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/slab.h>
28#include <linux/kthread.h>
29#include <linux/string.h>
30#include <linux/mm.h>
31#include <linux/init.h>
32#include <linux/completion.h>
33#include <linux/transport_class.h>
34#include <linux/platform_device.h>
35#include <linux/pm_runtime.h>
36#include <linux/idr.h>
37#include <scsi/scsi_device.h>
38#include <scsi/scsi_host.h>
39#include <scsi/scsi_transport.h>
40
41#include "scsi_priv.h"
42#include "scsi_logging.h"
43
44
45static int shost_eh_deadline = -1;
46
47module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
48MODULE_PARM_DESC(eh_deadline,
49 "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
50
51static DEFINE_IDA(host_index_ida);
52
53
54static void scsi_host_cls_release(struct device *dev)
55{
56 put_device(&class_to_shost(dev)->shost_gendev);
57}
58
59static struct class shost_class = {
60 .name = "scsi_host",
61 .dev_release = scsi_host_cls_release,
62};
63
64/**
65 * scsi_host_set_state - Take the given host through the host state model.
66 * @shost: scsi host to change the state of.
67 * @state: state to change to.
68 *
69 * Returns zero if unsuccessful or an error if the requested
70 * transition is illegal.
71 **/
72int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
73{
74 enum scsi_host_state oldstate = shost->shost_state;
75
76 if (state == oldstate)
77 return 0;
78
79 switch (state) {
80 case SHOST_CREATED:
81 /* There are no legal states that come back to
82 * created. This is the manually initialised start
83 * state */
84 goto illegal;
85
86 case SHOST_RUNNING:
87 switch (oldstate) {
88 case SHOST_CREATED:
89 case SHOST_RECOVERY:
90 break;
91 default:
92 goto illegal;
93 }
94 break;
95
96 case SHOST_RECOVERY:
97 switch (oldstate) {
98 case SHOST_RUNNING:
99 break;
100 default:
101 goto illegal;
102 }
103 break;
104
105 case SHOST_CANCEL:
106 switch (oldstate) {
107 case SHOST_CREATED:
108 case SHOST_RUNNING:
109 case SHOST_CANCEL_RECOVERY:
110 break;
111 default:
112 goto illegal;
113 }
114 break;
115
116 case SHOST_DEL:
117 switch (oldstate) {
118 case SHOST_CANCEL:
119 case SHOST_DEL_RECOVERY:
120 break;
121 default:
122 goto illegal;
123 }
124 break;
125
126 case SHOST_CANCEL_RECOVERY:
127 switch (oldstate) {
128 case SHOST_CANCEL:
129 case SHOST_RECOVERY:
130 break;
131 default:
132 goto illegal;
133 }
134 break;
135
136 case SHOST_DEL_RECOVERY:
137 switch (oldstate) {
138 case SHOST_CANCEL_RECOVERY:
139 break;
140 default:
141 goto illegal;
142 }
143 break;
144 }
145 shost->shost_state = state;
146 return 0;
147
148 illegal:
149 SCSI_LOG_ERROR_RECOVERY(1,
150 shost_printk(KERN_ERR, shost,
151 "Illegal host state transition"
152 "%s->%s\n",
153 scsi_host_state_name(oldstate),
154 scsi_host_state_name(state)));
155 return -EINVAL;
156}
157
158/**
159 * scsi_remove_host - remove a scsi host
160 * @shost: a pointer to a scsi host to remove
161 **/
162void scsi_remove_host(struct Scsi_Host *shost)
163{
164 unsigned long flags;
165
166 mutex_lock(&shost->scan_mutex);
167 spin_lock_irqsave(shost->host_lock, flags);
168 if (scsi_host_set_state(shost, SHOST_CANCEL))
169 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
170 spin_unlock_irqrestore(shost->host_lock, flags);
171 mutex_unlock(&shost->scan_mutex);
172 return;
173 }
174 spin_unlock_irqrestore(shost->host_lock, flags);
175
176 scsi_autopm_get_host(shost);
177 flush_workqueue(shost->tmf_work_q);
178 scsi_forget_host(shost);
179 mutex_unlock(&shost->scan_mutex);
180 scsi_proc_host_rm(shost);
181
182 spin_lock_irqsave(shost->host_lock, flags);
183 if (scsi_host_set_state(shost, SHOST_DEL))
184 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
185 spin_unlock_irqrestore(shost->host_lock, flags);
186
187 transport_unregister_device(&shost->shost_gendev);
188 device_unregister(&shost->shost_dev);
189 device_del(&shost->shost_gendev);
190}
191EXPORT_SYMBOL(scsi_remove_host);
192
193/**
194 * scsi_add_host_with_dma - add a scsi host with dma device
195 * @shost: scsi host pointer to add
196 * @dev: a struct device of type scsi class
197 * @dma_dev: dma device for the host
198 *
199 * Note: You rarely need to worry about this unless you're in a
200 * virtualised host environments, so use the simpler scsi_add_host()
201 * function instead.
