1#ifndef _SCSI_SCSI_HOST_H 2#define _SCSI_SCSI_HOST_H 3 4#include <linux/device.h> 5#include <linux/list.h> 6#include <linux/types.h> 7#include <linux/workqueue.h> 8#include <linux/mutex.h> 9 10struct request_queue; 11struct block_device; 12struct completion; 13struct module; 14struct scsi_cmnd; 15struct scsi_device; 16struct scsi_target; 17struct Scsi_Host; 18struct scsi_host_cmd_pool; 19struct scsi_transport_template; 20struct blk_queue_tags; 21 22 23/* 24 * The various choices mean: 25 * NONE: Self evident. Host adapter is not capable of scatter-gather. 26 * ALL: Means that the host adapter module can do scatter-gather, 27 * and that there is no limit to the size of the table to which 28 * we scatter/gather data. 29 * Anything else: Indicates the maximum number of chains that can be 30 * used in one scatter-gather request. 31 */ 32#define SG_NONE 0 33#define SG_ALL 0xff 34 35 36#define DISABLE_CLUSTERING 0 37#define ENABLE_CLUSTERING 1 38 39enum scsi_eh_timer_return { 40 EH_NOT_HANDLED, 41 EH_HANDLED, 42 EH_RESET_TIMER, 43}; 44 45 46struct scsi_host_template { 47 struct module *module; 48 const char *name; 49 50 /* 51 * Used to initialize old-style drivers. For new-style drivers 52 * just perform all work in your module initialization function. 53 * 54 * Status: OBSOLETE 55 */ 56 int (* detect)(struct scsi_host_template *); 57 58 /* 59 * Used as unload callback for hosts with old-style drivers. 60 * 61 * Status: OBSOLETE 62 */ 63 int (* release)(struct Scsi_Host *); 64 65 /* 66 * The info function will return whatever useful information the 67 * developer sees fit. If not provided, then the name field will 68 * be used instead. 69 * 70 * Status: OPTIONAL 71 */ 72 const char *(* info)(struct Scsi_Host *); 73 74 /* 75 * Ioctl interface 76 * 77 * Status: OPTIONAL 78 */ 79 int (* ioctl)(struct scsi_device *dev, int cmd, void __user *arg); 80 81 82#ifdef CONFIG_COMPAT 83 /* 84 * Compat handler. Handle 32bit ABI. 85 * When unknown ioctl is passed return -ENOIOCTLCMD. 86 * 87 * Status: OPTIONAL 88 */ 89 int (* compat_ioctl)(struct scsi_device *dev, int cmd, void __user *arg); 90#endif 91 92 /* 93 * The queuecommand function is used to queue up a scsi 94 * command block to the LLDD. When the driver finished 95 * processing the command the done callback is invoked. 96 * 97 * If queuecommand returns 0, then the HBA has accepted the 98 * command. The done() function must be called on the command 99 * when the driver has finished with it. (you may call done on the 100 * command before queuecommand returns, but in this case you 101 * *must* return 0 from queuecommand). 102 * 103 * Queuecommand may also reject the command, in which case it may 104 * not touch the command and must not call done() for it. 105 * 106 * There are two possible rejection returns: 107 * 108 * SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but 109 * allow commands to other devices serviced by this host. 110 * 111 * SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this 112 * host temporarily. 113 * 114 * For compatibility, any other non-zero return is treated the 115 * same as SCSI_MLQUEUE_HOST_BUSY. 116 * 117 * NOTE: "temporarily" means either until the next command for# 118 * this device/host completes, or a period of time determined by 119 * I/O pressure in the system if there are no other outstanding 120 * commands. 121 * 122 * STATUS: REQUIRED 123 */ 124 int (* queuecommand)(struct scsi_cmnd *, 125 void (*done)(struct scsi_cmnd *)); 126 127 /* 128 * The transfer functions are used to queue a scsi command to 129 * the LLD. When the driver is finished processing the command 130 * the done callback is invoked. 131 * 132 * This is called to inform the LLD to transfer 133 * cmd->request_bufflen bytes. The cmd->use_sg speciefies the 134 * number of scatterlist entried in the command and 135 * cmd->request_buffer contains the scatterlist. 136 * 137 * return values: see queuecommand 138 * 139 * If the LLD accepts the cmd, it should set the result to an 140 * appropriate value when completed before calling the done function. 