2 * hosts.c Copyright (C) 1992 Drew Eckhardt
3 * Copyright (C) 1993, 1994, 1995 Eric Youngdale
4 * Copyright (C) 2002-2003 Christoph Hellwig
6 * mid to lowlevel SCSI driver interface
7 * Initial versions: Drew Eckhardt
8 * Subsequent revisions: Eric Youngdale
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
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>
20 * Restructured scsi_host lists and associated functions.
21 * September 04, 2002 Mike Anderson (andmike@us.ibm.com)
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>
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>
37 #include <scsi/scsi_device.h>
38 #include <scsi/scsi_host.h>
39 #include <scsi/scsi_transport.h>
41 #include "scsi_priv.h"
42 #include "scsi_logging.h"
45 static atomic_t scsi_host_next_hn = ATOMIC_INIT(0); /* host_no for next new host */
48 static void scsi_host_cls_release(struct device *dev)
50 put_device(&class_to_shost(dev)->shost_gendev);
53 static struct class shost_class = {
55 .dev_release = scsi_host_cls_release,
59 * scsi_host_set_state - Take the given host through the host state model.
60 * @shost: scsi host to change the state of.
61 * @state: state to change to.
63 * Returns zero if unsuccessful or an error if the requested
64 * transition is illegal.
66 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
68 enum scsi_host_state oldstate = shost->shost_state;
70 if (state == oldstate)
75 /* There are no legal states that come back to
76 * created. This is the manually initialised start
103 case SHOST_CANCEL_RECOVERY:
113 case SHOST_DEL_RECOVERY:
120 case SHOST_CANCEL_RECOVERY:
130 case SHOST_DEL_RECOVERY:
132 case SHOST_CANCEL_RECOVERY:
139 shost->shost_state = state;
143 SCSI_LOG_ERROR_RECOVERY(1,
144 shost_printk(KERN_ERR, shost,
145 "Illegal host state transition"
147 scsi_host_state_name(oldstate),
148 scsi_host_state_name(state)));
151 EXPORT_SYMBOL(scsi_host_set_state);
154 * scsi_remove_host - remove a scsi host
155 * @shost: a pointer to a scsi host to remove
157 void scsi_remove_host(struct Scsi_Host *shost)
161 mutex_lock(&shost->scan_mutex);
162 spin_lock_irqsave(shost->host_lock, flags);
163 if (scsi_host_set_state(shost, SHOST_CANCEL))
164 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
165 spin_unlock_irqrestore(shost->host_lock, flags);
166 mutex_unlock(&shost->scan_mutex);
169 spin_unlock_irqrestore(shost->host_lock, flags);
171 scsi_autopm_get_host(shost);
172 flush_workqueue(shost->tmf_work_q);
173 scsi_forget_host(shost);
174 mutex_unlock(&shost->scan_mutex);
175 scsi_proc_host_rm(shost);
177 spin_lock_irqsave(shost->host_lock, flags);
178 if (scsi_host_set_state(shost, SHOST_DEL))
179 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
180 spin_unlock_irqrestore(shost->host_lock, flags);
182 transport_unregister_device(&shost->shost_gendev);
183 device_unregister(&shost->shost_dev);
184 device_del(&shost->shost_gendev);
186 EXPORT_SYMBOL(scsi_remove_host);
189 * scsi_add_host_with_dma - add a scsi host with dma device
190 * @shost: scsi host pointer to add
191 * @dev: a struct device of type scsi class
192 * @dma_dev: dma device for the host
194 * Note: You rarely need to worry about this unless you're in a
195 * virtualised host environments, so use the simpler scsi_add_host()
199 * 0 on success / != 0 for error
201 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
202 struct device *dma_dev)
204 struct scsi_host_template *sht = shost->hostt;
207 shost_printk(KERN_INFO, shost, "%s\n",
208 sht->info ? sht->info(shost) : sht->name);
210 if (!shost->can_queue) {
211 shost_printk(KERN_ERR, shost,
212 "can_queue = 0 no longer supported\n");
216 if (shost_use_blk_mq(shost)) {
217 error = scsi_mq_setup_tags(shost);
221 shost->bqt = blk_init_tags(shost->can_queue,
222 shost->hostt->tag_alloc_policy);
230 * Note that we allocate the freelist even for the MQ case for now,
231 * as we need a command set aside for scsi_reset_provider. Having
232 * the full host freelist and one command available for that is a
233 * little heavy-handed, but avoids introducing a special allocator
234 * just for this. Eventually the structure of scsi_reset_provider
235 * will need a major overhaul.
