1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * hosts.c Copyright (C) 1992 Drew Eckhardt 4 * Copyright (C) 1993, 1994, 1995 Eric Youngdale 5 * Copyright (C) 2002-2003 Christoph Hellwig 6 * 7 * mid to lowlevel SCSI driver interface 8 * Initial versions: Drew Eckhardt 9 * Subsequent revisions: Eric Youngdale 10 * 11 * <drew@colorado.edu> 12 * 13 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli 14 * Added QLOGIC QLA1280 SCSI controller kernel host support. 15 * August 4, 1999 Fred Lewis, Intel DuPont 16 * 17 * Updated to reflect the new initialization scheme for the higher 18 * level of scsi drivers (sd/sr/st) 19 * September 17, 2000 Torben Mathiasen <tmm@image.dk> 20 * 21 * Restructured scsi_host lists and associated functions. 22 * September 04, 2002 Mike Anderson (andmike@us.ibm.com) 23 */ 24 25 #include <linux/module.h> 26 #include <linux/blkdev.h> 27 #include <linux/kernel.h> 28 #include <linux/slab.h> 29 #include <linux/kthread.h> 30 #include <linux/string.h> 31 #include <linux/mm.h> 32 #include <linux/init.h> 33 #include <linux/completion.h> 34 #include <linux/transport_class.h> 35 #include <linux/platform_device.h> 36 #include <linux/pm_runtime.h> 37 #include <linux/idr.h> 38 #include <scsi/scsi_device.h> 39 #include <scsi/scsi_host.h> 40 #include <scsi/scsi_transport.h> 41 42 #include "scsi_priv.h" 43 #include "scsi_logging.h" 44 45 46 static int shost_eh_deadline = -1; 47 48 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR); 49 MODULE_PARM_DESC(eh_deadline, 50 "SCSI EH timeout in seconds (should be between 0 and 2^31-1)"); 51 52 static DEFINE_IDA(host_index_ida); 53 54 55 static void scsi_host_cls_release(struct device *dev) 56 { 57 put_device(&class_to_shost(dev)->shost_gendev); 58 } 59 60 static struct class shost_class = { 61 .name = "scsi_host", 62 .dev_release = scsi_host_cls_release, 63 }; 64 65 /** 66 * scsi_host_set_state - Take the given host through the host state model. 67 * @shost: scsi host to change the state of. 68 * @state: state to change to. 69 * 70 * Returns zero if unsuccessful or an error if the requested 71 * transition is illegal. 72 **/ 73 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state) 74 { 75 enum scsi_host_state oldstate = shost->shost_state; 76 77 if (state == oldstate) 78 return 0; 79 80 switch (state) { 81 case SHOST_CREATED: 82 /* There are no legal states that come back to 83 * created. This is the manually initialised start 84 * state */ 85 goto illegal; 86 87 case SHOST_RUNNING: 88 switch (oldstate) { 89 case SHOST_CREATED: 90 case SHOST_RECOVERY: 91 break; 92 default: 93 goto illegal; 94 } 95 break; 96 97 case SHOST_RECOVERY: 98 switch (oldstate) { 99 case SHOST_RUNNING: 100 break; 101 default: 102 goto illegal; 103 } 104 break; 105 106 case SHOST_CANCEL: 107 switch (oldstate) { 108 case SHOST_CREATED: 109 case SHOST_RUNNING: 110 case SHOST_CANCEL_RECOVERY: 111 break; 112 default: 113 goto illegal; 114 } 115 break; 116 117 case SHOST_DEL: 118 switch (oldstate) { 119 case SHOST_CANCEL: 120 case SHOST_DEL_RECOVERY: 121 break; 122 default: 123 goto illegal; 124 } 125 break; 126 127 case SHOST_CANCEL_RECOVERY: 128 switch (oldstate) { 129 case SHOST_CANCEL: 130 case SHOST_RECOVERY: 131 break; 132 default: 133 goto illegal; 134 } 135 break; 136 137 case SHOST_DEL_RECOVERY: 138 switch (oldstate) { 139 case SHOST_CANCEL_RECOVERY: 140 break; 141 default: 142 goto illegal; 143 } 144 break; 145 } 146 shost->shost_state = state; 147 return 0; 148 149 illegal: 