141 * 142 * STATUS: REQUIRED FOR TARGET DRIVERS 143 */ 144 /* TODO: rename */ 145 int (* transfer_response)(struct scsi_cmnd *, 146 void (*done)(struct scsi_cmnd *)); 147 148 /* Used as callback for the completion of task management request. */ 149 int (* tsk_mgmt_response)(u64 mid, int result); 150 151 /* 152 * This is an error handling strategy routine. You don't need to 153 * define one of these if you don't want to - there is a default 154 * routine that is present that should work in most cases. For those 155 * driver authors that have the inclination and ability to write their 156 * own strategy routine, this is where it is specified. Note - the 157 * strategy routine is *ALWAYS* run in the context of the kernel eh 158 * thread. Thus you are guaranteed to *NOT* be in an interrupt 159 * handler when you execute this, and you are also guaranteed to 160 * *NOT* have any other commands being queued while you are in the 161 * strategy routine. When you return from this function, operations 162 * return to normal. 163 * 164 * See scsi_error.c scsi_unjam_host for additional comments about 165 * what this function should and should not be attempting to do. 166 * 167 * Status: REQUIRED (at least one of them) 168 */ 169 int (* eh_abort_handler)(struct scsi_cmnd *); 170 int (* eh_device_reset_handler)(struct scsi_cmnd *); 171 int (* eh_bus_reset_handler)(struct scsi_cmnd *); 172 int (* eh_host_reset_handler)(struct scsi_cmnd *); 173 174 /* 175 * Before the mid layer attempts to scan for a new device where none 176 * currently exists, it will call this entry in your driver. Should 177 * your driver need to allocate any structs or perform any other init 178 * items in order to send commands to a currently unused target/lun 179 * combo, then this is where you can perform those allocations. This 180 * is specifically so that drivers won't have to perform any kind of 181 * "is this a new device" checks in their queuecommand routine, 182 * thereby making the hot path a bit quicker. 183 * 184 * Return values: 0 on success, non-0 on failure 185 * 186 * Deallocation: If we didn't find any devices at this ID, you will 187 * get an immediate call to slave_destroy(). If we find something 188 * here then you will get a call to slave_configure(), then the 189 * device will be used for however long it is kept around, then when 190 * the device is removed from the system (or * possibly at reboot 191 * time), you will then get a call to slave_destroy(). This is 192 * assuming you implement slave_configure and slave_destroy. 193 * However, if you allocate memory and hang it off the device struct, 194 * then you must implement the slave_destroy() routine at a minimum 195 * in order to avoid leaking memory 196 * each time a device is tore down. 197 * 198 * Status: OPTIONAL 199 */ 200 int (* slave_alloc)(struct scsi_device *); 201 202 /* 203 * Once the device has responded to an INQUIRY and we know the 204 * device is online, we call into the low level driver with the 205 * struct scsi_device *. If the low level device driver implements 206 * this function, it *must* perform the task of setting the queue 207 * depth on the device. All other tasks are optional and depend 208 * on what the driver supports and various implementation details. 209 * 210 * Things currently recommended to be handled at this time include: 211 * 212 * 1. Setting the device queue depth. Proper setting of this is 213 * described in the comments for scsi_adjust_queue_depth. 214 * 2. Determining if the device supports the various synchronous 215 * negotiation protocols. The device struct will already have 216 * responded to INQUIRY and the results of the standard items 217 * will have been shoved into the various device flag bits, eg. 218 * device->sdtr will be true if the device supports SDTR messages. 219 * 3. Allocating command structs that the device will need. 220 * 4. Setting the default timeout on this device (if needed). 221 * 5. Anything else the low level driver might want to do on a device 222 * specific setup basis... 