aboutsummaryrefslogtreecommitdiffstats
path: root/include/scsi/scsi_host.h
blob: 25f637bd38b937a2765c5dc47ed5fb1d3f6b6c72 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
#ifndef _SCSI_SCSI_HOST_H
#define _SCSI_SCSI_HOST_H

#include <linux/device.h>
#include <linux/list.h>
#include <linux/types.h>
#include <linux/workqueue.h>

struct block_device;
struct completion;
struct module;
struct scsi_cmnd;
struct scsi_device;
struct scsi_target;
struct Scsi_Host;
struct scsi_host_cmd_pool;
struct scsi_transport_template;


/*
 * The various choices mean:
 * NONE: Self evident.	Host adapter is not capable of scatter-gather.
 * ALL:	 Means that the host adapter module can do scatter-gather,
 *	 and that there is no limit to the size of the table to which
 *	 we scatter/gather data.
 * Anything else:  Indicates the maximum number of chains that can be
 *	 used in one scatter-gather request.
 */
#define SG_NONE 0
#define SG_ALL 0xff


#define DISABLE_CLUSTERING 0
#define ENABLE_CLUSTERING 1

enum scsi_eh_timer_return {
	EH_NOT_HANDLED,
	EH_HANDLED,
	EH_RESET_TIMER,
};


struct scsi_host_template {
	struct module *module;
	const char *name;

	/*
	 * Used to initialize old-style drivers.  For new-style drivers
	 * just perform all work in your module initialization function.
	 *
	 * Status:  OBSOLETE
	 */
	int (* detect)(struct scsi_host_template *);

	/*
	 * Used as unload callback for hosts with old-style drivers.
	 *
	 * Status: OBSOLETE
	 */
	int (* release)(struct Scsi_Host *);

	/*
	 * The info function will return whatever useful information the
	 * developer sees fit.  If not provided, then the name field will
	 * be used instead.
	 *
	 * Status: OPTIONAL
	 */
	const char *(* info)(struct Scsi_Host *);

	/*
	 * Ioctl interface
	 *
	 * Status: OPTIONAL
	 */
	int (* ioctl)(struct scsi_device *dev, int cmd, void __user *arg);


#ifdef CONFIG_COMPAT
	/* 
	 * Compat handler. Handle 32bit ABI.
	 * When unknown ioctl is passed return -ENOIOCTLCMD.
	 *
	 * Status: OPTIONAL
	 */
	int (* compat_ioctl)(struct scsi_device *dev, int cmd, void __user *arg);
#endif

	/*
	 * The queuecommand function is used to queue up a scsi
	 * command block to the LLDD.  When the driver finished
	 * processing the command the done callback is invoked.
	 *
	 * If queuecommand returns 0, then the HBA has accepted the
	 * command.  The done() function must be called on the command
	 * when the driver has finished with it. (you may call done on the
	 * command before queuecommand returns, but in this case you
	 * *must* return 0 from queuecommand).
	 *
	 * Queuecommand may also reject the command, in which case it may
	 * not touch the command and must not call done() for it.
	 *
	 * There are two possible rejection returns:
	 *
	 *   SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but
	 *   allow commands to other devices serviced by this host.
	 *
	 *   SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this
	 *   host temporarily.
	 *
         * For compatibility, any other non-zero return is treated the
         * same as SCSI_MLQUEUE_HOST_BUSY.
	 *
	 * NOTE: "temporarily" means either until the next command for#
	 * this device/host completes, or a period of time determined by
	 * I/O pressure in the system if there are no other outstanding
	 * commands.
	 *
	 * STATUS: REQUIRED
	 */
	int (* queuecommand)(struct scsi_cmnd *,
			     void (*done)(struct scsi_cmnd *));

	/*
	 * This is an error handling strategy routine.  You don't need to
	 * define one of these if you don't want to - there is a default
	 * routine that is present that should work in most cases.  For those
	 * driver authors that have the inclination and ability to write their
	 * own strategy routine, this is where it is specified.  Note - the
	 * strategy routine is *ALWAYS* run in the context of the kernel eh
	 * thread.  Thus you are guaranteed to *NOT* be in an interrupt
	 * handler when you execute this, and you are also guaranteed to
	 * *NOT* have any other commands being queued while you are in the
	 * strategy routine. When you return from this function, operations
	 * return to normal.
	 *
	 * See scsi_error.c scsi_unjam_host for additional comments about
	 * what this function should and should not be attempting to do.
	 *
	 * Status: REQUIRED	(at least one of them)
	 */
	int (* eh_strategy_handler)(struct Scsi_Host *);
	int (* eh_abort_handler)(struct scsi_cmnd *);
	int (* eh_device_reset_handler)(struct scsi_cmnd *);
	int (* eh_bus_reset_handler)(struct scsi_cmnd *);
	int (* eh_host_reset_handler)(struct scsi_cmnd *);

