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