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/string.h> 28 #include <linux/mm.h> 29 #include <linux/init.h> 30 #include <linux/completion.h> 31 #include <linux/transport_class.h> 32 33 #include <scsi/scsi_device.h> 34 #include <scsi/scsi_host.h> 35 #include <scsi/scsi_transport.h> 36 37 #include "scsi_priv.h" 38 #include "scsi_logging.h" 39 40 41 static int scsi_host_next_hn; /* host_no for next new host */ 42 43 44 static void scsi_host_cls_release(struct class_device *class_dev) 45 { 46 put_device(&class_to_shost(class_dev)->shost_gendev); 47 } 48 49 static struct class shost_class = { 50 .name = "scsi_host", 51 .release = scsi_host_cls_release, 52 }; 53 54 /** 55 * scsi_host_cancel - cancel outstanding IO to this host 56 * @shost: pointer to struct Scsi_Host 57 * recovery: recovery requested to run. 58 **/ 59 static void scsi_host_cancel(struct Scsi_Host *shost, int recovery) 60 { 61 struct scsi_device *sdev; 62 63 set_bit(SHOST_CANCEL, &shost->shost_state); 64 shost_for_each_device(sdev, shost) { 65 scsi_device_cancel(sdev, recovery); 66 } 67 wait_event(shost->host_wait, (!test_bit(SHOST_RECOVERY, 68 &shost->shost_state))); 69 } 70 71 /** 72 * scsi_remove_host - remove a scsi host 73 * @shost: a pointer to a scsi host to remove 74 **/ 75 void scsi_remove_host(struct Scsi_Host *shost) 76 { 77 scsi_forget_host(shost); 78 scsi_host_cancel(shost, 0); 79 scsi_proc_host_rm(shost); 80 81 set_bit(SHOST_DEL, &shost->shost_state); 82 83 transport_unregister_device(&shost->shost_gendev); 84 class_device_unregister(&shost->shost_classdev); 85 device_del(&shost->shost_gendev); 86 } 87 EXPORT_SYMBOL(scsi_remove_host); 88 89 /** 90 * scsi_add_host - add a scsi host 91 * @shost: scsi host pointer to add 92 * @dev: a struct device of type scsi class 93 * 94 * Return value: 95 * 0 on success / != 0 for error 96 **/ 97 int scsi_add_host(struct Scsi_Host *shost, struct device *dev) 98 { 99 struct scsi_host_template *sht = shost->hostt; 100 int error = -EINVAL; 101 102 printk(KERN_INFO "scsi%d : %s\n", shost->host_no, 103 sht->info ? sht->info(shost) : sht->name); 104 105 if (!shost->can_queue) { 106 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n", 107 sht->name); 108 goto out; 109 } 110 111 if (!shost->shost_gendev.parent) 112 shost->shost_gendev.parent = dev ? dev : &platform_bus; 113 114 error = device_add(&shost->shost_gendev); 115 if (error) 116 goto out; 117 118 set_bit(SHOST_ADD, &shost->shost_state); 119 get_device(shost->shost_gendev.parent); 120 121 error = class_device_add(&shost->shost_classdev); 122 if (error) 123 goto out_del_gendev; 124 125 get_device(&shost->shost_gendev); 126 127 if (shost->transportt->host_size && 128 (shost->shost_data = kmalloc(shost->transportt->host_size, 129 GFP_KERNEL)) == NULL) 130 goto out_del_classdev; 131 132 if (shost->transportt->create_work_queue) { 133 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d", 134 shost->host_no); 135 shost->work_q = create_singlethread_workqueue( 136 shost->work_q_name); 137 if (!shost->work_q) 138 goto out_free_shost_data; 139 } 140 141 error = scsi_sysfs_add_host(shost); 142 if (error) 143 goto out_destroy_host; 144 145 scsi_proc_host_add(shost); 146 return error; 147 148 out_destroy_host: 149 if (shost->work_q) 150 destroy_workqueue(shost->work_q); 151 out_free_shost_data: 152 kfree(shost->shost_data); 153 out_del_classdev: 154 class_device_del(&shost->shost_classdev); 155 out_del_gendev: 156 device_del(&shost->shost_gendev); 157 out: 158 return error; 159 } 160 EXPORT_SYMBOL(scsi_add_host); 161 162 static void scsi_host_dev_release(struct device *dev) 163 { 164 struct Scsi_Host *shost = dev_to_shost(dev); 165 struct device *parent = dev->parent; 166 167 if (shost->ehandler) { 168 DECLARE_COMPLETION(sem); 169 shost->eh_notify = &sem; 170 shost->eh_kill = 1; 171 up(shost->eh_wait); 172 wait_for_completion(&sem); 173 shost->eh_notify = NULL; 174 } 175 176 if (shost->work_q) 177 destroy_workqueue(shost->work_q); 178 179 scsi_proc_hostdir_rm(shost->hostt); 180 scsi_destroy_command_freelist(shost); 181 kfree(shost->shost_data); 182 183 /* 184 * Some drivers (eg aha1542) do scsi_register()/scsi_unregister() 185 * during probing without performing a scsi_set_device() in between. 