237 error = scsi_setup_command_freelist(shost);
239 goto out_destroy_tags;
242 if (!shost->shost_gendev.parent)
243 shost->shost_gendev.parent = dev ? dev : &platform_bus;
245 dma_dev = shost->shost_gendev.parent;
247 shost->dma_dev = dma_dev;
249 error = device_add(&shost->shost_gendev);
251 goto out_destroy_freelist;
253 pm_runtime_set_active(&shost->shost_gendev);
254 pm_runtime_enable(&shost->shost_gendev);
255 device_enable_async_suspend(&shost->shost_gendev);
257 scsi_host_set_state(shost, SHOST_RUNNING);
258 get_device(shost->shost_gendev.parent);
260 device_enable_async_suspend(&shost->shost_dev);
262 get_device(&shost->shost_gendev);
263 error = device_add(&shost->shost_dev);
267 if (shost->transportt->host_size) {
268 shost->shost_data = kzalloc(shost->transportt->host_size,
270 if (shost->shost_data == NULL) {
276 if (shost->transportt->create_work_queue) {
277 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
278 "scsi_wq_%d", shost->host_no);
279 shost->work_q = create_singlethread_workqueue(
281 if (!shost->work_q) {
283 goto out_free_shost_data;
287 error = scsi_sysfs_add_host(shost);
289 goto out_destroy_host;
291 scsi_proc_host_add(shost);
296 destroy_workqueue(shost->work_q);
298 kfree(shost->shost_data);
300 device_del(&shost->shost_dev);
303 * Host state is SHOST_RUNNING so we have to explicitly release
306 put_device(&shost->shost_dev);
307 device_del(&shost->shost_gendev);
308 out_destroy_freelist:
309 scsi_destroy_command_freelist(shost);
311 if (shost_use_blk_mq(shost))
312 scsi_mq_destroy_tags(shost);
316 EXPORT_SYMBOL(scsi_add_host_with_dma);
318 static void scsi_host_dev_release(struct device *dev)
320 struct Scsi_Host *shost = dev_to_shost(dev);
321 struct device *parent = dev->parent;
322 struct request_queue *q;
325 scsi_proc_hostdir_rm(shost->hostt);
327 if (shost->tmf_work_q)
328 destroy_workqueue(shost->tmf_work_q);
330 kthread_stop(shost->ehandler);
332 destroy_workqueue(shost->work_q);
333 q = shost->uspace_req_q;
335 queuedata = q->queuedata;
336 blk_cleanup_queue(q);
340 if (shost->shost_state == SHOST_CREATED) {
342 * Free the shost_dev device name here if scsi_host_alloc()
343 * and scsi_host_put() have been called but neither
344 * scsi_host_add() nor scsi_host_remove() has been called.
345 * This avoids that the memory allocated for the shost_dev
348 kfree(dev_name(&shost->shost_dev));
351 scsi_destroy_command_freelist(shost);
352 if (shost_use_blk_mq(shost)) {
353 if (shost->tag_set.tags)
354 scsi_mq_destroy_tags(shost);
357 blk_free_tags(shost->bqt);
360 kfree(shost->shost_data);
362 if (shost->shost_state != SHOST_CREATED)
367 static int shost_eh_deadline = -1;
369 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
370 MODULE_PARM_DESC(eh_deadline,
371 "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
373 static struct device_type scsi_host_type = {
375 .release = scsi_host_dev_release,
379 * scsi_host_alloc - register a scsi host adapter instance.
