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/kthread.h> 28 #include <linux/string.h> 29 #include <linux/mm.h> 30 #include <linux/init.h> 31 #include <linux/completion.h> 32 #include <linux/transport_class.h> 33 34 #include <scsi/scsi_device.h> 35 #include <scsi/scsi_host.h> 36 #include <scsi/scsi_transport.h> 37 38 #include "scsi_priv.h" 39 #include "scsi_logging.h" 40 41 42 static int scsi_host_next_hn; /* host_no for next new host */ 43 44 45 static void scsi_host_cls_release(struct class_device *class_dev) 46 { 47 put_device(&class_to_shost(class_dev)->shost_gendev); 48 } 49 50 static struct class shost_class = { 51 .name = "scsi_host", 52 .release = scsi_host_cls_release, 53 }; 54 55 /** 56 * scsi_host_set_state - Take the given host through the host 57 * state model. 58 * @shost: scsi host to change the state of. 59 * @state: state to change to. 60 * 61 * Returns zero if unsuccessful or an error if the requested 62 * transition is illegal. 63 **/ 64 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state) 65 { 66 enum scsi_host_state oldstate = shost->shost_state; 67 68 if (state == oldstate) 69 return 0; 70 71 switch (state) { 72 case SHOST_CREATED: 73 /* There are no legal states that come back to 74 * created. This is the manually initialised start 75 * state */ 76 goto illegal; 77 78 case SHOST_RUNNING: 79 switch (oldstate) { 80 case SHOST_CREATED: 81 case SHOST_RECOVERY: 82 break; 83 default: 84 goto illegal; 85 } 86 break; 87 88 case SHOST_RECOVERY: 89 switch (oldstate) { 90 case SHOST_RUNNING: 91 break; 92 default: 93 goto illegal; 94 } 95 break; 96 97 case SHOST_CANCEL: 98 switch (oldstate) { 99 case SHOST_CREATED: 100 case SHOST_RUNNING: 101 case SHOST_CANCEL_RECOVERY: 102 break; 103 default: 104 goto illegal; 105 } 106 break; 107 108 case SHOST_DEL: 109 switch (oldstate) { 110 case SHOST_CANCEL: 111 case SHOST_DEL_RECOVERY: 112 break; 113 default: 114 goto illegal; 115 } 116 break; 117 118 case SHOST_CANCEL_RECOVERY: 119 switch (oldstate) { 120 case SHOST_CANCEL: 121 case SHOST_RECOVERY: 122 break; 123 default: 124 goto illegal; 125 } 126 break; 127 128 case SHOST_DEL_RECOVERY: 129 switch (oldstate) { 130 case SHOST_CANCEL_RECOVERY: 131 break; 132 default: 133 goto illegal; 134 } 135 break; 136 } 137 shost->shost_state = state; 138 return 0; 139 140 illegal: 141 SCSI_LOG_ERROR_RECOVERY(1, 142 dev_printk(KERN_ERR, &shost->shost_gendev, 143 "Illegal host state transition" 144 "%s->%s\n", 145 scsi_host_state_name(oldstate), 146 scsi_host_state_name(state))); 147 return -EINVAL; 148 } 149 EXPORT_SYMBOL(scsi_host_set_state); 150 151 /** 152 * scsi_remove_host - remove a scsi host 153 * @shost: a pointer to a scsi host to remove 154 **/ 155 void scsi_remove_host(struct Scsi_Host *shost) 156 { 157 unsigned long flags; 158 down(&shost->scan_mutex); 159 spin_lock_irqsave(shost->host_lock, flags); 160 if (scsi_host_set_state(shost, SHOST_CANCEL)) 161 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) { 162 spin_unlock_irqrestore(shost->host_lock, flags); 163 up(&shost->scan_mutex); 164 return; 165 } 166 spin_unlock_irqrestore(shost->host_lock, flags); 167 up(&shost->scan_mutex); 168 scsi_forget_host(shost); 169 scsi_proc_host_rm(shost); 170 171 spin_lock_irqsave(shost->host_lock, flags); 172 if (scsi_host_set_state(shost, SHOST_DEL)) 173 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY)); 174 spin_unlock_irqrestore(shost->host_lock, flags); 175 