202 *
203 * Return value:
204 * 0 on success / != 0 for error
205 **/
206int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
207 struct device *dma_dev)
208{
209 struct scsi_host_template *sht = shost->hostt;
210 int error = -EINVAL;
211
212 shost_printk(KERN_INFO, shost, "%s\n",
213 sht->info ? sht->info(shost) : sht->name);
214
215 if (!shost->can_queue) {
216 shost_printk(KERN_ERR, shost,
217 "can_queue = 0 no longer supported\n");
218 goto fail;
219 }
220
221 error = scsi_init_sense_cache(shost);
222 if (error)
223 goto fail;
224
225 error = scsi_mq_setup_tags(shost);
226 if (error)
227 goto fail;
228
229 if (!shost->shost_gendev.parent)
230 shost->shost_gendev.parent = dev ? dev : &platform_bus;
231 if (!dma_dev)
232 dma_dev = shost->shost_gendev.parent;
233
234 shost->dma_dev = dma_dev;
235
236 /*
237 * Increase usage count temporarily here so that calling
238 * scsi_autopm_put_host() will trigger runtime idle if there is
239 * nothing else preventing suspending the device.
240 */
241 pm_runtime_get_noresume(&shost->shost_gendev);
242 pm_runtime_set_active(&shost->shost_gendev);
243 pm_runtime_enable(&shost->shost_gendev);
244 device_enable_async_suspend(&shost->shost_gendev);
245
246 error = device_add(&shost->shost_gendev);
247 if (error)
248 goto out_disable_runtime_pm;
249
250 scsi_host_set_state(shost, SHOST_RUNNING);
251 get_device(shost->shost_gendev.parent);
252
253 device_enable_async_suspend(&shost->shost_dev);
254
255 error = device_add(&shost->shost_dev);
256 if (error)
257 goto out_del_gendev;
258
259 get_device(&shost->shost_gendev);
260
261 if (shost->transportt->host_size) {
262 shost->shost_data = kzalloc(shost->transportt->host_size,
263 GFP_KERNEL);
264 if (shost->shost_data == NULL) {
265 error = -ENOMEM;
266 goto out_del_dev;
267 }
268 }
269
270 if (shost->transportt->create_work_queue) {
271 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
272 "scsi_wq_%d", shost->host_no);
273 shost->work_q = create_singlethread_workqueue(
274 shost->work_q_name);
275 if (!shost->work_q) {
276 error = -EINVAL;
277 goto out_free_shost_data;
278 }
279 }
280
281 error = scsi_sysfs_add_host(shost);
282 if (error)
283 goto out_destroy_host;
284
285 scsi_proc_host_add(shost);
286 scsi_autopm_put_host(shost);
287 return error;
288
289 out_destroy_host:
290 if (shost->work_q)
291 destroy_workqueue(shost->work_q);
292 out_free_shost_data:
293 kfree(shost->shost_data);
294 out_del_dev:
295 device_del(&shost->shost_dev);
296 out_del_gendev:
297 device_del(&shost->shost_gendev);
298 out_disable_runtime_pm:
299 device_disable_async_suspend(&shost->shost_gendev);
300 pm_runtime_disable(&shost->shost_gendev);
301 pm_runtime_set_suspended(&shost->shost_gendev);
302 pm_runtime_put_noidle(&shost->shost_gendev);
303 scsi_mq_destroy_tags(shost);
304 fail:
305 return error;
306}
307EXPORT_SYMBOL(scsi_add_host_with_dma);
308
309static void scsi_host_dev_release(struct device *dev)
310{
311 struct Scsi_Host *shost = dev_to_shost(dev);
312 struct device *parent = dev->parent;
313
314 scsi_proc_hostdir_rm(shost->hostt);
315
316 /* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
317 rcu_barrier();
318
319 if (shost->tmf_work_q)
320 destroy_workqueue(shost->tmf_work_q);
321 if (shost->ehandler)
322 kthread_stop(shost->ehandler);
323 if (shost->work_q)
324 destroy_workqueue(shost->work_q);
325
326 if (shost->shost_state == SHOST_CREATED) {
327 /*
328 * Free the shost_dev device name here if scsi_host_alloc()
329 * and scsi_host_put() have been called but neither
330 * scsi_host_add() nor scsi_host_remove() has been called.
331 * This avoids that the memory allocated for the shost_dev
332 * name is leaked.