186 * In this case dev->parent is NULL. 187 */ 188 if (parent) 189 put_device(parent); 190 kfree(shost); 191 } 192 193 /** 194 * scsi_host_alloc - register a scsi host adapter instance. 195 * @sht: pointer to scsi host template 196 * @privsize: extra bytes to allocate for driver 197 * 198 * Note: 199 * Allocate a new Scsi_Host and perform basic initialization. 200 * The host is not published to the scsi midlayer until scsi_add_host 201 * is called. 202 * 203 * Return value: 204 * Pointer to a new Scsi_Host 205 **/ 206 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) 207 { 208 struct Scsi_Host *shost; 209 int gfp_mask = GFP_KERNEL, rval; 210 DECLARE_COMPLETION(complete); 211 212 if (sht->unchecked_isa_dma && privsize) 213 gfp_mask |= __GFP_DMA; 214 215 /* Check to see if this host has any error handling facilities */ 216 if (!sht->eh_strategy_handler && !sht->eh_abort_handler && 217 !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler && 218 !sht->eh_host_reset_handler) { 219 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n" 220 "ERROR: This is not a safe way to run your " 221 "SCSI host\n" 222 "ERROR: The error handling must be added to " 223 "this driver\n", sht->proc_name); 224 dump_stack(); 225 } 226 227 shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask); 228 if (!shost) 229 return NULL; 230 memset(shost, 0, sizeof(struct Scsi_Host) + privsize); 231 232 spin_lock_init(&shost->default_lock); 233 scsi_assign_lock(shost, &shost->default_lock); 234 INIT_LIST_HEAD(&shost->__devices); 235 INIT_LIST_HEAD(&shost->__targets); 236 INIT_LIST_HEAD(&shost->eh_cmd_q); 237 INIT_LIST_HEAD(&shost->starved_list); 238 init_waitqueue_head(&shost->host_wait); 239 240 init_MUTEX(&shost->scan_mutex); 241 242 shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */ 243 shost->dma_channel = 0xff; 244 245 /* These three are default values which can be overridden */ 246 shost->max_channel = 0; 247 shost->max_id = 8; 248 shost->max_lun = 8; 249 250 /* Give each shost a default transportt */ 251 shost->transportt = &blank_transport_template; 252 253 /* 254 * All drivers right now should be able to handle 12 byte 255 * commands. Every so often there are requests for 16 byte 256 * commands, but individual low-level drivers need to certify that 257 * they actually do something sensible with such commands. 258 */ 259 shost->max_cmd_len = 12; 260 shost->hostt = sht; 261 shost->this_id = sht->this_id; 262 shost->can_queue = sht->can_queue; 263 shost->sg_tablesize = sht->sg_tablesize; 264 shost->cmd_per_lun = sht->cmd_per_lun; 265 shost->unchecked_isa_dma = sht->unchecked_isa_dma; 266 shost->use_clustering = sht->use_clustering; 267 shost->ordered_flush = sht->ordered_flush; 268 shost->ordered_tag = sht->ordered_tag; 269 270 /* 271 * hosts/devices that do queueing must support ordered tags 272 */ 273 if (shost->can_queue > 1 && shost->ordered_flush) { 274 printk(KERN_ERR "scsi: ordered flushes don't support queueing\n"); 275 shost->ordered_flush = 0; 276 } 277 278 if (sht->max_host_blocked) 279 shost->max_host_blocked = sht->max_host_blocked; 280 else 281 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED; 282 283 /* 284 * If the driver imposes no hard sector transfer limit, start at 285 * machine infinity initially. 