55522b7162d3b92368a84ff0a2a3cc3dbd3e7655
[sfrench/cifs-2.6.git] / drivers / scsi / hosts.c
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
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  **/
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  **/
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  **/
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
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  **/
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
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  **/
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  **/
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  **/
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  **/
571 void scsi_host_put(struct Scsi_Host *shost)
572 {
573         put_device(&shost->shost_gendev);
574 }
575 EXPORT_SYMBOL(scsi_host_put);
576
577 int scsi_init_hosts(void)
578 {
579         return class_register(&shost_class);
580 }
581
582 void scsi_exit_hosts(void)
583 {
584         class_unregister(&shost_class);
585         ida_destroy(&host_index_ida);
586 }
587
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  **/
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  **/
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);