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