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 unsigned int busy = scsi_host_busy(shost); 282 283 spin_lock_irqsave(shost->host_lock, flags); 284 if (shost->host_failed || shost->host_eh_scheduled) 285 scsi_eh_wakeup(shost, busy); 286 spin_unlock_irqrestore(shost->host_lock, flags); 287 } 288 rcu_read_unlock(); 289 } 290 291 void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd) 292 { 293 struct Scsi_Host *shost = sdev->host; 294 struct scsi_target *starget = scsi_target(sdev); 295 296 scsi_dec_host_busy(shost, cmd); 297 298 if (starget->can_queue > 0) 299 atomic_dec(&starget->target_busy); 300 301 sbitmap_put(&sdev->budget_map, cmd->budget_token); 302 cmd->budget_token = -1; 303 } 304 305 /* 306 * Kick the queue of SCSI device @sdev if @sdev != current_sdev. Called with 307 * interrupts disabled. 308 */ 309 static void scsi_kick_sdev_queue(struct scsi_device *sdev, void *data) 310 { 311 struct scsi_device *current_sdev = data; 312 313 if (sdev != current_sdev) 314 blk_mq_run_hw_queues(sdev->request_queue, true); 315 } 316 317 /* 318 * Called for single_lun devices on IO completion. Clear starget_sdev_user, 319 * and call blk_run_queue for all the scsi_devices on the target - 320 * including current_sdev first. 321 * 322 * Called with *no* scsi locks held. 323 */ 324 static void scsi_single_lun_run(struct scsi_device *current_sdev) 325 { 326 struct Scsi_Host *shost = current_sdev->host; 327 struct scsi_target *starget = scsi_target(current_sdev); 328 unsigned long flags; 329 330 spin_lock_irqsave(shost->host_lock, flags); 331 starget->starget_sdev_user = NULL; 332 spin_unlock_irqrestore(shost->host_lock, flags); 333 334 /* 335 * Call blk_run_queue for all LUNs on the target, starting with 336 * current_sdev. We race with others (to set starget_sdev_user), 337 * but in most cases, we will be first. Ideally, each LU on the 338 * target would get some limited time or requests on the target. 339 */ 340 blk_mq_run_hw_queues(current_sdev->request_queue, 341 shost->queuecommand_may_block); 342 343 spin_lock_irqsave(shost->host_lock, flags); 344 if (!starget->starget_sdev_user) 345 __starget_for_each_device(starget, current_sdev, 346 scsi_kick_sdev_queue); 347 spin_unlock_irqrestore(shost->host_lock, flags); 348 } 349 350 static inline bool scsi_device_is_busy(struct scsi_device *sdev) 351 { 352 if (scsi_device_busy(sdev) >= sdev->queue_depth) 353 return true; 354 if (atomic_read(&sdev->device_blocked) > 0) 355 return true; 356 return false; 357 } 358 359 static inline bool scsi_target_is_busy(struct scsi_target *starget) 360 { 361 if (starget->can_queue > 0) { 362 if (atomic_read(&starget->target_busy) >= starget->can_queue) 363 return true; 364 if (atomic_read(&starget->target_blocked) > 0) 365 return true; 366 } 367 return false; 368 } 369 370 static inline bool scsi_host_is_busy(struct Scsi_Host *shost) 371 { 372 if (atomic_read(&shost->host_blocked) > 0) 373 return true; 374 if (shost->host_self_blocked) 375 return true; 376 return false; 377 } 378 379 static void scsi_starved_list_run(struct Scsi_Host *shost) 380 { 381 LIST_HEAD(starved_list); 382 struct scsi_device *sdev; 383 unsigned long flags; 384 385 spin_lock_irqsave(shost->host_lock, flags); 386 list_splice_init(&shost->starved_list, &starved_list); 387 388 while (!list_empty(&starved_list)) { 389 struct request_queue *slq; 390 391 /* 392 * As long as shost is accepting commands and we have 393 * starved queues, call blk_run_queue. scsi_request_fn 394 * drops the queue_lock and can add us back to the 395 * starved_list. 396 * 397 * host_lock protects the starved_list and starved_entry. 398 * scsi_request_fn must get the host_lock before checking 399 * or modifying starved_list or starved_entry. 400 */ 401 if (scsi_host_is_busy(shost)) 402 break; 403 404 sdev = list_entry(starved_list.next, 405 struct scsi_device, starved_entry); 406 list_del_init(&sdev->starved_entry); 407 if (scsi_target_is_busy(scsi_target(sdev))) { 408 list_move_tail(&sdev->starved_entry, 409 &shost->starved_list); 410 continue; 411 } 412 413 /* 414 * Once we drop the host lock, a racing scsi_remove_device() 415 * call may remove the sdev from the starved list and destroy 416 * it and the queue. Mitigate by taking a reference to the 417 * queue and never touching the sdev again after we drop the 418 * host lock. Note: if __scsi_remove_device() invokes 419 * blk_mq_destroy_queue() before the queue is run from this 420 * function then blk_run_queue() will return immediately since 421 * blk_mq_destroy_queue() marks the queue with QUEUE_FLAG_DYING. 422 */ 423 slq = sdev->request_queue; 424 if (!blk_get_queue(slq)) 425 continue; 426 spin_unlock_irqrestore(shost->host_lock, flags); 427 428 blk_mq_run_hw_queues(slq, false); 429 blk_put_queue(slq); 430 431 spin_lock_irqsave(shost->host_lock, flags); 432 } 433 /* put any unprocessed entries back */ 434 list_splice(&starved_list, &shost->starved_list); 435 spin_unlock_irqrestore(shost->host_lock, flags); 436 } 437 438 /** 439 * scsi_run_queue - Select a proper request queue to serve next. 440 * @q: last request's queue 441 * 442 * The previous command was completely finished, start a new one if possible. 443 */ 444 static void scsi_run_queue(struct request_queue *q) 445 { 446 struct scsi_device *sdev = q->queuedata; 447 448 if (scsi_target(sdev)->single_lun) 449 scsi_single_lun_run(sdev); 450 if (!list_empty(&sdev->host->starved_list)) 451 scsi_starved_list_run(sdev->host); 452 453 /* Note: blk_mq_kick_requeue_list() runs the queue asynchronously. */ 454 blk_mq_kick_requeue_list(q); 455 } 456 457 void scsi_requeue_run_queue(struct work_struct *work) 458 { 459 struct scsi_device *sdev; 460 struct request_queue *q; 461 462 sdev = container_of(work, struct scsi_device, requeue_work); 463 q = sdev->request_queue; 464 scsi_run_queue(q); 465 } 466 467 void scsi_run_host_queues(struct Scsi_Host *shost) 468 { 469 struct scsi_device *sdev; 470 471 shost_for_each_device(sdev, shost) 472 scsi_run_queue(sdev->request_queue); 473 } 474 475 static void scsi_uninit_cmd(struct scsi_cmnd *cmd) 476 { 477 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) { 478 struct scsi_driver *drv = scsi_cmd_to_driver(cmd); 479 480 if (drv->uninit_command) 481 drv->uninit_command(cmd); 482 } 483 } 484 485 void scsi_free_sgtables(struct scsi_cmnd *cmd) 486 { 487 if (cmd->sdb.table.nents) 488 sg_free_table_chained(&cmd->sdb.table, 489 SCSI_INLINE_SG_CNT); 490 if (scsi_prot_sg_count(cmd)) 491 sg_free_table_chained(&cmd->prot_sdb->table, 492 SCSI_INLINE_PROT_SG_CNT); 493 } 494 EXPORT_SYMBOL_GPL(scsi_free_sgtables); 495 496 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd) 497 { 498 scsi_free_sgtables(cmd); 499 scsi_uninit_cmd(cmd); 500 } 501 502 static void scsi_run_queue_async(struct scsi_device *sdev) 503 { 504 if (scsi_host_in_recovery(sdev->host)) 505 return; 506 507 if (scsi_target(sdev)->single_lun || 508 !list_empty(&sdev->host->starved_list)) { 509 kblockd_schedule_work(&sdev->requeue_work); 510 } else { 511 /* 512 * smp_mb() present in sbitmap_queue_clear() or implied in 513 * .end_io is for ordering writing .device_busy in 514 * scsi_device_unbusy() and reading sdev->restarts. 515 */ 516 int old = atomic_read(&sdev->restarts); 517 518 /* 519 * ->restarts has to be kept as non-zero if new budget 520 * contention occurs. 521 * 522 * No need to run queue when either another re-run 523 * queue wins in updating ->restarts or a new budget 524 * contention occurs. 525 */ 526 if (old && atomic_cmpxchg(&sdev->restarts, old, 0) == old) 527 blk_mq_run_hw_queues(sdev->request_queue, true); 528 } 529 } 530 531 /* Returns false when no more bytes to process, true if there are more */ 532 static bool scsi_end_request(struct request *req, blk_status_t error, 533 unsigned int bytes) 534 { 535 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 536 struct scsi_device *sdev = cmd->device; 537 struct request_queue *q = sdev->request_queue; 538 539 if (blk_update_request(req, error, bytes)) 540 return true; 541 542 // XXX: 543 if (blk_queue_add_random(q)) 544 add_disk_randomness(req->q->disk); 545 546 if (!blk_rq_is_passthrough(req)) { 547 WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED)); 548 cmd->flags &= ~SCMD_INITIALIZED; 549 } 550 551 /* 552 * Calling rcu_barrier() is not necessary here because the 553 * SCSI error handler guarantees that the function called by 554 * call_rcu() has been called before scsi_end_request() is 555 * called. 556 */ 557 destroy_rcu_head(&cmd->rcu); 558 559 /* 560 * In the MQ case the command gets freed by __blk_mq_end_request, 561 * so we have to do all cleanup that depends on it earlier. 562 * 563 * We also can't kick the queues from irq context, so we 564 * will have to defer it to a workqueue. 565 */ 566 scsi_mq_uninit_cmd(cmd); 567 568 /* 569 * queue is still alive, so grab the ref for preventing it 570 * from being cleaned up during running queue. 571 */ 572 percpu_ref_get(&q->q_usage_counter); 573 574 __blk_mq_end_request(req, error); 575 576 scsi_run_queue_async(sdev); 577 578 percpu_ref_put(&q->q_usage_counter); 579 return false; 580 } 581 582 /** 583 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t 584 * @result: scsi error code 585 * 586 * Translate a SCSI result code into a blk_status_t value. 587 */ 588 static blk_status_t scsi_result_to_blk_status(int result) 589 { 590 /* 591 * Check the scsi-ml byte first in case we converted a host or status 592 * byte. 593 */ 594 switch (scsi_ml_byte(result)) { 595 case SCSIML_STAT_OK: 596 break; 597 case SCSIML_STAT_RESV_CONFLICT: 598 return BLK_STS_RESV_CONFLICT; 599 case SCSIML_STAT_NOSPC: 600 return BLK_STS_NOSPC; 601 case SCSIML_STAT_MED_ERROR: 602 return BLK_STS_MEDIUM; 603 case SCSIML_STAT_TGT_FAILURE: 604 return BLK_STS_TARGET; 605 case SCSIML_STAT_DL_TIMEOUT: 606 return BLK_STS_DURATION_LIMIT; 607 } 608 609 switch (host_byte(result)) { 610 case DID_OK: 611 if (scsi_status_is_good(result)) 612 return BLK_STS_OK; 613 return BLK_STS_IOERR; 614 case DID_TRANSPORT_FAILFAST: 615 case DID_TRANSPORT_MARGINAL: 616 return BLK_STS_TRANSPORT; 617 default: 618 return BLK_STS_IOERR; 619 } 620 } 621 622 /** 623 * scsi_rq_err_bytes - determine number of bytes till the next failure boundary 624 * @rq: request to examine 625 * 626 * Description: 627 * A request could be merge of IOs which require different failure 628 * handling. This function determines the number of bytes which 629 * can be failed from the beginning of the request without 630 * crossing into area which need to be retried further. 631 * 632 * Return: 633 * The number of bytes to fail. 634 */ 635 static unsigned int scsi_rq_err_bytes(const struct request *rq) 636 { 637 blk_opf_t ff = rq->cmd_flags & REQ_FAILFAST_MASK; 638 unsigned int bytes = 0; 639 struct bio *bio; 640 641 if (!