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); 224 if (shost->shost_data == NULL) { 225 error = -ENOMEM; 226 goto out_del_classdev; 227 } 228 } 229 230 if (shost->transportt->create_work_queue) { 231 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d", 232 shost->host_no); 233 shost->work_q = create_singlethread_workqueue( 234 shost->work_q_name); 235 if (!shost->work_q) { 236 error = -EINVAL; 237 goto out_free_shost_data; 238 } 239 } 240 241 error = scsi_sysfs_add_host(shost); 242 if (error) 243 goto out_destroy_host; 244 245 scsi_proc_host_add(shost); 246 return error; 247 248 out_destroy_host: 249 if (shost->work_q) 250 destroy_workqueue(shost->work_q); 251 out_free_shost_data: 252 kfree(shost->shost_data); 253 out_del_classdev: 254 class_device_del(&shost->shost_classdev); 255 out_del_gendev: 256 device_del(&shost->shost_gendev); 257 out: 258 return error; 259 } 260 EXPORT_SYMBOL(scsi_add_host); 261 262 static void scsi_host_dev_release(struct device *dev) 263 { 264 struct Scsi_Host *shost = dev_to_shost(dev); 265 struct device *parent = dev->parent; 266 267 if (shost->ehandler) 268 kthread_stop(shost->ehandler); 269 if (shost->work_q) 270 destroy_workqueue(shost->work_q); 271 if (shost->uspace_req_q) { 272 kfree(shost->uspace_req_q->queuedata); 273 scsi_free_queue(shost->uspace_req_q); 274 } 275 276 scsi_destroy_command_freelist(shost); 277 if (shost->bqt) 278 blk_free_tags(shost->bqt); 279 280 kfree(shost->shost_data); 281 282 if (parent) 283 put_device(parent); 284 kfree(shost); 285 } 286 287 /** 288 * scsi_host_alloc - register a scsi host adapter instance. 289 * @sht: pointer to scsi host template 290 * @privsize: extra bytes to allocate for driver 291 * 292 * Note: 293 * Allocate a new Scsi_Host and perform basic initialization. 294 * The host is not published to the scsi midlayer until scsi_add_host 295 * is called. 296 * 297 * Return value: 298 * Pointer to a new Scsi_Host 299 **/ 300 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) 301 { 302 struct Scsi_Host *shost; 303 gfp_t gfp_mask = GFP_KERNEL; 304 int rval; 305 306 if (sht->unchecked_isa_dma && privsize) 307 gfp_mask |= __GFP_DMA; 308 309 shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask); 310 if (!shost) 311 return NULL; 312 313 shost->host_lock = &shost->default_lock; 314 spin_lock_init(shost->host_lock); 315 shost->shost_state = SHOST_CREATED; 316 INIT_LIST_HEAD(&shost->__devices); 317 INIT_LIST_HEAD(&shost->__targets); 318 INIT_LIST_HEAD(&shost->eh_cmd_q); 319 INIT_LIST_HEAD(&shost->starved_list); 320 init_waitqueue_head(&shost->host_wait); 321 322 mutex_init(&shost->scan_mutex); 323 324 shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */ 325 shost->dma_channel = 0xff; 326 327 /* These three are default values which can be overridden */ 328 shost->max_channel = 0; 329 shost->max_id = 8; 330 shost->max_lun = 8; 331 332 /* Give each shost a default transportt */ 333 shost->transportt = &blank_transport_template; 334 335 /* 336 * All drivers right now should be able to handle 12 byte 337 * commands. Every so often there are requests for 16 byte 338 * commands, but individual low-level drivers need to certify that 339 * they actually do something sensible with such commands. 340 */ 341 shost->max_cmd_len = 12; 342 shost->hostt = sht; 343 shost->this_id = sht->this_id; 344 shost->can_queue = sht->can_queue; 345 shost->sg_tablesize = sht->sg_tablesize; 346 shost->cmd_per_lun = sht->cmd_per_lun; 347 shost->unchecked_isa_dma = sht->unchecked_isa_dma; 348 shost->use_clustering = sht->use_clustering; 349 shost->ordered_tag = sht->ordered_tag; 350 351 if (sht->supported_mode == MODE_UNKNOWN) 352 /* means we didn't set it ... default to INITIATOR */ 353 shost->active_mode = MODE_INITIATOR; 354 else 355 shost->active_mode = sht->supported_mode; 356 357 if (sht->max_host_blocked) 358 shost->max_host_blocked = sht->max_host_blocked; 359 else 360 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED; 361 362 /* 363 * If the driver imposes no hard sector transfer limit, start at 364 * machine infinity initially. 