380 * @sht: pointer to scsi host template
381 * @privsize: extra bytes to allocate for driver
384 * Allocate a new Scsi_Host and perform basic initialization.
385 * The host is not published to the scsi midlayer until scsi_add_host
389 * Pointer to a new Scsi_Host
391 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
393 struct Scsi_Host *shost;
394 gfp_t gfp_mask = GFP_KERNEL;
396 if (sht->unchecked_isa_dma && privsize)
397 gfp_mask |= __GFP_DMA;
399 shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
403 shost->host_lock = &shost->default_lock;
404 spin_lock_init(shost->host_lock);
405 shost->shost_state = SHOST_CREATED;
406 INIT_LIST_HEAD(&shost->__devices);
407 INIT_LIST_HEAD(&shost->__targets);
408 INIT_LIST_HEAD(&shost->eh_cmd_q);
409 INIT_LIST_HEAD(&shost->starved_list);
410 init_waitqueue_head(&shost->host_wait);
411 mutex_init(&shost->scan_mutex);
414 * subtract one because we increment first then return, but we need to
415 * know what the next host number was before increment
417 shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
418 shost->dma_channel = 0xff;
420 /* These three are default values which can be overridden */
421 shost->max_channel = 0;
425 /* Give each shost a default transportt */
426 shost->transportt = &blank_transport_template;
429 * All drivers right now should be able to handle 12 byte
430 * commands. Every so often there are requests for 16 byte
431 * commands, but individual low-level drivers need to certify that
432 * they actually do something sensible with such commands.
434 shost->max_cmd_len = 12;
436 shost->this_id = sht->this_id;
437 shost->can_queue = sht->can_queue;
438 shost->sg_tablesize = sht->sg_tablesize;
439 shost->sg_prot_tablesize = sht->sg_prot_tablesize;
440 shost->cmd_per_lun = sht->cmd_per_lun;
441 shost->unchecked_isa_dma = sht->unchecked_isa_dma;
442 shost->use_clustering = sht->use_clustering;
443 shost->no_write_same = sht->no_write_same;
445 if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
446 shost->eh_deadline = -1;
447 else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
448 shost_printk(KERN_WARNING, shost,
449 "eh_deadline %u too large, setting to %u\n",
450 shost_eh_deadline, INT_MAX / HZ);
451 shost->eh_deadline = INT_MAX;
453 shost->eh_deadline = shost_eh_deadline * HZ;
455 if (sht->supported_mode == MODE_UNKNOWN)
456 /* means we didn't set it ... default to INITIATOR */
457 shost->active_mode = MODE_INITIATOR;
459 shost->active_mode = sht->supported_mode;
461 if (sht->max_host_blocked)
462 shost->max_host_blocked = sht->max_host_blocked;
464 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
467 * If the driver imposes no hard sector transfer limit, start at
468 * machine infinity initially.