223 * 6. Return 0 on success, non-0 on error. The device will be marked 224 * as offline on error so that no access will occur. If you return 225 * non-0, your slave_destroy routine will never get called for this 226 * device, so don't leave any loose memory hanging around, clean 227 * up after yourself before returning non-0 228 * 229 * Status: OPTIONAL 230 */ 231 int (* slave_configure)(struct scsi_device *); 232 233 /* 234 * Immediately prior to deallocating the device and after all activity 235 * has ceased the mid layer calls this point so that the low level 236 * driver may completely detach itself from the scsi device and vice 237 * versa. The low level driver is responsible for freeing any memory 238 * it allocated in the slave_alloc or slave_configure calls. 239 * 240 * Status: OPTIONAL 241 */ 242 void (* slave_destroy)(struct scsi_device *); 243 244 /* 245 * Before the mid layer attempts to scan for a new device attached 246 * to a target where no target currently exists, it will call this 247 * entry in your driver. Should your driver need to allocate any 248 * structs or perform any other init items in order to send commands 249 * to a currently unused target, then this is where you can perform 250 * those allocations. 251 * 252 * Return values: 0 on success, non-0 on failure 253 * 254 * Status: OPTIONAL 255 */ 256 int (* target_alloc)(struct scsi_target *); 257 258 /* 259 * Immediately prior to deallocating the target structure, and 260 * after all activity to attached scsi devices has ceased, the 261 * midlayer calls this point so that the driver may deallocate 262 * and terminate any references to the target. 263 * 264 * Status: OPTIONAL 265 */ 266 void (* target_destroy)(struct scsi_target *); 267 268 /* 269 * If a host has the ability to discover targets on its own instead 270 * of scanning the entire bus, it can fill in this function and 271 * call scsi_scan_host(). This function will be called periodically 272 * until it returns 1 with the scsi_host and the elapsed time of 273 * the scan in jiffies. 274 * 275 * Status: OPTIONAL 276 */ 277 int (* scan_finished)(struct Scsi_Host *, unsigned long); 278 279 /* 280 * If the host wants to be called before the scan starts, but 281 * after the midlayer has set up ready for the scan, it can fill 282 * in this function. 283 */ 284 void (* scan_start)(struct Scsi_Host *); 285 286 /* 287 * fill in this function to allow the queue depth of this host 288 * to be changeable (on a per device basis). returns either 289 * the current queue depth setting (may be different from what 290 * was passed in) or an error. An error should only be 291 * returned if the requested depth is legal but the driver was 292 * unable to set it. If the requested depth is illegal, the 293 * driver should set and return the closest legal queue depth. 294 * 295 */ 296 int (* change_queue_depth)(struct scsi_device *, int); 297 298 /* 299 * fill in this function to allow the changing of tag types 300 * (this also allows the enabling/disabling of tag command 301 * queueing). An error should only be returned if something 302 * went wrong in the driver while trying to set the tag type. 303 * If the driver doesn't support the requested tag type, then 304 * it should set the closest type it does support without 305 * returning an error. Returns the actual tag type set. 306 */ 307 int (* change_queue_type)(struct scsi_device *, int); 308 309 /* 310 * This function determines the bios parameters for a given 311 * harddisk. These tend to be numbers that are made up by 312 * the host adapter. Parameters: 313 * size, device, list (heads, sectors, cylinders) 314 * 315 * Status: OPTIONAL */ 316 int (* bios_param)(struct scsi_device *, struct block_device *, 317 sector_t, int []); 318 319 /* 320 * Can be used to export driver statistics and other infos to the 321 * world outside the kernel ie. userspace and it also provides an 322 * interface to feed the driver with information. 323 * 324 * Status: OBSOLETE 325 */ 326 int (*proc_info)(struct Scsi_Host *, char *, char **, off_t, int, int); 327 328 /* 329 * This is an optional routine that allows the transport to become 330 * involved when a scsi io timer fires. The return value tells the 331 * timer routine how to finish the io timeout handling: 332 * EH_HANDLED: I fixed the error, please complete the command 333 * EH_RESET_TIMER: I need more time, reset the timer and 334 * begin counting again 335 * EH_NOT_HANDLED Begin normal error recovery 336 * 337 * Status: OPTIONAL 338 */ 339 enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *); 340 341 /* 342 * suspend support 343 */ 344 int (*resume)(struct scsi_device *); 345 int (*suspend)(struct scsi_device *, pm_message_t state); 346 347 /* 348 * Name of proc directory 349 */ 350 char *proc_name; 351 352 /* 353 * Used to store the procfs directory if a driver implements the 354 * proc_info method. 