365 */ 366 if (sht->max_sectors) 367 shost->max_sectors = sht->max_sectors; 368 else 369 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS; 370 371 /* 372 * assume a 4GB boundary, if not set 373 */ 374 if (sht->dma_boundary) 375 shost->dma_boundary = sht->dma_boundary; 376 else 377 shost->dma_boundary = 0xffffffff; 378 379 rval = scsi_setup_command_freelist(shost); 380 if (rval) 381 goto fail_kfree; 382 383 device_initialize(&shost->shost_gendev); 384 snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d", 385 shost->host_no); 386 shost->shost_gendev.release = scsi_host_dev_release; 387 388 class_device_initialize(&shost->shost_classdev); 389 shost->shost_classdev.dev = &shost->shost_gendev; 390 shost->shost_classdev.class = &shost_class; 391 snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d", 392 shost->host_no); 393 394 shost->ehandler = kthread_run(scsi_error_handler, shost, 395 "scsi_eh_%d", shost->host_no); 396 if (IS_ERR(shost->ehandler)) { 397 rval = PTR_ERR(shost->ehandler); 398 goto fail_destroy_freelist; 399 } 400 401 scsi_proc_hostdir_add(shost->hostt); 402 return shost; 403 404 fail_destroy_freelist: 405 scsi_destroy_command_freelist(shost); 406 fail_kfree: 407 kfree(shost); 408 return NULL; 409 } 410 EXPORT_SYMBOL(scsi_host_alloc); 411 412 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize) 413 { 414 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize); 415 416 if (!sht->detect) { 417 printk(KERN_WARNING "scsi_register() called on new-style " 418 "template for driver %s\n", sht->name); 419 dump_stack(); 420 } 421 422 if (shost) 423 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts); 424 return shost; 425 } 426 EXPORT_SYMBOL(scsi_register); 427 428 void scsi_unregister(struct Scsi_Host *shost) 429 { 430 list_del(&shost->sht_legacy_list); 431 scsi_host_put(shost); 432 } 433 EXPORT_SYMBOL(scsi_unregister); 434 435 static int __scsi_host_match(struct class_device *cdev, void *data) 436 { 437 struct Scsi_Host *p; 438 unsigned short *hostnum = (unsigned short *)data; 439 440 p = class_to_shost(cdev); 441 return p->host_no == *hostnum; 442 } 443 444 /** 445 * scsi_host_lookup - get a reference to a Scsi_Host by host no 446 * @hostnum: host number to locate 447 * 448 * Return value: 449 * A pointer to located Scsi_Host or NULL. 450 **/ 451 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum) 452 { 453 struct class_device *cdev; 454 struct Scsi_Host *shost = ERR_PTR(-ENXIO); 455 456 cdev = class_find_child(&shost_class, &hostnum, __scsi_host_match); 457 if (cdev) 458 shost = scsi_host_get(class_to_shost(cdev)); 459 460 return shost; 461 } 462 EXPORT_SYMBOL(scsi_host_lookup); 463 464 /** 465 * scsi_host_get - inc a Scsi_Host ref count 466 * @shost: Pointer to Scsi_Host to inc. 467 **/ 468 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost) 469 { 470 if ((shost->shost_state == SHOST_DEL) || 471 !get_device(&shost->shost_gendev)) 472 return NULL; 473 return shost; 474 } 475 EXPORT_SYMBOL(scsi_host_get); 476 477 /** 478 * scsi_host_put - dec a Scsi_Host ref count 479 * @shost: Pointer to Scsi_Host to dec. 480 **/ 481 void scsi_host_put(struct Scsi_Host *shost) 482 { 483 put_device(&shost->shost_gendev); 484 } 485 EXPORT_SYMBOL(scsi_host_put); 486 487 int scsi_init_hosts(void) 488 { 489 return class_register(&shost_class); 490 } 491 492 void scsi_exit_hosts(void) 493 { 494 class_unregister(&shost_class); 495 } 496 497 int scsi_is_host_device(const struct device *dev) 498 { 499 return dev->release == scsi_host_dev_release; 500 } 501 EXPORT_SYMBOL(scsi_is_host_device); 502 503 /** 504 * scsi_queue_work - Queue work to the Scsi_Host workqueue. 505 * @shost: Pointer to Scsi_Host. 506 * @work: Work to queue for execution. 507 * 508 * Return value: 509 * 1 - work queued for execution 510 * 0 - work is already queued 511 * -EINVAL - work queue doesn't exist 512 **/ 513 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work) 514 { 515 if (unlikely(!shost->work_q)) { 516 printk(KERN_ERR 517 "ERROR: Scsi host '%s' attempted to queue scsi-work, " 518 "when no workqueue created.\n", shost->hostt->name); 519 dump_stack(); 520 521 return -EINVAL; 522 } 523 524 return queue_work(shost->work_q, work); 525 } 526 EXPORT_SYMBOL_GPL(scsi_queue_work); 527 528 /** 529 * scsi_flush_work - Flush a Scsi_Host's workqueue. 530 * @shost: Pointer to Scsi_Host. 531 **/ 532 void scsi_flush_work(struct Scsi_Host *shost) 533 { 534 if (!shost->work_q) { 535 printk(KERN_ERR 536 "ERROR: Scsi host '%s' attempted to flush scsi-work, " 537 "when no workqueue created.\n", shost->hostt->name); 538 dump_stack(); 539 return; 540 } 541 542 flush_workqueue(shost->work_q); 543 } 544 EXPORT_SYMBOL_GPL(scsi_flush_work); 545