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