355 */ 356 struct proc_dir_entry *proc_dir; 357 358 /* 359 * This determines if we will use a non-interrupt driven 360 * or an interrupt driven scheme, It is set to the maximum number 361 * of simultaneous commands a given host adapter will accept. 362 */ 363 int can_queue; 364 365 /* 366 * In many instances, especially where disconnect / reconnect are 367 * supported, our host also has an ID on the SCSI bus. If this is 368 * the case, then it must be reserved. Please set this_id to -1 if 369 * your setup is in single initiator mode, and the host lacks an 370 * ID. 371 */ 372 int this_id; 373 374 /* 375 * This determines the degree to which the host adapter is capable 376 * of scatter-gather. 377 */ 378 unsigned short sg_tablesize; 379 380 /* 381 * If the host adapter has limitations beside segment count 382 */ 383 unsigned short max_sectors; 384 385 /* 386 * dma scatter gather segment boundary limit. a segment crossing this 387 * boundary will be split in two. 388 */ 389 unsigned long dma_boundary; 390 391 /* 392 * This specifies "machine infinity" for host templates which don't 393 * limit the transfer size. Note this limit represents an absolute 394 * maximum, and may be over the transfer limits allowed for 395 * individual devices (e.g. 256 for SCSI-1) 396 */ 397#define SCSI_DEFAULT_MAX_SECTORS 1024 398 399 /* 400 * True if this host adapter can make good use of linked commands. 401 * This will allow more than one command to be queued to a given 402 * unit on a given host. Set this to the maximum number of command 403 * blocks to be provided for each device. Set this to 1 for one 404 * command block per lun, 2 for two, etc. Do not set this to 0. 405 * You should make sure that the host adapter will do the right thing 406 * before you try setting this above 1. 407 */ 408 short cmd_per_lun; 409 410 /* 411 * present contains counter indicating how many boards of this 412 * type were found when we did the scan. 413 */ 414 unsigned char present; 415 416 /* 417 * true if this host adapter uses unchecked DMA onto an ISA bus. 418 */ 419 unsigned unchecked_isa_dma:1; 420 421 /* 422 * true if this host adapter can make good use of clustering. 423 * I originally thought that if the tablesize was large that it 424 * was a waste of CPU cycles to prepare a cluster list, but 425 * it works out that the Buslogic is faster if you use a smaller 426 * number of segments (i.e. use clustering). I guess it is 427 * inefficient. 428 */ 429 unsigned use_clustering:1; 430 431 /* 432 * True for emulated SCSI host adapters (e.g. ATAPI) 433 */ 434 unsigned emulated:1; 435 436 /* 437 * True if the low-level driver performs its own reset-settle delays. 438 */ 439 unsigned skip_settle_delay:1; 440 441 /* 442 * ordered write support 443 */ 444 unsigned ordered_tag:1; 445 446 /* 447 * Countdown for host blocking with no commands outstanding 448 */ 449 unsigned int max_host_blocked; 450 451#define SCSI_DEFAULT_HOST_BLOCKED 7 452 453 /* 454 * Pointer to the sysfs class properties for this host, NULL terminated. 455 */ 456 struct class_device_attribute **shost_attrs; 457 458 /* 459 * Pointer to the SCSI device properties for this host, NULL terminated. 460 */ 461 struct device_attribute **sdev_attrs; 462 463 /* 464 * List of hosts per template. 465 * 466 * This is only for use by scsi_module.c for legacy templates. 467 * For these access to it is synchronized implicitly by 468 * module_init/module_exit. 469 */ 470 struct list_head legacy_hosts; 471}; 472 473/* 474 * shost state: If you alter this, you also need to alter scsi_sysfs.c 475 * (for the ascii descriptions) and the state model enforcer: 476 * scsi_host_set_state() 477 */ 478enum scsi_host_state { 479 SHOST_CREATED = 1, 480 SHOST_RUNNING, 481 SHOST_CANCEL, 482 SHOST_DEL, 483 SHOST_RECOVERY, 484 SHOST_CANCEL_RECOVERY, 485 SHOST_DEL_RECOVERY, 486}; 487 488struct Scsi_Host { 489 /* 490 * __devices is protected by the host_lock, but you should 491 * usually use scsi_device_lookup / shost_for_each_device 492 * to access it and don't care about locking yourself. 