue() must be called with the state_mutex 2804 * held. Otherwise a simultaneous scsi_start_queue() call 2805 * might unquiesce the queue before we quiesce it. 2806 */ 2807 scsi_stop_queue(sdev); 2808 2809 mutex_unlock(&sdev->state_mutex); 2810 2811 WARN_ONCE(err, "%s: failed to block %s in state %d\n", 2812 __func__, dev_name(&sdev->sdev_gendev), state); 2813 } 2814 2815 /** 2816 * scsi_internal_device_unblock_nowait - resume a device after a block request 2817 * @sdev: device to resume 2818 * @new_state: state to set the device to after unblocking 2819 * 2820 * Restart the device queue for a previously suspended SCSI device. Does not 2821 * sleep. 2822 * 2823 * Returns zero if successful or a negative error code upon failure. 2824 * 2825 * Notes: 2826 * This routine transitions the device to the SDEV_RUNNING state or to one of 2827 * the offline states (which must be a legal transition) allowing the midlayer 2828 * to goose the queue for this device. 2829 */ 2830 int scsi_internal_device_unblock_nowait(struct scsi_device *sdev, 2831 enum scsi_device_state new_state) 2832 { 2833 switch (new_state) { 2834 case SDEV_RUNNING: 2835 case SDEV_TRANSPORT_OFFLINE: 2836 break; 2837 default: 2838 return -EINVAL; 2839 } 2840 2841 /* 2842 * Try to transition the scsi device to SDEV_RUNNING or one of the 2843 * offlined states and goose the device queue if successful. 2844 */ 2845 switch (sdev->sdev_state) { 2846 case SDEV_BLOCK: 2847 case SDEV_TRANSPORT_OFFLINE: 2848 sdev->sdev_state = new_state; 2849 break; 2850 case SDEV_CREATED_BLOCK: 2851 if (new_state == SDEV_TRANSPORT_OFFLINE || 2852 new_state == SDEV_OFFLINE) 2853 sdev->sdev_state = new_state; 2854 else 2855 sdev->sdev_state = SDEV_CREATED; 2856 break; 2857 case SDEV_CANCEL: 2858 case SDEV_OFFLINE: 2859 break; 2860 default: 2861 return -EINVAL; 2862 } 2863 scsi_start_queue(sdev); 2864 2865 return 0; 2866 } 2867 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait); 2868 2869 /** 2870 * scsi_internal_device_unblock - resume a device after a block request 2871 * @sdev: device to resume 2872 * @new_state: state to set the device to after unblocking 2873 * 2874 * Restart the device queue for a previously suspended SCSI device. May sleep. 2875 * 2876 * Returns zero if successful or a negative error code upon failure. 2877 * 2878 * Notes: 2879 * This routine transitions the device to the SDEV_RUNNING state or to one of 2880 * the offline states (which must be a legal transition) allowing the midlayer 2881 * to goose the queue for this device. 2882 */ 2883 static int scsi_internal_device_unblock(struct scsi_device *sdev, 2884 enum scsi_device_state new_state) 2885 { 2886 int ret; 2887 2888 mutex_lock(&sdev->state_mutex); 2889 ret = scsi_internal_device_unblock_nowait(sdev, new_state); 2890 mutex_unlock(&sdev->state_mutex); 2891 2892 return ret; 2893 } 2894 2895 static int 2896 target_block(struct device *dev, void *data) 2897 { 2898 if (scsi_is_target_device(dev)) 2899 starget_for_each_device(to_scsi_target(dev), NULL, 2900 scsi_device_block); 2901 return 0; 2902 } 2903 2904 /** 2905 * scsi_block_targets - transition all SCSI child devices to SDEV_BLOCK state 2906 * @dev: a parent device of one or more scsi_target devices 2907 * @shost: the Scsi_Host to which this device belongs 2908 * 2909 * Iterate over all children of @dev, which should be scsi_target devices, 2910 * and switch all subordinate scsi devices to SDEV_BLOCK state. Wait for 2911 * ongoing scsi_queue_rq() calls to finish. May sleep. 2912 * 2913 * Note: 2914 * @dev must not itself be a scsi_target device. 