1 // SPDX-License-Identifier: GPL-2.0-only
3 * hosts.c Copyright (C) 1992 Drew Eckhardt
4 * Copyright (C) 1993, 1994, 1995 Eric Youngdale
5 * Copyright (C) 2002-2003 Christoph Hellwig
7 * mid to lowlevel SCSI driver interface
8 * Initial versions: Drew Eckhardt
9 * Subsequent revisions: Eric Youngdale
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
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>
21 * Restructured scsi_host lists and associated functions.
22 * September 04, 2002 Mike Anderson (andmike@us.ibm.com)
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>
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>
42 #include "scsi_priv.h"
43 #include "scsi_logging.h"
46 static int shost_eh_deadline = -1;
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)");
52 static DEFINE_IDA(host_index_ida);
55 static void scsi_host_cls_release(struct device *dev)
57 put_device(&class_to_shost(dev)->shost_gendev);
60 static struct class shost_class = {
62 .dev_release = scsi_host_cls_release,
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.
70 * Returns zero if unsuccessful or an error if the requested
71 * transition is illegal.
73 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
75 enum scsi_host_state oldstate = shost->shost_state;
77 if (state == oldstate)
82 /* There are no legal states that come back to
83 * created. This is the manually initialised start
110 case SHOST_CANCEL_RECOVERY:
120 case SHOST_DEL_RECOVERY:
127 case SHOST_CANCEL_RECOVERY:
137 case SHOST_DEL_RECOVERY:
139 case SHOST_CANCEL_RECOVERY:
146 shost->shost_state = state;
150 SCSI_LOG_ERROR_RECOVERY(1,
151 shost_printk(KERN_ERR, shost,
152 "Illegal host state transition"
154 scsi_host_state_name(oldstate),
155 scsi_host_state_name(state)));
160 * scsi_remove_host - remove a scsi host
161 * @shost: a pointer to a scsi host to remove
163 void scsi_remove_host(struct Scsi_Host *shost)
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);
175 spin_unlock_irqrestore(shost->host_lock, flags);
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);
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);
188 transport_unregister_device(&shost->shost_gendev);
189 device_unregister(&shost->shost_dev);
190 device_del(&shost->shost_gendev);
192 EXPORT_SYMBOL(scsi_remove_host);
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
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()
205 * 0 on success / != 0 for error
207 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
208 struct device *dma_dev)
210 struct scsi_host_template *sht = shost->hostt;
213 shost_printk(KERN_INFO, shost, "%s\n",
214 sht->info ? sht->info(shost) : sht->name);
216 if (!shost->can_queue) {
217 shost_printk(KERN_ERR, shost,
218 "can_queue = 0 no longer supported\n");
222 /* Use min_t(int, ...) in case shost->can_queue exceeds SHRT_MAX */
223 shost->cmd_per_lun = min_t(int, shost->cmd_per_lun,
226 error = scsi_init_sense_cache(shost);
230 error = scsi_mq_setup_tags(shost);
234 if (!shost->shost_gendev.parent)
235 shost->shost_gendev.parent = dev ? dev : &platform_bus;
237 dma_dev = shost->shost_gendev.parent;
239 shost->dma_dev = dma_dev;
242 * Increase usage count temporarily here so that calling
243 * scsi_autopm_put_host() will trigger runtime idle if there is
244 * nothing else preventing suspending the device.
246 pm_runtime_get_noresume(&shost->shost_gendev);
247 pm_runtime_set_active(&shost->shost_gendev);
248 pm_runtime_enable(&shost->shost_gendev);
249 device_enable_async_suspend(&shost->shost_gendev);
251 error = device_add(&shost->shost_gendev);
253 goto out_disable_runtime_pm;
255 scsi_host_set_state(shost, SHOST_RUNNING);
256 get_device(shost->shost_gendev.parent);
258 device_enable_async_suspend(&shost->shost_dev);
260 get_device(&shost->shost_gendev);
261 error = device_add(&shost->shost_dev);
265 if (shost->transportt->host_size) {
266 shost->shost_data = kzalloc(shost->transportt->host_size,
268 if (shost->shost_data == NULL) {
274 if (shost->transportt->create_work_queue) {
275 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
276 "scsi_wq_%d", shost->host_no);
277 shost->work_q = create_singlethread_workqueue(
279 if (!shost->work_q) {
285 error = scsi_sysfs_add_host(shost);
289 scsi_proc_host_add(shost);
290 scsi_autopm_put_host(shost);
294 * Any host allocation in this function will be freed in
295 * scsi_host_dev_release().