(rq->rq_flags & RQF_MIXED_MERGE)) 642 return blk_rq_bytes(rq); 643 644 /* 645 * Currently the only 'mixing' which can happen is between 646 * different fastfail types. We can safely fail portions 647 * which have all the failfast bits that the first one has - 648 * the ones which are at least as eager to fail as the first 649 * one. 650 */ 651 for (bio = rq->bio; bio; bio = bio->bi_next) { 652 if ((bio->bi_opf & ff) != ff) 653 break; 654 bytes += bio->bi_iter.bi_size; 655 } 656 657 /* this could lead to infinite loop */ 658 BUG_ON(blk_rq_bytes(rq) && !bytes); 659 return bytes; 660 } 661 662 static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd) 663 { 664 struct request *req = scsi_cmd_to_rq(cmd); 665 unsigned long wait_for; 666 667 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT) 668 return false; 669 670 wait_for = (cmd->allowed + 1) * req->timeout; 671 if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { 672 scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n", 673 wait_for/HZ); 674 return true; 675 } 676 return false; 677 } 678 679 /* 680 * When ALUA transition state is returned, reprep the cmd to 681 * use the ALUA handler's transition timeout. Delay the reprep 682 * 1 sec to avoid aggressive retries of the target in that 683 * state. 684 */ 685 #define ALUA_TRANSITION_REPREP_DELAY 1000 686 687 /* Helper for scsi_io_completion() when special action required. */ 688 static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result) 689 { 690 struct request *req = scsi_cmd_to_rq(cmd); 691 int level = 0; 692 enum {ACTION_FAIL, ACTION_REPREP, ACTION_DELAYED_REPREP, 693 ACTION_RETRY, ACTION_DELAYED_RETRY} action; 694 struct scsi_sense_hdr sshdr; 695 bool sense_valid; 696 bool sense_current = true; /* false implies "deferred sense" */ 697 blk_status_t blk_stat; 698 699 sense_valid = scsi_command_normalize_sense(cmd, &sshdr); 700 if (sense_valid) 701 sense_current = !scsi_sense_is_deferred(&sshdr); 702 703 blk_stat = scsi_result_to_blk_status(result); 704 705 if (host_byte(result) == DID_RESET) { 706 /* Third party bus reset or reset for error recovery 707 * reasons. Just retry the command and see what 708 * happens. 709 */ 710 action = ACTION_RETRY; 711 } else if (sense_valid && sense_current) { 712 switch (sshdr.sense_key) { 713 case UNIT_ATTENTION: 714 if (cmd->device->removable) { 715 /* Detected disc change. Set a bit 716 * and quietly refuse further access. 717 */ 718 cmd->device->changed = 1; 719 action = ACTION_FAIL; 720 } else { 721 /* Must have been a power glitch, or a 722 * bus reset. Could not have been a 723 * media change, so we just retry the 724 * command and see what happens. 725 */ 726 action = ACTION_RETRY; 727 } 728 break; 729 case ILLEGAL_REQUEST: 730 /* If we had an ILLEGAL REQUEST returned, then 731 * we may have performed an unsupported 732 * command. The only thing this should be 733 * would be a ten byte read where only a six 734 * byte read was supported. Also, on a system 735 * where READ CAPACITY failed, we may have 736 * read past the end of the disk. 737 */ 738 if ((cmd->device->use_10_for_rw && 739 sshdr.asc == 0x20 && sshdr.ascq == 0x00) && 740 (cmd->cmnd[0] == READ_10 || 741 cmd->cmnd[0] == WRITE_10)) { 742 /* This will issue a new 6-byte command. */ 743 cmd->device->use_10_for_rw = 0; 744 action = ACTION_REPREP; 745 } else if (sshdr.asc == 0x10) /* DIX */ { 746 action = ACTION_FAIL; 747 blk_stat = BLK_STS_PROTECTION; 748 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */ 749 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) { 750 action = ACTION_FAIL; 751 blk_stat = BLK_STS_TARGET; 752 } else 753 action = ACTION_FAIL; 754 break; 755 case ABORTED_COMMAND: 756 action = ACTION_FAIL; 757 if (sshdr.asc == 0x10) /* DIF */ 758 blk_stat = BLK_STS_PROTECTION; 759 break; 760 case NOT_READY: 761 /* If the device is in the process of becoming 762 * ready, or has a temporary blockage, retry. 763 */ 764 if (sshdr.asc == 0x04) { 765 switch (sshdr.ascq) { 766 case 0x01: /* becoming ready */ 767 case 0x04: /* format in progress */ 768 case 0x05: /* rebuild in progress */ 769 case 0x06: /* recalculation in progress */ 770 case 0x07: /* operation in progress */ 771 case 0x08: /* Long write in progress */ 772 case 0x09: /* self test in progress */ 773 case 0x11: /* notify (enable spinup) required */ 774 case 0x14: /* space allocation in progress */ 775 case 0x1a: /* start stop unit in progress */ 776 case 0x1b: /* sanitize in progress */ 777 case 0x1d: /* configuration in progress */ 778 case 0x24: /* depopulation in progress */ 779 case 0x25: /* depopulation restore in progress */ 780 action = ACTION_DELAYED_RETRY; 781 break; 782 case 0x0a: /* ALUA state transition */ 783 action = ACTION_DELAYED_REPREP; 784 break; 785 default: 786 action = ACTION_FAIL; 787 break; 788 } 789 } else 790 action = ACTION_FAIL; 791 break; 792 case VOLUME_OVERFLOW: 793 /* See SSC3rXX or current. */ 794 action = ACTION_FAIL; 795 break; 796 case DATA_PROTECT: 797 action = ACTION_FAIL; 798 if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) || 799 (sshdr.asc == 0x55 && 800 (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) { 801 /* Insufficient zone resources */ 802 blk_stat = BLK_STS_ZONE_OPEN_RESOURCE; 803 } 804 break; 805 case COMPLETED: 806 fallthrough; 807 default: 808 action = ACTION_FAIL; 809 break; 810 } 811 } else 812 action = ACTION_FAIL; 813 814 if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd)) 815 action = ACTION_FAIL; 816 817 switch (action) { 818 case ACTION_FAIL: 819 /* Give up and fail the remainder of the request */ 820 if (!(req->rq_flags & RQF_QUIET)) { 821 static DEFINE_RATELIMIT_STATE(_rs, 822 DEFAULT_RATELIMIT_INTERVAL, 823 DEFAULT_RATELIMIT_BURST); 824 825 if (unlikely(scsi_logging_level)) 826 level = 827 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT, 828 SCSI_LOG_MLCOMPLETE_BITS); 829 830 /* 831 * if logging is enabled the failure will be printed 832 * in scsi_log_completion(), so avoid duplicate messages 833 */ 834 if (!level && __ratelimit(&_rs)) { 835 scsi_print_result(cmd, NULL, FAILED); 836 if (sense_valid) 837 scsi_print_sense(cmd); 838 scsi_print_command(cmd); 839 } 840 } 841 if (!scsi_end_request(req, blk_stat, scsi_rq_err_bytes(req))) 842 return; 843 fallthrough; 844 case ACTION_REPREP: 845 scsi_mq_requeue_cmd(cmd, 0); 846 break; 847 case ACTION_DELAYED_REPREP: 848 scsi_mq_requeue_cmd(cmd, ALUA_TRANSITION_REPREP_DELAY); 849 break; 850 case ACTION_RETRY: 851 /* Retry the same command immediately */ 852 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false); 853 break; 854 case ACTION_DELAYED_RETRY: 855 /* Retry the same command after a delay */ 856 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false); 857 break; 858 } 859 } 860 861 /* 862 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a 863 * new result that may suppress further error checking. Also modifies 864 * *blk_statp in some cases. 865 */ 866 static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result, 867 blk_status_t *blk_statp) 868 { 869 bool sense_valid; 870 bool sense_current = true; /* false implies "deferred sense" */ 871 struct request *req = scsi_cmd_to_rq(cmd); 872 struct scsi_sense_hdr sshdr; 873 874 sense_valid = scsi_command_normalize_sense(cmd, &sshdr); 875 if (sense_valid) 876 sense_current = !scsi_sense_is_deferred(&sshdr); 877 878 if (blk_rq_is_passthrough(req)) { 879 if (sense_valid) { 880 /* 881 * SG_IO wants current and deferred errors 882 */ 883 cmd->sense_len = min(8 + cmd->sense_buffer[7], 884 SCSI_SENSE_BUFFERSIZE); 885 } 886 if (sense_current) 887 *blk_statp = scsi_result_to_blk_status(result); 888 } else if (blk_rq_bytes(req) == 0 && sense_current) { 889 /* 890 * Flush commands do not transfers any data, and thus cannot use 891 * good_bytes != blk_rq_bytes(req) as the signal for an error. 892 * This sets *blk_statp explicitly for the problem case. 893 */ 894 *blk_statp = scsi_result_to_blk_status(result); 895 } 896 /* 897 * Recovered errors need reporting, but they're always treated as 898 * success, so fiddle the result code here. For passthrough requests 899 * we already took a copy of the original into sreq->result which 900 * is what gets returned to the user 901 */ 902 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) { 903 bool do_print = true; 904 /* 905 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d] 906 * skip print since caller wants ATA registers. Only occurs 907 * on SCSI ATA PASS_THROUGH commands when CK_COND=1 908 */ 909 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d)) 910 do_print = false; 911 else if (req->rq_flags & RQF_QUIET) 912 do_print = false; 913 if (do_print) 914 scsi_print_sense(cmd); 915 result = 0; 916 /* for passthrough, *blk_statp may be set */ 917 *blk_statp = BLK_STS_OK; 918 } 919 /* 920 * Another corner case: the SCSI status byte is non-zero but 'good'. 921 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when 922 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD 923 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related 924 * intermediate statuses (both obsolete in SAM-4) as good. 925 */ 926 if ((result & 0xff) && scsi_status_is_good(result)) { 927 result = 0; 928 *blk_statp = BLK_STS_OK; 929 } 930 return result; 931 } 932 933 /** 934 * scsi_io_completion - Completion processing for SCSI commands. 935 * @cmd: command that is finished. 936 * @good_bytes: number of processed bytes. 937 * 938 * We will finish off the specified number of sectors. If we are done, the 939 * command block will be released and the queue function will be goosed. If we 940 * are not done then we have to figure out what to do next: 941 * 942 * a) We can call scsi_mq_requeue_cmd(). The request will be 943 * unprepared and put back on the queue. Then a new command will 944 * be created for it. This should be used if we made forward 945 * progress, or if we want to switch from READ(10) to READ(6) for 946 * example. 947 * 948 * b) We can call scsi_io_completion_action(). The request will be 949 * put back on the queue and retried using the same command as 950 * before, possibly after a delay. 951 * 952 * c) We can call scsi_end_request() with blk_stat other than 953 * BLK_STS_OK, to fail the remainder of the request. 954 */ 955 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) 956 { 957 int result = cmd->result; 958 struct request *req = scsi_cmd_to_rq(cmd); 959 blk_status_t blk_stat = BLK_STS_OK; 960 961 if (unlikely(result)) /* a nz result may or may not be an error */ 962 result = scsi_io_completion_nz_result(cmd, result, &blk_stat); 963 964 /* 965 * Next deal with any sectors which we were able to correctly 966 * handle. 967 */ 968 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd, 969 "%u sectors total, %d bytes done.\n", 970 blk_rq_sectors(req), good_bytes)); 971 972 /* 973 * Failed, zero length commands always need to drop down 974 * to retry code. Fast path should return in this block. 975 */ 976 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) { 977 if (likely(!scsi_end_request(req, blk_stat, good_bytes))) 978 return; /* no bytes remaining */ 979 } 980 981 /* Kill remainder if no retries. */ 982 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) { 983 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req))) 984 WARN_ONCE(true, 985 "Bytes remaining after failed, no-retry command"); 986 return; 987 } 988 989 /* 990 * If there had been no error, but we have leftover bytes in the 991 * request just queue the command up again. 992 */ 993 if (likely(result == 0)) 994 scsi_mq_requeue_cmd(cmd, 0); 995 else 996 scsi_io_completion_action(cmd, result); 997 } 998 999 static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev, 1000 struct request *rq) 1001 { 1002 return sdev->dma_drain_len && blk_rq_is_passthrough(rq) && 1003 !op_is_write(req_op(rq)) && 1004 sdev->host->hostt->dma_need_drain(rq); 1005 } 1006 1007 /** 1008 * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists 1009 * @cmd: SCSI command data structure to initialize. 