2915 */ 2916 void 2917 scsi_block_targets(struct Scsi_Host *shost, struct device *dev) 2918 { 2919 WARN_ON_ONCE(scsi_is_target_device(dev)); 2920 device_for_each_child(dev, NULL, target_block); 2921 blk_mq_wait_quiesce_done(&shost->tag_set); 2922 } 2923 EXPORT_SYMBOL_GPL(scsi_block_targets); 2924 2925 static void 2926 device_unblock(struct scsi_device *sdev, void *data) 2927 { 2928 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data); 2929 } 2930 2931 static int 2932 target_unblock(struct device *dev, void *data) 2933 { 2934 if (scsi_is_target_device(dev)) 2935 starget_for_each_device(to_scsi_target(dev), data, 2936 device_unblock); 2937 return 0; 2938 } 2939 2940 void 2941 scsi_target_unblock(struct device *dev, enum scsi_device_state new_state) 2942 { 2943 if (scsi_is_target_device(dev)) 2944 starget_for_each_device(to_scsi_target(dev), &new_state, 2945 device_unblock); 2946 else 2947 device_for_each_child(dev, &new_state, target_unblock); 2948 } 2949 EXPORT_SYMBOL_GPL(scsi_target_unblock); 2950 2951 /** 2952 * scsi_host_block - Try to transition all logical units to the SDEV_BLOCK state 2953 * @shost: device to block 2954 * 2955 * Pause SCSI command processing for all logical units associated with the SCSI 2956 * host and wait until pending scsi_queue_rq() calls have finished. 2957 * 2958 * Returns zero if successful or a negative error code upon failure. 2959 */ 2960 int 2961 scsi_host_block(struct Scsi_Host *shost) 2962 { 2963 struct scsi_device *sdev; 2964 int ret; 2965 2966 /* 2967 * Call scsi_internal_device_block_nowait so we can avoid 2968 * calling synchronize_rcu() for each LUN. 2969 */ 2970 shost_for_each_device(sdev, shost) { 2971 mutex_lock(&sdev->state_mutex); 2972 ret = scsi_internal_device_block_nowait(sdev); 2973 mutex_unlock(&sdev->state_mutex); 2974 if (ret) { 2975 scsi_device_put(sdev); 2976 return ret; 2977 } 2978 } 2979 2980 /* Wait for ongoing scsi_queue_rq() calls to finish. */ 2981 blk_mq_wait_quiesce_done(&shost->tag_set); 2982 2983 return 0; 2984 } 2985 EXPORT_SYMBOL_GPL(scsi_host_block); 2986 2987 int 2988 scsi_host_unblock(struct Scsi_Host *shost, int new_state) 2989 { 2990 struct scsi_device *sdev; 2991 int ret = 0; 2992 2993 shost_for_each_device(sdev, shost) { 2994 ret = scsi_internal_device_unblock(sdev, new_state); 2995 if (ret) { 2996 scsi_device_put(sdev); 2997 break; 2998 } 2999 } 3000 return ret; 3001 } 3002 EXPORT_SYMBOL_GPL(scsi_host_unblock); 3003 3004 /** 3005 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt 3006 * @sgl: scatter-gather list 3007 * @sg_count: number of segments in sg 3008 * @offset: offset in bytes into sg, on return offset into the mapped area 3009 * @len: bytes to map, on return number of bytes mapped 3010 * 3011 * Returns virtual address of the start of the mapped page 3012 */ 3013 void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count, 3014 size_t *offset, size_t *len) 3015 { 3016 int i; 3017 size_t sg_len = 0, len_complete = 0; 3018 struct scatterlist *sg; 3019 struct page *page; 3020 3021 WARN_ON(!irqs_disabled()); 3022 3023 for_each_sg(sgl, sg, sg_count, i) { 3024 len_complete = sg_len; /* Complete sg-entries */ 3025 sg_len += sg->length; 3026 if (sg_len > *offset) 3027 break; 3028 } 3029 3030 if (unlikely(i == sg_count)) { 3031 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " 3032 "elements %d\n", 3033 __func__, sg_len, *offset, sg_count); 3034 WARN_ON(1); 3035 return NULL; 3036 } 3037 3038 /* Offset starting from the beginning of first page in this sg-entry */ 3039 *offset = *offset - len_complete + sg->offset; 3040 3041 /* Assumption: contiguous pages can be accessed as "page + i" */ 3042 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT)); 