176 transport_unregister_device(&shost->shost_gendev); 177 class_device_unregister(&shost->shost_classdev); 178 device_del(&shost->shost_gendev); 179 scsi_proc_hostdir_rm(shost->hostt); 180 } 181 EXPORT_SYMBOL(scsi_remove_host); 182 183 /** 184 * scsi_add_host - add a scsi host 185 * @shost: scsi host pointer to add 186 * @dev: a struct device of type scsi class 187 * 188 * Return value: 189 * 0 on success / != 0 for error 190 **/ 191 int scsi_add_host(struct Scsi_Host *shost, struct device *dev) 192 { 193 struct scsi_host_template *sht = shost->hostt; 194 int error = -EINVAL; 195 196 printk(KERN_INFO "scsi%d : %s\n", shost->host_no, 197 sht->info ? sht->info(shost) : sht->name); 198 199 if (!shost->can_queue) { 200 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n", 201 sht->name); 202 goto out; 203 } 204 205 if (!shost->shost_gendev.parent) 206 shost->shost_gendev.parent = dev ? dev : &platform_bus; 207 208 error = device_add(&shost->shost_gendev); 209 if (error) 210 goto out; 211 212 scsi_host_set_state(shost, SHOST_RUNNING); 213 get_device(shost->shost_gendev.parent); 214 215 error = class_device_add(&shost->shost_classdev); 216 if (error) 217 goto out_del_gendev; 218 219 get_device(&shost->shost_gendev); 220 221 if (shost->transportt->host_size && 222 (shost->shost_data = kmalloc(shost->transportt->host_size, 223 GFP_KERNEL)) == NULL) 224 goto out_del_classdev; 225 226 if (shost->transportt->create_work_queue) { 227 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d", 228 shost->host_no); 229 shost->work_q = create_singlethread_workqueue( 230 shost->work_q_name); 231 if (!shost->work_q) 232 goto out_free_shost_data; 233 } 234 235 error = scsi_sysfs_add_host(shost); 236 if (error) 237 goto out_destroy_host; 238 239 scsi_proc_host_add(shost); 240 return error; 241 242 out_destroy_host: 243 if (shost->work_q) 244 destroy_workqueue(shost->work_q); 245 out_free_shost_data: 246 kfree(shost->shost_data); 247 out_del_classdev: 248 class_device_del(&shost->shost_classdev); 249 out_del_gendev: 250 device_del(&shost->shost_gendev); 251 out: 252 return error; 253 } 254 EXPORT_SYMBOL(scsi_add_host); 255 256 static void scsi_host_dev_release(struct device *dev) 257 { 258 struct Scsi_Host *shost = dev_to_shost(dev); 259 struct device *parent = dev->parent; 260 261 if (shost->ehandler) 262 kthread_stop(shost->ehandler); 263 if (shost->work_q) 264 destroy_workqueue(shost->work_q); 265 266 scsi_destroy_command_freelist(shost); 267 kfree(shost->shost_data); 268 269 if (parent) 270 put_device(parent); 271 kfree(shost); 272 } 273 274 /** 275 * scsi_host_alloc - register a scsi host adapter instance. 276 * @sht: pointer to scsi host template 277 * @privsize: extra bytes to allocate for driver 278 * 279 * Note: 280 * Allocate a new Scsi_Host and perform basic initialization. 281 * The host is not published to the scsi midlayer until scsi_add_host 282 * is called. 283 * 284 * Return value: 285 * Pointer to a new Scsi_Host 286 **/ 287 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) 288 { 289 struct Scsi_Host *shost; 290 int gfp_mask = GFP_KERNEL, rval; 291 292 if (sht->unchecked_isa_dma && privsize) 293 gfp_mask |= __GFP_DMA; 294 295 /* Check to see if this host has any error handling facilities */ 296 if (!sht->eh_strategy_handler && !sht->eh_abort_handler && 297 !