1010 * 1011 * Initializes @cmd->sdb and also @cmd->prot_sdb if data integrity is enabled 1012 * for @cmd. 1013 * 1014 * Returns: 1015 * * BLK_STS_OK - on success 1016 * * BLK_STS_RESOURCE - if the failure is retryable 1017 * * BLK_STS_IOERR - if the failure is fatal 1018 */ 1019 blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd) 1020 { 1021 struct scsi_device *sdev = cmd->device; 1022 struct request *rq = scsi_cmd_to_rq(cmd); 1023 unsigned short nr_segs = blk_rq_nr_phys_segments(rq); 1024 struct scatterlist *last_sg = NULL; 1025 blk_status_t ret; 1026 bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq); 1027 int count; 1028 1029 if (WARN_ON_ONCE(!nr_segs)) 1030 return BLK_STS_IOERR; 1031 1032 /* 1033 * Make sure there is space for the drain. The driver must adjust 1034 * max_hw_segments to be prepared for this. 1035 */ 1036 if (need_drain) 1037 nr_segs++; 1038 1039 /* 1040 * If sg table allocation fails, requeue request later. 1041 */ 1042 if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs, 1043 cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT))) 1044 return BLK_STS_RESOURCE; 1045 1046 /* 1047 * Next, walk the list, and fill in the addresses and sizes of 1048 * each segment. 1049 */ 1050 count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg); 1051 1052 if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) { 1053 unsigned int pad_len = 1054 (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1; 1055 1056 last_sg->length += pad_len; 1057 cmd->extra_len += pad_len; 1058 } 1059 1060 if (need_drain) { 1061 sg_unmark_end(last_sg); 1062 last_sg = sg_next(last_sg); 1063 sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len); 1064 sg_mark_end(last_sg); 1065 1066 cmd->extra_len += sdev->dma_drain_len; 1067 count++; 1068 } 1069 1070 BUG_ON(count > cmd->sdb.table.nents); 1071 cmd->sdb.table.nents = count; 1072 cmd->sdb.length = blk_rq_payload_bytes(rq); 1073 1074 if (blk_integrity_rq(rq)) { 1075 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb; 1076 int ivecs; 1077 1078 if (WARN_ON_ONCE(!prot_sdb)) { 1079 /* 1080 * This can happen if someone (e.g. multipath) 1081 * queues a command to a device on an adapter 1082 * that does not support DIX. 1083 */ 1084 ret = BLK_STS_IOERR; 1085 goto out_free_sgtables; 1086 } 1087 1088 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio); 1089 1090 if (sg_alloc_table_chained(&prot_sdb->table, ivecs, 1091 prot_sdb->table.sgl, 1092 SCSI_INLINE_PROT_SG_CNT)) { 1093 ret = BLK_STS_RESOURCE; 1094 goto out_free_sgtables; 1095 } 1096 1097 count = blk_rq_map_integrity_sg(rq->q, rq->bio, 1098 prot_sdb->table.sgl); 1099 BUG_ON(count > ivecs); 1100 BUG_ON(count > queue_max_integrity_segments(rq->q)); 1101 1102 cmd->prot_sdb = prot_sdb; 1103 cmd->prot_sdb->table.nents = count; 1104 } 1105 1106 return BLK_STS_OK; 1107 out_free_sgtables: 1108 scsi_free_sgtables(cmd); 1109 return ret; 1110 } 1111 EXPORT_SYMBOL(scsi_alloc_sgtables); 1112 1113 /** 1114 * scsi_initialize_rq - initialize struct scsi_cmnd partially 1115 * @rq: Request associated with the SCSI command to be initialized. 1116 * 1117 * This function initializes the members of struct scsi_cmnd that must be 1118 * initialized before request processing starts and that won't be 1119 * reinitialized if a SCSI command is requeued. 1120 */ 1121 static void scsi_initialize_rq(struct request *rq) 1122 { 1123 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); 1124 1125 memset(cmd->cmnd, 0, sizeof(cmd->cmnd)); 1126 cmd->cmd_len = MAX_COMMAND_SIZE; 1127 cmd->sense_len = 0; 1128 init_rcu_head(&cmd->rcu); 1129 cmd->jiffies_at_alloc = jiffies; 1130 cmd->retries = 0; 1131 } 1132 1133 struct request *scsi_alloc_request(struct request_queue *q, blk_opf_t opf, 1134 blk_mq_req_flags_t flags) 1135 { 1136 struct request *rq; 1137 1138 rq = blk_mq_alloc_request(q, opf, flags); 1139 if (!IS_ERR(rq)) 1140 scsi_initialize_rq(rq); 1141 return rq; 1142 } 1143 EXPORT_SYMBOL_GPL(scsi_alloc_request); 1144 1145 /* 1146 * Only called when the request isn't completed by SCSI, and not freed by 1147 * SCSI 1148 */ 1149 static void scsi_cleanup_rq(struct request *rq) 1150 { 1151 if (rq->rq_flags & RQF_DONTPREP) { 1152 scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq)); 1153 rq->rq_flags &= ~RQF_DONTPREP; 1154 } 1155 } 1156 1157 /* Called before a request is prepared. See also scsi_mq_prep_fn(). */ 1158 void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd) 1159 { 1160 struct request *rq = scsi_cmd_to_rq(cmd); 1161 1162 if (!blk_rq_is_passthrough(rq) && !(cmd->flags & SCMD_INITIALIZED)) { 1163 cmd->flags |= SCMD_INITIALIZED; 1164 scsi_initialize_rq(rq); 1165 } 1166 1167 cmd->device = dev; 1168 INIT_LIST_HEAD(&cmd->eh_entry); 1169 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler); 1170 } 1171 1172 static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev, 1173 struct request *req) 1174 { 1175 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 1176 1177 /* 1178 * Passthrough requests may transfer data, in which case they must 1179 * a bio attached to them. Or they might contain a SCSI command 1180 * that does not transfer data, in which case they may optionally 1181 * submit a request without an attached bio. 1182 */ 1183 if (req->bio) { 1184 blk_status_t ret = scsi_alloc_sgtables(cmd); 1185 if (unlikely(ret != BLK_STS_OK)) 1186 return ret; 1187 } else { 1188 BUG_ON(blk_rq_bytes(req)); 1189 1190 memset(&cmd->sdb, 0, sizeof(cmd->sdb)); 1191 } 1192 1193 cmd->transfersize = blk_rq_bytes(req); 1194 return BLK_STS_OK; 1195 } 1196 1197 static blk_status_t 1198 scsi_device_state_check(struct scsi_device *sdev, struct request *req) 1199 { 1200 switch (sdev->sdev_state) { 1201 case SDEV_CREATED: 1202 return BLK_STS_OK; 1203 case SDEV_OFFLINE: 1204 case SDEV_TRANSPORT_OFFLINE: 1205 /* 1206 * If the device is offline we refuse to process any 1207 * commands. The device must be brought online 1208 * before trying any recovery commands. 1209 */ 1210 if (!sdev->offline_already) { 1211 sdev->offline_already = true; 1212 sdev_printk(KERN_ERR, sdev, 1213 "rejecting I/O to offline device\n"); 1214 } 1215 return BLK_STS_IOERR; 1216 case SDEV_DEL: 1217 /* 1218 * If the device is fully deleted, we refuse to 1219 * process any commands as well. 1220 */ 1221 sdev_printk(KERN_ERR, sdev, 1222 "rejecting I/O to dead device\n"); 1223 return BLK_STS_IOERR; 1224 case SDEV_BLOCK: 1225 case SDEV_CREATED_BLOCK: 1226 return BLK_STS_RESOURCE; 1227 case SDEV_QUIESCE: 1228 /* 1229 * If the device is blocked we only accept power management 1230 * commands. 1231 */ 1232 if (req && WARN_ON_ONCE(!(req->rq_flags & RQF_PM))) 1233 return BLK_STS_RESOURCE; 1234 return BLK_STS_OK; 1235 default: 1236 /* 1237 * For any other not fully online state we only allow 1238 * power management commands. 1239 */ 1240 if (req && !(req->rq_flags & RQF_PM)) 1241 return BLK_STS_OFFLINE; 1242 return BLK_STS_OK; 1243 } 1244 } 1245 1246 /* 1247 * scsi_dev_queue_ready: if we can send requests to sdev, assign one token 1248 * and return the token else return -1. 1249 */ 1250 static inline int scsi_dev_queue_ready(struct request_queue *q, 1251 struct scsi_device *sdev) 1252 { 1253 int token; 1254 1255 token = sbitmap_get(&sdev->budget_map); 1256 if (token < 0) 1257 return -1; 1258 1259 if (!atomic_read(&sdev->device_blocked)) 1260 return token; 1261 1262 /* 1263 * Only unblock if no other commands are pending and 1264 * if device_blocked has decreased to zero 1265 */ 1266 if (scsi_device_busy(sdev) > 1 || 1267 atomic_dec_return(&sdev->device_blocked) > 0) { 1268 sbitmap_put(&sdev->budget_map, token); 1269 return -1; 1270 } 1271 1272 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev, 1273 "unblocking device at zero depth\n")); 1274 1275 return token; 1276 } 1277 1278 /* 1279 * scsi_target_queue_ready: checks if there we can send commands to target 1280 * @sdev: scsi device on starget to check. 1281 */ 1282 static inline int scsi_target_queue_ready(struct Scsi_Host *shost, 1283 struct scsi_device *sdev) 1284 { 1285 struct scsi_target *starget = scsi_target(sdev); 1286 unsigned int busy; 1287 1288 if (starget->single_lun) { 1289 spin_lock_irq(shost->host_lock); 1290 if (starget->starget_sdev_user && 1291 starget->starget_sdev_user != sdev) { 1292 spin_unlock_irq(shost->host_lock); 1293 return 0; 1294 } 1295 starget->starget_sdev_user = sdev; 1296 spin_unlock_irq(shost->host_lock); 1297 } 1298 1299 if (starget->can_queue <= 0) 1300 return 1; 1301 1302 busy = atomic_inc_return(&starget->target_busy) - 1; 1303 if (atomic_read(&starget->target_blocked) > 0) { 1304 if (busy) 1305 goto starved; 1306 1307 /* 1308 * unblock after target_blocked iterates to zero 1309 */ 1310 if (atomic_dec_return(&starget->target_blocked) > 0) 1311 goto out_dec; 1312 1313 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget, 1314 "unblocking target at zero depth\n")); 1315 } 1316 1317 if (busy >= starget->can_queue) 1318 goto starved; 1319 1320 return 1; 1321 1322 starved: 1323 spin_lock_irq(shost->host_lock); 1324 list_move_tail(&sdev->starved_entry, &shost->starved_list); 1325 spin_unlock_irq(shost->host_lock); 1326 out_dec: 1327 if (starget->can_queue > 0) 1328 atomic_dec(&starget->target_busy); 1329 return 0; 1330 } 1331 1332 /* 1333 * scsi_host_queue_ready: if we can send requests to shost, return 1 else 1334 * return 0. We must end up running the queue again whenever 0 is 1335 * returned, else IO can hang. 1336 */ 1337 static inline int scsi_host_queue_ready(struct request_queue *q, 1338 struct Scsi_Host *shost, 1339 struct scsi_device *sdev, 1340 struct scsi_cmnd *cmd) 1341 { 1342 if (atomic_read(&shost->host_blocked) > 0) { 1343 if (scsi_host_busy(shost) > 0) 1344 goto starved; 1345 1346 /* 1347 * unblock after host_blocked iterates to zero 1348 */ 1349 if (atomic_dec_return(&shost->host_blocked) > 0) 1350 goto out_dec; 1351 1352 SCSI_LOG_MLQUEUE(3, 1353 shost_printk(KERN_INFO, shost, 1354 "unblocking host at zero depth\n")); 1355 } 1356 1357 if (shost->host_self_blocked) 1358 goto starved; 1359 1360 /* We're OK to process the command, so we can't be starved */ 1361 if (!list_empty(&sdev->starved_entry)) { 1362 spin_lock_irq(shost->host_lock); 1363 if (!list_empty(&sdev->starved_entry)) 1364 list_del_init(&sdev->starved_entry); 1365 spin_unlock_irq(shost->host_lock); 1366 } 1367 1368 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state); 1369 1370 return 1; 1371 1372 starved: 1373 spin_lock_irq(shost->host_lock); 1374 if (list_empty(&sdev->starved_entry)) 1375 list_add_tail(&sdev->starved_entry, &shost->starved_list); 1376 spin_unlock_irq(shost->host_lock); 1377 out_dec: 1378 scsi_dec_host_busy(shost, cmd); 1379 return 0; 1380 } 1381 1382 /* 1383 * Busy state exporting function for request stacking drivers. 1384 * 1385 * For efficiency, no lock is taken to check the busy state of 1386 * shost/starget/sdev, since the returned value is not guaranteed and 1387 * may be changed after request stacking drivers call the function, 1388 * regardless of taking lock or not. 1389 * 1390 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi 1391 * needs to return 'not busy'. Otherwise, request stacking drivers 1392 * may hold requests forever. 1393 */ 1394 static bool scsi_mq_lld_busy(struct request_queue *q) 1395 { 1396 struct scsi_device *sdev = q->queuedata; 1397 struct Scsi_Host *shost; 1398 1399 if (blk_queue_dying(q)) 1400 return false; 1401 1402 shost = sdev->host; 1403 1404 /* 1405 * Ignore host/starget busy state. 