493 * In the rare case of beeing in irq context you can use 494 * their __ prefixed variants with the lock held. NEVER 495 * access this list directly from a driver. 496 */ 497 struct list_head __devices; 498 struct list_head __targets; 499 500 struct scsi_host_cmd_pool *cmd_pool; 501 spinlock_t free_list_lock; 502 struct list_head free_list; /* backup store of cmd structs */ 503 struct list_head starved_list; 504 505 spinlock_t default_lock; 506 spinlock_t *host_lock; 507 508 struct mutex scan_mutex;/* serialize scanning activity */ 509 510 struct list_head eh_cmd_q; 511 struct task_struct * ehandler; /* Error recovery thread. */ 512 struct completion * eh_action; /* Wait for specific actions on the 513 host. */ 514 wait_queue_head_t host_wait; 515 struct scsi_host_template *hostt; 516 struct scsi_transport_template *transportt; 517 518 /* 519 * area to keep a shared tag map (if needed, will be 520 * NULL if not) 521 */ 522 struct blk_queue_tag *bqt; 523 524 /* 525 * The following two fields are protected with host_lock; 526 * however, eh routines can safely access during eh processing 527 * without acquiring the lock. 528 */ 529 unsigned int host_busy; /* commands actually active on low-level */ 530 unsigned int host_failed; /* commands that failed. */ 531 unsigned int host_eh_scheduled; /* EH scheduled without command */ 532 533 unsigned short host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */ 534 int resetting; /* if set, it means that last_reset is a valid value */ 535 unsigned long last_reset; 536 537 /* 538 * These three parameters can be used to allow for wide scsi, 539 * and for host adapters that support multiple busses 540 * The first two should be set to 1 more than the actual max id 541 * or lun (i.e. 8 for normal systems). 542 */ 543 unsigned int max_id; 544 unsigned int max_lun; 545 unsigned int max_channel; 546 547 /* 548 * This is a unique identifier that must be assigned so that we 549 * have some way of identifying each detected host adapter properly 550 * and uniquely. For hosts that do not support more than one card 551 * in the system at one time, this does not need to be set. It is 552 * initialized to 0 in scsi_register. 553 */ 554 unsigned int unique_id; 555 556 /* 557 * The maximum length of SCSI commands that this host can accept. 558 * Probably 12 for most host adapters, but could be 16 for others. 559 * For drivers that don't set this field, a value of 12 is 560 * assumed. I am leaving this as a number rather than a bit 561 * because you never know what subsequent SCSI standards might do 562 * (i.e. could there be a 20 byte or a 24-byte command a few years 563 * down the road?). 564 */ 565 unsigned char max_cmd_len; 566 567 int this_id; 568 int can_queue; 569 short cmd_per_lun; 570 short unsigned int sg_tablesize; 571 short unsigned int max_sectors; 572 unsigned long dma_boundary; 573 /* 574 * Used to assign serial numbers to the cmds. 575 * Protected by the host lock. 576 */ 577 unsigned long cmd_serial_number, cmd_pid; 578 579 unsigned unchecked_isa_dma:1; 580 unsigned use_clustering:1; 581 unsigned use_blk_tcq:1; 582 583 /* 584 * Host has requested that no further requests come through for the 585 * time being. 586 */ 587 unsigned host_self_blocked:1; 588 589 /* 590 * Host uses correct SCSI ordering not PC ordering. The bit is 591 * set for the minority of drivers whose authors actually read 592 * the spec ;) 593 */ 594 unsigned reverse_ordering:1; 595 596 /* 597 * ordered write support 598 */ 599 unsigned ordered_tag:1; 600 601 /* task mgmt function in progress */ 602 unsigned tmf_in_progress:1; 603 604 /* Asynchronous scan in progress */ 605 unsigned async_scan:1; 606 607 /* 608 * Optional work queue to be utilized by the transport 609 */ 610 char work_q_name[KOBJ_NAME_LEN]; 611 struct workqueue_struct *work_q; 612 613 /* 614 * Host has rejected a command