1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * hosts.c Copyright (C) 1992 Drew Eckhardt
4 * Copyright (C) 1993, 1994, 1995 Eric Youngdale
5 * Copyright (C) 2002-2003 Christoph Hellwig
6 *
7 * mid to lowlevel SCSI driver interface
8 * Initial versions: Drew Eckhardt
9 * Subsequent revisions: Eric Youngdale
10 *
11 * <drew@colorado.edu>
12 *
13 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
14 * Added QLOGIC QLA1280 SCSI controller kernel host support.
15 * August 4, 1999 Fred Lewis, Intel DuPont
16 *
17 * Updated to reflect the new initialization scheme for the higher
18 * level of scsi drivers (sd/sr/st)
19 * September 17, 2000 Torben Mathiasen <tmm@image.dk>
20 *
21 * Restructured scsi_host lists and associated functions.
22 * September 04, 2002 Mike Anderson (andmike@us.ibm.com)
23 */
24
25 #include <linux/module.h>
26 #include <linux/blkdev.h>
27 #include <linux/kernel.h>
28 #include <linux/slab.h>
29 #include <linux/kthread.h>
30 #include <linux/string.h>
31 #include <linux/mm.h>
32 #include <linux/init.h>
33 #include <linux/completion.h>
34 #include <linux/transport_class.h>
35 #include <linux/platform_device.h>
36 #include <linux/pm_runtime.h>
37 #include <linux/idr.h>
38 #include <scsi/scsi_device.h>
39 #include <scsi/scsi_host.h>
40 #include <scsi/scsi_transport.h>
41
42 #include "scsi_priv.h"
43 #include "scsi_logging.h"
44
45
46 static int shost_eh_deadline = -1;
47
48 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
49 MODULE_PARM_DESC(eh_deadline,
50 "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
51
52 static DEFINE_IDA(host_index_ida);
53
54
scsi_host_cls_release(struct device * dev)55 static void scsi_host_cls_release(struct device *dev)
56 {
57 put_device(&class_to_shost(dev)->shost_gendev);
58 }
59
60 static struct class shost_class = {
61 .name = "scsi_host",
62 .dev_release = scsi_host_cls_release,
63 };
64
65 /**
66 * scsi_host_set_state - Take the given host through the host state model.
67 * @shost: scsi host to change the state of.
68 * @state: state to change to.
69 *
70 * Returns zero if unsuccessful or an error if the requested
71 * transition is illegal.
72 **/
scsi_host_set_state(struct Scsi_Host * shost,enum scsi_host_state state)73 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
74 {
75 enum scsi_host_state oldstate = shost->shost_state;
76
77 if (state == oldstate)
78 return 0;
79
80 switch (state) {
81 case SHOST_CREATED:
82 /* There are no legal states that come back to
83 * created. This is the manually initialised start
84 * state */
85 goto illegal;
86
87 case SHOST_RUNNING:
88 switch (oldstate) {
89 case SHOST_CREATED:
90 case SHOST_RECOVERY:
91 break;
92 default:
93 goto illegal;
94 }
95 break;
96
97 case SHOST_RECOVERY:
98 switch (oldstate) {
99 case SHOST_RUNNING:
100 break;
101 default:
102 goto illegal;
103 }
104 break;
105
106 case SHOST_CANCEL:
107 switch (oldstate) {
108 case SHOST_CREATED:
109 case SHOST_RUNNING:
110 case SHOST_CANCEL_RECOVERY:
111 break;
112 default:
113 goto illegal;
114 }
115 break;
116
117 case SHOST_DEL:
118 switch (oldstate) {
119 case SHOST_CANCEL:
120 case SHOST_DEL_RECOVERY:
121 break;
122 default:
123 goto illegal;
124 }
125 break;
126