333 */
334 kfree(dev_name(&shost->shost_dev));
335 }
336
337 if (shost->tag_set.tags)
338 scsi_mq_destroy_tags(shost);
339
340 kfree(shost->shost_data);
341
342 ida_simple_remove(&host_index_ida, shost->host_no);
343
344 if (parent)
345 put_device(parent);
346 kfree(shost);
347}
348
349static struct device_type scsi_host_type = {
350 .name = "scsi_host",
351 .release = scsi_host_dev_release,
352};
353
354/**
355 * scsi_host_alloc - register a scsi host adapter instance.
356 * @sht: pointer to scsi host template
357 * @privsize: extra bytes to allocate for driver
358 *
359 * Note:
360 * Allocate a new Scsi_Host and perform basic initialization.
361 * The host is not published to the scsi midlayer until scsi_add_host
362 * is called.
363 *
364 * Return value:
365 * Pointer to a new Scsi_Host
366 **/
367struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
368{
369 struct Scsi_Host *shost;
370 gfp_t gfp_mask = GFP_KERNEL;
371 int index;
372
373 if (sht->unchecked_isa_dma && privsize)
374 gfp_mask |= __GFP_DMA;
375
376 shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
377 if (!shost)
378 return NULL;
379
380 shost->host_lock = &shost->default_lock;
381 spin_lock_init(shost->host_lock);
382 shost->shost_state = SHOST_CREATED;
383 INIT_LIST_HEAD(&shost->__devices);
384 INIT_LIST_HEAD(&shost->__targets);
385 INIT_LIST_HEAD(&shost->eh_cmd_q);
386 INIT_LIST_HEAD(&shost->starved_list);
387 init_waitqueue_head(&shost->host_wait);
388 mutex_init(&shost->scan_mutex);
389
390 index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
391 if (index < 0)
392 goto fail_kfree;
393 shost->host_no = index;
394
395 shost->dma_channel = 0xff;
396
397 /* These three are default values which can be overridden */
398 shost->max_channel = 0;
399 shost->max_id = 8;
400 shost->max_lun = 8;
401
402 /* Give each shost a default transportt */
403 shost->transportt = &blank_transport_template;
404
405 /*
406 * All drivers right now should be able to handle 12 byte
407 * commands. Every so often there are requests for 16 byte
408 * commands, but individual low-level drivers need to certify that
409 * they actually do something sensible with such commands.
410 */
411 shost->max_cmd_len = 12;
412 shost->hostt = sht;
413 shost->this_id = sht->this_id;
414 shost->can_queue = sht->can_queue;
415 shost->sg_tablesize = sht->sg_tablesize;
416 shost->sg_prot_tablesize = sht->sg_prot_tablesize;
417 shost->cmd_per_lun = sht->cmd_per_lun;
418 shost->unchecked_isa_dma = sht->unchecked_isa_dma;
419 shost->no_write_same = sht->no_write_same;
420
421 if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
422 shost->eh_deadline = -1;
423 else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
424 shost_printk(KERN_WARNING, shost,
425 "eh_deadline %u too large, setting to %u\n",
426 shost_eh_deadline, INT_MAX / HZ);
427 shost->eh_deadline = INT_MAX;
428 } else
429 shost->eh_deadline = shost_eh_deadline * HZ;
430
431 if (sht->supported_mode == MODE_UNKNOWN)
432 /* means we didn't set it ... default to INITIATOR */
433 shost->active_mode = MODE_INITIATOR;
434 else
435 shost->active_mode = sht->supported_mode;
436
437 if (sht->max_host_blocked)
438 shost->max_host_blocked = sht->max_host_blocked;
439 else
440 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
441
442 /*
443 * If the driver imposes no hard sector transfer limit, start at
444 * machine infinity initially.