1406 * Since block layer does not have a concept of fairness across 1407 * multiple queues, congestion of host/starget needs to be handled 1408 * in SCSI layer. 1409 */ 1410 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev)) 1411 return true; 1412 1413 return false; 1414 } 1415 1416 /* 1417 * Block layer request completion callback. May be called from interrupt 1418 * context. 1419 */ 1420 static void scsi_complete(struct request *rq) 1421 { 1422 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); 1423 enum scsi_disposition disposition; 1424 1425 INIT_LIST_HEAD(&cmd->eh_entry); 1426 1427 atomic_inc(&cmd->device->iodone_cnt); 1428 if (cmd->result) 1429 atomic_inc(&cmd->device->ioerr_cnt); 1430 1431 disposition = scsi_decide_disposition(cmd); 1432 if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd)) 1433 disposition = SUCCESS; 1434 1435 scsi_log_completion(cmd, disposition); 1436 1437 switch (disposition) { 1438 case SUCCESS: 1439 scsi_finish_command(cmd); 1440 break; 1441 case NEEDS_RETRY: 1442 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY); 1443 break; 1444 case ADD_TO_MLQUEUE: 1445 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); 1446 break; 1447 default: 1448 scsi_eh_scmd_add(cmd); 1449 break; 1450 } 1451 } 1452 1453 /** 1454 * scsi_dispatch_cmd - Dispatch a command to the low-level driver. 1455 * @cmd: command block we are dispatching. 1456 * 1457 * Return: nonzero return request was rejected and device's queue needs to be 1458 * plugged. 1459 */ 1460 static int scsi_dispatch_cmd(struct scsi_cmnd *cmd) 1461 { 1462 struct Scsi_Host *host = cmd->device->host; 1463 int rtn = 0; 1464 1465 atomic_inc(&cmd->device->iorequest_cnt); 1466 1467 /* check if the device is still usable */ 1468 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) { 1469 /* in SDEV_DEL we error all commands. DID_NO_CONNECT 1470 * returns an immediate error upwards, and signals 1471 * that the device is no longer present */ 1472 cmd->result = DID_NO_CONNECT << 16; 1473 goto done; 1474 } 1475 1476 /* Check to see if the scsi lld made this device blocked. */ 1477 if (unlikely(scsi_device_blocked(cmd->device))) { 1478 /* 1479 * in blocked state, the command is just put back on 1480 * the device queue. The suspend state has already 1481 * blocked the queue so future requests should not 1482 * occur until the device transitions out of the 1483 * suspend state. 1484 */ 1485 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, 1486 "queuecommand : device blocked\n")); 1487 atomic_dec(&cmd->device->iorequest_cnt); 1488 return SCSI_MLQUEUE_DEVICE_BUSY; 1489 } 1490 1491 /* Store the LUN value in cmnd, if needed. */ 1492 if (cmd->device->lun_in_cdb) 1493 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) | 1494 (cmd->device->lun << 5 & 0xe0); 1495 1496 scsi_log_send(cmd); 1497 1498 /* 1499 * Before we queue this command, check if the command 1500 * length exceeds what the host adapter can handle. 1501 */ 1502 if (cmd->cmd_len > cmd->device->host->max_cmd_len) { 1503 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, 1504 "queuecommand : command too long. " 1505 "cdb_size=%d host->max_cmd_len=%d\n", 1506 cmd->cmd_len, cmd->device->host->max_cmd_len)); 1507 cmd->result = (DID_ABORT << 16); 1508 goto done; 1509 } 1510 1511 if (unlikely(host->shost_state == SHOST_DEL)) { 1512 cmd->result = (DID_NO_CONNECT << 16); 1513 goto done; 1514 1515 } 1516 1517 trace_scsi_dispatch_cmd_start(cmd); 1518 rtn = host->hostt->queuecommand(host, cmd); 1519 if (rtn) { 1520 atomic_dec(&cmd->device->iorequest_cnt); 1521 trace_scsi_dispatch_cmd_error(cmd, rtn); 1522 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY && 1523 rtn != SCSI_MLQUEUE_TARGET_BUSY) 1524 rtn = SCSI_MLQUEUE_HOST_BUSY; 1525 1526 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, 1527 "queuecommand : request rejected\n")); 1528 } 1529 1530 return rtn; 1531 done: 1532 scsi_done(cmd); 1533 return 0; 1534 } 1535 1536 /* Size in bytes of the sg-list stored in the scsi-mq command-private data. */ 1537 static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost) 1538 { 1539 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) * 1540 sizeof(struct scatterlist); 1541 } 1542 1543 static blk_status_t scsi_prepare_cmd(struct request *req) 1544 { 1545 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 1546 struct scsi_device *sdev = req->q->queuedata; 1547 struct Scsi_Host *shost = sdev->host; 1548 bool in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state); 1549 struct scatterlist *sg; 1550 1551 scsi_init_command(sdev, cmd); 1552 1553 cmd->eh_eflags = 0; 1554 cmd->prot_type = 0; 1555 cmd->prot_flags = 0; 1556 cmd->submitter = 0; 1557 memset(&cmd->sdb, 0, sizeof(cmd->sdb)); 1558 cmd->underflow = 0; 1559 cmd->transfersize = 0; 1560 cmd->host_scribble = NULL; 1561 cmd->result = 0; 1562 cmd->extra_len = 0; 1563 cmd->state = 0; 1564 if (in_flight) 1565 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state); 1566 1567 /* 1568 * Only clear the driver-private command data if the LLD does not supply 1569 * a function to initialize that data. 1570 */ 1571 if (!shost->hostt->init_cmd_priv) 1572 memset(cmd + 1, 0, shost->hostt->cmd_size); 1573 1574 cmd->prot_op = SCSI_PROT_NORMAL; 1575 if (blk_rq_bytes(req)) 1576 cmd->sc_data_direction = rq_dma_dir(req); 1577 else 1578 cmd->sc_data_direction = DMA_NONE; 1579 1580 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size; 1581 cmd->sdb.table.sgl = sg; 1582 1583 if (scsi_host_get_prot(shost)) { 1584 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer)); 1585 1586 cmd->prot_sdb->table.sgl = 1587 (struct scatterlist *)(cmd->prot_sdb + 1); 1588 } 1589 1590 /* 1591 * Special handling for passthrough commands, which don't go to the ULP 1592 * at all: 1593 */ 1594 if (blk_rq_is_passthrough(req)) 1595 return scsi_setup_scsi_cmnd(sdev, req); 1596 1597 if (sdev->handler && sdev->handler->prep_fn) { 1598 blk_status_t ret = sdev->handler->prep_fn(sdev, req); 1599 1600 if (ret != BLK_STS_OK) 1601 return ret; 1602 } 1603 1604 /* Usually overridden by the ULP */ 1605 cmd->allowed = 0; 1606 memset(cmd->cmnd, 0, sizeof(cmd->cmnd)); 1607 return scsi_cmd_to_driver(cmd)->init_command(cmd); 1608 } 1609 1610 static void scsi_done_internal(struct scsi_cmnd *cmd, bool complete_directly) 1611 { 1612 struct request *req = scsi_cmd_to_rq(cmd); 1613 1614 switch (cmd->submitter) { 1615 case SUBMITTED_BY_BLOCK_LAYER: 1616 break; 1617 case SUBMITTED_BY_SCSI_ERROR_HANDLER: 1618 return scsi_eh_done(cmd); 1619 case SUBMITTED_BY_SCSI_RESET_IOCTL: 1620 return; 1621 } 1622 1623 if (unlikely(blk_should_fake_timeout(scsi_cmd_to_rq(cmd)->q))) 1624 return; 1625 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state))) 1626 return; 1627 trace_scsi_dispatch_cmd_done(cmd); 1628 1629 if (complete_directly) 1630 blk_mq_complete_request_direct(req, scsi_complete); 1631 else 1632 blk_mq_complete_request(req); 1633 } 1634 1635 void scsi_done(struct scsi_cmnd *cmd) 1636 { 1637 scsi_done_internal(cmd, false); 1638 } 1639 EXPORT_SYMBOL(scsi_done); 1640 1641 void scsi_done_direct(struct scsi_cmnd *cmd) 1642 { 1643 scsi_done_internal(cmd, true); 1644 } 1645 EXPORT_SYMBOL(scsi_done_direct); 1646 1647 static void scsi_mq_put_budget(struct request_queue *q, int budget_token) 1648 { 1649 struct scsi_device *sdev = q->queuedata; 1650 1651 sbitmap_put(&sdev->budget_map, budget_token); 1652 } 1653 1654 /* 1655 * When to reinvoke queueing after a resource shortage. It's 3 msecs to 1656 * not change behaviour from the previous unplug mechanism, experimentation 1657 * may prove this needs changing. 1658 */ 1659 #define SCSI_QUEUE_DELAY 3 1660 1661 static int scsi_mq_get_budget(struct request_queue *q) 1662 { 1663 struct scsi_device *sdev = q->queuedata; 1664 int token = scsi_dev_queue_ready(q, sdev); 1665 1666 if (token >= 0) 1667 return token; 1668 1669 atomic_inc(&sdev->restarts); 1670 1671 /* 1672 * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy). 1673 * .restarts must be incremented before .device_busy is read because the 1674 * code in scsi_run_queue_async() depends on the order of these operations. 1675 */ 1676 smp_mb__after_atomic(); 1677 1678 /* 1679 * If all in-flight requests originated from this LUN are completed 1680 * before reading .device_busy, sdev->device_busy will be observed as 1681 * zero, then blk_mq_delay_run_hw_queues() will dispatch this request 1682 * soon. Otherwise, completion of one of these requests will observe 1683 * the .restarts flag, and the request queue will be run for handling 1684 * this request, see scsi_end_request(). 1685 */ 1686 if (unlikely(scsi_device_busy(sdev) == 0 && 1687 !scsi_device_blocked(sdev))) 1688 blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY); 1689 return -1; 1690 } 1691 1692 static void scsi_mq_set_rq_budget_token(struct request *req, int token) 1693 { 1694 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 1695 1696 cmd->budget_token = token; 1697 } 1698 1699 static int scsi_mq_get_rq_budget_token(struct request *req) 1700 { 1701 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 1702 1703 return cmd->budget_token; 1704 } 1705 1706 static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx, 1707 const struct blk_mq_queue_data *bd) 1708 { 1709 struct request *req = bd->rq; 1710 struct request_queue *q = req->q; 1711 struct scsi_device *sdev = q->queuedata; 1712 struct Scsi_Host *shost = sdev->host; 1713 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); 1714 blk_status_t ret; 1715 int reason; 1716 1717 WARN_ON_ONCE(cmd->budget_token < 0); 1718 1719 /* 1720 * If the device is not in running state we will reject some or all 1721 * commands. 1722 */ 1723 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { 1724 ret = scsi_device_state_check(sdev, req); 1725 if (ret != BLK_STS_OK) 1726 goto out_put_budget; 1727 } 1728 1729 ret = BLK_STS_RESOURCE; 1730 if (!scsi_target_queue_ready(shost, sdev)) 1731 goto out_put_budget; 1732 if (unlikely(scsi_host_in_recovery(shost))) { 1733 if (cmd->flags & SCMD_FAIL_IF_RECOVERING) 1734 ret = BLK_STS_OFFLINE; 1735 goto out_dec_target_busy; 1736 } 1737 if (!scsi_host_queue_ready(q, shost, sdev, cmd)) 1738 goto out_dec_target_busy; 1739 1740 if (!(req->rq_flags & RQF_DONTPREP)) { 1741 ret = scsi_prepare_cmd(req); 1742 if (ret != BLK_STS_OK) 1743 goto out_dec_host_busy; 1744 req->rq_flags |= RQF_DONTPREP; 1745 } else { 1746 clear_bit(SCMD_STATE_COMPLETE, &cmd->state); 1747 } 1748 1749 cmd->flags &= SCMD_PRESERVED_FLAGS; 1750 if (sdev->simple_tags) 1751 cmd->flags |= SCMD_TAGGED; 1752 if (bd->last) 1753 cmd->flags |= SCMD_LAST; 1754 1755 scsi_set_resid(cmd, 0); 1756 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE); 1757 cmd->submitter = SUBMITTED_BY_BLOCK_LAYER; 1758 1759 blk_mq_start_request(req); 1760 reason = scsi_dispatch_cmd(cmd); 1761 if (reason) { 1762 scsi_set_blocked(cmd, reason); 1763 ret = BLK_STS_RESOURCE; 1764 goto out_dec_host_busy; 1765 } 1766 1767 return BLK_STS_OK; 1768 1769 out_dec_host_busy: 1770 scsi_dec_host_busy(shost, cmd); 1771 out_dec_target_busy: 1772 if (scsi_target(sdev)->can_queue > 0) 1773 atomic_dec(&scsi_target(sdev)->target_busy); 1774 out_put_budget: 1775 scsi_mq_put_budget(q, cmd->budget_token); 1776 cmd->budget_token = -1; 1777 switch (ret) { 1778 case BLK_STS_OK: 1779 break; 1780 case BLK_STS_RESOURCE: 1781 case BLK_STS_ZONE_RESOURCE: 1782 if (scsi_device_blocked(sdev)) 1783 ret = BLK_STS_DEV_RESOURCE; 1784 break; 1785 case BLK_STS_AGAIN: 1786 cmd->result = DID_BUS_BUSY << 16; 1787 if (req->rq_flags & RQF_DONTPREP) 1788 scsi_mq_uninit_cmd(cmd); 1789 break; 1790 default: 1791 if (unlikely(!scsi_device_online(sdev))) 1792 cmd->result = DID_NO_CONNECT << 16; 1793 else 1794 cmd->result = DID_ERROR << 16; 1795 /* 1796 * Make sure to release all allocated resources when 1797 * we hit an error, as we will never see this command 1798 * again. 