150 SCSI_LOG_ERROR_RECOVERY(1, 151 shost_printk(KERN_ERR, shost, 152 "Illegal host state transition" 153 "%s->%s\n", 154 scsi_host_state_name(oldstate), 155 scsi_host_state_name(state))); 156 return -EINVAL; 157 } 158 159 /** 160 * scsi_remove_host - remove a scsi host 161 * @shost: a pointer to a scsi host to remove 162 **/ 163 void scsi_remove_host(struct Scsi_Host *shost) 164 { 165 unsigned long flags; 166 167 mutex_lock(&shost->scan_mutex); 168 spin_lock_irqsave(shost->host_lock, flags); 169 if (scsi_host_set_state(shost, SHOST_CANCEL)) 170 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) { 171 spin_unlock_irqrestore(shost->host_lock, flags); 172 mutex_unlock(&shost->scan_mutex); 173 return; 174 } 175 spin_unlock_irqrestore(shost->host_lock, flags); 176 177 scsi_autopm_get_host(shost); 178 flush_workqueue(shost->tmf_work_q); 179 scsi_forget_host(shost); 180 mutex_unlock(&shost->scan_mutex); 181 scsi_proc_host_rm(shost); 182 183 spin_lock_irqsave(shost->host_lock, flags); 184 if (scsi_host_set_state(shost, SHOST_DEL)) 185 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY)); 186 spin_unlock_irqrestore(shost->host_lock, flags); 187 188 transport_unregister_device(&shost->shost_gendev); 189 device_unregister(&shost->shost_dev); 190 device_del(&shost->shost_gendev); 191 } 192 EXPORT_SYMBOL(scsi_remove_host); 193 194 /** 195 * scsi_add_host_with_dma - add a scsi host with dma device 196 * @shost: scsi host pointer to add 197 * @dev: a struct device of type scsi class 198 * @dma_dev: dma device for the host 199 * 200 * Note: You rarely need to worry about this unless you're in a 201 * virtualised host environments, so use the simpler scsi_add_host() 202 * function instead. 203 * 204 * Return value: 205 * 0 on success / != 0 for error 206 **/ 207 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev, 208 struct device *dma_dev) 209 { 210 struct scsi_host_template *sht = shost->hostt; 211 int error = -EINVAL; 212 213 shost_printk(KERN_INFO, shost, "%s\n", 214 sht->info ? sht->info(shost) : sht->name); 215 216 if (!shost->can_queue) { 217 shost_printk(KERN_ERR, shost, 218 "can_queue = 0 no longer supported\n"); 219 goto fail; 220 } 221 222 error = scsi_init_sense_cache(shost); 223 if (error) 224 goto fail; 225 226 error = scsi_mq_setup_tags(shost); 227 if (error) 228 goto fail; 229 230 if (!shost->shost_gendev.parent) 231 shost->shost_gendev.parent = dev ? dev : &platform_bus; 232 if (!dma_dev) 233 dma_dev = shost->shost_gendev.parent; 234 235 shost->dma_dev = dma_dev; 236 237 /* 238 * Increase usage count temporarily here so that calling 239 * scsi_autopm_put_host() will trigger runtime idle if there is 240 * nothing else preventing suspending the device. 241 */ 242 pm_runtime_get_noresume(&shost->shost_gendev); 243 pm_runtime_set_active(&shost->shost_gendev); 244 pm_runtime_enable(&shost->shost_gendev); 245 device_enable_async_suspend(&shost->shost_gendev); 246 247 error = device_add(&shost->shost_gendev); 248 if (error) 249 goto out_disable_runtime_pm; 250 251 scsi_host_set_state(shost, SHOST_RUNNING); 252 get_device(shost->shost_gendev.parent); 253 254 device_enable_async_suspend(&shost->shost_dev); 255 256 error = device_add(&shost->shost_dev); 257 if (error) 258 goto out_del_gendev; 259 260 get_device(&shost->shost_gendev); 261 262 if (shost->transportt->host_size) { 263 shost->shost_data = kzalloc(shost->transportt->host_size, 264 GFP_KERNEL); 265 if (shost->shost_data == NULL) { 266 error = -ENOMEM; 