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler && 298 !sht->eh_host_reset_handler) { 299 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n" 300 "ERROR: This is not a safe way to run your " 301 "SCSI host\n" 302 "ERROR: The error handling must be added to " 303 "this driver\n", sht->proc_name); 304 dump_stack(); 305 } 306 307 shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask); 308 if (!shost) 309 return NULL; 310 memset(shost, 0, sizeof(struct Scsi_Host) + privsize); 311 312 spin_lock_init(&shost->default_lock); 313 scsi_assign_lock(shost, &shost->default_lock); 314 shost->shost_state = SHOST_CREATED; 315 INIT_LIST_HEAD(&shost->__devices); 316 INIT_LIST_HEAD(&shost->__targets); 317 INIT_LIST_HEAD(&shost->eh_cmd_q); 318 INIT_LIST_HEAD(&shost->starved_list); 319 init_waitqueue_head(&shost->host_wait); 320 321 init_MUTEX(&shost->scan_mutex); 322 323 shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */ 324 shost->dma_channel = 0xff; 325 326 /* These three are default values which can be overridden */ 327 shost->max_channel = 0; 328 shost->max_id = 8; 329 shost->max_lun = 8; 330 331 /* Give each shost a default transportt */ 332 shost->transportt = &blank_transport_template; 333 334 /* 335 * All drivers right now should be able to handle 12 byte 336 * commands. Every so often there are requests for 16 byte 337 * commands, but individual low-level drivers need to certify that 338 * they actually do something sensible with such commands. 339 */ 340 shost->max_cmd_len = 12; 341 shost->hostt = sht; 342 shost->this_id = sht->this_id; 343 shost->can_queue = sht->can_queue; 344 shost->sg_tablesize = sht->sg_tablesize; 345 shost->cmd_per_lun = sht->cmd_per_lun; 346 shost->unchecked_isa_dma = sht->unchecked_isa_dma; 347 shost->use_clustering = sht->use_clustering; 348 shost->ordered_flush = sht->ordered_flush; 349 shost->ordered_tag = sht->ordered_tag; 350 351 /* 352 * hosts/devices that do queueing must support ordered tags 353 */ 354 if (shost->can_queue > 1 && shost->ordered_flush) { 355 printk(KERN_ERR "scsi: ordered flushes don't support queueing\n"); 356 shost->ordered_flush = 0; 357 } 358 359 if (sht->max_host_blocked) 360 shost->max_host_blocked = sht->max_host_blocked; 361 else 362 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED; 363 364 /* 365 * If the driver imposes no hard sector transfer limit, start at 366 * machine infinity initially. 367 */ 368 if (sht->max_sectors) 369 shost->max_sectors = sht->max_sectors; 370 else 371 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS; 372 373 /* 374 * assume a 4GB boundary, if not set 375 */ 376 if (sht->dma_boundary) 377 shost->dma_boundary = sht->dma_boundary; 378 else 379 shost->dma_boundary = 0xffffffff; 380 381 rval = scsi_setup_command_freelist(shost); 382 if (rval) 383 goto fail_kfree; 384 385 device_initialize(&shost->shost_gendev); 386 snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d", 387 shost->host_no); 388 shost->shost_gendev.release = scsi_host_dev_release; 389 390 class_device_initialize(&shost->shost_classdev); 391 shost->shost_classdev.dev = &shost->shost_gendev; 392 shost->shost_classdev.class = &shost_class; 393 snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d", 394 shost->host_no); 395 396 shost->ehandler = kthread_run(scsi_error_handler, shost, 397 "scsi_eh_%d", shost->host_no); 398 if (IS_ERR(shost->ehandler)) { 399 rval = PTR_ERR(shost->ehandler); 400 goto fail_destroy_freelist; 401 } 402 403 scsi_proc_hostdir_add(shost->hostt); 404 return shost; 405 406 fail_destroy_freelist: 