1799 */ 1800 if (req->rq_flags & RQF_DONTPREP) 1801 scsi_mq_uninit_cmd(cmd); 1802 scsi_run_queue_async(sdev); 1803 break; 1804 } 1805 return ret; 1806 } 1807 1808 static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq, 1809 unsigned int hctx_idx, unsigned int numa_node) 1810 { 1811 struct Scsi_Host *shost = set->driver_data; 1812 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); 1813 struct scatterlist *sg; 1814 int ret = 0; 1815 1816 cmd->sense_buffer = 1817 kmem_cache_alloc_node(scsi_sense_cache, GFP_KERNEL, numa_node); 1818 if (!cmd->sense_buffer) 1819 return -ENOMEM; 1820 1821 if (scsi_host_get_prot(shost)) { 1822 sg = (void *)cmd + sizeof(struct scsi_cmnd) + 1823 shost->hostt->cmd_size; 1824 cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost); 1825 } 1826 1827 if (shost->hostt->init_cmd_priv) { 1828 ret = shost->hostt->init_cmd_priv(shost, cmd); 1829 if (ret < 0) 1830 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer); 1831 } 1832 1833 return ret; 1834 } 1835 1836 static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq, 1837 unsigned int hctx_idx) 1838 { 1839 struct Scsi_Host *shost = set->driver_data; 1840 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); 1841 1842 if (shost->hostt->exit_cmd_priv) 1843 shost->hostt->exit_cmd_priv(shost, cmd); 1844 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer); 1845 } 1846 1847 1848 static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob) 1849 { 1850 struct Scsi_Host *shost = hctx->driver_data; 1851 1852 if (shost->hostt->mq_poll) 1853 return shost->hostt->mq_poll(shost, hctx->queue_num); 1854 1855 return 0; 1856 } 1857 1858 static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data, 1859 unsigned int hctx_idx) 1860 { 1861 struct Scsi_Host *shost = data; 1862 1863 hctx->driver_data = shost; 1864 return 0; 1865 } 1866 1867 static void scsi_map_queues(struct blk_mq_tag_set *set) 1868 { 1869 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set); 1870 1871 if (shost->hostt->map_queues) 1872 return shost->hostt->map_queues(shost); 1873 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]); 1874 } 1875 1876 void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q) 1877 { 1878 struct device *dev = shost->dma_dev; 1879 1880 /* 1881 * this limit is imposed by hardware restrictions 1882 */ 1883 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize, 1884 SG_MAX_SEGMENTS)); 1885 1886 if (scsi_host_prot_dma(shost)) { 1887 shost->sg_prot_tablesize = 1888 min_not_zero(shost->sg_prot_tablesize, 1889 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS); 1890 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize); 1891 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize); 1892 } 1893 1894 blk_queue_max_hw_sectors(q, shost->max_sectors); 1895 blk_queue_segment_boundary(q, shost->dma_boundary); 1896 dma_set_seg_boundary(dev, shost->dma_boundary); 1897 1898 blk_queue_max_segment_size(q, shost->max_segment_size); 1899 blk_queue_virt_boundary(q, shost->virt_boundary_mask); 1900 dma_set_max_seg_size(dev, queue_max_segment_size(q)); 1901 1902 /* 1903 * Set a reasonable default alignment: The larger of 32-byte (dword), 1904 * which is a common minimum for HBAs, and the minimum DMA alignment, 1905 * which is set by the platform. 1906 * 1907 * Devices that require a bigger alignment can increase it later. 1908 */ 1909 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1); 1910 } 1911 EXPORT_SYMBOL_GPL(__scsi_init_queue); 1912 1913 static const struct blk_mq_ops scsi_mq_ops_no_commit = { 1914 .get_budget = scsi_mq_get_budget, 1915 .put_budget = scsi_mq_put_budget, 1916 .queue_rq = scsi_queue_rq, 1917 .complete = scsi_complete, 1918 .timeout = scsi_timeout, 1919 #ifdef CONFIG_BLK_DEBUG_FS 1920 .show_rq = scsi_show_rq, 1921 #endif 1922 .init_request = scsi_mq_init_request, 1923 .exit_request = scsi_mq_exit_request, 1924 .cleanup_rq = scsi_cleanup_rq, 1925 .busy = scsi_mq_lld_busy, 1926 .map_queues = scsi_map_queues, 1927 .init_hctx = scsi_init_hctx, 1928 .poll = scsi_mq_poll, 1929 .set_rq_budget_token = scsi_mq_set_rq_budget_token, 1930 .get_rq_budget_token = scsi_mq_get_rq_budget_token, 1931 }; 1932 1933 1934 static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx) 1935 { 1936 struct Scsi_Host *shost = hctx->driver_data; 1937 1938 shost->hostt->commit_rqs(shost, hctx->queue_num); 1939 } 1940 1941 static const struct blk_mq_ops scsi_mq_ops = { 1942 .get_budget = scsi_mq_get_budget, 1943 .put_budget = scsi_mq_put_budget, 1944 .queue_rq = scsi_queue_rq, 1945 .commit_rqs = scsi_commit_rqs, 1946 .complete = scsi_complete, 1947 .timeout = scsi_timeout, 1948 #ifdef CONFIG_BLK_DEBUG_FS 1949 .show_rq = scsi_show_rq, 1950 #endif 1951 .init_request = scsi_mq_init_request, 1952 .exit_request = scsi_mq_exit_request, 1953 .cleanup_rq = scsi_cleanup_rq, 1954 .busy = scsi_mq_lld_busy, 1955 .map_queues = scsi_map_queues, 1956 .init_hctx = scsi_init_hctx, 1957 .poll = scsi_mq_poll, 1958 .set_rq_budget_token = scsi_mq_set_rq_budget_token, 1959 .get_rq_budget_token = scsi_mq_get_rq_budget_token, 1960 }; 1961 1962 int scsi_mq_setup_tags(struct Scsi_Host *shost) 1963 { 1964 unsigned int cmd_size, sgl_size; 1965 struct blk_mq_tag_set *tag_set = &shost->tag_set; 1966 1967 sgl_size = max_t(unsigned int, sizeof(struct scatterlist), 1968 scsi_mq_inline_sgl_size(shost)); 1969 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size; 1970 if (scsi_host_get_prot(shost)) 1971 cmd_size += sizeof(struct scsi_data_buffer) + 1972 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT; 1973 1974 memset(tag_set, 0, sizeof(*tag_set)); 1975 if (shost->hostt->commit_rqs) 1976 tag_set->ops = &scsi_mq_ops; 1977 else 1978 tag_set->ops = &scsi_mq_ops_no_commit; 1979 tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1; 1980 tag_set->nr_maps = shost->nr_maps ? : 1; 1981 tag_set->queue_depth = shost->can_queue; 1982 tag_set->cmd_size = cmd_size; 1983 tag_set->numa_node = dev_to_node(shost->dma_dev); 1984 tag_set->flags = BLK_MQ_F_SHOULD_MERGE; 1985 tag_set->flags |= 1986 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy); 1987 if (shost->queuecommand_may_block) 1988 tag_set->flags |= BLK_MQ_F_BLOCKING; 1989 tag_set->driver_data = shost; 1990 if (shost->host_tagset) 1991 tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED; 1992 1993 return blk_mq_alloc_tag_set(tag_set); 1994 } 1995 1996 void scsi_mq_free_tags(struct kref *kref) 1997 { 1998 struct Scsi_Host *shost = container_of(kref, typeof(*shost), 1999 tagset_refcnt); 2000 2001 blk_mq_free_tag_set(&shost->tag_set); 2002 complete(&shost->tagset_freed); 2003 } 2004 2005 /** 2006 * scsi_device_from_queue - return sdev associated with a request_queue 2007 * @q: The request queue to return the sdev from 2008 * 2009 * Return the sdev associated with a request queue or NULL if the 2010 * request_queue does not reference a SCSI device. 2011 */ 2012 struct scsi_device *scsi_device_from_queue(struct request_queue *q) 2013 { 2014 struct scsi_device *sdev = NULL; 2015 2016 if (q->mq_ops == &scsi_mq_ops_no_commit || 2017 q->mq_ops == &scsi_mq_ops) 2018 sdev = q->queuedata; 2019 if (!sdev || !get_device(&sdev->sdev_gendev)) 2020 sdev = NULL; 2021 2022 return sdev; 2023 } 2024 /* 2025 * pktcdvd should have been integrated into the SCSI layers, but for historical 2026 * reasons like the old IDE driver it isn't. This export allows it to safely 2027 * probe if a given device is a SCSI one and only attach to that. 2028 */ 2029 #ifdef CONFIG_CDROM_PKTCDVD_MODULE 2030 EXPORT_SYMBOL_GPL(scsi_device_from_queue); 2031 #endif 2032 2033 /** 2034 * scsi_block_requests - Utility function used by low-level drivers to prevent 2035 * further commands from being queued to the device. 2036 * @shost: host in question 2037 * 2038 * There is no timer nor any other means by which the requests get unblocked 2039 * other than the low-level driver calling scsi_unblock_requests(). 2040 */ 2041 void scsi_block_requests(struct Scsi_Host *shost) 2042 { 2043 shost->host_self_blocked = 1; 2044 } 2045 EXPORT_SYMBOL(scsi_block_requests); 2046 2047 /** 2048 * scsi_unblock_requests - Utility function used by low-level drivers to allow 2049 * further commands to be queued to the device. 2050 * @shost: host in question 2051 * 2052 * There is no timer nor any other means by which the requests get unblocked 2053 * other than the low-level driver calling scsi_unblock_requests(). This is done 2054 * as an API function so that changes to the internals of the scsi mid-layer 2055 * won't require wholesale changes to drivers that use this feature. 2056 */ 2057 void scsi_unblock_requests(struct Scsi_Host *shost) 2058 { 2059 shost->host_self_blocked = 0; 2060 scsi_run_host_queues(shost); 2061 } 2062 EXPORT_SYMBOL(scsi_unblock_requests); 2063 2064 void scsi_exit_queue(void) 2065 { 2066 kmem_cache_destroy(scsi_sense_cache); 2067 } 2068 2069 /** 2070 * scsi_mode_select - issue a mode select 2071 * @sdev: SCSI device to be queried 2072 * @pf: Page format bit (1 == standard, 0 == vendor specific) 2073 * @sp: Save page bit (0 == don't save, 1 == save) 2074 * @buffer: request buffer (may not be smaller than eight bytes) 2075 * @len: length of request buffer. 2076 * @timeout: command timeout 2077 * @retries: number of retries before failing 2078 * @data: returns a structure abstracting the mode header data 2079 * @sshdr: place to put sense data (or NULL if no sense to be collected). 2080 * must be SCSI_SENSE_BUFFERSIZE big. 2081 * 2082 * Returns zero if successful; negative error number or scsi 2083 * status on error 2084 * 2085 */ 2086 int scsi_mode_select(struct scsi_device *sdev, int pf, int sp, 2087 unsigned char *buffer, int len, int timeout, int retries, 2088 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) 2089 { 2090 unsigned char cmd[10]; 2091 unsigned char *real_buffer; 2092 const struct scsi_exec_args exec_args = { 2093 .sshdr = sshdr, 2094 }; 2095 int ret; 2096 2097 memset(cmd, 0, sizeof(cmd)); 2098 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); 2099 2100 /* 2101 * Use MODE SELECT(10) if the device asked for it or if the mode page 2102 * and the mode select header cannot fit within the maximumm 255 bytes 2103 * of the MODE SELECT(6) command. 2104 */ 2105 if (sdev->use_10_for_ms || 2106 len + 4 > 255 || 2107 data->block_descriptor_length > 255) { 2108 if (len > 65535 - 8) 2109 return -EINVAL; 2110 real_buffer = kmalloc(8 + len, GFP_KERNEL); 2111 if (!real_buffer) 2112 return -ENOMEM; 2113 memcpy(real_buffer + 8, buffer, len); 2114 len += 8; 2115 real_buffer[0] = 0; 2116 real_buffer[1] = 0; 2117 real_buffer[2] = data->medium_type; 2118 real_buffer[3] = data->device_specific; 2119 real_buffer[4] = data->longlba ? 