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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Christoph Hellwigc5478de2005-09-06 14:04:26 +020027#include <linux/kthread.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#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>
Russell Kingd052d1b2005-10-29 19:07:23 +010033#include <linux/platform_device.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
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
43static int scsi_host_next_hn; /* host_no for next new host */
44
45
46static void scsi_host_cls_release(struct class_device *class_dev)
47{
48 put_device(&class_to_shost(class_dev)->shost_gendev);
49}
50
51static struct class shost_class = {
52 .name = "scsi_host",
53 .release = scsi_host_cls_release,
54};
55
56/**
Mike Andersond3301872005-06-16 11:12:38 -070057 * scsi_host_set_state - Take the given host through the host
58 * state model.
59 * @shost: scsi host to change the state of.
60 * @state: state to change to.
61 *
62 * Returns zero if unsuccessful or an error if the requested
63 * transition is illegal.
64 **/
65int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
66{
67 enum scsi_host_state oldstate = shost->shost_state;
68
69 if (state == oldstate)
70 return 0;
71
72 switch (state) {
73 case SHOST_CREATED:
74 /* There are no legal states that come back to
75 * created. This is the manually initialised start
76 * state */
77 goto illegal;
78
79 case SHOST_RUNNING:
80 switch (oldstate) {
81 case SHOST_CREATED:
82 case SHOST_RECOVERY:
83 break;
84 default:
85 goto illegal;
86 }
87 break;
88
89 case SHOST_RECOVERY:
90 switch (oldstate) {
91 case SHOST_RUNNING:
92 break;
93 default:
94 goto illegal;
95 }
96 break;
97
98 case SHOST_CANCEL:
99 switch (oldstate) {
100 case SHOST_CREATED:
101 case SHOST_RUNNING:
James Bottomley939647e2005-09-18 15:05:20 -0500102 case SHOST_CANCEL_RECOVERY:
Mike Andersond3301872005-06-16 11:12:38 -0700103 break;
104 default:
105 goto illegal;
106 }
107 break;
108
109 case SHOST_DEL:
110 switch (oldstate) {
111 case SHOST_CANCEL:
James Bottomley939647e2005-09-18 15:05:20 -0500112 case SHOST_DEL_RECOVERY:
Mike Andersond3301872005-06-16 11:12:38 -0700113 break;
114 default:
115 goto illegal;
116 }
117 break;
118
James Bottomley939647e2005-09-18 15:05:20 -0500119 case SHOST_CANCEL_RECOVERY:
120 switch (oldstate) {
121 case SHOST_CANCEL:
122 case SHOST_RECOVERY:
123 break;
124 default:
125 goto illegal;
126 }
127 break;
128
129 case SHOST_DEL_RECOVERY:
130 switch (oldstate) {
131 case SHOST_CANCEL_RECOVERY:
132 break;
133 default:
134 goto illegal;
135 }
136 break;
Mike Andersond3301872005-06-16 11:12:38 -0700137 }
138 shost->shost_state = state;
139 return 0;
140
141 illegal:
142 SCSI_LOG_ERROR_RECOVERY(1,
James Bottomley9ccfc752005-10-02 11:45:08 -0500143 shost_printk(KERN_ERR, shost,
144 "Illegal host state transition"
145 "%s->%s\n",
146 scsi_host_state_name(oldstate),
147 scsi_host_state_name(state)));
Mike Andersond3301872005-06-16 11:12:38 -0700148 return -EINVAL;
149}
150EXPORT_SYMBOL(scsi_host_set_state);
151
152/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 * scsi_remove_host - remove a scsi host
154 * @shost: a pointer to a scsi host to remove
155 **/
156void scsi_remove_host(struct Scsi_Host *shost)
157{
James Bottomley939647e2005-09-18 15:05:20 -0500158 unsigned long flags;
Arjan van de Ven0b950672006-01-11 13:16:10 +0100159 mutex_lock(&shost->scan_mutex);
James Bottomley939647e2005-09-18 15:05:20 -0500160 spin_lock_irqsave(shost->host_lock, flags);
161 if (scsi_host_set_state(shost, SHOST_CANCEL))
162 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
163 spin_unlock_irqrestore(shost->host_lock, flags);
Arjan van de Ven0b950672006-01-11 13:16:10 +0100164 mutex_unlock(&shost->scan_mutex);
James Bottomley939647e2005-09-18 15:05:20 -0500165 return;
166 }
167 spin_unlock_irqrestore(shost->host_lock, flags);
Arjan van de Ven0b950672006-01-11 13:16:10 +0100168 mutex_unlock(&shost->scan_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 scsi_forget_host(shost);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 scsi_proc_host_rm(shost);
171
James Bottomley939647e2005-09-18 15:05:20 -0500172 spin_lock_irqsave(shost->host_lock, flags);
173 if (scsi_host_set_state(shost, SHOST_DEL))
174 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
175 spin_unlock_irqrestore(shost->host_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176
177 transport_unregister_device(&shost->shost_gendev);
178 class_device_unregister(&shost->shost_classdev);
179 device_del(&shost->shost_gendev);
James Bottomley9e705922005-10-02 12:59:49 -0500180 scsi_proc_hostdir_rm(shost->hostt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181}
182EXPORT_SYMBOL(scsi_remove_host);
183
184/**
185 * scsi_add_host - add a scsi host