407 scsi_destroy_command_freelist(shost); 408 fail_kfree: 409 kfree(shost); 410 return NULL; 411 } 412 EXPORT_SYMBOL(scsi_host_alloc); 413 414 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize) 415 { 416 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize); 417 418 if (!sht->detect) { 419 printk(KERN_WARNING "scsi_register() called on new-style " 420 "template for driver %s\n", sht->name); 421 dump_stack(); 422 } 423 424 if (shost) 425 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts); 426 return shost; 427 } 428 EXPORT_SYMBOL(scsi_register); 429 430 void scsi_unregister(struct Scsi_Host *shost) 431 { 432 list_del(&shost->sht_legacy_list); 433 scsi_host_put(shost); 434 } 435 EXPORT_SYMBOL(scsi_unregister); 436 437 /** 438 * scsi_host_lookup - get a reference to a Scsi_Host by host no 439 * 440 * @hostnum: host number to locate 441 * 442 * Return value: 443 * A pointer to located Scsi_Host or NULL. 444 **/ 445 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum) 446 { 447 struct class *class = &shost_class; 448 struct class_device *cdev; 449 struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p; 450 451 down_read(&class->subsys.rwsem); 452 list_for_each_entry(cdev, &class->children, node) { 453 p = class_to_shost(cdev); 454 if (p->host_no == hostnum) { 455 shost = scsi_host_get(p); 456 break; 457 } 458 } 459 up_read(&class->subsys.rwsem); 460 461 return shost; 462 } 463 EXPORT_SYMBOL(scsi_host_lookup); 464 465 /** 466 * scsi_host_get - inc a Scsi_Host ref count 467 * @shost: Pointer to Scsi_Host to inc. 468 **/ 469 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost) 470 { 471 if ((shost->shost_state == SHOST_DEL) || 472 !get_device(&shost->shost_gendev)) 473 return NULL; 474 return shost; 475 } 476 EXPORT_SYMBOL(scsi_host_get); 477 478 /** 479 * scsi_host_put - dec a Scsi_Host ref count 480 * @shost: Pointer to Scsi_Host to dec. 481 **/ 482 void scsi_host_put(struct Scsi_Host *shost) 483 { 484 put_device(&shost->shost_gendev); 485 } 486 EXPORT_SYMBOL(scsi_host_put); 487 488 int scsi_init_hosts(void) 489 { 490 return class_register(&shost_class); 491 } 492 493 void scsi_exit_hosts(void) 494 { 495 class_unregister(&shost_class); 496 } 497 498 int scsi_is_host_device(const struct device *dev) 499 { 500 return dev->release == scsi_host_dev_release; 501 } 502 EXPORT_SYMBOL(scsi_is_host_device); 503 504 /** 505 * scsi_queue_work - Queue work to the Scsi_Host workqueue. 506 * @shost: Pointer to Scsi_Host. 507 * @work: Work to queue for execution. 508 * 509 * Return value: 510 * 0 on success / != 0 for error 511 **/ 512 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work) 513 { 514 if (unlikely(!shost->work_q)) { 515 printk(KERN_ERR 516 "ERROR: Scsi host '%s' attempted to queue scsi-work, " 517 "when no workqueue created.\n", shost->hostt->name); 518 dump_stack(); 519 520 return -EINVAL; 521 } 522 523 return queue_work(shost->work_q, work); 524 } 525 EXPORT_SYMBOL_GPL(scsi_queue_work); 526 527 /** 528 * scsi_flush_work - Flush a Scsi_Host's workqueue. 529 * @shost: Pointer to Scsi_Host. 530 **/ 531 void scsi_flush_work(struct Scsi_Host *shost) 532 { 533 if (!shost->work_q) { 534 printk(KERN_ERR 535 "ERROR: Scsi host '%s' attempted to flush scsi-work, " 536 "when no workqueue created.\n", shost->hostt->name); 537 dump_stack(); 538 return; 539 } 540 541 flush_workqueue(shost->work_q); 542 } 543 EXPORT_SYMBOL_GPL(scsi_flush_work); 544