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>
36 #include <linux/idr.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 int shost_eh_deadline = -1;
47 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
48 MODULE_PARM_DESC(eh_deadline,
49 "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
51 static DEFINE_IDA(host_index_ida);
54 static void scsi_host_cls_release(struct device *dev)
56 put_device(&class_to_shost(dev)->shost_gendev);
59 static struct class shost_class = {
61 .dev_release = scsi_host_cls_release,
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.
69 * Returns zero if unsuccessful or an error if the requested
70 * transition is illegal.
72 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
74 enum scsi_host_state oldstate = shost->shost_state;
76 if (state == oldstate)
81 /* There are no legal states that come back to
82 * created. This is the manually initialised start
109 case SHOST_CANCEL_RECOVERY:
119 case SHOST_DEL_RECOVERY:
126 case SHOST_CANCEL_RECOVERY:
136 case SHOST_DEL_RECOVERY:
138 case SHOST_CANCEL_RECOVERY:
145 shost->shost_state = state;
149 SCSI_LOG_ERROR_RECOVERY(1,
150 shost_printk(KERN_ERR, shost,
151 "Illegal host state transition"
153 scsi_host_state_name(oldstate),
154 scsi_host_state_name(state)));
159 * scsi_remove_host - remove a scsi host
160 * @shost: a pointer to a scsi host to remove
162 void scsi_remove_host(struct Scsi_Host *shost)
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);
174 spin_unlock_irqrestore(shost->host_lock, flags);
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 scsi_proc_hostdir_rm(shost->hostt);
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 if (shost_use_blk_mq(shost)) {
231 error = scsi_mq_setup_tags(shost);
235 shost->bqt = blk_init_tags(shost->can_queue,
236 shost->hostt->tag_alloc_policy);
243 if (!shost->shost_gendev.parent)
244 shost->shost_gendev.parent = dev ? dev : &platform_bus;
246 dma_dev = shost->shost_gendev.parent;
248 shost->dma_dev = dma_dev;
251 * Increase usage count temporarily here so that calling
252 * scsi_autopm_put_host() will trigger runtime idle if there is
253 * nothing else preventing suspending the device.
255 pm_runtime_get_noresume(&shost->shost_gendev);
256 pm_runtime_set_active(&shost->shost_gendev);
257 pm_runtime_enable(&shost->shost_gendev);
258 device_enable_async_suspend(&shost->shost_gendev);
260 error = device_add(&shost->shost_gendev);
262 goto out_disable_runtime_pm;
264 scsi_host_set_state(shost, SHOST_RUNNING);
265 get_device(shost->shost_gendev.parent);
267 device_enable_async_suspend(&shost->shost_dev);
269 get_device(&shost->shost_gendev);
270 error = device_add(&shost->shost_dev);
274 if (shost->transportt->host_size) {
275 shost->shost_data = kzalloc(shost->transportt->host_size,
277 if (shost->shost_data == NULL) {
283 if (shost->transportt->create_work_queue) {
284 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
285 "scsi_wq_%d", shost->host_no);
286 shost->work_q = create_singlethread_workqueue(
288 if (!shost->work_q) {
290 goto out_free_shost_data;
294 error = scsi_sysfs_add_host(shost);
296 goto out_destroy_host;
298 scsi_proc_host_add(shost);
299 scsi_autopm_put_host(shost);
304 destroy_workqueue(shost->work_q);
306 kfree(shost->shost_data);
308 device_del(&shost->shost_dev);
311 * Host state is SHOST_RUNNING so we have to explicitly release
314 put_device(&shost->shost_dev);
315 device_del(&shost->shost_gendev);
316 out_disable_runtime_pm:
317 device_disable_async_suspend(&shost->shost_gendev);
318 pm_runtime_disable(&shost->shost_gendev);
319 pm_runtime_set_suspended(&shost->shost_gendev);
320 pm_runtime_put_noidle(&shost->shost_gendev);
321 if (shost_use_blk_mq(shost))
322 scsi_mq_destroy_tags(shost);
326 EXPORT_SYMBOL(scsi_add_host_with_dma);
328 static void scsi_host_dev_release(struct device *dev)
330 struct Scsi_Host *shost = dev_to_shost(dev);
331 struct device *parent = dev->parent;
333 /* In case scsi_remove_host() has not been called. */
334 scsi_proc_hostdir_rm(shost->hostt);
336 /* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
339 if (shost->tmf_work_q)
340 destroy_workqueue(shost->tmf_work_q);
342 kthread_stop(shost->ehandler);
344 destroy_workqueue(shost->work_q);
346 if (shost->shost_state == SHOST_CREATED) {
348 * Free the shost_dev device name here if scsi_host_alloc()
349 * and scsi_host_put() have been called but neither
350 * scsi_host_add() nor scsi_host_remove() has been called.
