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 if (parent) 184 put_device(parent); 185 kfree(shost); 186 } 187 188 /** 189 * scsi_host_alloc - register a scsi host adapter instance. 190 * @sht: pointer to scsi host template 191 * @privsize: extra bytes to allocate for driver 192 * 193 * Note: 194 * Allocate a new Scsi_Host and perform basic initialization. 195 * The host is not published to the scsi midlayer until scsi_add_host 196 * is called. 197 * 198 * Return value: 199 * Pointer to a new Scsi_Host 200 **/ 201 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) 202 { 203 struct Scsi_Host *shost; 204 int gfp_mask = GFP_KERNEL, rval; 205 DECLARE_COMPLETION(complete); 206 207 if (sht->unchecked_isa_dma && privsize) 208 gfp_mask |= __GFP_DMA; 209 210 /* Check to see if this host has any error handling facilities */ 211 if (!sht->eh_strategy_handler && !sht->eh_abort_handler && 212 !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler && 213 !sht->eh_host_reset_handler) { 214 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n" 215 "ERROR: This is not a safe way to run your " 216 "SCSI host\n" 217 "ERROR: The error handling must be added to " 218 "this driver\n", sht->proc_name); 219 dump_stack(); 220 } 221 222 shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask); 223 if (!shost) 224 return NULL; 225 memset(shost, 0, sizeof(struct Scsi_Host) + privsize); 226 227 spin_lock_init(&shost->default_lock); 228 scsi_assign_lock(shost, &shost->default_lock); 229 INIT_LIST_HEAD(&shost->__devices); 230 INIT_LIST_HEAD(&shost->__targets); 231 INIT_LIST_HEAD(&shost->eh_cmd_q); 232 INIT_LIST_HEAD(&shost->starved_list); 233 init_waitqueue_head(&shost->host_wait); 234 235 init_MUTEX(&shost->scan_mutex); 236 237 shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */ 238 shost->dma_channel = 0xff; 239 240 /* These three are default values which can be overridden */ 241 shost->max_channel = 0; 242 shost->max_id = 8; 243 shost->max_lun = 8; 244 245 /* Give each shost a default transportt */ 246 shost->transportt = &blank_transport_template; 247 248 /* 249 * All drivers right now should be able to handle 12 byte 250 * commands. Every so often there are requests for 16 byte 251 * commands, but individual low-level drivers need to certify that 252 * they actually do something sensible with such commands. 253 */ 254 shost->max_cmd_len = 12; 255 shost->hostt = sht; 256 shost->this_id = sht->this_id; 257 shost->can_queue = sht->can_queue; 258 shost->sg_tablesize = sht->sg_tablesize; 259 shost->cmd_per_lun = sht->cmd_per_lun; 260 shost->unchecked_isa_dma = sht->unchecked_isa_dma; 261 shost->use_clustering = sht->use_clustering; 262 shost->ordered_flush = sht->ordered_flush; 263 shost->ordered_tag = sht->ordered_tag; 264 265 /* 266 * hosts/devices that do queueing must support ordered tags 267 */ 268 if (shost->can_queue > 1 && shost->ordered_flush) { 269 printk(KERN_ERR "scsi: ordered flushes don't support queueing\n"); 270 shost->ordered_flush = 0; 271 } 272 273 if (sht->max_host_blocked) 274 shost->max_host_blocked = sht->max_host_blocked; 275 else 276 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED; 277 278 /* 279 * If the driver imposes no hard sector transfer limit, start at 280 * machine infinity initially. 281 */ 282 if (sht->max_sectors) 283 shost->max_sectors = sht->max_sectors; 284 else 285 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS; 286 287 /* 288 * assume a 4GB boundary, if not set 289 */ 290 if (sht->dma_boundary) 291 shost->dma_boundary = sht->dma_boundary; 292 else 293 shost->dma_boundary = 0xffffffff; 294 295 rval = scsi_setup_command_freelist(shost); 296 if (rval) 297 goto fail_kfree; 298 299 device_initialize(&shost->shost_gendev); 300 snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d", 301 shost->host_no); 302 shost->shost_gendev.release = scsi_host_dev_release; 303 304 class_device_initialize(&shost->shost_classdev); 