298 device_del(&shost->shost_dev);
301 * Host state is SHOST_RUNNING so we have to explicitly release
304 put_device(&shost->shost_dev);
305 device_del(&shost->shost_gendev);
306 out_disable_runtime_pm:
307 device_disable_async_suspend(&shost->shost_gendev);
308 pm_runtime_disable(&shost->shost_gendev);
309 pm_runtime_set_suspended(&shost->shost_gendev);
310 pm_runtime_put_noidle(&shost->shost_gendev);
314 EXPORT_SYMBOL(scsi_add_host_with_dma);
316 static void scsi_host_dev_release(struct device *dev)
318 struct Scsi_Host *shost = dev_to_shost(dev);
319 struct device *parent = dev->parent;
321 scsi_proc_hostdir_rm(shost->hostt);
323 /* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
326 if (shost->tmf_work_q)
327 destroy_workqueue(shost->tmf_work_q);
329 kthread_stop(shost->ehandler);
331 destroy_workqueue(shost->work_q);
333 if (shost->shost_state == SHOST_CREATED) {
335 * Free the shost_dev device name here if scsi_host_alloc()
336 * and scsi_host_put() have been called but neither
337 * scsi_host_add() nor scsi_host_remove() has been called.
338 * This avoids that the memory allocated for the shost_dev
341 kfree(dev_name(&shost->shost_dev));
344 if (shost->tag_set.tags)
345 scsi_mq_destroy_tags(shost);
347 kfree(shost->shost_data);
349 ida_simple_remove(&host_index_ida, shost->host_no);
351 if (shost->shost_state != SHOST_CREATED)
356 static struct device_type scsi_host_type = {
358 .release = scsi_host_dev_release,
362 * scsi_host_alloc - register a scsi host adapter instance.
363 * @sht: pointer to scsi host template
364 * @privsize: extra bytes to allocate for driver
367 * Allocate a new Scsi_Host and perform basic initialization.
368 * The host is not published to the scsi midlayer until scsi_add_host
372 * Pointer to a new Scsi_Host
374 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
376 struct Scsi_Host *shost;
377 gfp_t gfp_mask = GFP_KERNEL;
380 if (sht->unchecked_isa_dma && privsize)
381 gfp_mask |= __GFP_DMA;
383 shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
387 shost->host_lock = &shost->default_lock;
388 spin_lock_init(shost->host_lock);
389 shost->shost_state = SHOST_CREATED;
390 INIT_LIST_HEAD(&shost->__devices);
391 INIT_LIST_HEAD(&shost->__targets);
392 INIT_LIST_HEAD(&shost->eh_cmd_q);
393 INIT_LIST_HEAD(&shost->starved_list);
394 init_waitqueue_head(&shost->host_wait);
395 mutex_init(&shost->scan_mutex);
397 index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
402 shost->host_no = index;
404 shost->dma_channel = 0xff;
406 /* These three are default values which can be overridden */
407 shost->max_channel = 0;
411 /* Give each shost a default transportt */
412 shost->transportt = &blank_transport_template;
415 * All drivers right now should be able to handle 12 byte
416 * commands. Every so often there are requests for 16 byte
417 * commands, but individual low-level drivers need to certify that
418 * they actually do something sensible with such commands.
420 shost->max_cmd_len = 12;
422 shost->this_id = sht->this_id;
423 shost->can_queue = sht->can_queue;
424 shost->sg_tablesize = sht->sg_tablesize;
425 shost->sg_prot_tablesize = sht->sg_prot_tablesize;
426 shost->cmd_per_lun = sht->cmd_per_lun;
427 shost->unchecked_isa_dma = sht->unchecked_isa_dma;
428 shost->no_write_same = sht->no_write_same;
430 if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
431 shost->eh_deadline = -1;
432 else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
433 shost_printk(KERN_WARNING, shost,
434 "eh_deadline %u too large, setting to %u\n",
435 shost_eh_deadline, INT_MAX / HZ);
436 shost->eh_deadline = INT_MAX;
438 shost->eh_deadline = shost_eh_deadline * HZ;
440 if (sht->supported_mode == MODE_UNKNOWN)
441 /* means we didn't set it ... default to INITIATOR */
442 shost->active_mode = MODE_INITIATOR;
444 shost->active_mode = sht->supported_mode;
446 if (sht->max_host_blocked)
447 shost->max_host_blocked = sht->max_host_blocked;
449 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
452 * If the driver imposes no hard sector transfer limit, start at
453 * machine infinity initially.