186 * @shost: scsi host pointer to add
187 * @dev: a struct device of type scsi class
188 *
189 * Return value:
190 * 0 on success / != 0 for error
191 **/
192int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
193{
194 struct scsi_host_template *sht = shost->hostt;
195 int error = -EINVAL;
196
197 printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
198 sht->info ? sht->info(shost) : sht->name);
199
200 if (!shost->can_queue) {
201 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
202 sht->name);
203 goto out;
204 }
205
206 if (!shost->shost_gendev.parent)
207 shost->shost_gendev.parent = dev ? dev : &platform_bus;
208
209 error = device_add(&shost->shost_gendev);
210 if (error)
211 goto out;
212
Mike Andersond3301872005-06-16 11:12:38 -0700213 scsi_host_set_state(shost, SHOST_RUNNING);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 get_device(shost->shost_gendev.parent);
215
216 error = class_device_add(&shost->shost_classdev);
217 if (error)
218 goto out_del_gendev;
219
220 get_device(&shost->shost_gendev);
221
222 if (shost->transportt->host_size &&
223 (shost->shost_data = kmalloc(shost->transportt->host_size,
224 GFP_KERNEL)) == NULL)
225 goto out_del_classdev;
226
227 if (shost->transportt->create_work_queue) {
228 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
229 shost->host_no);
230 shost->work_q = create_singlethread_workqueue(
231 shost->work_q_name);
232 if (!shost->work_q)
233 goto out_free_shost_data;
234 }
235
236 error = scsi_sysfs_add_host(shost);
237 if (error)
238 goto out_destroy_host;
239
240 scsi_proc_host_add(shost);
241 return error;
242
243 out_destroy_host:
244 if (shost->work_q)
245 destroy_workqueue(shost->work_q);
246 out_free_shost_data:
247 kfree(shost->shost_data);
248 out_del_classdev:
249 class_device_del(&shost->shost_classdev);
250 out_del_gendev:
251 device_del(&shost->shost_gendev);
252 out:
253 return error;
254}
255EXPORT_SYMBOL(scsi_add_host);
256
257static void scsi_host_dev_release(struct device *dev)
258{
259 struct Scsi_Host *shost = dev_to_shost(dev);
260 struct device *parent = dev->parent;
261
Christoph Hellwigc5478de2005-09-06 14:04:26 +0200262 if (shost->ehandler)
263 kthread_stop(shost->ehandler);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 if (shost->work_q)
265 destroy_workqueue(shost->work_q);
266
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 scsi_destroy_command_freelist(shost);
268 kfree(shost->shost_data);
269
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 if (parent)
271 put_device(parent);
272 kfree(shost);
273}
274
275/**
276 * scsi_host_alloc - register a scsi host adapter instance.
277 * @sht: pointer to scsi host template
278 * @privsize: extra bytes to allocate for driver
279 *
280 * Note:
281 * Allocate a new Scsi_Host and perform basic initialization.
282 * The host is not published to the scsi midlayer until scsi_add_host
283 * is called.
284 *
285 * Return value:
286 * Pointer to a new Scsi_Host
287 **/
288struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
289{
290 struct Scsi_Host *shost;
Al Viroc53033f2005-10-21 03:22:08 -0400291 gfp_t gfp_mask = GFP_KERNEL;
292 int rval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
294 if (sht->unchecked_isa_dma && privsize)
295 gfp_mask |= __GFP_DMA;
296
297 /* Check to see if this host has any error handling facilities */
298 if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
299 !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
300 !sht->eh_host_reset_handler) {
301 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
302 "ERROR: This is not a safe way to run your "
303 "SCSI host\n"
304 "ERROR: The error handling must be added to "
305 "this driver\n", sht->proc_name);
306 dump_stack();
307 }
308
Jes Sorensen24669f752006-01-16 10:31:18 -0500309 shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 if (!shost)
311 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312
313 spin_lock_init(&shost->default_lock);
314 scsi_assign_lock(shost, &shost->default_lock);
Mike Andersond3301872005-06-16 11:12:38 -0700315 shost->shost_state = SHOST_CREATED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 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
Arjan van de Ven0b950672006-01-11 13:16:10 +0100322 mutex_init(&shost->scan_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323
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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 shost->ordered_tag = sht->ordered_tag;
350
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 if (sht->max_host_blocked)
352 shost->max_host_blocked = sht->max_host_blocked;
353 else
354 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
355
356 /*
357 * If the driver imposes no hard sector transfer limit, start at
358 * machine infinity initially.