267 goto out_del_dev; 268 } 269 } 270 271 if (shost->transportt->create_work_queue) { 272 snprintf(shost->work_q_name, sizeof(shost->work_q_name), 273 "scsi_wq_%d", shost->host_no); 274 shost->work_q = create_singlethread_workqueue( 275 shost->work_q_name); 276 if (!shost->work_q) { 277 error = -EINVAL; 278 goto out_free_shost_data; 279 } 280 } 281 282 error = scsi_sysfs_add_host(shost); 283 if (error) 284 goto out_destroy_host; 285 286 scsi_proc_host_add(shost); 287 scsi_autopm_put_host(shost); 288 return error; 289 290 out_destroy_host: 291 if (shost->work_q) 292 destroy_workqueue(shost->work_q); 293 out_free_shost_data: 294 kfree(shost->shost_data); 295 out_del_dev: 296 device_del(&shost->shost_dev); 297 out_del_gendev: 298 device_del(&shost->shost_gendev); 299 out_disable_runtime_pm: 300 device_disable_async_suspend(&shost->shost_gendev); 301 pm_runtime_disable(&shost->shost_gendev); 302 pm_runtime_set_suspended(&shost->shost_gendev); 303 pm_runtime_put_noidle(&shost->shost_gendev); 304 scsi_mq_destroy_tags(shost); 305 fail: 306 return error; 307 } 308 EXPORT_SYMBOL(scsi_add_host_with_dma); 309 310 static void scsi_host_dev_release(struct device *dev) 311 { 312 struct Scsi_Host *shost = dev_to_shost(dev); 313 struct device *parent = dev->parent; 314 315 scsi_proc_hostdir_rm(shost->hostt); 316 317 /* Wait for functions invoked through call_rcu(&shost->rcu, ...) */ 318 rcu_barrier(); 319 320 if (shost->tmf_work_q) 321 destroy_workqueue(shost->tmf_work_q); 322 if (shost->ehandler) 323 kthread_stop(shost->ehandler); 324 if (shost->work_q) 325 destroy_workqueue(shost->work_q); 326 327 if (shost->shost_state == SHOST_CREATED) { 328 /* 329 * Free the shost_dev device name here if scsi_host_alloc() 330 * and scsi_host_put() have been called but neither 331 * scsi_host_add() nor scsi_host_remove() has been called. 332 * This avoids that the memory allocated for the shost_dev 333 * name is leaked. 334 */ 335 kfree(dev_name(&shost->shost_dev)); 336 } 337 338 if (shost->tag_set.tags) 339 scsi_mq_destroy_tags(shost); 340 341 kfree(shost->shost_data); 342 343 ida_simple_remove(&host_index_ida, shost->host_no); 344 345 if (parent) 346 put_device(parent); 347 kfree(shost); 348 } 349 350 static struct device_type scsi_host_type = { 351 .name = "scsi_host", 352 .release = scsi_host_dev_release, 353 }; 354 355 /** 356 * scsi_host_alloc - register a scsi host adapter instance. 357 * @sht: pointer to scsi host template 358 * @privsize: extra bytes to allocate for driver 359 * 360 * Note: 361 * Allocate a new Scsi_Host and perform basic initialization. 362 * The host is not published to the scsi midlayer until scsi_add_host 363 * is called. 364 * 365 * Return value: 366 * Pointer to a new Scsi_Host 367 **/ 368 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) 369 { 370 struct Scsi_Host *shost; 371 gfp_t gfp_mask = GFP_KERNEL; 372 int index; 373 374 if (sht->unchecked_isa_dma && privsize) 375 gfp_mask |= __GFP_DMA; 376 377 shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask); 378 if (!shost) 379 return NULL; 380 381 shost->host_lock = &shost->default_lock; 382 spin_lock_init(shost->host_lock); 383 shost->shost_state = SHOST_CREATED; 384 INIT_LIST_HEAD(&shost->__devices); 385 INIT_LIST_HEAD(&shost->__targets); 386 INIT_LIST_HEAD(&shost->eh_cmd_q); 387 INIT_LIST_HEAD(&shost->starved_list); 388 init_waitqueue_head(&shost->host_wait); 389 mutex_init(&shost->scan_mutex); 390 391 index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL); 