	/*
	 * This is an optional routine to notify the host that the scsi
	 * timer just fired.  The returns tell the timer routine what to
	 * do about this:
	 *
	 * EH_HANDLED:		I fixed the error, please complete the command
	 * EH_RESET_TIMER:	I need more time, reset the timer and
	 *			begin counting again
	 * EH_NOT_HANDLED	Begin normal error recovery
	 *
	 * Status: OPTIONAL
	 */
	enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);

	/*
	 * Before the mid layer attempts to scan for a new device where none
	 * currently exists, it will call this entry in your driver.  Should
	 * your driver need to allocate any structs or perform any other init
	 * items in order to send commands to a currently unused target/lun
	 * combo, then this is where you can perform those allocations.  This
	 * is specifically so that drivers won't have to perform any kind of
	 * "is this a new device" checks in their queuecommand routine,
	 * thereby making the hot path a bit quicker.
	 *
	 * Return values: 0 on success, non-0 on failure
	 *
	 * Deallocation:  If we didn't find any devices at this ID, you will
	 * get an immediate call to slave_destroy().  If we find something
	 * here then you will get a call to slave_configure(), then the
	 * device will be used for however long it is kept around, then when
	 * the device is removed from the system (or * possibly at reboot
	 * time), you will then get a call to slave_destroy().  This is
	 * assuming you implement slave_configure and slave_destroy.
	 * However, if you allocate memory and hang it off the device struct,
	 * then you must implement the slave_destroy() routine at a minimum
	 * in order to avoid leaking memory
	 * each time a device is tore down.
	 *
	 * Status: OPTIONAL
	 */
	int (* slave_alloc)(struct scsi_device *);

	/*
	 * Once the device has responded to an INQUIRY and we know the
	 * device is online, we call into the low level driver with the
	 * struct scsi_device *.  If the low level device driver implements
	 * this function, it *must* perform the task of setting the queue
	 * depth on the device.  All other tasks are optional and depend
	 * on what the driver supports and various implementation details.
	 * 
	 * Things currently recommended to be handled at this time include:
	 *
	 * 1.  Setting the device queue depth.  Proper setting of this is
	 *     described in the comments for scsi_adjust_queue_depth.
	 * 2.  Determining if the device supports the various synchronous
	 *     negotiation protocols.  The device struct will already have
	 *     responded to INQUIRY and the results of the standard items
	 *     will have been shoved into the various device flag bits, eg.
	 *     device->sdtr will be true if the device supports SDTR messages.
	 * 3.  Allocating command structs that the device will need.
	 * 4.  Setting the default timeout on this device (if needed).
	 * 5.  Anything else the low level driver might want to do on a device
	 *     specific setup basis...
	 * 6.  Return 0 on success, non-0 on error.  The device will be marked
	 *     as offline on error so that no access will occur.  If you return
	 *     non-0, your slave_destroy routine will never get called for this
	 *     device, so don't leave any loose memory hanging around, clean
	 *     up after yourself before returning non-0
	 *
	 * Status: OPTIONAL
	 */
	int (* slave_configure)(struct scsi_device *);

	/*
	 * Immediately prior to deallocating the device and after all activity
	 * has ceased the mid layer calls this point so that the low level
	 * driver may completely detach itself from the scsi device and vice
	 * versa.  The low level driver is responsible for freeing any memory
	 * it allocated in the slave_alloc or slave_configure calls. 
	 *
	 * Status: OPTIONAL
	 */
	void (* slave_destroy)(struct scsi_device *);

	/*
	 * Before the mid layer attempts to scan for a new device attached
	 * to a target where no target currently exists, it will call this
	 * entry in your driver.  Should your driver need to allocate any
	 * structs or perform any other init items in order to send commands
	 * to a currently unused target, then this is where you can perform
	 * those allocations.
	 *
	 * Return values: 0 on success, non-0 on failure
	 *
	 * Status: OPTIONAL
	 */
	int (* target_alloc)(struct scsi_target *);