0x01 : 0; 2120 real_buffer[5] = 0; 2121 put_unaligned_be16(data->block_descriptor_length, 2122 &real_buffer[6]); 2123 2124 cmd[0] = MODE_SELECT_10; 2125 put_unaligned_be16(len, &cmd[7]); 2126 } else { 2127 if (data->longlba) 2128 return -EINVAL; 2129 2130 real_buffer = kmalloc(4 + len, GFP_KERNEL); 2131 if (!real_buffer) 2132 return -ENOMEM; 2133 memcpy(real_buffer + 4, buffer, len); 2134 len += 4; 2135 real_buffer[0] = 0; 2136 real_buffer[1] = data->medium_type; 2137 real_buffer[2] = data->device_specific; 2138 real_buffer[3] = data->block_descriptor_length; 2139 2140 cmd[0] = MODE_SELECT; 2141 cmd[4] = len; 2142 } 2143 2144 ret = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_OUT, real_buffer, len, 2145 timeout, retries, &exec_args); 2146 kfree(real_buffer); 2147 return ret; 2148 } 2149 EXPORT_SYMBOL_GPL(scsi_mode_select); 2150 2151 /** 2152 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary. 2153 * @sdev: SCSI device to be queried 2154 * @dbd: set to prevent mode sense from returning block descriptors 2155 * @modepage: mode page being requested 2156 * @subpage: sub-page of the mode page being requested 2157 * @buffer: request buffer (may not be smaller than eight bytes) 2158 * @len: length of request buffer. 2159 * @timeout: command timeout 2160 * @retries: number of retries before failing 2161 * @data: returns a structure abstracting the mode header data 2162 * @sshdr: place to put sense data (or NULL if no sense to be collected). 2163 * must be SCSI_SENSE_BUFFERSIZE big. 2164 * 2165 * Returns zero if successful, or a negative error number on failure 2166 */ 2167 int 2168 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, int subpage, 2169 unsigned char *buffer, int len, int timeout, int retries, 2170 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) 2171 { 2172 unsigned char cmd[12]; 2173 int use_10_for_ms; 2174 int header_length; 2175 int result, retry_count = retries; 2176 struct scsi_sense_hdr my_sshdr; 2177 const struct scsi_exec_args exec_args = { 2178 /* caller might not be interested in sense, but we need it */ 2179 .sshdr = sshdr ? : &my_sshdr, 2180 }; 2181 2182 memset(data, 0, sizeof(*data)); 2183 memset(&cmd[0], 0, 12); 2184 2185 dbd = sdev->set_dbd_for_ms ? 8 : dbd; 2186 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ 2187 cmd[2] = modepage; 2188 cmd[3] = subpage; 2189 2190 sshdr = exec_args.sshdr; 2191 2192 retry: 2193 use_10_for_ms = sdev->use_10_for_ms || len > 255; 2194 2195 if (use_10_for_ms) { 2196 if (len < 8 || len > 65535) 2197 return -EINVAL; 2198 2199 cmd[0] = MODE_SENSE_10; 2200 put_unaligned_be16(len, &cmd[7]); 2201 header_length = 8; 2202 } else { 2203 if (len < 4) 2204 return -EINVAL; 2205 2206 cmd[0] = MODE_SENSE; 2207 cmd[4] = len; 2208 header_length = 4; 2209 } 2210 2211 memset(buffer, 0, len); 2212 2213 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer, len, 2214 timeout, retries, &exec_args); 2215 if (result < 0) 2216 return result; 2217 2218 /* This code looks awful: what it's doing is making sure an 2219 * ILLEGAL REQUEST sense return identifies the actual command 2220 * byte as the problem. MODE_SENSE commands can return 2221 * ILLEGAL REQUEST if the code page isn't supported */ 2222 2223 if (!scsi_status_is_good(result)) { 2224 if (scsi_sense_valid(sshdr)) { 2225 if ((sshdr->sense_key == ILLEGAL_REQUEST) && 2226 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { 2227 /* 2228 * Invalid command operation code: retry using 2229 * MODE SENSE(6) if this was a MODE SENSE(10) 2230 * request, except if the request mode page is 2231 * too large for MODE SENSE single byte 2232 * allocation length field. 2233 */ 2234 if (use_10_for_ms) { 2235 if (len > 255) 2236 return -EIO; 2237 sdev->use_10_for_ms = 0; 2238 goto retry; 2239 } 2240 } 2241 if (scsi_status_is_check_condition(result) && 2242 sshdr->sense_key == UNIT_ATTENTION && 2243 retry_count) { 2244 retry_count--; 2245 goto retry; 2246 } 2247 } 2248 return -EIO; 2249 } 2250 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && 2251 (modepage == 6 || modepage == 8))) { 2252 /* Initio breakage? */ 2253 header_length = 0; 2254 data->length = 13; 2255 data->medium_type = 0; 2256 data->device_specific = 0; 2257 data->longlba = 0; 2258 data->block_descriptor_length = 0; 2259 } else if (use_10_for_ms) { 2260 data->length = get_unaligned_be16(&buffer[0]) + 2; 2261 data->medium_type = buffer[2]; 2262 data->device_specific = buffer[3]; 2263 data->longlba = buffer[4] & 0x01; 2264 data->block_descriptor_length = get_unaligned_be16(&buffer[6]); 2265 } else { 2266 data->length = buffer[0] + 1; 2267 data->medium_type = buffer[1]; 2268 data->device_specific = buffer[2]; 2269 data->block_descriptor_length = buffer[3]; 2270 } 2271 data->header_length = header_length; 2272 2273 return 0; 2274 } 2275 EXPORT_SYMBOL(scsi_mode_sense); 2276 2277 /** 2278 * scsi_test_unit_ready - test if unit is ready 2279 * @sdev: scsi device to change the state of. 2280 * @timeout: command timeout 2281 * @retries: number of retries before failing 2282 * @sshdr: outpout pointer for decoded sense information. 2283 * 2284 * Returns zero if unsuccessful or an error if TUR failed. For 2285 * removable media, UNIT_ATTENTION sets ->changed flag. 2286 **/ 2287 int 2288 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, 2289 struct scsi_sense_hdr *sshdr) 2290 { 2291 char cmd[] = { 2292 TEST_UNIT_READY, 0, 0, 0, 0, 0, 2293 }; 2294 const struct scsi_exec_args exec_args = { 2295 .sshdr = sshdr, 2296 }; 2297 int result; 2298 2299 /* try to eat the UNIT_ATTENTION if there are enough retries */ 2300 do { 2301 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, NULL, 0, 2302 timeout, 1, &exec_args); 2303 if (sdev->removable && result > 0 && scsi_sense_valid(sshdr) && 2304 sshdr->sense_key == UNIT_ATTENTION) 2305 sdev->changed = 1; 2306 } while (result > 0 && scsi_sense_valid(sshdr) && 2307 sshdr->sense_key == UNIT_ATTENTION && --retries); 2308 2309 return result; 2310 } 2311 EXPORT_SYMBOL(scsi_test_unit_ready); 2312 2313 /** 2314 * scsi_device_set_state - Take the given device through the device state model. 2315 * @sdev: scsi device to change the state of. 2316 * @state: state to change to. 2317 * 2318 * Returns zero if successful or an error if the requested 2319 * transition is illegal. 2320 */ 2321 int 2322 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) 2323 { 2324 enum scsi_device_state oldstate = sdev->sdev_state; 2325 2326 if (state == oldstate) 2327 return 0; 2328 2329 switch (state) { 2330 case SDEV_CREATED: 2331 switch (oldstate) { 2332 case SDEV_CREATED_BLOCK: 2333 break; 2334 default: 2335 goto illegal; 2336 } 2337 break; 2338 2339 case SDEV_RUNNING: 2340 switch (oldstate) { 2341 case SDEV_CREATED: 2342 case SDEV_OFFLINE: 2343 case SDEV_TRANSPORT_OFFLINE: 2344 case SDEV_QUIESCE: 2345 case SDEV_BLOCK: 2346 break; 2347 default: 2348 goto illegal; 2349 } 2350 break; 2351 2352 case SDEV_QUIESCE: 2353 switch (oldstate) { 2354 case SDEV_RUNNING: 2355 case SDEV_OFFLINE: 2356 case SDEV_TRANSPORT_OFFLINE: 2357 break; 2358 default: 2359 goto illegal; 2360 } 2361 break; 2362 2363 case SDEV_OFFLINE: 2364 case SDEV_TRANSPORT_OFFLINE: 2365 switch (oldstate) { 2366 case SDEV_CREATED: 2367 case SDEV_RUNNING: 2368 case SDEV_QUIESCE: 2369 case SDEV_BLOCK: 2370 break; 2371 default: 2372 goto illegal; 2373 } 2374 break; 2375 2376 case SDEV_BLOCK: 2377 switch (oldstate) { 2378 case SDEV_RUNNING: 2379 case SDEV_CREATED_BLOCK: 2380 case SDEV_QUIESCE: 2381 case SDEV_OFFLINE: 2382 break; 2383 default: 2384 goto illegal; 2385 } 2386 break; 2387 2388 case SDEV_CREATED_BLOCK: 2389 switch (oldstate) { 2390 case SDEV_CREATED: 2391 break; 2392 default: 2393 goto illegal; 2394 } 2395 break; 2396 2397 case SDEV_CANCEL: 2398 switch (oldstate) { 2399 case SDEV_CREATED: 2400 case SDEV_RUNNING: 2401 case SDEV_QUIESCE: 2402 case SDEV_OFFLINE: 2403 case SDEV_TRANSPORT_OFFLINE: 2404 break; 2405 default: 2406 goto illegal; 2407 } 2408 break; 2409 2410 case SDEV_DEL: 2411 switch (oldstate) { 2412 case SDEV_CREATED: 2413 case SDEV_RUNNING: 2414 case SDEV_OFFLINE: 2415 case SDEV_TRANSPORT_OFFLINE: 2416 case SDEV_CANCEL: 2417 case SDEV_BLOCK: 2418 case SDEV_CREATED_BLOCK: 2419 break; 2420 default: 2421 goto illegal; 2422 } 2423 break; 2424 2425 } 2426 sdev->offline_already = false; 2427 sdev->sdev_state = state; 2428 return 0; 2429 2430 illegal: 2431 SCSI_LOG_ERROR_RECOVERY(1, 2432 sdev_printk(KERN_ERR, sdev, 2433 "Illegal state transition %s->%s", 2434 scsi_device_state_name(oldstate), 2435 scsi_device_state_name(state)) 2436 ); 2437 return -EINVAL; 2438 } 2439 EXPORT_SYMBOL(scsi_device_set_state); 2440 2441 /** 2442 * scsi_evt_emit - emit a single SCSI device uevent 2443 * @sdev: associated SCSI device 2444 * @evt: event to emit 2445 * 2446 * Send a single uevent (scsi_event) to the associated scsi_device. 2447 */ 2448 static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt) 2449 { 2450 int idx = 0; 2451 char *envp[3]; 2452 2453 switch (evt->evt_type) { 2454 case SDEV_EVT_MEDIA_CHANGE: 2455 envp[idx++] = "SDEV_MEDIA_CHANGE=1"; 2456 break; 2457 case SDEV_EVT_INQUIRY_CHANGE_REPORTED: 2458 scsi_rescan_device(sdev); 2459 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED"; 2460 break; 2461 case SDEV_EVT_CAPACITY_CHANGE_REPORTED: 2462 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED"; 2463 break; 2464 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED: 2465 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED"; 2466 break; 2467 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED: 2468 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED"; 2469 break; 2470 case SDEV_EVT_LUN_CHANGE_REPORTED: 2471 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED"; 2472 break; 2473 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED: 2474 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED"; 2475 break; 2476 case SDEV_EVT_POWER_ON_RESET_OCCURRED: 2477 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED"; 2478 break; 2479 default: 2480 /* do nothing */ 2481 break; 2482 } 2483 2484 envp[idx++] = NULL; 2485 2486 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp); 2487 } 2488 2489 /** 2490 * scsi_evt_thread - send a uevent for each scsi event 2491 * @work: work struct for scsi_device 2492 * 2493 * Dispatch queued events to their associated scsi_device kobjects 2494 * as uevents. 2495 */ 2496 void scsi_evt_thread(struct work_struct *work) 2497 { 2498 struct scsi_device *sdev; 2499 enum scsi_device_event evt_type; 2500 LIST_HEAD(event_list); 2501 2502 sdev = container_of(work, struct scsi_device, event_work); 2503 2504 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++) 2505 if (test_and_clear_bit(evt_type, sdev->pending_events)) 2506 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL); 2507 2508 while (1) { 2509 struct scsi_event *evt; 2510 struct list_head *this, *tmp; 2511 unsigned long flags; 2512 2513 spin_lock_irqsave(&sdev->list_lock, flags); 2514 list_splice_init(&sdev->event_list, &event_list); 2515 spin_unlock_irqrestore(&sdev->list_lock, flags); 2516 2517 if (list_empty(&event_list)) 2518 break; 2519 2520 list_for_each_safe(this, tmp, &event_list) { 2521 evt = list_entry(this, struct scsi_event, node); 2522 list_del(&evt->node); 2523 scsi_evt_emit(sdev, evt); 2524 kfree(evt); 2525 } 2526 } 2527 } 2528 2529 /** 2530 * sdev_evt_send - send asserted event to uevent thread 2531 * @sdev: scsi_device event occurred on 2532 * @evt: event to send 2533 * 2534 * Assert scsi device event asynchronously. 