127 case SHOST_CANCEL_RECOVERY:
128 switch (oldstate) {
129 case SHOST_CANCEL:
130 case SHOST_RECOVERY:
131 break;
132 default:
133 goto illegal;
134 }
135 break;
136
137 case SHOST_DEL_RECOVERY:
138 switch (oldstate) {
139 case SHOST_CANCEL_RECOVERY:
140 break;
141 default:
142 goto illegal;
143 }
144 break;
145 }
146 shost->shost_state = state;
147 return 0;
148
149 illegal:
150 SCSI_LOG_ERROR_RECOVERY(1,
151 shost_printk(KERN_ERR, shost,
152 "Illegal host state transition"
153 "%s->%s\n",
154 scsi_host_state_name(oldstate),
155 scsi_host_state_name(state)));
156 return -EINVAL;
157 }
158
159 /**
160 * scsi_remove_host - remove a scsi host
161 * @shost: a pointer to a scsi host to remove
162 **/
scsi_remove_host(struct Scsi_Host * shost)163 void scsi_remove_host(struct Scsi_Host *shost)
164 {
165 unsigned long flags;
166
167 mutex_lock(&shost->scan_mutex);
168 spin_lock_irqsave(shost->host_lock, flags);
169 if (scsi_host_set_state(shost, SHOST_CANCEL))
170 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
171 spin_unlock_irqrestore(shost->host_lock, flags);
172 mutex_unlock(&shost->scan_mutex);
173 return;
174 }
175 spin_unlock_irqrestore(shost->host_lock, flags);
176
177 scsi_autopm_get_host(shost);
178 flush_workqueue(shost->tmf_work_q);
179 scsi_forget_host(shost);
180 mutex_unlock(&shost->scan_mutex);
181 scsi_proc_host_rm(shost);
182
183 spin_lock_irqsave(shost->host_lock, flags);
184 if (scsi_host_set_state(shost, SHOST_DEL))
185 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
186 spin_unlock_irqrestore(shost->host_lock, flags);
187
188 transport_unregister_device(&shost->shost_gendev);
189 device_unregister(&shost->shost_dev);
190 device_del(&shost->shost_gendev);
191 }
192 EXPORT_SYMBOL(scsi_remove_host);
193
194 /**
195 * scsi_add_host_with_dma - add a scsi host with dma device
196 * @shost: scsi host pointer to add
197 * @dev: a struct device of type scsi class
198 * @dma_dev: dma device for the host
199 *
200 * Note: You rarely need to worry about this unless you're in a
201 * virtualised host environments, so use the simpler scsi_add_host()
202 * function instead.
203 *
204 * Return value:
205 * 0 on success / != 0 for error
206 **/
scsi_add_host_with_dma(struct Scsi_Host * shost,struct device * dev,struct device * dma_dev)207 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
208 struct device *dma_dev)
209 {
210 struct scsi_host_template *sht = shost->hostt;
211 int error = -EINVAL;
212
213 shost_printk(KERN_INFO, shost, "%s\n",
214 sht->info ? sht->info(shost) : sht->name);
215
216 if (!shost->can_queue) {
217 shost_printk(KERN_ERR, shost,
218 "can_queue = 0 no longer supported\n");
219 goto fail;
220 }
221
222 error = scsi_init_sense_cache(shost);
223 if (error)
224 goto fail;
225
226 error = scsi_mq_setup_tags(shost);
227 if (error)
228 goto fail;
229
230 if (!shost->shost_gendev.parent)
231 shost->shost_gendev.parent = dev ? dev : &platform_bus;
232 if (!dma_dev)
233 dma_dev = shost->shost_gendev.parent;
234
235 shost->dma_dev = dma_dev;
236
237 /*
238 * Increase usage count temporarily here so that calling
239 * scsi_autopm_put_host() will trigger runtime idle if there is
240 * nothing else preventing suspending the device.