	/*
	 * Immediately prior to deallocating the target structure, and
	 * after all activity to attached scsi devices has ceased, the
	 * midlayer calls this point so that the driver may deallocate
	 * and terminate any references to the target.
	 *
	 * Status: OPTIONAL
	 */
	void (* target_destroy)(struct scsi_target *);

	/*
	 * fill in this function to allow the queue depth of this host
	 * to be changeable (on a per device basis).  returns either
	 * the current queue depth setting (may be different from what
	 * was passed in) or an error.  An error should only be
	 * returned if the requested depth is legal but the driver was
	 * unable to set it.  If the requested depth is illegal, the
	 * driver should set and return the closest legal queue depth.
	 *
	 */
	int (* change_queue_depth)(struct scsi_device *, int);

	/*
	 * fill in this function to allow the changing of tag types
	 * (this also allows the enabling/disabling of tag command
	 * queueing).  An error should only be returned if something
	 * went wrong in the driver while trying to set the tag type.
	 * If the driver doesn't support the requested tag type, then
	 * it should set the closest type it does support without
	 * returning an error.  Returns the actual tag type set.
	 */
	int (* change_queue_type)(struct scsi_device *, int);

	/*
	 * This function determines the bios parameters for a given
	 * harddisk.  These tend to be numbers that are made up by
	 * the host adapter.  Parameters:
	 * size, device, list (heads, sectors, cylinders)
	 *
	 * Status: OPTIONAL */
	int (* bios_param)(struct scsi_device *, struct block_device *,
			sector_t, int []);

	/*
	 * Can be used to export driver statistics and other infos to the
	 * world outside the kernel ie. userspace and it also provides an
	 * interface to feed the driver with information.
	 *
	 * Status: OBSOLETE
	 */
	int (*proc_info)(struct Scsi_Host *, char *, char **, off_t, int, int);

	/*
	 * Name of proc directory
	 */
	char *proc_name;

	/*
	 * Used to store the procfs directory if a driver implements the
	 * proc_info method.
	 */
	struct proc_dir_entry *proc_dir;

	/*
	 * This determines if we will use a non-interrupt driven
	 * or an interrupt driven scheme,  It is set to the maximum number
	 * of simultaneous commands a given host adapter will accept.
	 */
	int can_queue;

	/*
	 * In many instances, especially where disconnect / reconnect are
	 * supported, our host also has an ID on the SCSI bus.  If this is
	 * the case, then it must be reserved.  Please set this_id to -1 if
	 * your setup is in single initiator mode, and the host lacks an
	 * ID.
	 */
	int this_id;

	/*
	 * This determines the degree to which the host adapter is capable
	 * of scatter-gather.
	 */
	unsigned short sg_tablesize;

	/*
	 * If the host adapter has limitations beside segment count
	 */
	unsigned short max_sectors;

	/*
	 * dma scatter gather segment boundary limit. a segment crossing this
	 * boundary will be split in two.
	 */
	unsigned long dma_boundary;

	/*
	 * This specifies "machine infinity" for host templates which don't
	 * limit the transfer size.  Note this limit represents an absolute
	 * maximum, and may be over the transfer limits allowed for
	 * individual devices (e.g. 256 for SCSI-1)
	 */
#define SCSI_DEFAULT_MAX_SECTORS	1024

	/*
	 * True if this host adapter can make good use of linked commands.
	 * This will allow more than one command to be queued to a given
	 * unit on a given host.  Set this to the maximum number of command
	 * blocks to be provided for each device.  Set this to 1 for one
	 * command block per lun, 2 for two, etc.  Do not set this to 0.
	 * You should make sure that the host adapter will do the right thing
	 * before you try setting this above 1.
	 */
	short cmd_per_lun;

	/*
	 * present contains counter indicating how many boards of this
	 * type were found when we did the scan.
	 */
	unsigned char present;

	/*
	 * true if this host adapter uses unchecked DMA onto an ISA bus.
	 */
	unsigned unchecked_isa_dma:1;

	/*
	 * true if this host adapter can make good use of clustering.
	 * I originally thought that if the tablesize was large that it
	 * was a waste of CPU cycles to prepare a cluster list, but
	 * it works out that the Buslogic is faster if you use a smaller
	 * number of segments (i.e. use clustering).  I guess it is
	 * inefficient.
	 */
	unsigned use_clustering:1;

	/*
	 * True for emulated SCSI host adapters (e.g. ATAPI)
	 */
	unsigned emulated:1;

	/*
	 * True if the low-level driver performs its own reset-settle delays.
	 */
	unsigned skip_settle_delay:1;

	/*
	 * ordered write support
	 */
	unsigned ordered_tag:1;