455 if (sht->max_sectors)
456 shost->max_sectors = sht->max_sectors;
458 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
460 if (sht->max_segment_size)
461 shost->max_segment_size = sht->max_segment_size;
463 shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
466 * assume a 4GB boundary, if not set
468 if (sht->dma_boundary)
469 shost->dma_boundary = sht->dma_boundary;
471 shost->dma_boundary = 0xffffffff;
473 if (sht->virt_boundary_mask)
474 shost->virt_boundary_mask = sht->virt_boundary_mask;
476 device_initialize(&shost->shost_gendev);
477 dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
478 shost->shost_gendev.bus = &scsi_bus_type;
479 shost->shost_gendev.type = &scsi_host_type;
481 device_initialize(&shost->shost_dev);
482 shost->shost_dev.parent = &shost->shost_gendev;
483 shost->shost_dev.class = &shost_class;
484 dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
485 shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
487 shost->ehandler = kthread_run(scsi_error_handler, shost,
488 "scsi_eh_%d", shost->host_no);
489 if (IS_ERR(shost->ehandler)) {
490 shost_printk(KERN_WARNING, shost,
491 "error handler thread failed to spawn, error = %ld\n",
492 PTR_ERR(shost->ehandler));
493 shost->ehandler = NULL;
497 shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
498 WQ_UNBOUND | WQ_MEM_RECLAIM,
500 if (!shost->tmf_work_q) {
501 shost_printk(KERN_WARNING, shost,
502 "failed to create tmf workq\n");
505 scsi_proc_hostdir_add(shost->hostt);
509 * Host state is still SHOST_CREATED and that is enough to release
510 * ->shost_gendev. scsi_host_dev_release() will free
511 * dev_name(&shost->shost_dev).
513 put_device(&shost->shost_gendev);
517 EXPORT_SYMBOL(scsi_host_alloc);
519 static int __scsi_host_match(struct device *dev, const void *data)
522 const unsigned short *hostnum = data;
524 p = class_to_shost(dev);
525 return p->host_no == *hostnum;
529 * scsi_host_lookup - get a reference to a Scsi_Host by host no
530 * @hostnum: host number to locate
533 * A pointer to located Scsi_Host or NULL.
535 * The caller must do a scsi_host_put() to drop the reference
536 * that scsi_host_get() took. The put_device() below dropped
537 * the reference from class_find_device().
539 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
542 struct Scsi_Host *shost = NULL;
544 cdev = class_find_device(&shost_class, NULL, &hostnum,
547 shost = scsi_host_get(class_to_shost(cdev));
552 EXPORT_SYMBOL(scsi_host_lookup);
555 * scsi_host_get - inc a Scsi_Host ref count
556 * @shost: Pointer to Scsi_Host to inc.
558 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
560 if ((shost->shost_state == SHOST_DEL) ||
561 !get_device(&shost->shost_gendev))
565 EXPORT_SYMBOL(scsi_host_get);
568 * scsi_host_busy - Return the host busy counter
569 * @shost: Pointer to Scsi_Host to inc.
571 int scsi_host_busy(struct Scsi_Host *shost)
573 return atomic_read(&shost->host_busy);
575 EXPORT_SYMBOL(scsi_host_busy);
578 * scsi_host_put - dec a Scsi_Host ref count
579 * @shost: Pointer to Scsi_Host to dec.
581 void scsi_host_put(struct Scsi_Host *shost)
583 put_device(&shost->shost_gendev);
585 EXPORT_SYMBOL(scsi_host_put);
587 int scsi_init_hosts(void)
589 return class_register(&shost_class);
592 void scsi_exit_hosts(void)
594 class_unregister(&shost_class);
595 ida_destroy(&host_index_ida);
598 int scsi_is_host_device(const struct device *dev)
600 return dev->type == &scsi_host_type;
602 EXPORT_SYMBOL(scsi_is_host_device);
605 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
606 * @shost: Pointer to Scsi_Host.
607 * @work: Work to queue for execution.
610 * 1 - work queued for execution
611 * 0 - work is already queued
612 * -EINVAL - work queue doesn't exist
614 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
616 if (unlikely(!shost->work_q)) {
617 shost_printk(KERN_ERR, shost,
618 "ERROR: Scsi host '%s' attempted to queue scsi-work, "
619 "when no workqueue created.\n", shost->hostt->name);
625 return queue_work(shost->work_q, work);
627 EXPORT_SYMBOL_GPL(scsi_queue_work);
630 * scsi_flush_work - Flush a Scsi_Host's workqueue.
631 * @shost: Pointer to Scsi_Host.
633 void scsi_flush_work(struct Scsi_Host *shost)
635 if (!shost->work_q) {
636 shost_printk(KERN_ERR, shost,
637 "ERROR: Scsi host '%s' attempted to flush scsi-work, "
638 "when no workqueue created.\n", shost->hostt->name);
643 flush_workqueue(shost->work_q);
645 EXPORT_SYMBOL_GPL(scsi_flush_work);