351 * This avoids that the memory allocated for the shost_dev
354 kfree(dev_name(&shost->shost_dev));
357 if (shost_use_blk_mq(shost)) {
358 if (shost->tag_set.tags)
359 scsi_mq_destroy_tags(shost);
362 blk_free_tags(shost->bqt);
365 kfree(shost->shost_data);
367 ida_simple_remove(&host_index_ida, shost->host_no);
369 if (shost->shost_state != SHOST_CREATED)
374 static struct device_type scsi_host_type = {
376 .release = scsi_host_dev_release,
380 * scsi_host_alloc - register a scsi host adapter instance.
381 * @sht: pointer to scsi host template
382 * @privsize: extra bytes to allocate for driver
385 * Allocate a new Scsi_Host and perform basic initialization.
386 * The host is not published to the scsi midlayer until scsi_add_host
390 * Pointer to a new Scsi_Host
392 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
394 struct Scsi_Host *shost;
395 gfp_t gfp_mask = GFP_KERNEL;
398 if (sht->unchecked_isa_dma && privsize)
399 gfp_mask |= __GFP_DMA;
401 shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
405 shost->host_lock = &shost->default_lock;
406 spin_lock_init(shost->host_lock);
407 shost->shost_state = SHOST_CREATED;
408 INIT_LIST_HEAD(&shost->__devices);
409 INIT_LIST_HEAD(&shost->__targets);
410 INIT_LIST_HEAD(&shost->eh_cmd_q);
411 INIT_LIST_HEAD(&shost->starved_list);
412 init_waitqueue_head(&shost->host_wait);
413 mutex_init(&shost->scan_mutex);
415 index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
420 shost->host_no = index;
422 shost->dma_channel = 0xff;
424 /* These three are default values which can be overridden */
425 shost->max_channel = 0;
429 /* Give each shost a default transportt */
430 shost->transportt = &blank_transport_template;
433 * All drivers right now should be able to handle 12 byte
434 * commands. Every so often there are requests for 16 byte
435 * commands, but individual low-level drivers need to certify that
436 * they actually do something sensible with such commands.
438 shost->max_cmd_len = 12;
440 shost->this_id = sht->this_id;
441 shost->can_queue = sht->can_queue;
442 shost->sg_tablesize = sht->sg_tablesize;
443 shost->sg_prot_tablesize = sht->sg_prot_tablesize;
444 shost->cmd_per_lun = sht->cmd_per_lun;
445 shost->unchecked_isa_dma = sht->unchecked_isa_dma;
446 shost->use_clustering = sht->use_clustering;
447 shost->no_write_same = sht->no_write_same;
449 if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
450 shost->eh_deadline = -1;
451 else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
452 shost_printk(KERN_WARNING, shost,
453 "eh_deadline %u too large, setting to %u\n",
454 shost_eh_deadline, INT_MAX / HZ);
455 shost->eh_deadline = INT_MAX;
457 shost->eh_deadline = shost_eh_deadline * HZ;
459 if (sht->supported_mode == MODE_UNKNOWN)
460 /* means we didn't set it ... default to INITIATOR */
461 shost->active_mode = MODE_INITIATOR;
463 shost->active_mode = sht->supported_mode;
465 if (sht->max_host_blocked)
466 shost->max_host_blocked = sht->max_host_blocked;
468 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
471 * If the driver imposes no hard sector transfer limit, start at
472 * machine infinity initially.