359 */
360 if (sht->max_sectors)
361 shost->max_sectors = sht->max_sectors;
362 else
363 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
364
365 /*
366 * assume a 4GB boundary, if not set
367 */
368 if (sht->dma_boundary)
369 shost->dma_boundary = sht->dma_boundary;
370 else
371 shost->dma_boundary = 0xffffffff;
372
373 rval = scsi_setup_command_freelist(shost);
374 if (rval)
375 goto fail_kfree;
376
377 device_initialize(&shost->shost_gendev);
378 snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
379 shost->host_no);
380 shost->shost_gendev.release = scsi_host_dev_release;
381
382 class_device_initialize(&shost->shost_classdev);
383 shost->shost_classdev.dev = &shost->shost_gendev;
384 shost->shost_classdev.class = &shost_class;
385 snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
386 shost->host_no);
387
Christoph Hellwigc5478de2005-09-06 14:04:26 +0200388 shost->ehandler = kthread_run(scsi_error_handler, shost,
389 "scsi_eh_%d", shost->host_no);
390 if (IS_ERR(shost->ehandler)) {
391 rval = PTR_ERR(shost->ehandler);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 goto fail_destroy_freelist;
Christoph Hellwigc5478de2005-09-06 14:04:26 +0200393 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394
395 scsi_proc_hostdir_add(shost->hostt);
396 return shost;
397
398 fail_destroy_freelist:
399 scsi_destroy_command_freelist(shost);
400 fail_kfree:
401 kfree(shost);
402 return NULL;
403}
404EXPORT_SYMBOL(scsi_host_alloc);
405
406struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
407{
408 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
409
410 if (!sht->detect) {
411 printk(KERN_WARNING "scsi_register() called on new-style "
412 "template for driver %s\n", sht->name);
413 dump_stack();
414 }
415
416 if (shost)
417 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
418 return shost;
419}
420EXPORT_SYMBOL(scsi_register);
421
422void scsi_unregister(struct Scsi_Host *shost)
423{
424 list_del(&shost->sht_legacy_list);
425 scsi_host_put(shost);
426}
427EXPORT_SYMBOL(scsi_unregister);
428
429/**
430 * scsi_host_lookup - get a reference to a Scsi_Host by host no
431 *
432 * @hostnum: host number to locate
433 *
434 * Return value:
435 * A pointer to located Scsi_Host or NULL.
436 **/
437struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
438{
439 struct class *class = &shost_class;
440 struct class_device *cdev;
441 struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
442
443 down_read(&class->subsys.rwsem);
444 list_for_each_entry(cdev, &class->children, node) {
445 p = class_to_shost(cdev);
446 if (p->host_no == hostnum) {
447 shost = scsi_host_get(p);
448 break;
449 }
450 }
451 up_read(&class->subsys.rwsem);
452
453 return shost;
454}
455EXPORT_SYMBOL(scsi_host_lookup);
456
457/**
458 * scsi_host_get - inc a Scsi_Host ref count
459 * @shost: Pointer to Scsi_Host to inc.
460 **/
461struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
462{
Mike Andersond3301872005-06-16 11:12:38 -0700463 if ((shost->shost_state == SHOST_DEL) ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 !get_device(&shost->shost_gendev))
465 return NULL;
466 return shost;
467}
468EXPORT_SYMBOL(scsi_host_get);
469
470/**
471 * scsi_host_put - dec a Scsi_Host ref count
472 * @shost: Pointer to Scsi_Host to dec.
473 **/
474void scsi_host_put(struct Scsi_Host *shost)
475{
476 put_device(&shost->shost_gendev);
477}
478EXPORT_SYMBOL(scsi_host_put);
479
480int scsi_init_hosts(void)
481{
482 return class_register(&shost_class);
483}
484
485void scsi_exit_hosts(void)
486{
487 class_unregister(&shost_class);
488}
489
490int scsi_is_host_device(const struct device *dev)
491{
492 return dev->release == scsi_host_dev_release;
493}
494EXPORT_SYMBOL(scsi_is_host_device);
495
496/**
497 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
498 * @shost: Pointer to Scsi_Host.
499 * @work: Work to queue for execution.
500 *
501 * Return value:
502 * 0 on success / != 0 for error
503 **/
504int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
505{
506 if (unlikely(!shost->work_q)) {
507 printk(KERN_ERR
508 "ERROR: Scsi host '%s' attempted to queue scsi-work, "
509 "when no workqueue created.\n", shost->hostt->name);
510 dump_stack();
511
512 return -EINVAL;
513 }
514
515 return queue_work(shost->work_q, work);
516}
517EXPORT_SYMBOL_GPL(scsi_queue_work);
518
519/**
520 * scsi_flush_work - Flush a Scsi_Host's workqueue.
521 * @shost: Pointer to Scsi_Host.
522 **/
523void scsi_flush_work(struct Scsi_Host *shost)
524{
525 if (!shost->work_q) {
526 printk(KERN_ERR
527 "ERROR: Scsi host '%s' attempted to flush scsi-work, "
528 "when no workqueue created.\n", shost->hostt->name);
529 dump_stack();
530 return;
531 }
532
533 flush_workqueue(shost->work_q);
534}
535EXPORT_SYMBOL_GPL(scsi_flush_work);