392 if (index < 0) 393 goto fail_kfree; 394 shost->host_no = index; 395 396 shost->dma_channel = 0xff; 397 398 /* These three are default values which can be overridden */ 399 shost->max_channel = 0; 400 shost->max_id = 8; 401 shost->max_lun = 8; 402 403 /* Give each shost a default transportt */ 404 shost->transportt = &blank_transport_template; 405 406 /* 407 * All drivers right now should be able to handle 12 byte 408 * commands. Every so often there are requests for 16 byte 409 * commands, but individual low-level drivers need to certify that 410 * they actually do something sensible with such commands. 411 */ 412 shost->max_cmd_len = 12; 413 shost->hostt = sht; 414 shost->this_id = sht->this_id; 415 shost->can_queue = sht->can_queue; 416 shost->sg_tablesize = sht->sg_tablesize; 417 shost->sg_prot_tablesize = sht->sg_prot_tablesize; 418 shost->cmd_per_lun = sht->cmd_per_lun; 419 shost->unchecked_isa_dma = sht->unchecked_isa_dma; 420 shost->no_write_same = sht->no_write_same; 421 422 if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler) 423 shost->eh_deadline = -1; 424 else if ((ulong) shost_eh_deadline * HZ > INT_MAX) { 425 shost_printk(KERN_WARNING, shost, 426 "eh_deadline %u too large, setting to %u\n", 427 shost_eh_deadline, INT_MAX / HZ); 428 shost->eh_deadline = INT_MAX; 429 } else 430 shost->eh_deadline = shost_eh_deadline * HZ; 431 432 if (sht->supported_mode == MODE_UNKNOWN) 433 /* means we didn't set it ... default to INITIATOR */ 434 shost->active_mode = MODE_INITIATOR; 435 else 436 shost->active_mode = sht->supported_mode; 437 438 if (sht->max_host_blocked) 439 shost->max_host_blocked = sht->max_host_blocked; 440 else 441 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED; 442 443 /* 444 * If the driver imposes no hard sector transfer limit, start at 445 * machine infinity initially. 446 */ 447 if (sht->max_sectors) 448 shost->max_sectors = sht->max_sectors; 449 else 450 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS; 451 452 if (sht->max_segment_size) 453 shost->max_segment_size = sht->max_segment_size; 454 else 455 shost->max_segment_size = BLK_MAX_SEGMENT_SIZE; 456 457 /* 458 * assume a 4GB boundary, if not set 459 */ 460 if (sht->dma_boundary) 461 shost->dma_boundary = sht->dma_boundary; 462 else 463 shost->dma_boundary = 0xffffffff; 464 465 device_initialize(&shost->shost_gendev); 466 dev_set_name(&shost->shost_gendev, "host%d", shost->host_no); 467 shost->shost_gendev.bus = &scsi_bus_type; 468 shost->shost_gendev.type = &scsi_host_type; 469 470 device_initialize(&shost->shost_dev); 471 shost->shost_dev.parent = &shost->shost_gendev; 472 shost->shost_dev.class = &shost_class; 473 dev_set_name(&shost->shost_dev, "host%d", shost->host_no); 474 shost->shost_dev.groups = scsi_sysfs_shost_attr_groups; 475 476 shost->ehandler = kthread_run(scsi_error_handler, shost, 477 "scsi_eh_%d", shost->host_no); 478 if (IS_ERR(shost->ehandler)) { 479 shost_printk(KERN_WARNING, shost, 480 "error handler thread failed to spawn, error = %ld\n", 481 PTR_ERR(shost->ehandler)); 482 goto fail_index_remove; 483 } 484 485 shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d", 486 WQ_UNBOUND | WQ_MEM_RECLAIM, 487 1, shost->host_no); 488 if (!shost->tmf_work_q) { 489 shost_printk(KERN_WARNING, shost, 490 "failed to create tmf workq\n"); 491 goto fail_kthread; 492 } 493 scsi_proc_hostdir_add(shost->hostt); 494 return shost; 495 496 fail_kthread: 497 kthread_stop(shost->ehandler); 498 