241 */
242 pm_runtime_get_noresume(&shost->shost_gendev);
243 pm_runtime_set_active(&shost->shost_gendev);
244 pm_runtime_enable(&shost->shost_gendev);
245 device_enable_async_suspend(&shost->shost_gendev);
246
247 error = device_add(&shost->shost_gendev);
248 if (error)
249 goto out_disable_runtime_pm;
250
251 scsi_host_set_state(shost, SHOST_RUNNING);
252 get_device(shost->shost_gendev.parent);
253
254 device_enable_async_suspend(&shost->shost_dev);
255
256 error = device_add(&shost->shost_dev);
257 if (error)
258 goto out_del_gendev;
259
260 get_device(&shost->shost_gendev);
261
262 if (shost->transportt->host_size) {
263 shost->shost_data = kzalloc(shost->transportt->host_size,
264 GFP_KERNEL);
265 if (shost->shost_data == NULL) {
266 error = -ENOMEM;
267 goto out_del_dev;
268 }
269 }
270
271 if (shost->transportt->create_work_queue) {
272 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
273 "scsi_wq_%d", shost->host_no);
274 shost->work_q = create_singlethread_workqueue(
275 shost->work_q_name);
276 if (!shost->work_q) {
277 error = -EINVAL;
278 goto out_free_shost_data;
279 }
280 }
281
282 error = scsi_sysfs_add_host(shost);
283 if (error)
284 goto out_destroy_host;
285
286 scsi_proc_host_add(shost);
287 scsi_autopm_put_host(shost);
288 return error;
289
290 out_destroy_host:
291 if (shost->work_q)
292 destroy_workqueue(shost->work_q);
293 out_free_shost_data:
294 kfree(shost->shost_data);
295 out_del_dev:
296 device_del(&shost->shost_dev);
297 out_del_gendev:
298 device_del(&shost->shost_gendev);
299 out_disable_runtime_pm:
300 device_disable_async_suspend(&shost->shost_gendev);
301 pm_runtime_disable(&shost->shost_gendev);
302 pm_runtime_set_suspended(&shost->shost_gendev);
303 pm_runtime_put_noidle(&shost->shost_gendev);
304 scsi_mq_destroy_tags(shost);
305 fail:
306 return error;
307 }
308 EXPORT_SYMBOL(scsi_add_host_with_dma);
309
scsi_host_dev_release(struct device * dev)310 static void scsi_host_dev_release(struct device *dev)
311 {
312 struct Scsi_Host *shost = dev_to_shost(dev);
313 struct device *parent = dev->parent;
314
315 scsi_proc_hostdir_rm(shost->hostt);
316
317 /* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
318 rcu_barrier();
319
320 if (shost->tmf_work_q)
321 destroy_workqueue(shost->tmf_work_q);
322 if (shost->ehandler)
323 kthread_stop(shost->ehandler);
324 if (shost->work_q)
325 destroy_workqueue(shost->work_q);
326
327 if (shost->shost_state == SHOST_CREATED) {
328 /*
329 * Free the shost_dev device name here if scsi_host_alloc()
330 * and scsi_host_put() have been called but neither
331 * scsi_host_add() nor scsi_host_remove() has been called.
332 * This avoids that the memory allocated for the shost_dev
333 * name is leaked.
334 */
335 kfree(dev_name(&shost->shost_dev));
336 }
337
338 if (shost->tag_set.tags)
339 scsi_mq_destroy_tags(shost);
340
341 kfree(shost->shost_data);
342
343 ida_simple_remove(&host_index_ida, shost->host_no);
344
345 if (parent)
346 put_device(parent);
347 kfree(shost);
348 }
349
350 static struct device_type scsi_host_type = {
351 .name = "scsi_host",
352 .release = scsi_host_dev_release,
353 };
354
355 /**
356 * scsi_host_alloc - register a scsi host adapter instance.
357 * @sht: pointer to scsi host template
358 * @privsize: extra bytes to allocate for driver
359 *
360 * Note:
361 * Allocate a new Scsi_Host and perform basic initialization.
362 * The host is not published to the scsi midlayer until scsi_add_host
363 * is called.
364 *
365 * Return value:
366 * Pointer to a new Scsi_Host
367 **/
scsi_host_alloc(struct scsi_host_template * sht,int privsize)368 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
369 {
370 struct Scsi_Host *shost;
371 gfp_t gfp_mask = GFP_KERNEL;
372 int index;
373
374 if (sht->unchecked_isa_dma && privsize)
375 gfp_mask |= __GFP_DMA;
376
377 shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
378 if (!shost)
379 return NULL;
380
381 shost->host_lock = &shost->default_lock;
382 spin_lock_init(shost->host_lock);
383 shost->shost_state = SHOST_CREATED;
384 INIT_LIST_HEAD(&shost->__devices);
385 INIT_LIST_HEAD(&shost->__targets);
386 INIT_LIST_HEAD(&shost->eh_cmd_q);
387 INIT_LIST_HEAD(&shost->starved_list);
388 init_waitqueue_head(&shost->host_wait);
389 mutex_init(&shost->scan_mutex);
390
391 index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
392 if (index < 0)
393 goto fail_kfree;
394 shost->host_no = index;
395
396 shost->dma_channel = 0xff;
397
398 /* These three are default values which can be overridden */
399 shost->max_channel = 0;
400 shost->max_id = 8;
401 shost->max_lun = 8;
402
403 /* Give each shost a default transportt */
404 shost->transportt = &blank_transport_template;
405
406 /*
407 * All drivers right now should be able to handle 12 byte
408 * commands. Every so often there are requests for 16 byte
409 * commands, but individual low-level drivers need to certify that
410 * they actually do something sensible with such commands.