	/*
	 * Countdown for host blocking with no commands outstanding
	 */
	unsigned int max_host_blocked;

	/*
	 * Default value for the blocking.  If the queue is empty,
	 * host_blocked counts down in the request_fn until it restarts
	 * host operations as zero is reached.  
	 *
	 * FIXME: This should probably be a value in the template
	 */
#define SCSI_DEFAULT_HOST_BLOCKED	7

	/*
	 * Pointer to the sysfs class properties for this host, NULL terminated.
	 */
	struct class_device_attribute **shost_attrs;

	/*
	 * Pointer to the SCSI device properties for this host, NULL terminated.
	 */
	struct device_attribute **sdev_attrs;

	/*
	 * List of hosts per template.
	 *
	 * This is only for use by scsi_module.c for legacy templates.
	 * For these access to it is synchronized implicitly by
	 * module_init/module_exit.
	 */
	struct list_head legacy_hosts;
};

/*
 * shost state: If you alter this, you also need to alter scsi_sysfs.c
 * (for the ascii descriptions) and the state model enforcer:
 * scsi_host_set_state()
 */
enum scsi_host_state {
	SHOST_CREATED = 1,
	SHOST_RUNNING,
	SHOST_CANCEL,
	SHOST_DEL,
	SHOST_RECOVERY,
	SHOST_CANCEL_RECOVERY,
	SHOST_DEL_RECOVERY,
};

struct Scsi_Host {
	/*
	 * __devices is protected by the host_lock, but you should
	 * usually use scsi_device_lookup / shost_for_each_device
	 * to access it and don't care about locking yourself.
	 * In the rare case of beeing in irq context you can use
	 * their __ prefixed variants with the lock held. NEVER
	 * access this list directly from a driver.
	 */
	struct list_head	__devices;
	struct list_head	__targets;
	
	struct scsi_host_cmd_pool *cmd_pool;
	spinlock_t		free_list_lock;
	struct list_head	free_list; /* backup store of cmd structs */
	struct list_head	starved_list;

	spinlock_t		default_lock;
	spinlock_t		*host_lock;

	struct semaphore	scan_mutex;/* serialize scanning activity */

	struct list_head	eh_cmd_q;
	struct task_struct    * ehandler;  /* Error recovery thread. */
	struct completion     * eh_action; /* Wait for specific actions on the
					      host. */
	wait_queue_head_t       host_wait;
	struct scsi_host_template *hostt;
	struct scsi_transport_template *transportt;

	/*
	 * The following two fields are protected with host_lock;
	 * however, eh routines can safely access during eh processing
	 * without acquiring the lock.
	 */
	unsigned int host_busy;		   /* commands actually active on low-level */
	unsigned int host_failed;	   /* commands that failed. */
    
	unsigned short host_no;  /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
	int resetting; /* if set, it means that last_reset is a valid value */
	unsigned long last_reset;

	/*
	 * These three parameters can be used to allow for wide scsi,
	 * and for host adapters that support multiple busses
	 * The first two should be set to 1 more than the actual max id
	 * or lun (i.e. 8 for normal systems).
	 */
	unsigned int max_id;
	unsigned int max_lun;
	unsigned int max_channel;

	/*
	 * This is a unique identifier that must be assigned so that we
	 * have some way of identifying each detected host adapter properly
	 * and uniquely.  For hosts that do not support more than one card
	 * in the system at one time, this does not need to be set.  It is
	 * initialized to 0 in scsi_register.
	 */
	unsigned int unique_id;

	/*
	 * The maximum length of SCSI commands that this host can accept.
	 * Probably 12 for most host adapters, but could be 16 for others.
	 * For drivers that don't set this field, a value of 12 is
	 * assumed.  I am leaving this as a number rather than a bit
	 * because you never know what subsequent SCSI standards might do
	 * (i.e. could there be a 20 byte or a 24-byte command a few years
	 * down the road?).  
	 */
	unsigned char max_cmd_len;

	int this_id;
	int can_queue;
	short cmd_per_lun;
	short unsigned int sg_tablesize;
	short unsigned int max_sectors;
	unsigned long dma_boundary;
	/* 
	 * Used to assign serial numbers to the cmds.
	 * Protected by the host lock.
	 */
	unsigned long cmd_serial_number, cmd_pid; 
	
	unsigned unchecked_isa_dma:1;
	unsigned use_clustering:1;
	unsigned use_blk_tcq:1;

