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 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 shost_printk(KERN_ERR, shost, 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 mutex_lock(&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 mutex_unlock(&shost->scan_mutex); 164 return; 165 } 166 spin_unlock_irqrestore(shost->host_lock, flags); 167 mutex_unlock(&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 = kzalloc(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 if (shost->uspace_req_q) { 266 kfree(shost->uspace_req_q->queuedata); 267 scsi_free_queue(shost->uspace_req_q); 268 } 269 270 scsi_destroy_command_freelist(shost); 271 if (shost->bqt) 272 blk_free_tags(shost->bqt); 273 274 kfree(shost->shost_data); 275 276 if (parent) 277 put_device(parent); 278 kfree(shost); 279 } 280 281 /** 282 * scsi_host_alloc - register a scsi host adapter instance. 283 * @sht: pointer to scsi host template 284 * @privsize: extra bytes to allocate for driver 285 * 286 * Note: 287 * Allocate a new Scsi_Host and perform basic initialization. 288 * The host is not published to the scsi midlayer until scsi_add_host 289 * is called. 290 * 291 * Return value: 292 * Pointer to a new Scsi_Host 293 **/ 294 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) 295 { 296 struct Scsi_Host *shost; 297 gfp_t gfp_mask = GFP_KERNEL; 298 int rval; 299 300 if (sht->unchecked_isa_dma && privsize) 301 gfp_mask |= __GFP_DMA; 302 303 shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask); 304 if (!shost) 305 return NULL; 306 307 shost->host_lock = &shost->default_lock; 308 spin_lock_init(shost->host_lock); 309 shost->shost_state = SHOST_CREATED; 310 INIT_LIST_HEAD(&shost->__devices); 311 INIT_LIST_HEAD(&shost->__targets); 312 INIT_LIST_HEAD(&shost->eh_cmd_q); 313 INIT_LIST_HEAD(&shost->starved_list); 314 init_waitqueue_head(&shost->host_wait); 315 316 mutex_init(&shost->scan_mutex); 317 318 shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */ 319 shost->dma_channel = 0xff; 320 321 /* These three are default values which can be overridden */ 322 shost->max_channel = 0; 323 shost->max_id = 8; 324 shost->max_lun = 8; 325 326 /* Give each shost a default transportt */ 327 shost->transportt = &blank_transport_template; 328 329 /* 330 * All drivers right now should be able to handle 12 byte 331 * commands. Every so often there are requests for 16 byte 332 * commands, but individual low-level drivers need to certify that 333 * they actually do something sensible with such commands. 334 */ 335 shost->max_cmd_len = 12; 336 shost->hostt = sht; 337 shost->this_id = sht->this_id; 338 shost->can_queue = sht->can_queue; 339 shost->sg_tablesize = sht->sg_tablesize; 340 shost->cmd_per_lun = sht->cmd_per_lun; 341 shost->unchecked_isa_dma = sht->unchecked_isa_dma; 342 shost->use_clustering = sht->use_clustering; 343 shost->ordered_tag = sht->ordered_tag; 344 shost->active_mode = sht->supported_mode; 345 346 if (sht->supported_mode == MODE_UNKNOWN) 347 /* means we didn't set it ... default to INITIATOR */ 348 shost->active_mode = MODE_INITIATOR; 349 else 350 shost->active_mode = sht->supported_mode; 351 352 if (sht->max_host_blocked) 353 shost->max_host_blocked = sht->max_host_blocked; 354 else 355 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED; 356 357 /* 358 * If the driver imposes no hard sector transfer limit, start at 359 * machine infinity initially. 360 */ 361 if (sht->max_sectors) 362 shost->max_sectors = sht->max_sectors; 363 else 364 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS; 365 366 /* 367 * assume a 4GB boundary, if not set 368 */ 369 if (sht->dma_boundary) 370 shost->dma_boundary = sht->dma_boundary; 371 else 372 shost->dma_boundary = 0xffffffff; 373 374 rval = scsi_setup_command_freelist(shost); 375 if (rval) 376 goto fail_kfree; 377 378 device_initialize(&shost->shost_gendev); 379 snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d", 380 shost->host_no); 381 shost->shost_gendev.release = scsi_host_dev_release; 382 383 class_device_initialize(&shost->shost_classdev); 