411 */
412 shost->max_cmd_len = 12;
413 shost->hostt = sht;
414 shost->this_id = sht->this_id;
415 shost->can_queue = sht->can_queue;
416 shost->sg_tablesize = sht->sg_tablesize;
417 shost->sg_prot_tablesize = sht->sg_prot_tablesize;
418 shost->cmd_per_lun = sht->cmd_per_lun;
419 shost->unchecked_isa_dma = sht->unchecked_isa_dma;
420 shost->no_write_same = sht->no_write_same;
421
422 if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
423 shost->eh_deadline = -1;
424 else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
425 shost_printk(KERN_WARNING, shost,
426 "eh_deadline %u too large, setting to %u\n",
427 shost_eh_deadline, INT_MAX / HZ);
428 shost->eh_deadline = INT_MAX;
429 } else
430 shost->eh_deadline = shost_eh_deadline * HZ;
431
432 if (sht->supported_mode == MODE_UNKNOWN)
433 /* means we didn't set it ... default to INITIATOR */
434 shost->active_mode = MODE_INITIATOR;
435 else
436 shost->active_mode = sht->supported_mode;
437
438 if (sht->max_host_blocked)
439 shost->max_host_blocked = sht->max_host_blocked;
440 else
441 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
442
443 /*
444 * If the driver imposes no hard sector transfer limit, start at
445 * machine infinity initially.
446 */
447 if (sht->max_sectors)
448 shost->max_sectors = sht->max_sectors;
449 else
450 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
451
452 if (sht->max_segment_size)
453 shost->max_segment_size = sht->max_segment_size;
454 else
455 shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
456
457 /*
458 * assume a 4GB boundary, if not set
459 */
460 if (sht->dma_boundary)
461 shost->dma_boundary = sht->dma_boundary;
462 else
463 shost->dma_boundary = 0xffffffff;
464
465 if (sht->virt_boundary_mask)
466 shost->virt_boundary_mask = sht->virt_boundary_mask;
467
468 device_initialize(&shost->shost_gendev);
469 dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
470 shost->shost_gendev.bus = &scsi_bus_type;
471 shost->shost_gendev.type = &scsi_host_type;
472
473 device_initialize(&shost->shost_dev);
474 shost->shost_dev.parent = &shost->shost_gendev;
475 shost->shost_dev.class = &shost_class;
476 dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
477 shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
478
479 shost->ehandler = kthread_run(scsi_error_handler, shost,
480 "scsi_eh_%d", shost->host_no);
481 if (IS_ERR(shost->ehandler)) {
482 shost_printk(KERN_WARNING, shost,
483 "error handler thread failed to spawn, error = %ld\n",
484 PTR_ERR(shost->ehandler));
485 goto fail_index_remove;
486 }
487
488 shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
489 WQ_UNBOUND | WQ_MEM_RECLAIM,
490 1, shost->host_no);
491 if (!shost->tmf_work_q) {
492 shost_printk(KERN_WARNING, shost,
493 "failed to create tmf workq\n");
494 goto fail_kthread;
495 }
496 scsi_proc_hostdir_add(shost->hostt);
497 return shost;
498
499 fail_kthread:
500 kthread_stop(shost->ehandler);
501 fail_index_remove:
502 ida_simple_remove(&host_index_ida, shost->host_no);
503 fail_kfree:
504 kfree(shost);
505 return NULL;
506 }
507 EXPORT_SYMBOL(scsi_host_alloc);
508
__scsi_host_match(struct device * dev,const void * data)509 static int __scsi_host_match(struct device *dev, const void *data)
510 {
511 struct Scsi_Host *p;
512 const unsigned short *hostnum = data;
513
514 p = class_to_shost(dev);
515 return p->host_no == *hostnum;
516 }
517
518 /**
519 * scsi_host_lookup - get a reference to a Scsi_Host by host no
520 * @hostnum: host number to locate
521 *
522 * Return value:
523 * A pointer to located Scsi_Host or NULL.