445 */
446 if (sht->max_sectors)
447 shost->max_sectors = sht->max_sectors;
448 else
449 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
450
451 if (sht->max_segment_size)
452 shost->max_segment_size = sht->max_segment_size;
453 else
454 shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
455
456 /*
457 * assume a 4GB boundary, if not set
458 */
459 if (sht->dma_boundary)
460 shost->dma_boundary = sht->dma_boundary;
461 else
462 shost->dma_boundary = 0xffffffff;
463
464 device_initialize(&shost->shost_gendev);
465 dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
466 shost->shost_gendev.bus = &scsi_bus_type;
467 shost->shost_gendev.type = &scsi_host_type;
468
469 device_initialize(&shost->shost_dev);
470 shost->shost_dev.parent = &shost->shost_gendev;
471 shost->shost_dev.class = &shost_class;
472 dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
473 shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
474
475 shost->ehandler = kthread_run(scsi_error_handler, shost,
476 "scsi_eh_%d", shost->host_no);
477 if (IS_ERR(shost->ehandler)) {
478 shost_printk(KERN_WARNING, shost,
479 "error handler thread failed to spawn, error = %ld\n",
480 PTR_ERR(shost->ehandler));
481 goto fail_index_remove;
482 }
483
484 shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
485 WQ_UNBOUND | WQ_MEM_RECLAIM,
486 1, shost->host_no);
487 if (!shost->tmf_work_q) {
488 shost_printk(KERN_WARNING, shost,
489 "failed to create tmf workq\n");
490 goto fail_kthread;
491 }
492 scsi_proc_hostdir_add(shost->hostt);
493 return shost;
494
495 fail_kthread:
496 kthread_stop(shost->ehandler);
497 fail_index_remove:
498 ida_simple_remove(&host_index_ida, shost->host_no);
499 fail_kfree:
500 kfree(shost);
501 return NULL;
502}
503EXPORT_SYMBOL(scsi_host_alloc);
504
505static int __scsi_host_match(struct device *dev, const void *data)
506{
507 struct Scsi_Host *p;
508 const unsigned short *hostnum = data;
509
510 p = class_to_shost(dev);
511 return p->host_no == *hostnum;
512}
513
514/**
515 * scsi_host_lookup - get a reference to a Scsi_Host by host no
516 * @hostnum: host number to locate
517 *
518 * Return value:
519 * A pointer to located Scsi_Host or NULL.
520 *
521 * The caller must do a scsi_host_put() to drop the reference
522 * that scsi_host_get() took. The put_device() below dropped
523 * the reference from class_find_device().
524 **/
525struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
526{
527 struct device *cdev;
528 struct Scsi_Host *shost = NULL;
529
530 cdev = class_find_device(&shost_class, NULL, &hostnum,
531 __scsi_host_match);
532 if (cdev) {
533 shost = scsi_host_get(class_to_shost(cdev));
534 put_device(cdev);
535 }
536 return shost;
537}
538EXPORT_SYMBOL(scsi_host_lookup);
539
540/**
541 * scsi_host_get - inc a Scsi_Host ref count
542 * @shost: Pointer to Scsi_Host to inc.
543 **/
544struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
545{
546 if ((shost->shost_state == SHOST_DEL) ||
547 !get_device(&shost->shost_gendev))
548 return NULL;
549 return shost;
550}
551EXPORT_SYMBOL(scsi_host_get);
552
553/**
554 * scsi_host_busy - Return the host busy counter
555 * @shost: Pointer to Scsi_Host to inc.
556 **/
557int scsi_host_busy(struct Scsi_Host *shost)
558{
559 return atomic_read(&shost->host_busy);
560}
561EXPORT_SYMBOL(scsi_host_busy);
562
563/**
564 * scsi_host_put - dec a Scsi_Host ref count
565 * @shost: Pointer to Scsi_Host to dec.
566 **/
567void scsi_host_put(struct Scsi_Host *shost)
568{
569 put_device(&shost->shost_gendev);
570}
571EXPORT_SYMBOL(scsi_host_put);
572
573int scsi_init_hosts(void)
574{
575 return class_register(&shost_class);
576}
577
578void scsi_exit_hosts(void)
579{
580 class_unregister(&shost_class);
581 ida_destroy(&host_index_ida);
582}
583
584int scsi_is_host_device(const struct device *dev)
585{
586 return dev->type == &scsi_host_type;
587}
588EXPORT_SYMBOL(scsi_is_host_device);
589
590/**
591 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
592 * @shost: Pointer to Scsi_Host.
593 * @work: Work to queue for execution.
594 *
595 * Return value:
596 * 1 - work queued for execution
597 * 0 - work is already queued
598 * -EINVAL - work queue doesn't exist
599 **/
600int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
601{
602 if (unlikely(!shost->work_q)) {
603 shost_printk(KERN_ERR, shost,
604 "ERROR: Scsi host '%s' attempted to queue scsi-work, "
605 "when no workqueue created.\n", shost->hostt->name);
606 dump_stack();
607
608 return -EINVAL;
609 }
610
611 return queue_work(shost->work_q, work);
612}
613EXPORT_SYMBOL_GPL(scsi_queue_work);
614
615/**
616 * scsi_flush_work - Flush a Scsi_Host's workqueue.
617 * @shost: Pointer to Scsi_Host.
618 **/
619void scsi_flush_work(struct Scsi_Host *shost)
620{
621 if (!shost->work_q) {
622 shost_printk(KERN_ERR, shost,
623 "ERROR: Scsi host '%s' attempted to flush scsi-work, "
624 "when no workqueue created.\n", shost->hostt->name);
625 dump_stack();
626 return;
627 }
628
629 flush_workqueue(shost->work_q);
630}
631EXPORT_SYMBOL_GPL(scsi_flush_work);
632