fail_index_remove: 499 ida_simple_remove(&host_index_ida, shost->host_no); 500 fail_kfree: 501 kfree(shost); 502 return NULL; 503 } 504 EXPORT_SYMBOL(scsi_host_alloc); 505 506 static int __scsi_host_match(struct device *dev, const void *data) 507 { 508 struct Scsi_Host *p; 509 const unsigned short *hostnum = data; 510 511 p = class_to_shost(dev); 512 return p->host_no == *hostnum; 513 } 514 515 /** 516 * scsi_host_lookup - get a reference to a Scsi_Host by host no 517 * @hostnum: host number to locate 518 * 519 * Return value: 520 * A pointer to located Scsi_Host or NULL. 521 * 522 * The caller must do a scsi_host_put() to drop the reference 523 * that scsi_host_get() took. The put_device() below dropped 524 * the reference from class_find_device(). 525 **/ 526 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum) 527 { 528 struct device *cdev; 529 struct Scsi_Host *shost = NULL; 530 531 cdev = class_find_device(&shost_class, NULL, &hostnum, 532 __scsi_host_match); 533 if (cdev) { 534 shost = scsi_host_get(class_to_shost(cdev)); 535 put_device(cdev); 536 } 537 return shost; 538 } 539 EXPORT_SYMBOL(scsi_host_lookup); 540 541 /** 542 * scsi_host_get - inc a Scsi_Host ref count 543 * @shost: Pointer to Scsi_Host to inc. 544 **/ 545 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost) 546 { 547 if ((shost->shost_state == SHOST_DEL) || 548 !get_device(&shost->shost_gendev)) 549 return NULL; 550 return shost; 551 } 552 EXPORT_SYMBOL(scsi_host_get); 553 554 /** 555 * scsi_host_busy - Return the host busy counter 556 * @shost: Pointer to Scsi_Host to inc. 557 **/ 558 int scsi_host_busy(struct Scsi_Host *shost) 559 { 560 return atomic_read(&shost->host_busy); 561 } 562 EXPORT_SYMBOL(scsi_host_busy); 563 564 /** 565 * scsi_host_put - dec a Scsi_Host ref count 566 * @shost: Pointer to Scsi_Host to dec. 567 **/ 568 void scsi_host_put(struct Scsi_Host *shost) 569 { 570 put_device(&shost->shost_gendev); 571 } 572 EXPORT_SYMBOL(scsi_host_put); 573 574 int scsi_init_hosts(void) 575 { 576 return class_register(&shost_class); 577 } 578 579 void scsi_exit_hosts(void) 580 { 581 class_unregister(&shost_class); 582 ida_destroy(&host_index_ida); 583 } 584 585 int scsi_is_host_device(const struct device *dev) 586 { 587 return dev->type == &scsi_host_type; 588 } 589 EXPORT_SYMBOL(scsi_is_host_device); 590 591 /** 592 * scsi_queue_work - Queue work to the Scsi_Host workqueue. 593 * @shost: Pointer to Scsi_Host. 594 * @work: Work to queue for execution. 595 * 596 * Return value: 597 * 1 - work queued for execution 598 * 0 - work is already queued 599 * -EINVAL - work queue doesn't exist 600 **/ 601 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work) 602 { 603 if (unlikely(!shost->work_q)) { 604 shost_printk(KERN_ERR, shost, 605 "ERROR: Scsi host '%s' attempted to queue scsi-work, " 606 "when no workqueue created.\n", shost->hostt->name); 607 dump_stack(); 608 609 return -EINVAL; 610 } 611 612 return queue_work(shost->work_q, work); 613 } 614 EXPORT_SYMBOL_GPL(scsi_queue_work); 615 616 /** 617 * scsi_flush_work - Flush a Scsi_Host's workqueue. 618 * @shost: Pointer to Scsi_Host. 619 **/ 620 void scsi_flush_work(struct Scsi_Host *shost) 621 { 622 if (!shost->work_q) { 623 shost_printk(KERN_ERR, shost, 624 "ERROR: Scsi host '%s' attempted to flush scsi-work, " 625 "when no workqueue created.\n", shost->hostt->name); 626 dump_stack(); 627 return; 628 } 629 630 flush_workqueue(shost->work_q); 631 } 632 EXPORT_SYMBOL_GPL(scsi_flush_work); 633