because it was busy. 615 */ 616 unsigned int host_blocked; 617 618 /* 619 * Value host_blocked counts down from 620 */ 621 unsigned int max_host_blocked; 622 623 /* 624 * q used for scsi_tgt msgs, async events or any other requests that 625 * need to be processed in userspace 626 */ 627 struct request_queue *uspace_req_q; 628 629 /* legacy crap */ 630 unsigned long base; 631 unsigned long io_port; 632 unsigned char n_io_port; 633 unsigned char dma_channel; 634 unsigned int irq; 635 636 637 enum scsi_host_state shost_state; 638 639 /* ldm bits */ 640 struct device shost_gendev; 641 struct class_device shost_classdev; 642 643 /* 644 * List of hosts per template. 645 * 646 * This is only for use by scsi_module.c for legacy templates. 647 * For these access to it is synchronized implicitly by 648 * module_init/module_exit. 649 */ 650 struct list_head sht_legacy_list; 651 652 /* 653 * Points to the transport data (if any) which is allocated 654 * separately 655 */ 656 void *shost_data; 657 658 /* 659 * We should ensure that this is aligned, both for better performance 660 * and also because some compilers (m68k) don't automatically force 661 * alignment to a long boundary. 662 */ 663 unsigned long hostdata[0] /* Used for storage of host specific stuff */ 664 __attribute__ ((aligned (sizeof(unsigned long)))); 665}; 666 667#define class_to_shost(d) \ 668 container_of(d, struct Scsi_Host, shost_classdev) 669 670#define shost_printk(prefix, shost, fmt, a...) \ 671 dev_printk(prefix, &(shost)->shost_gendev, fmt, ##a) 672 673 674int scsi_is_host_device(const struct device *); 675 676static inline struct Scsi_Host *dev_to_shost(struct device *dev) 677{ 678 while (!scsi_is_host_device(dev)) { 679 if (!dev->parent) 680 return NULL; 681 dev = dev->parent; 682 } 683 return container_of(dev, struct Scsi_Host, shost_gendev); 684} 685 686static inline int scsi_host_in_recovery(struct Scsi_Host *shost) 687{ 688 return shost->shost_state == SHOST_RECOVERY || 689 shost->shost_state == SHOST_CANCEL_RECOVERY || 690 shost->shost_state == SHOST_DEL_RECOVERY || 691 shost->tmf_in_progress; 692} 693 694extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *); 695extern void scsi_flush_work(struct Scsi_Host *); 696 697extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int); 698extern int __must_check scsi_add_host(struct Scsi_Host *, struct device *); 699extern void scsi_scan_host(struct Scsi_Host *); 700extern void scsi_rescan_device(struct device *); 701extern void scsi_remove_host(struct Scsi_Host *); 702extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *); 703extern void scsi_host_put(struct Scsi_Host *t); 704extern struct Scsi_Host *scsi_host_lookup(unsigned short); 705extern const char *scsi_host_state_name(enum scsi_host_state); 706 707extern u64 scsi_calculate_bounce_limit(struct Scsi_Host *); 708 709static inline struct device *scsi_get_device(struct Scsi_Host *shost) 710{ 711 return shost->shost_gendev.parent; 712} 713 714/** 715 * scsi_host_scan_allowed - Is scanning of this host allowed 716 * @shost: Pointer to Scsi_Host. 717 **/ 718static inline int scsi_host_scan_allowed(struct Scsi_Host *shost) 719{ 720 return shost->shost_state == SHOST_RUNNING; 721} 722 723extern void scsi_unblock_requests(struct Scsi_Host *); 724extern void scsi_block_requests(struct Scsi_Host *); 725 726struct class_container; 727 728extern struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost, 729 void (*) (struct request_queue *)); 730/* 731 * These two functions are used to allocate and free a pseudo device 732 * which will connect to the host adapter itself rather than any 733 * physical device. You must deallocate when you are done with the 734 * thing. This physical pseudo-device isn't real and won't be available 735 * from any high-level drivers. 736 */ 737extern void scsi_free_host_dev(struct scsi_device *); 738extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *); 739 740/* legacy interfaces */ 741extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int); 742extern void scsi_unregister(struct Scsi_Host *); 743extern int scsi_host_set_state(struct Scsi_Host *, enum scsi_host_state); 744 745#endif /* _SCSI_SCSI_HOST_H */ 746