	/*
	 * Host has requested that no further requests come through for the
	 * time being.
	 */
	unsigned host_self_blocked:1;
    
	/*
	 * Host uses correct SCSI ordering not PC ordering. The bit is
	 * set for the minority of drivers whose authors actually read
	 * the spec ;)
	 */
	unsigned reverse_ordering:1;

	/*
	 * ordered write support
	 */
	unsigned ordered_flush:1;
	unsigned ordered_tag:1;

	/*
	 * Optional work queue to be utilized by the transport
	 */
	char work_q_name[KOBJ_NAME_LEN];
	struct workqueue_struct *work_q;

	/*
	 * Host has rejected a command because it was busy.
	 */
	unsigned int host_blocked;

	/*
	 * Value host_blocked counts down from
	 */
	unsigned int max_host_blocked;

	/* legacy crap */
	unsigned long base;
	unsigned long io_port;
	unsigned char n_io_port;
	unsigned char dma_channel;
	unsigned int  irq;
	

	enum scsi_host_state shost_state;

	/* ldm bits */
	struct device		shost_gendev;
	struct class_device	shost_classdev;

	/*
	 * List of hosts per template.
	 *
	 * This is only for use by scsi_module.c for legacy templates.
	 * For these access to it is synchronized implicitly by
	 * module_init/module_exit.
	 */
	struct list_head sht_legacy_list;

	/*
	 * Points to the transport data (if any) which is allocated
	 * separately
	 */
	void *shost_data;

	/*
	 * We should ensure that this is aligned, both for better performance
	 * and also because some compilers (m68k) don't automatically force
	 * alignment to a long boundary.
	 */
	unsigned long hostdata[0]  /* Used for storage of host specific stuff */
		__attribute__ ((aligned (sizeof(unsigned long))));
};

#define		class_to_shost(d)	\
	container_of(d, struct Scsi_Host, shost_classdev)

#define shost_printk(prefix, shost, fmt, a...)	\
	dev_printk(prefix, &(shost)->shost_gendev, fmt, ##a)


int scsi_is_host_device(const struct device *);

static inline struct Scsi_Host *dev_to_shost(struct device *dev)
{
	while (!scsi_is_host_device(dev)) {
		if (!dev->parent)
			return NULL;
		dev = dev->parent;
	}
	return container_of(dev, struct Scsi_Host, shost_gendev);
}

static inline int scsi_host_in_recovery(struct Scsi_Host *shost)
{
	return shost->shost_state == SHOST_RECOVERY ||
		shost->shost_state == SHOST_CANCEL_RECOVERY ||
		shost->shost_state == SHOST_DEL_RECOVERY;
}

extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *);
extern void scsi_flush_work(struct Scsi_Host *);

extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int);
extern int __must_check scsi_add_host(struct Scsi_Host *, struct device *);
extern void scsi_scan_host(struct Scsi_Host *);
extern void scsi_rescan_device(struct device *);
extern void scsi_remove_host(struct Scsi_Host *);
extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);
extern void scsi_host_put(struct Scsi_Host *t);
extern struct Scsi_Host *scsi_host_lookup(unsigned short);
extern const char *scsi_host_state_name(enum scsi_host_state);

extern u64 scsi_calculate_bounce_limit(struct Scsi_Host *);

static inline void scsi_assign_lock(struct Scsi_Host *shost, spinlock_t *lock)
{
	shost->host_lock = lock;
}

static inline struct device *scsi_get_device(struct Scsi_Host *shost)
{
        return shost->shost_gendev.parent;
}

/**
 * scsi_host_scan_allowed - Is scanning of this host allowed
 * @shost:	Pointer to Scsi_Host.
 **/
static inline int scsi_host_scan_allowed(struct Scsi_Host *shost)
{
	return shost->shost_state == SHOST_RUNNING;
}

extern void scsi_unblock_requests(struct Scsi_Host *);
extern void scsi_block_requests(struct Scsi_Host *);

struct class_container;
/*
 * These two functions are used to allocate and free a pseudo device
 * which will connect to the host adapter itself rather than any
 * physical device.  You must deallocate when you are done with the
 * thing.  This physical pseudo-device isn't real and won't be available
 * from any high-level drivers.
 */
extern void scsi_free_host_dev(struct scsi_device *);
extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *);

/* legacy interfaces */
extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int);
extern void scsi_unregister(struct Scsi_Host *);
extern int scsi_host_set_state(struct Scsi_Host *, enum scsi_host_state);

#endif /* _SCSI_SCSI_HOST_H */