305 shost->shost_classdev.dev = &shost->shost_gendev; 306 shost->shost_classdev.class = &shost_class; 307 snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d", 308 shost->host_no); 309 310 shost->eh_notify = &complete; 311 rval = kernel_thread(scsi_error_handler, shost, 0); 312 if (rval < 0) 313 goto fail_destroy_freelist; 314 wait_for_completion(&complete); 315 shost->eh_notify = NULL; 316 317 scsi_proc_hostdir_add(shost->hostt); 318 return shost; 319 320 fail_destroy_freelist: 321 scsi_destroy_command_freelist(shost); 322 fail_kfree: 323 kfree(shost); 324 return NULL; 325 } 326 EXPORT_SYMBOL(scsi_host_alloc); 327 328 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize) 329 { 330 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize); 331 332 if (!sht->detect) { 333 printk(KERN_WARNING "scsi_register() called on new-style " 334 "template for driver %s\n", sht->name); 335 dump_stack(); 336 } 337 338 if (shost) 339 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts); 340 return shost; 341 } 342 EXPORT_SYMBOL(scsi_register); 343 344 void scsi_unregister(struct Scsi_Host *shost) 345 { 346 list_del(&shost->sht_legacy_list); 347 scsi_host_put(shost); 348 } 349 EXPORT_SYMBOL(scsi_unregister); 350 351 /** 352 * scsi_host_lookup - get a reference to a Scsi_Host by host no 353 * 354 * @hostnum: host number to locate 355 * 356 * Return value: 357 * A pointer to located Scsi_Host or NULL. 358 **/ 359 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum) 360 { 361 struct class *class = &shost_class; 362 struct class_device *cdev; 363 struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p; 364 365 down_read(&class->subsys.rwsem); 366 list_for_each_entry(cdev, &class->children, node) { 367 p = class_to_shost(cdev); 368 if (p->host_no == hostnum) { 369 shost = scsi_host_get(p); 370 break; 371 } 372 } 373 up_read(&class->subsys.rwsem); 374 375 return shost; 376 } 377 EXPORT_SYMBOL(scsi_host_lookup); 378 379 /** 380 * scsi_host_get - inc a Scsi_Host ref count 381 * @shost: Pointer to Scsi_Host to inc. 382 **/ 383 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost) 384 { 385 if (test_bit(SHOST_DEL, &shost->shost_state) || 386 !get_device(&shost->shost_gendev)) 387 return NULL; 388 return shost; 389 } 390 EXPORT_SYMBOL(scsi_host_get); 391 392 /** 393 * scsi_host_put - dec a Scsi_Host ref count 394 * @shost: Pointer to Scsi_Host to dec. 395 **/ 396 void scsi_host_put(struct Scsi_Host *shost) 397 { 398 put_device(&shost->shost_gendev); 399 } 400 EXPORT_SYMBOL(scsi_host_put); 401 402 int scsi_init_hosts(void) 403 { 404 return class_register(&shost_class); 405 } 406 407 void scsi_exit_hosts(void) 408 { 409 class_unregister(&shost_class); 410 } 411 412 int scsi_is_host_device(const struct device *dev) 413 { 414 return dev->release == scsi_host_dev_release; 415 } 416 EXPORT_SYMBOL(scsi_is_host_device); 417 418 /** 419 * scsi_queue_work - Queue work to the Scsi_Host workqueue. 420 * @shost: Pointer to Scsi_Host. 421 * @work: Work to queue for execution. 422 * 423 * Return value: 424 * 0 on success / != 0 for error 425 **/ 426 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work) 427 { 428 if (unlikely(!shost->work_q)) { 429 printk(KERN_ERR 430 "ERROR: Scsi host '%s' attempted to queue scsi-work, " 431 "when no workqueue created.\n", shost->hostt->name); 432 dump_stack(); 433 434 return -EINVAL; 435 } 436 437 return queue_work(shost->work_q, work); 438 } 439 EXPORT_SYMBOL_GPL(scsi_queue_work); 440 441 /** 442 * scsi_flush_work - Flush a Scsi_Host's workqueue. 443 * @shost: Pointer to Scsi_Host. 444 **/ 445 void scsi_flush_work(struct Scsi_Host *shost) 446 { 447 if (!shost->work_q) { 448 printk(KERN_ERR 449 "ERROR: Scsi host '%s' attempted to flush scsi-work, " 450 "when no workqueue created.\n", shost->hostt->name); 451 dump_stack(); 452 return; 453 } 454 455 flush_workqueue(shost->work_q); 456 } 457 EXPORT_SYMBOL_GPL(scsi_flush_work); 458