524 *
525 * The caller must do a scsi_host_put() to drop the reference
526 * that scsi_host_get() took. The put_device() below dropped
527 * the reference from class_find_device().
528 **/
scsi_host_lookup(unsigned short hostnum)529 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
530 {
531 struct device *cdev;
532 struct Scsi_Host *shost = NULL;
533
534 cdev = class_find_device(&shost_class, NULL, &hostnum,
535 __scsi_host_match);
536 if (cdev) {
537 shost = scsi_host_get(class_to_shost(cdev));
538 put_device(cdev);
539 }
540 return shost;
541 }
542 EXPORT_SYMBOL(scsi_host_lookup);
543
544 /**
545 * scsi_host_get - inc a Scsi_Host ref count
546 * @shost: Pointer to Scsi_Host to inc.
547 **/
scsi_host_get(struct Scsi_Host * shost)548 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
549 {
550 if ((shost->shost_state == SHOST_DEL) ||
551 !get_device(&shost->shost_gendev))
552 return NULL;
553 return shost;
554 }
555 EXPORT_SYMBOL(scsi_host_get);
556
557 /**
558 * scsi_host_busy - Return the host busy counter
559 * @shost: Pointer to Scsi_Host to inc.
560 **/
scsi_host_busy(struct Scsi_Host * shost)561 int scsi_host_busy(struct Scsi_Host *shost)
562 {
563 return atomic_read(&shost->host_busy);
564 }
565 EXPORT_SYMBOL(scsi_host_busy);
566
567 /**
568 * scsi_host_put - dec a Scsi_Host ref count
569 * @shost: Pointer to Scsi_Host to dec.
570 **/
scsi_host_put(struct Scsi_Host * shost)571 void scsi_host_put(struct Scsi_Host *shost)
572 {
573 put_device(&shost->shost_gendev);
574 }
575 EXPORT_SYMBOL(scsi_host_put);
576
scsi_init_hosts(void)577 int scsi_init_hosts(void)
578 {
579 return class_register(&shost_class);
580 }
581
scsi_exit_hosts(void)582 void scsi_exit_hosts(void)
583 {
584 class_unregister(&shost_class);
585 ida_destroy(&host_index_ida);
586 }
587
scsi_is_host_device(const struct device * dev)588 int scsi_is_host_device(const struct device *dev)
589 {
590 return dev->type == &scsi_host_type;
591 }
592 EXPORT_SYMBOL(scsi_is_host_device);
593
594 /**
595 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
596 * @shost: Pointer to Scsi_Host.
597 * @work: Work to queue for execution.
598 *
599 * Return value:
600 * 1 - work queued for execution
601 * 0 - work is already queued
602 * -EINVAL - work queue doesn't exist
603 **/
scsi_queue_work(struct Scsi_Host * shost,struct work_struct * work)604 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
605 {
606 if (unlikely(!shost->work_q)) {
607 shost_printk(KERN_ERR, shost,
608 "ERROR: Scsi host '%s' attempted to queue scsi-work, "
609 "when no workqueue created.\n", shost->hostt->name);
610 dump_stack();
611
612 return -EINVAL;
613 }
614
615 return queue_work(shost->work_q, work);
616 }
617 EXPORT_SYMBOL_GPL(scsi_queue_work);
618
619 /**
620 * scsi_flush_work - Flush a Scsi_Host's workqueue.
621 * @shost: Pointer to Scsi_Host.
622 **/
scsi_flush_work(struct Scsi_Host * shost)623 void scsi_flush_work(struct Scsi_Host *shost)
624 {
625 if (!shost->work_q) {
626 shost_printk(KERN_ERR, shost,
627 "ERROR: Scsi host '%s' attempted to flush scsi-work, "
628 "when no workqueue created.\n", shost->hostt->name);
629 dump_stack();
630 return;
631 }
632
633 flush_workqueue(shost->work_q);
634 }
635 EXPORT_SYMBOL_GPL(scsi_flush_work);
636