2535 */ 2536 void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt) 2537 { 2538 unsigned long flags; 2539 2540 #if 0 2541 /* FIXME: currently this check eliminates all media change events 2542 * for polled devices. Need to update to discriminate between AN 2543 * and polled events */ 2544 if (!test_bit(evt->evt_type, sdev->supported_events)) { 2545 kfree(evt); 2546 return; 2547 } 2548 #endif 2549 2550 spin_lock_irqsave(&sdev->list_lock, flags); 2551 list_add_tail(&evt->node, &sdev->event_list); 2552 schedule_work(&sdev->event_work); 2553 spin_unlock_irqrestore(&sdev->list_lock, flags); 2554 } 2555 EXPORT_SYMBOL_GPL(sdev_evt_send); 2556 2557 /** 2558 * sdev_evt_alloc - allocate a new scsi event 2559 * @evt_type: type of event to allocate 2560 * @gfpflags: GFP flags for allocation 2561 * 2562 * Allocates and returns a new scsi_event. 2563 */ 2564 struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type, 2565 gfp_t gfpflags) 2566 { 2567 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags); 2568 if (!evt) 2569 return NULL; 2570 2571 evt->evt_type = evt_type; 2572 INIT_LIST_HEAD(&evt->node); 2573 2574 /* evt_type-specific initialization, if any */ 2575 switch (evt_type) { 2576 case SDEV_EVT_MEDIA_CHANGE: 2577 case SDEV_EVT_INQUIRY_CHANGE_REPORTED: 2578 case SDEV_EVT_CAPACITY_CHANGE_REPORTED: 2579 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED: 2580 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED: 2581 case SDEV_EVT_LUN_CHANGE_REPORTED: 2582 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED: 2583 case SDEV_EVT_POWER_ON_RESET_OCCURRED: 2584 default: 2585 /* do nothing */ 2586 break; 2587 } 2588 2589 return evt; 2590 } 2591 EXPORT_SYMBOL_GPL(sdev_evt_alloc); 2592 2593 /** 2594 * sdev_evt_send_simple - send asserted event to uevent thread 2595 * @sdev: scsi_device event occurred on 2596 * @evt_type: type of event to send 2597 * @gfpflags: GFP flags for allocation 2598 * 2599 * Assert scsi device event asynchronously, given an event type. 2600 */ 2601 void sdev_evt_send_simple(struct scsi_device *sdev, 2602 enum scsi_device_event evt_type, gfp_t gfpflags) 2603 { 2604 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags); 2605 if (!evt) { 2606 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n", 2607 evt_type); 2608 return; 2609 } 2610 2611 sdev_evt_send(sdev, evt); 2612 } 2613 EXPORT_SYMBOL_GPL(sdev_evt_send_simple); 2614 2615 /** 2616 * scsi_device_quiesce - Block all commands except power management. 2617 * @sdev: scsi device to quiesce. 2618 * 2619 * This works by trying to transition to the SDEV_QUIESCE state 2620 * (which must be a legal transition). When the device is in this 2621 * state, only power management requests will be accepted, all others will 2622 * be deferred. 2623 * 2624 * Must be called with user context, may sleep. 2625 * 2626 * Returns zero if unsuccessful or an error if not. 2627 */ 2628 int 2629 scsi_device_quiesce(struct scsi_device *sdev) 2630 { 2631 struct request_queue *q = sdev->request_queue; 2632 int err; 2633 2634 /* 2635 * It is allowed to call scsi_device_quiesce() multiple times from 2636 * the same context but concurrent scsi_device_quiesce() calls are 2637 * not allowed. 2638 */ 2639 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current); 2640 2641 if (sdev->quiesced_by == current) 2642 return 0; 2643 2644 blk_set_pm_only(q); 2645 2646 blk_mq_freeze_queue(q); 2647 /* 2648 * Ensure that the effect of blk_set_pm_only() will be visible 2649 * for percpu_ref_tryget() callers that occur after the queue 2650 * unfreeze even if the queue was already frozen before this function 2651 * was called. See also https://lwn.net/Articles/573497/. 2652 */ 2653 synchronize_rcu(); 2654 blk_mq_unfreeze_queue(q); 2655 2656 mutex_lock(&sdev->state_mutex); 2657 err = scsi_device_set_state(sdev, SDEV_QUIESCE); 2658 if (err == 0) 2659 sdev->quiesced_by = current; 2660 else 2661 blk_clear_pm_only(q); 2662 mutex_unlock(&sdev->state_mutex); 2663 2664 return err; 2665 } 2666 EXPORT_SYMBOL(scsi_device_quiesce); 2667 2668 /** 2669 * scsi_device_resume - Restart user issued commands to a quiesced device. 2670 * @sdev: scsi device to resume. 2671 * 2672 * Moves the device from quiesced back to running and restarts the 2673 * queues. 2674 * 2675 * Must be called with user context, may sleep. 2676 */ 2677 void scsi_device_resume(struct scsi_device *sdev) 2678 { 2679 /* check if the device state was mutated prior to resume, and if 2680 * so assume the state is being managed elsewhere (for example 2681 * device deleted during suspend) 2682 */ 2683 mutex_lock(&sdev->state_mutex); 2684 if (sdev->sdev_state == SDEV_QUIESCE) 2685 scsi_device_set_state(sdev, SDEV_RUNNING); 2686 if (sdev->quiesced_by) { 2687 sdev->quiesced_by = NULL; 2688 blk_clear_pm_only(sdev->request_queue); 2689 } 2690 mutex_unlock(&sdev->state_mutex); 2691 } 2692 EXPORT_SYMBOL(scsi_device_resume); 2693 2694 static void 2695 device_quiesce_fn(struct scsi_device *sdev, void *data) 2696 { 2697 scsi_device_quiesce(sdev); 2698 } 2699 2700 void 2701 scsi_target_quiesce(struct scsi_target *starget) 2702 { 2703 starget_for_each_device(starget, NULL, device_quiesce_fn); 2704 } 2705 EXPORT_SYMBOL(scsi_target_quiesce); 2706 2707 static void 2708 device_resume_fn(struct scsi_device *sdev, void *data) 2709 { 2710 scsi_device_resume(sdev); 2711 } 2712 2713 void 2714 scsi_target_resume(struct scsi_target *starget) 2715 { 2716 starget_for_each_device(starget, NULL, device_resume_fn); 2717 } 2718 EXPORT_SYMBOL(scsi_target_resume); 2719 2720 static int __scsi_internal_device_block_nowait(struct scsi_device *sdev) 2721 { 2722 if (scsi_device_set_state(sdev, SDEV_BLOCK)) 2723 return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK); 2724 2725 return 0; 2726 } 2727 2728 void scsi_start_queue(struct scsi_device *sdev) 2729 { 2730 if (cmpxchg(&sdev->queue_stopped, 1, 0)) 2731 blk_mq_unquiesce_queue(sdev->request_queue); 2732 } 2733 2734 static void scsi_stop_queue(struct scsi_device *sdev) 2735 { 2736 /* 2737 * The atomic variable of ->queue_stopped covers that 2738 * blk_mq_quiesce_queue* is balanced with blk_mq_unquiesce_queue. 2739 * 2740 * The caller needs to wait until quiesce is done. 2741 */ 2742 if (!cmpxchg(&sdev->queue_stopped, 0, 1)) 2743 blk_mq_quiesce_queue_nowait(sdev->request_queue); 2744 } 2745 2746 /** 2747 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state 2748 * @sdev: device to block 2749 * 2750 * Pause SCSI command processing on the specified device. Does not sleep. 2751 * 2752 * Returns zero if successful or a negative error code upon failure. 2753 * 2754 * Notes: 2755 * This routine transitions the device to the SDEV_BLOCK state (which must be 2756 * a legal transition). When the device is in this state, command processing 2757 * is paused until the device leaves the SDEV_BLOCK state. See also 2758 * scsi_internal_device_unblock_nowait(). 2759 */ 2760 int scsi_internal_device_block_nowait(struct scsi_device *sdev) 2761 { 2762 int ret = __scsi_internal_device_block_nowait(sdev); 2763 2764 /* 2765 * The device has transitioned to SDEV_BLOCK. Stop the 2766 * block layer from calling the midlayer with this device's 2767 * request queue. 2768 */ 2769 if (!ret) 2770 scsi_stop_queue(sdev); 2771 return ret; 2772 } 2773 EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait); 2774 2775 /** 2776 * scsi_device_block - try to transition to the SDEV_BLOCK state 2777 * @sdev: device to block 2778 * @data: dummy argument, ignored 2779 * 2780 * Pause SCSI command processing on the specified device. Callers must wait 2781 * until all ongoing scsi_queue_rq() calls have finished after this function 2782 * returns. 2783 * 2784 * Note: 2785 * This routine transitions the device to the SDEV_BLOCK state (which must be 2786 * a legal transition). When the device is in this state, command processing 2787 * is paused until the device leaves the SDEV_BLOCK state. See also 2788 * scsi_internal_device_unblock(). 2789 */ 2790 static void scsi_device_block(struct scsi_device *sdev, void *data) 2791 { 2792 int err; 2793 enum scsi_device_state state; 2794 2795 mutex_lock(&sdev->state_mutex); 2796 err = __scsi_internal_device_block_nowait(sdev); 2797 state = sdev->sdev_state; 2798 if (err == 0) 2799 /* 2800 * scsi_stop_queue() must be called with the state_mutex 2801 * held. Otherwise a simultaneous scsi_start_queue() call 2802 * might unquiesce the queue before we quiesce it. 2803 */ 2804 scsi_stop_queue(sdev); 2805 2806 mutex_unlock(&sdev->state_mutex); 2807 2808 WARN_ONCE(err, "%s: failed to block %s in state %d\n", 2809 __func__, dev_name(&sdev->sdev_gendev), state); 2810 } 2811 2812 /** 2813 * scsi_internal_device_unblock_nowait - resume a device after a block request 2814 * @sdev: device to resume 2815 * @new_state: state to set the device to after unblocking 2816 * 2817 * Restart the device queue for a previously suspended SCSI device. Does not 2818 * sleep. 2819 * 2820 * Returns zero if successful or a negative error code upon failure. 2821 * 2822 * Notes: 2823 * This routine transitions the device to the SDEV_RUNNING state or to one of 2824 * the offline states (which must be a legal transition) allowing the midlayer 2825 * to goose the queue for this device. 2826 */ 2827 int scsi_internal_device_unblock_nowait(struct scsi_device *sdev, 2828 enum scsi_device_state new_state) 2829 { 2830 switch (new_state) { 2831 case SDEV_RUNNING: 2832 case SDEV_TRANSPORT_OFFLINE: 2833 break; 2834 default: 2835 return -EINVAL; 2836 } 2837 2838 /* 2839 * Try to transition the scsi device to SDEV_RUNNING or one of the 2840 * offlined states and goose the device queue if successful. 2841 */ 2842 switch (sdev->sdev_state) { 2843 case SDEV_BLOCK: 2844 case SDEV_TRANSPORT_OFFLINE: 2845 sdev->sdev_state = new_state; 2846 break; 2847 case SDEV_CREATED_BLOCK: 2848 if (new_state == SDEV_TRANSPORT_OFFLINE || 2849 new_state == SDEV_OFFLINE) 2850 sdev->sdev_state = new_state; 2851 else 2852 sdev->sdev_state = SDEV_CREATED; 2853 break; 2854 case SDEV_CANCEL: 2855 case SDEV_OFFLINE: 2856 break; 2857 default: 2858 return -EINVAL; 2859 } 2860 scsi_start_queue(sdev); 2861 2862 return 0; 2863 } 2864 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait); 2865 2866 /** 2867 * scsi_internal_device_unblock - resume a device after a block request 2868 * @sdev: device to resume 2869 * @new_state: state to set the device to after unblocking 2870 * 2871 * Restart the device queue for a previously suspended SCSI device. May sleep. 2872 * 2873 * Returns zero if successful or a negative error code upon failure. 2874 * 2875 * Notes: 2876 * This routine transitions the device to the SDEV_RUNNING state or to one of 2877 * the offline states (which must be a legal transition) allowing the midlayer 2878 * to goose the queue for this device. 2879 */ 2880 static int scsi_internal_device_unblock(struct scsi_device *sdev, 2881 enum scsi_device_state new_state) 2882 { 2883 int ret; 2884 2885 mutex_lock(&sdev->state_mutex); 2886 ret = scsi_internal_device_unblock_nowait(sdev, new_state); 2887 mutex_unlock(&sdev->state_mutex); 2888 2889 return ret; 2890 } 2891 2892 static int 2893 target_block(struct device *dev, void *data) 2894 { 2895 if (scsi_is_target_device(dev)) 2896 starget_for_each_device(to_scsi_target(dev), NULL, 2897 scsi_device_block); 2898 return 0; 2899 } 2900 2901 /** 2902 * scsi_block_targets - transition all SCSI child devices to SDEV_BLOCK state 2903 * @dev: a parent device of one or more scsi_target devices 2904 * @shost: the Scsi_Host to which this device belongs 2905 * 2906 * Iterate over all children of @dev, which should be scsi_target devices, 2907 * and switch all subordinate scsi devices to SDEV_BLOCK state. Wait for 2908 * ongoing scsi_queue_rq() calls to finish. May sleep. 