384 shost->shost_classdev.dev = &shost->shost_gendev; 385 shost->shost_classdev.class = &shost_class; 386 snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d", 387 shost->host_no); 388 389 shost->ehandler = kthread_run(scsi_error_handler, shost, 390 "scsi_eh_%d", shost->host_no); 391 if (IS_ERR(shost->ehandler)) { 392 rval = PTR_ERR(shost->ehandler); 393 goto fail_destroy_freelist; 394 } 395 396 scsi_proc_hostdir_add(shost->hostt); 397 return shost; 398 399 fail_destroy_freelist: 400 scsi_destroy_command_freelist(shost); 401 fail_kfree: 402 kfree(shost); 403 return NULL; 404 } 405 EXPORT_SYMBOL(scsi_host_alloc); 406 407 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize) 408 { 409 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize); 410 411 if (!sht->detect) { 412 printk(KERN_WARNING "scsi_register() called on new-style " 413 "template for driver %s\n", sht->name); 414 dump_stack(); 415 } 416 417 if (shost) 418 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts); 419 return shost; 420 } 421 EXPORT_SYMBOL(scsi_register); 422 423 void scsi_unregister(struct Scsi_Host *shost) 424 { 425 list_del(&shost->sht_legacy_list); 426 scsi_host_put(shost); 427 } 428 EXPORT_SYMBOL(scsi_unregister); 429 430 static int __scsi_host_match(struct class_device *cdev, void *data) 431 { 432 struct Scsi_Host *p; 433 unsigned short *hostnum = (unsigned short *)data; 434 435 p = class_to_shost(cdev); 436 return p->host_no == *hostnum; 437 } 438 439 /** 440 * scsi_host_lookup - get a reference to a Scsi_Host by host no 441 * @hostnum: host number to locate 442 * 443 * Return value: 444 * A pointer to located Scsi_Host or NULL. 445 **/ 446 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum) 447 { 448 struct class_device *cdev; 449 struct Scsi_Host *shost = ERR_PTR(-ENXIO); 450 451 cdev = class_find_child(&shost_class, &hostnum, __scsi_host_match); 452 if (cdev) 453 shost = scsi_host_get(class_to_shost(cdev)); 454 455 return shost; 456 } 457 EXPORT_SYMBOL(scsi_host_lookup); 458 459 /** 460 * scsi_host_get - inc a Scsi_Host ref count 461 * @shost: Pointer to Scsi_Host to inc. 462 **/ 463 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost) 464 { 465 if ((shost->shost_state == SHOST_DEL) || 466 !get_device(&shost->shost_gendev)) 467 return NULL; 468 return shost; 469 } 470 EXPORT_SYMBOL(scsi_host_get); 471 472 /** 473 * scsi_host_put - dec a Scsi_Host ref count 474 * @shost: Pointer to Scsi_Host to dec. 475 **/ 476 void scsi_host_put(struct Scsi_Host *shost) 477 { 478 put_device(&shost->shost_gendev); 479 } 480 EXPORT_SYMBOL(scsi_host_put); 481 482 int scsi_init_hosts(void) 483 { 484 return class_register(&shost_class); 485 } 486 487 void scsi_exit_hosts(void) 488 { 489 class_unregister(&shost_class); 490 } 491 492 int scsi_is_host_device(const struct device *dev) 493 { 494 return dev->release == scsi_host_dev_release; 495 } 496 EXPORT_SYMBOL(scsi_is_host_device); 497 498 /** 499 * scsi_queue_work - Queue work to the Scsi_Host workqueue. 500 * @shost: Pointer to Scsi_Host. 501 * @work: Work to queue for execution. 502 * 503 * Return value: 504 * 1 - work queued for execution 505 * 0 - work is already queued 506 * -EINVAL - work queue doesn't exist 507 **/ 508 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work) 509 { 510 if (unlikely(!shost->work_q)) { 511 printk(KERN_ERR 512 "ERROR: Scsi host '%s' attempted to queue scsi-work, " 513 "when no workqueue created.\n", shost->hostt->name); 514 dump_stack(); 515 516 return -EINVAL; 517 } 518 519 return queue_work(shost->work_q, work); 520 } 521 EXPORT_SYMBOL_GPL(scsi_queue_work); 522 523 /** 524 * scsi_flush_work - Flush a Scsi_Host's workqueue. 525 * @shost: Pointer to Scsi_Host. 526 **/ 527 void scsi_flush_work(struct Scsi_Host *shost) 528 { 529 if (!shost->work_q) { 530 printk(KERN_ERR 531 "ERROR: Scsi host '%s' attempted to flush scsi-work, " 532 "when no workqueue created.\n", shost->hostt->name); 533 dump_stack(); 534 return; 535 } 536 537 flush_workqueue(shost->work_q); 538 } 539 EXPORT_SYMBOL_GPL(scsi_flush_work); 540