286 */ 287 if (sht->max_sectors) 288 shost->max_sectors = sht->max_sectors; 289 else 290 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS; 291 292 /* 293 * assume a 4GB boundary, if not set 294 */ 295 if (sht->dma_boundary) 296 shost->dma_boundary = sht->dma_boundary; 297 else 298 shost->dma_boundary = 0xffffffff; 299 300 rval = scsi_setup_command_freelist(shost); 301 if (rval) 302 goto fail_kfree; 303 304 device_initialize(&shost->shost_gendev); 305 snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d", 306 shost->host_no); 307 shost->shost_gendev.release = scsi_host_dev_release; 308 309 class_device_initialize(&shost->shost_classdev); 310 shost->shost_classdev.dev = &shost->shost_gendev; 311 shost->shost_classdev.class = &shost_class; 312 snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d", 313 shost->host_no); 314 315 shost->eh_notify = &complete; 316 rval = kernel_thread(scsi_error_handler, shost, 0); 317 if (rval < 0) 318 goto fail_destroy_freelist; 319 wait_for_completion(&complete); 320 shost->eh_notify = NULL; 321 322 scsi_proc_hostdir_add(shost->hostt); 323 return shost; 324 325 fail_destroy_freelist: 326 scsi_destroy_command_freelist(shost); 327 fail_kfree: 328 kfree(shost); 329 return NULL; 330 } 331 EXPORT_SYMBOL(scsi_host_alloc); 332 333 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize) 334 { 335 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize); 336 337 if (!sht->detect) { 338 printk(KERN_WARNING "scsi_register() called on new-style " 339 "template for driver %s\n", sht->name); 340 dump_stack(); 341 } 342 343 if (shost) 344 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts); 345 return shost; 346 } 347 EXPORT_SYMBOL(scsi_register); 348 349 void scsi_unregister(struct Scsi_Host *shost) 350 { 351 list_del(&shost->sht_legacy_list); 352 scsi_host_put(shost); 353 } 354 EXPORT_SYMBOL(scsi_unregister); 355 356 /** 357 * scsi_host_lookup - get a reference to a Scsi_Host by host no 358 * 359 * @hostnum: host number to locate 360 * 361 * Return value: 362 * A pointer to located Scsi_Host or NULL. 363 **/ 364 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum) 365 { 366 struct class *class = &shost_class; 367 struct class_device *cdev; 368 struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p; 369 370 down_read(&class->subsys.rwsem); 371 list_for_each_entry(cdev, &class->children, node) { 372 p = class_to_shost(cdev); 373 if (p->host_no == hostnum) { 374 shost = scsi_host_get(p); 375 break; 376 } 377 } 378 up_read(&class->subsys.rwsem); 379 380 return shost; 381 } 382 EXPORT_SYMBOL(scsi_host_lookup); 383 384 /** 385 * scsi_host_get - inc a Scsi_Host ref count 386 * @shost: Pointer to Scsi_Host to inc. 387 **/ 388 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost) 389 { 390 if (test_bit(SHOST_DEL, &shost->shost_state) || 391 !get_device(&shost->shost_gendev)) 392 return NULL; 393 return shost; 394 } 395 EXPORT_SYMBOL(scsi_host_get); 396 397 /** 398 * scsi_host_put - dec a Scsi_Host ref count 399 * @shost: Pointer to Scsi_Host to dec. 400 **/ 401 void scsi_host_put(struct Scsi_Host *shost) 402 { 403 put_device(&shost->shost_gendev); 404 } 405 EXPORT_SYMBOL(scsi_host_put); 406 407 int scsi_init_hosts(void) 408 { 409 return class_register(&shost_class); 410 } 411 412 void scsi_exit_hosts(void) 413 { 414 class_unregister(&shost_class); 415 } 416 417 int scsi_is_host_device(const struct device *dev) 418 { 419 return dev->release == scsi_host_dev_release; 420 } 421 EXPORT_SYMBOL(scsi_is_host_device); 422 423 /** 424 * scsi_queue_work - Queue work to the Scsi_Host workqueue. 425 * @shost: Pointer to Scsi_Host. 426 * @work: Work to queue for execution. 427 * 428 * Return value: 429 * 0 on success / != 0 for error 430 **/ 431 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work) 432 { 433 if (unlikely(!shost->work_q)) { 434 printk(KERN_ERR 435 "ERROR: Scsi host '%s' attempted to queue scsi-work, " 436 "when no workqueue created.\n", shost->hostt->name); 437 dump_stack(); 438 439 return -EINVAL; 440 } 441 442 return queue_work(shost->work_q, work); 443 } 444 EXPORT_SYMBOL_GPL(scsi_queue_work); 445 446 /** 447 * scsi_flush_work - Flush a Scsi_Host's workqueue. 448 * @shost: Pointer to Scsi_Host. 449 **/ 450 void scsi_flush_work(struct Scsi_Host *shost) 451 { 452 if (!shost->work_q) { 453 printk(KERN_ERR 454 "ERROR: Scsi host '%s' attempted to flush scsi-work, " 455 "when no workqueue created.\n", shost->hostt->name); 456 dump_stack(); 457 return; 458 } 459 460 flush_workqueue(shost->work_q); 461 } 462 EXPORT_SYMBOL_GPL(scsi_flush_work); 463