3043 *offset &= ~PAGE_MASK; 3044 3045 /* Bytes in this sg-entry from *offset to the end of the page */ 3046 sg_len = PAGE_SIZE - *offset; 3047 if (*len > sg_len) 3048 *len = sg_len; 3049 3050 return kmap_atomic(page); 3051 } 3052 EXPORT_SYMBOL(scsi_kmap_atomic_sg); 3053 3054 /** 3055 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg 3056 * @virt: virtual address to be unmapped 3057 */ 3058 void scsi_kunmap_atomic_sg(void *virt) 3059 { 3060 kunmap_atomic(virt); 3061 } 3062 EXPORT_SYMBOL(scsi_kunmap_atomic_sg); 3063 3064 void sdev_disable_disk_events(struct scsi_device *sdev) 3065 { 3066 atomic_inc(&sdev->disk_events_disable_depth); 3067 } 3068 EXPORT_SYMBOL(sdev_disable_disk_events); 3069 3070 void sdev_enable_disk_events(struct scsi_device *sdev) 3071 { 3072 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0)) 3073 return; 3074 atomic_dec(&sdev->disk_events_disable_depth); 3075 } 3076 EXPORT_SYMBOL(sdev_enable_disk_events); 3077 3078 static unsigned char designator_prio(const unsigned char *d) 3079 { 3080 if (d[1] & 0x30) 3081 /* not associated with LUN */ 3082 return 0; 3083 3084 if (d[3] == 0) 3085 /* invalid length */ 3086 return 0; 3087 3088 /* 3089 * Order of preference for lun descriptor: 3090 * - SCSI name string 3091 * - NAA IEEE Registered Extended 3092 * - EUI-64 based 16-byte 3093 * - EUI-64 based 12-byte 3094 * - NAA IEEE Registered 3095 * - NAA IEEE Extended 3096 * - EUI-64 based 8-byte 3097 * - SCSI name string (truncated) 3098 * - T10 Vendor ID 3099 * as longer descriptors reduce the likelyhood 3100 * of identification clashes. 3101 */ 3102 3103 switch (d[1] & 0xf) { 3104 case 8: 3105 /* SCSI name string, variable-length UTF-8 */ 3106 return 9; 3107 case 3: 3108 switch (d[4] >> 4) { 3109 case 6: 3110 /* NAA registered extended */ 3111 return 8; 3112 case 5: 3113 /* NAA registered */ 3114 return 5; 3115 case 4: 3116 /* NAA extended */ 3117 return 4; 3118 case 3: 3119 /* NAA locally assigned */ 3120 return 1; 3121 default: 3122 break; 3123 } 3124 break; 3125 case 2: 3126 switch (d[3]) { 3127 case 16: 3128 /* EUI64-based, 16 byte */ 3129 return 7; 3130 case 12: 3131 /* EUI64-based, 12 byte */ 3132 return 6; 3133 case 8: 3134 /* EUI64-based, 8 byte */ 3135 return 3; 3136 default: 3137 break; 3138 } 3139 break; 3140 case 1: 3141 /* T10 vendor ID */ 3142 return 1; 3143 default: 3144 break; 3145 } 3146 3147 return 0; 3148 } 3149 3150 /** 3151 * scsi_vpd_lun_id - return a unique device identification 3152 * @sdev: SCSI device 3153 * @id: buffer for the identification 3154 * @id_len: length of the buffer 3155 * 3156 * Copies a unique device identification into @id based 3157 * on the information in the VPD page 0x83 of the device. 3158 * The string will be formatted as a SCSI name string. 3159 * 3160 * Returns the length of the identification or error on failure. 3161 * If the identifier is longer than the supplied buffer the actual 3162 * identifier length is returned and the buffer is not zero-padded. 3163 */ 3164 int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len) 3165 { 3166 u8 cur_id_prio = 0; 3167 u8 cur_id_size = 0; 3168 const unsigned char *d, *cur_id_str; 3169 const struct scsi_vpd *vpd_pg83; 3170 int id_size = -EINVAL; 3171 3172 rcu_read_lock(); 3173 vpd_pg83 = rcu_dereference(sdev->vpd_pg83); 3174 if (!vpd_pg83) { 3175 rcu_read_unlock(); 3176 return -ENXIO; 3177 } 3178 3179 /* The id string must be at least 20 bytes + terminating NULL byte */ 3180 if (id_len < 21) { 3181 rcu_read_unlock(); 3182 return -EINVAL; 3183 } 3184 3185 memset(id, 0, id_len); 3186 for (d = vpd_pg83->data + 4; 3187 d < vpd_pg83->data + vpd_pg83->len; 3188 d += d[3] + 4) { 3189 u8 prio = designator_prio(d); 3190 3191 if (prio == 0 || cur_id_prio > prio) 3192 continue; 3193 3194 switch (d[1] & 0xf) { 3195 case 0x1: 3196 /* T10 Vendor ID */ 3197 if (cur_id_size > d[3]) 3198 break; 3199 cur_id_prio = prio; 3200 cur_id_size = d[3]; 3201 if (cur_id_size + 4 > id_len) 3202 cur_id_size = id_len - 4; 3203 cur_id_str = d + 4; 3204 id_size = snprintf(id, id_len, "t10.