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 shost->use_sg_chaining = sht->use_sg_chaining; 346 347 if (sht->supported_mode == MODE_UNKNOWN) 348 /* means we didn't set it ... default to INITIATOR */ 349 shost->active_mode = MODE_INITIATOR; 350 else 351 shost->active_mode = sht->supported_mode; 352 353 if (sht->max_host_blocked) 354 shost->max_host_blocked = sht->max_host_blocked; 355 else 356 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED; 357 358 /* 359 * If the driver imposes no hard sector transfer limit, start at 360 * machine infinity initially. 361 */ 362 if (sht->max_sectors) 363 shost->max_sectors = sht->max_sectors; 364 else 365 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS; 366 367 /* 368 * assume a 4GB boundary, if not set 369 */ 370 if (sht->dma_boundary) 371 shost->dma_boundary = sht->dma_boundary; 372 else 373 shost->dma_boundary = 0xffffffff; 374 375 rval = scsi_setup_command_freelist(shost); 376 if (rval) 377 goto fail_kfree; 378 379 device_initialize(&shost->shost_gendev); 380 snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d", 381 shost->host_no); 382 shost->shost_gendev.release = scsi_host_dev_release; 383 384 class_device_initialize(&shost->shost_classdev); 385 shost->shost_classdev.dev = &shost->shost_gendev; 386 shost->shost_classdev.class = &shost_class; 387 snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d", 388 shost->host_no); 389 390 shost->ehandler = kthread_run(scsi_error_handler, shost, 391 "scsi_eh_%d", shost->host_no); 392 if (IS_ERR(shost->ehandler)) { 393 rval = PTR_ERR(shost->ehandler); 394 goto fail_destroy_freelist; 395 } 396 397 scsi_proc_hostdir_add(shost->hostt); 398 return shost; 399 400 fail_destroy_freelist: 401 scsi_destroy_command_freelist(shost); 402 fail_kfree: 403 kfree(shost); 404 return NULL; 405 } 406 EXPORT_SYMBOL(scsi_host_alloc); 407 408 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize) 409 { 410 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize); 411 412 if (!sht->detect) { 413 printk(KERN_WARNING "scsi_register() called on new-style " 414 "template for driver %s\n", sht->name); 415 dump_stack(); 416 } 417 418 if (shost) 419 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts); 420 return shost; 421 } 422 EXPORT_SYMBOL(scsi_register); 423 424 void scsi_unregister(struct Scsi_Host *shost) 425 { 426 list_del(&shost->sht_legacy_list); 427 scsi_host_put(shost); 428 } 429 EXPORT_SYMBOL(scsi_unregister); 430 431 static int __scsi_host_match(struct class_device *cdev, void *data) 432 { 433 struct Scsi_Host *p; 434 unsigned short *hostnum = (unsigned short *)data; 435 436 p = class_to_shost(cdev); 437 return p->host_no == *hostnum; 438 } 439 440 /** 441 * scsi_host_lookup - get a reference to a Scsi_Host by host no 442 * @hostnum: host number to locate 443 * 444 * Return value: 445 * A pointer to located Scsi_Host or NULL. 446 **/ 447 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum) 448 { 449 struct class_device *cdev; 450 struct Scsi_Host *shost = ERR_PTR(-ENXIO); 451 452 cdev = class_find_child(&shost_class, &hostnum, __scsi_host_match); 453 if (cdev) 454 shost = scsi_host_get(class_to_shost(cdev)); 455 456 return shost; 457 } 458 EXPORT_SYMBOL(scsi_host_lookup); 459 460 /** 461 * scsi_host_get - inc a Scsi_Host ref count 462 * @shost: Pointer to Scsi_Host to inc. 463 **/ 464 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost) 465 { 466 if ((shost->shost_state == SHOST_DEL) || 467 !get_device(&shost->shost_gendev)) 468 return NULL; 469 return shost; 470 } 471 EXPORT_SYMBOL(scsi_host_get); 472 473 /** 474 * scsi_host_put - dec a Scsi_Host ref count 475 * @shost: Pointer to Scsi_Host to dec. 476 **/ 477 void scsi_host_put(struct Scsi_Host *shost) 478 { 479 put_device(&shost->shost_gendev); 480 } 481 EXPORT_SYMBOL(scsi_host_put); 482 483 int scsi_init_hosts(void) 484 { 485 return class_register(&shost_class); 486 } 487 488 void scsi_exit_hosts(void) 489 { 490 class_unregister(&shost_class); 491 } 492 493 int scsi_is_host_device(const struct device *dev) 494 { 495 return dev->release == scsi_host_dev_release; 496 } 497 EXPORT_SYMBOL(scsi_is_host_device); 498 499 /** 500 * scsi_queue_work - Queue work to the Scsi_Host workqueue. 501 * @shost: Pointer to Scsi_Host. 502 * @work: Work to queue for execution. 503 * 504 * Return value: 505 * 1 - work queued for execution 506 * 0 - work is already queued 507 * -EINVAL - work queue doesn't exist 508 **/ 509 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work) 510 { 511 if (unlikely(!shost->work_q)) { 512 printk(KERN_ERR 513 "ERROR: Scsi host '%s' attempted to queue scsi-work, " 514 "when no workqueue created.\n", shost->hostt->name); 515 dump_stack(); 516 517 return -EINVAL; 518 } 519 520 return queue_work(shost->work_q, work); 521 } 522 EXPORT_SYMBOL_GPL(scsi_queue_work); 523 524 /** 525 * scsi_flush_work - Flush a Scsi_Host's workqueue. 526 * @shost: Pointer to Scsi_Host. 527 **/ 528 void scsi_flush_work(struct Scsi_Host *shost) 529 { 530 if (!shost->work_q) { 531 printk(KERN_ERR 532 "ERROR: Scsi host '%s' attempted to flush scsi-work, " 533 "when no workqueue created.\n", shost->hostt->name); 534 dump_stack(); 535 return; 536 } 537 538 flush_workqueue(shost->work_q); 539 } 540 EXPORT_SYMBOL_GPL(scsi_flush_work); 541