2909 * 2910 * Note: 2911 * @dev must not itself be a scsi_target device. 2912 */ 2913 void 2914 scsi_block_targets(struct Scsi_Host *shost, struct device *dev) 2915 { 2916 WARN_ON_ONCE(scsi_is_target_device(dev)); 2917 device_for_each_child(dev, NULL, target_block); 2918 blk_mq_wait_quiesce_done(&shost->tag_set); 2919 } 2920 EXPORT_SYMBOL_GPL(scsi_block_targets); 2921 2922 static void 2923 device_unblock(struct scsi_device *sdev, void *data) 2924 { 2925 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data); 2926 } 2927 2928 static int 2929 target_unblock(struct device *dev, void *data) 2930 { 2931 if (scsi_is_target_device(dev)) 2932 starget_for_each_device(to_scsi_target(dev), data, 2933 device_unblock); 2934 return 0; 2935 } 2936 2937 void 2938 scsi_target_unblock(struct device *dev, enum scsi_device_state new_state) 2939 { 2940 if (scsi_is_target_device(dev)) 2941 starget_for_each_device(to_scsi_target(dev), &new_state, 2942 device_unblock); 2943 else 2944 device_for_each_child(dev, &new_state, target_unblock); 2945 } 2946 EXPORT_SYMBOL_GPL(scsi_target_unblock); 2947 2948 /** 2949 * scsi_host_block - Try to transition all logical units to the SDEV_BLOCK state 2950 * @shost: device to block 2951 * 2952 * Pause SCSI command processing for all logical units associated with the SCSI 2953 * host and wait until pending scsi_queue_rq() calls have finished. 2954 * 2955 * Returns zero if successful or a negative error code upon failure. 2956 */ 2957 int 2958 scsi_host_block(struct Scsi_Host *shost) 2959 { 2960 struct scsi_device *sdev; 2961 int ret; 2962 2963 /* 2964 * Call scsi_internal_device_block_nowait so we can avoid 2965 * calling synchronize_rcu() for each LUN. 2966 */ 2967 shost_for_each_device(sdev, shost) { 2968 mutex_lock(&sdev->state_mutex); 2969 ret = scsi_internal_device_block_nowait(sdev); 2970 mutex_unlock(&sdev->state_mutex); 2971 if (ret) { 2972 scsi_device_put(sdev); 2973 return ret; 2974 } 2975 } 2976 2977 /* Wait for ongoing scsi_queue_rq() calls to finish. */ 2978 blk_mq_wait_quiesce_done(&shost->tag_set); 2979 2980 return 0; 2981 } 2982 EXPORT_SYMBOL_GPL(scsi_host_block); 2983 2984 int 2985 scsi_host_unblock(struct Scsi_Host *shost, int new_state) 2986 { 2987 struct scsi_device *sdev; 2988 int ret = 0; 2989 2990 shost_for_each_device(sdev, shost) { 2991 ret = scsi_internal_device_unblock(sdev, new_state); 2992 if (ret) { 2993 scsi_device_put(sdev); 2994 break; 2995 } 2996 } 2997 return ret; 2998 } 2999 EXPORT_SYMBOL_GPL(scsi_host_unblock); 3000 3001 /** 3002 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt 3003 * @sgl: scatter-gather list 3004 * @sg_count: number of segments in sg 3005 * @offset: offset in bytes into sg, on return offset into the mapped area 3006 * @len: bytes to map, on return number of bytes mapped 3007 * 3008 * Returns virtual address of the start of the mapped page 3009 */ 3010 void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count, 3011 size_t *offset, size_t *len) 3012 { 3013 int i; 3014 size_t sg_len = 0, len_complete = 0; 3015 struct scatterlist *sg; 3016 struct page *page; 3017 3018 WARN_ON(!irqs_disabled()); 3019 3020 for_each_sg(sgl, sg, sg_count, i) { 3021 len_complete = sg_len; /* Complete sg-entries */ 3022 sg_len += sg->length; 3023 if (sg_len > *offset) 3024 break; 3025 } 3026 3027 if (unlikely(i == sg_count)) { 3028 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " 3029 "elements %d\n", 3030 __func__, sg_len, *offset, sg_count); 3031 WARN_ON(1); 3032 return NULL; 3033 } 3034 3035 /* Offset starting from the beginning of first page in this sg-entry */ 3036 *offset = *offset - len_complete + sg->offset; 3037 3038 /* Assumption: contiguous pages can be accessed as "page + i" */ 3039 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT)); 3040 *offset &= ~PAGE_MASK; 3041 3042 /* Bytes in this sg-entry from *offset to the end of the page */ 3043 sg_len = PAGE_SIZE - *offset; 3044 if (*len > sg_len) 3045 *len = sg_len; 3046 3047 return kmap_atomic(page); 3048 } 3049 EXPORT_SYMBOL(scsi_kmap_atomic_sg); 3050 3051 /** 3052 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg 3053 * @virt: virtual address to be unmapped 3054 */ 3055 void scsi_kunmap_atomic_sg(void *virt) 3056 { 3057 kunmap_atomic(virt); 3058 } 3059 EXPORT_SYMBOL(scsi_kunmap_atomic_sg); 3060 3061 void sdev_disable_disk_events(struct scsi_device *sdev) 3062 { 3063 atomic_inc(&sdev->disk_events_disable_depth); 3064 } 3065 EXPORT_SYMBOL(sdev_disable_disk_events); 3066 3067 void sdev_enable_disk_events(struct scsi_device *sdev) 3068 { 3069 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0)) 3070 return; 3071 atomic_dec(&sdev->disk_events_disable_depth); 3072 } 3073 EXPORT_SYMBOL(sdev_enable_disk_events); 3074 3075 static unsigned char designator_prio(const unsigned char *d) 3076 { 3077 if (d[1] & 0x30) 3078 /* not associated with LUN */ 3079 return 0; 3080 3081 if (d[3] == 0) 3082 /* invalid length */ 3083 return 0; 3084 3085 /* 3086 * Order of preference for lun descriptor: 3087 * - SCSI name string 3088 * - NAA IEEE Registered Extended 3089 * - EUI-64 based 16-byte 3090 * - EUI-64 based 12-byte 3091 * - NAA IEEE Registered 3092 * - NAA IEEE Extended 3093 * - EUI-64 based 8-byte 3094 * - SCSI name string (truncated) 3095 * - T10 Vendor ID 3096 * as longer descriptors reduce the likelyhood 3097 * of identification clashes. 3098 */ 3099 3100 switch (d[1] & 0xf) { 3101 case 8: 3102 /* SCSI name string, variable-length UTF-8 */ 3103 return 9; 3104 case 3: 3105 switch (d[4] >> 4) { 3106 case 6: 3107 /* NAA registered extended */ 3108 return 8; 3109 case 5: 3110 /* NAA registered */ 3111 return 5; 3112 case 4: 3113 /* NAA extended */ 3114 return 4; 3115 case 3: 3116 /* NAA locally assigned */ 3117 return 1; 3118 default: 3119 break; 3120 } 3121 break; 3122 case 2: 3123 switch (d[3]) { 3124 case 16: 3125 /* EUI64-based, 16 byte */ 3126 return 7; 3127 case 12: 3128 /* EUI64-based, 12 byte */ 3129 return 6; 3130 case 8: 3131 /* EUI64-based, 8 byte */ 3132 return 3; 3133 default: 3134 break; 3135 } 3136 break; 3137 case 1: 3138 /* T10 vendor ID */ 3139 return 1; 3140 default: 3141 break; 3142 } 3143 3144 return 0; 3145 } 3146 3147 /** 3148 * scsi_vpd_lun_id - return a unique device identification 3149 * @sdev: SCSI device 3150 * @id: buffer for the identification 3151 * @id_len: length of the buffer 3152 * 3153 * Copies a unique device identification into @id based 3154 * on the information in the VPD page 0x83 of the device. 3155 * The string will be formatted as a SCSI name string. 3156 * 3157 * Returns the length of the identification or error on failure. 3158 * If the identifier is longer than the supplied buffer the actual 3159 * identifier length is returned and the buffer is not zero-padded. 3160 */ 3161 int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len) 3162 { 3163 u8 cur_id_prio = 0; 3164 u8 cur_id_size = 0; 3165 const unsigned char *d, *cur_id_str; 3166 const struct scsi_vpd *vpd_pg83; 3167 int id_size = -EINVAL; 3168 3169 rcu_read_lock(); 3170 vpd_pg83 = rcu_dereference(sdev->vpd_pg83); 3171 if (!vpd_pg83) { 3172 rcu_read_unlock(); 3173 return -ENXIO; 3174 } 3175 3176 /* The id string must be at least 20 bytes + terminating NULL byte */ 3177 if (id_len < 21) { 3178 rcu_read_unlock(); 3179 return -EINVAL; 3180 } 3181 3182 memset(id, 0, id_len); 3183 for (d = vpd_pg83->data + 4; 3184 d < vpd_pg83->data + vpd_pg83->len; 3185 d += d[3] + 4) { 3186 u8 prio = designator_prio(d); 3187 3188 if (prio == 0 || cur_id_prio > prio) 3189 continue; 3190 3191 switch (d[1] & 0xf) { 3192 case 0x1: 3193 /* T10 Vendor ID */ 3194 if (cur_id_size > d[3]) 3195 break; 3196 cur_id_prio = prio; 3197 cur_id_size = d[3]; 3198 if (cur_id_size + 4 > id_len) 3199 cur_id_size = id_len - 4; 3200 cur_id_str = d + 4; 3201 id_size = snprintf(id, id_len, "t10.%*pE", 3202 cur_id_size, cur_id_str); 3203 break; 3204 case 0x2: 3205 /* EUI-64 */ 3206 cur_id_prio = prio; 3207 cur_id_size = d[3]; 3208 cur_id_str = d + 4; 3209 switch (cur_id_size) { 3210 case 8: 3211 id_size = snprintf(id, id_len, 3212 "eui.%8phN", 3213 cur_id_str); 3214 break; 3215 case 12: 3216 id_size = snprintf(id, id_len, 3217 "eui.%12phN", 3218 cur_id_str); 3219 break; 3220 case 16: 3221 id_size = snprintf(id, id_len, 3222 "eui.%16phN", 3223 cur_id_str); 3224 break; 3225 default: 3226 break; 3227 } 3228 break; 3229 case 0x3: 3230 /* NAA */ 3231 cur_id_prio = prio; 3232 cur_id_size = d[3]; 3233 cur_id_str = d + 4; 3234 switch (cur_id_size) { 3235 case 8: 3236 id_size = snprintf(id, id_len, 3237 "naa.%8phN", 3238 cur_id_str); 3239 break; 3240 case 16: 3241 id_size = snprintf(id, id_len, 3242 "naa.%16phN", 3243 cur_id_str); 3244 break; 3245 default: 3246 break; 3247 } 3248 break; 3249 case 0x8: 3250 /* SCSI name string */ 3251 if (cur_id_size > d[3]) 3252 break; 3253 /* Prefer others for truncated descriptor */ 3254 if (d[3] > id_len) { 3255 prio = 2; 3256 if (cur_id_prio > prio) 3257 break; 3258 } 3259 cur_id_prio = prio; 3260 cur_id_size = id_size = d[3]; 3261 cur_id_str = d + 4; 3262 if (cur_id_size >= id_len) 3263 cur_id_size = id_len - 1; 3264 memcpy(id, cur_id_str, cur_id_size); 3265 break; 3266 default: 3267 break; 3268 } 3269 } 3270 rcu_read_unlock(); 3271 3272 return id_size; 3273 } 3274 EXPORT_SYMBOL(scsi_vpd_lun_id); 3275 3276 /* 3277 * scsi_vpd_tpg_id - return a target port group identifier 3278 * @sdev: SCSI device 3279 * 3280 * Returns the Target Port Group identifier from the information 3281 * froom VPD page 0x83 of the device. 3282 * 3283 * Returns the identifier or error on failure. 3284 */ 3285 int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id) 3286 { 3287 const unsigned char *d; 3288 const struct scsi_vpd *vpd_pg83; 3289 int group_id = -EAGAIN, rel_port = -1; 3290 3291 rcu_read_lock(); 3292 vpd_pg83 = rcu_dereference(sdev->vpd_pg83); 3293 if (!vpd_pg83) { 3294 rcu_read_unlock(); 3295 return -ENXIO; 3296 } 3297 3298 d = vpd_pg83->data + 4; 3299 while (d < vpd_pg83->data + vpd_pg83->len) { 3300 switch (d[1] & 0xf) { 3301 case 0x4: 3302 /* Relative target port */ 3303 rel_port = get_unaligned_be16(&d[6]); 3304 break; 3305 case 0x5: 3306 /* Target port group */ 3307 group_id = get_unaligned_be16(&d[6]); 3308 break; 3309 default: 3310 break; 3311 } 3312 d += d[3] + 4; 3313 } 3314 rcu_read_unlock(); 3315 3316 if (group_id >= 0 && rel_id && rel_port != -1) 3317 *rel_id = rel_port; 3318 3319 return group_id; 3320 } 3321 EXPORT_SYMBOL(scsi_vpd_tpg_id); 3322 3323 /** 3324 * scsi_build_sense - build sense data for a command 3325 * @scmd: scsi command for which the sense should be formatted 3326 * @desc: Sense format (non-zero == descriptor format, 3327 * 0 == fixed format) 3328 * @key: Sense key 3329 * @asc: Additional sense code 3330 * @ascq: Additional sense code qualifier 3331 * 3332 **/ 3333 void scsi_build_sense(struct scsi_cmnd *scmd, int desc, u8 key, u8 asc, u8 ascq) 3334 { 3335 scsi_build_sense_buffer(desc, scmd->sense_buffer, key, asc, ascq); 3336 scmd->result = SAM_STAT_CHECK_CONDITION; 3337 } 3338 EXPORT_SYMBOL_GPL(scsi_build_sense); 3339