%*pE", 3205 cur_id_size, cur_id_str); 3206 break; 3207 case 0x2: 3208 /* EUI-64 */ 3209 cur_id_prio = prio; 3210 cur_id_size = d[3]; 3211 cur_id_str = d + 4; 3212 switch (cur_id_size) { 3213 case 8: 3214 id_size = snprintf(id, id_len, 3215 "eui.%8phN", 3216 cur_id_str); 3217 break; 3218 case 12: 3219 id_size = snprintf(id, id_len, 3220 "eui.%12phN", 3221 cur_id_str); 3222 break; 3223 case 16: 3224 id_size = snprintf(id, id_len, 3225 "eui.%16phN", 3226 cur_id_str); 3227 break; 3228 default: 3229 break; 3230 } 3231 break; 3232 case 0x3: 3233 /* NAA */ 3234 cur_id_prio = prio; 3235 cur_id_size = d[3]; 3236 cur_id_str = d + 4; 3237 switch (cur_id_size) { 3238 case 8: 3239 id_size = snprintf(id, id_len, 3240 "naa.%8phN", 3241 cur_id_str); 3242 break; 3243 case 16: 3244 id_size = snprintf(id, id_len, 3245 "naa.%16phN", 3246 cur_id_str); 3247 break; 3248 default: 3249 break; 3250 } 3251 break; 3252 case 0x8: 3253 /* SCSI name string */ 3254 if (cur_id_size > d[3]) 3255 break; 3256 /* Prefer others for truncated descriptor */ 3257 if (d[3] > id_len) { 3258 prio = 2; 3259 if (cur_id_prio > prio) 3260 break; 3261 } 3262 cur_id_prio = prio; 3263 cur_id_size = id_size = d[3]; 3264 cur_id_str = d + 4; 3265 if (cur_id_size >= id_len) 3266 cur_id_size = id_len - 1; 3267 memcpy(id, cur_id_str, cur_id_size); 3268 break; 3269 default: 3270 break; 3271 } 3272 } 3273 rcu_read_unlock(); 3274 3275 return id_size; 3276 } 3277 EXPORT_SYMBOL(scsi_vpd_lun_id); 3278 3279 /* 3280 * scsi_vpd_tpg_id - return a target port group identifier 3281 * @sdev: SCSI device 3282 * 3283 * Returns the Target Port Group identifier from the information 3284 * froom VPD page 0x83 of the device. 3285 * 3286 * Returns the identifier or error on failure. 3287 */ 3288 int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id) 3289 { 3290 const unsigned char *d; 3291 const struct scsi_vpd *vpd_pg83; 3292 int group_id = -EAGAIN, rel_port = -1; 3293 3294 rcu_read_lock(); 3295 vpd_pg83 = rcu_dereference(sdev->vpd_pg83); 3296 if (!vpd_pg83) { 3297 rcu_read_unlock(); 3298 return -ENXIO; 3299 } 3300 3301 d = vpd_pg83->data + 4; 3302 while (d < vpd_pg83->data + vpd_pg83->len) { 3303 switch (d[1] & 0xf) { 3304 case 0x4: 3305 /* Relative target port */ 3306 rel_port = get_unaligned_be16(&d[6]); 3307 break; 3308 case 0x5: 3309 /* Target port group */ 3310 group_id = get_unaligned_be16(&d[6]); 3311 break; 3312 default: 3313 break; 3314 } 3315 d += d[3] + 4; 3316 } 3317 rcu_read_unlock(); 3318 3319 if (group_id >= 0 && rel_id && rel_port != -1) 3320 *rel_id = rel_port; 3321 3322 return group_id; 3323 } 3324 EXPORT_SYMBOL(scsi_vpd_tpg_id); 3325 3326 /** 3327 * scsi_build_sense - build sense data for a command 3328 * @scmd: scsi command for which the sense should be formatted 3329 * @desc: Sense format (non-zero == descriptor format, 3330 * 0 == fixed format) 3331 * @key: Sense key 3332 * @asc: Additional sense code 3333 * @ascq: Additional sense code qualifier 3334 * 3335 **/ 3336 void scsi_build_sense(struct scsi_cmnd *scmd, int desc, u8 key, u8 asc, u8 ascq) 3337 { 3338 scsi_build_sense_buffer(desc, scmd->sense_buffer, key, asc, ascq); 3339 scmd->result = SAM_STAT_CHECK_CONDITION; 3340 } 3341 EXPORT_SYMBOL_GPL(scsi_build_sense); 3342