470 if (sht->max_sectors)
471 shost->max_sectors = sht->max_sectors;
473 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
476 * assume a 4GB boundary, if not set
478 if (sht->dma_boundary)
479 shost->dma_boundary = sht->dma_boundary;
481 shost->dma_boundary = 0xffffffff;
483 shost->use_blk_mq = scsi_use_blk_mq && !shost->hostt->disable_blk_mq;
485 device_initialize(&shost->shost_gendev);
486 dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
487 shost->shost_gendev.bus = &scsi_bus_type;
488 shost->shost_gendev.type = &scsi_host_type;
490 device_initialize(&shost->shost_dev);
491 shost->shost_dev.parent = &shost->shost_gendev;
492 shost->shost_dev.class = &shost_class;
493 dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
494 shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
496 shost->ehandler = kthread_run(scsi_error_handler, shost,
497 "scsi_eh_%d", shost->host_no);
498 if (IS_ERR(shost->ehandler)) {
499 shost_printk(KERN_WARNING, shost,
500 "error handler thread failed to spawn, error = %ld\n",
501 PTR_ERR(shost->ehandler));
505 shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
506 WQ_UNBOUND | WQ_MEM_RECLAIM,
508 if (!shost->tmf_work_q) {
509 shost_printk(KERN_WARNING, shost,
510 "failed to create tmf workq\n");
513 scsi_proc_hostdir_add(shost->hostt);
517 kthread_stop(shost->ehandler);
522 EXPORT_SYMBOL(scsi_host_alloc);
524 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
526 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
529 printk(KERN_WARNING "scsi_register() called on new-style "
530 "template for driver %s\n", sht->name);
535 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
538 EXPORT_SYMBOL(scsi_register);
540 void scsi_unregister(struct Scsi_Host *shost)
542 list_del(&shost->sht_legacy_list);
543 scsi_host_put(shost);
545 EXPORT_SYMBOL(scsi_unregister);
547 static int __scsi_host_match(struct device *dev, const void *data)
550 const unsigned short *hostnum = data;
552 p = class_to_shost(dev);
553 return p->host_no == *hostnum;
557 * scsi_host_lookup - get a reference to a Scsi_Host by host no
558 * @hostnum: host number to locate
561 * A pointer to located Scsi_Host or NULL.
563 * The caller must do a scsi_host_put() to drop the reference
564 * that scsi_host_get() took. The put_device() below dropped
565 * the reference from class_find_device().
567 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
570 struct Scsi_Host *shost = NULL;
572 cdev = class_find_device(&shost_class, NULL, &hostnum,
575 shost = scsi_host_get(class_to_shost(cdev));
580 EXPORT_SYMBOL(scsi_host_lookup);
583 * scsi_host_get - inc a Scsi_Host ref count
584 * @shost: Pointer to Scsi_Host to inc.
586 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
588 if ((shost->shost_state == SHOST_DEL) ||
589 !get_device(&shost->shost_gendev))
593 EXPORT_SYMBOL(scsi_host_get);
596 * scsi_host_put - dec a Scsi_Host ref count
597 * @shost: Pointer to Scsi_Host to dec.
599 void scsi_host_put(struct Scsi_Host *shost)
601 put_device(&shost->shost_gendev);
603 EXPORT_SYMBOL(scsi_host_put);
605 int scsi_init_hosts(void)
607 return class_register(&shost_class);
610 void scsi_exit_hosts(void)
612 class_unregister(&shost_class);
615 int scsi_is_host_device(const struct device *dev)
617 return dev->type == &scsi_host_type;
619 EXPORT_SYMBOL(scsi_is_host_device);
622 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
623 * @shost: Pointer to Scsi_Host.
624 * @work: Work to queue for execution.
627 * 1 - work queued for execution
628 * 0 - work is already queued
629 * -EINVAL - work queue doesn't exist
631 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
633 if (unlikely(!shost->work_q)) {
634 shost_printk(KERN_ERR, shost,
635 "ERROR: Scsi host '%s' attempted to queue scsi-work, "
636 "when no workqueue created.\n", shost->hostt->name);
642 return queue_work(shost->work_q, work);
644 EXPORT_SYMBOL_GPL(scsi_queue_work);
647 * scsi_flush_work - Flush a Scsi_Host's workqueue.
648 * @shost: Pointer to Scsi_Host.
650 void scsi_flush_work(struct Scsi_Host *shost)
652 if (!shost->work_q) {
653 shost_printk(KERN_ERR, shost,
654 "ERROR: Scsi host '%s' attempted to flush scsi-work, "
655 "when no workqueue created.\n", shost->hostt->name);
660 flush_workqueue(shost->work_q);
662 EXPORT_SYMBOL_GPL(scsi_flush_work);