474 if (sht->max_sectors)
475 shost->max_sectors = sht->max_sectors;
477 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
480 * assume a 4GB boundary, if not set
482 if (sht->dma_boundary)
483 shost->dma_boundary = sht->dma_boundary;
485 shost->dma_boundary = 0xffffffff;
487 shost->use_blk_mq = scsi_use_blk_mq || shost->hostt->force_blk_mq;
489 device_initialize(&shost->shost_gendev);
490 dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
491 shost->shost_gendev.bus = &scsi_bus_type;
492 shost->shost_gendev.type = &scsi_host_type;
494 device_initialize(&shost->shost_dev);
495 shost->shost_dev.parent = &shost->shost_gendev;
496 shost->shost_dev.class = &shost_class;
497 dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
498 shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
500 shost->ehandler = kthread_run(scsi_error_handler, shost,
501 "scsi_eh_%d", shost->host_no);
502 if (IS_ERR(shost->ehandler)) {
503 shost_printk(KERN_WARNING, shost,
504 "error handler thread failed to spawn, error = %ld\n",
505 PTR_ERR(shost->ehandler));
506 shost->ehandler = NULL;
510 shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
511 WQ_UNBOUND | WQ_MEM_RECLAIM,
513 if (!shost->tmf_work_q) {
514 shost_printk(KERN_WARNING, shost,
515 "failed to create tmf workq\n");
518 scsi_proc_hostdir_add(shost->hostt);
522 * Host state is still SHOST_CREATED and that is enough to release
523 * ->shost_gendev. scsi_host_dev_release() will free
524 * dev_name(&shost->shost_dev).
526 put_device(&shost->shost_gendev);
530 EXPORT_SYMBOL(scsi_host_alloc);
532 static int __scsi_host_match(struct device *dev, const void *data)
535 const unsigned int *hostnum = data;
537 p = class_to_shost(dev);
538 return p->host_no == *hostnum;
542 * scsi_host_lookup - get a reference to a Scsi_Host by host no
543 * @hostnum: host number to locate
546 * A pointer to located Scsi_Host or NULL.
548 * The caller must do a scsi_host_put() to drop the reference
549 * that scsi_host_get() took. The put_device() below dropped
550 * the reference from class_find_device().
552 struct Scsi_Host *scsi_host_lookup(unsigned int hostnum)
555 struct Scsi_Host *shost = NULL;
557 cdev = class_find_device(&shost_class, NULL, &hostnum,
560 shost = scsi_host_get(class_to_shost(cdev));
565 EXPORT_SYMBOL(scsi_host_lookup);
568 * scsi_host_get - inc a Scsi_Host ref count
569 * @shost: Pointer to Scsi_Host to inc.
571 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
573 if ((shost->shost_state == SHOST_DEL) ||
574 !get_device(&shost->shost_gendev))
578 EXPORT_SYMBOL(scsi_host_get);
581 * scsi_host_busy - Return the host busy counter
582 * @shost: Pointer to Scsi_Host to inc.
584 int scsi_host_busy(struct Scsi_Host *shost)
586 return atomic_read(&shost->host_busy);
588 EXPORT_SYMBOL(scsi_host_busy);
591 * scsi_host_put - dec a Scsi_Host ref count
592 * @shost: Pointer to Scsi_Host to dec.
594 void scsi_host_put(struct Scsi_Host *shost)
596 put_device(&shost->shost_gendev);
598 EXPORT_SYMBOL(scsi_host_put);
600 int scsi_init_hosts(void)
602 return class_register(&shost_class);
605 void scsi_exit_hosts(void)
607 class_unregister(&shost_class);
608 ida_destroy(&host_index_ida);
611 int scsi_is_host_device(const struct device *dev)
613 return dev->type == &scsi_host_type;
615 EXPORT_SYMBOL(scsi_is_host_device);
618 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
619 * @shost: Pointer to Scsi_Host.
620 * @work: Work to queue for execution.
623 * 1 - work queued for execution
624 * 0 - work is already queued
625 * -EINVAL - work queue doesn't exist
627 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
629 if (unlikely(!shost->work_q)) {
630 shost_printk(KERN_ERR, shost,
631 "ERROR: Scsi host '%s' attempted to queue scsi-work, "
632 "when no workqueue created.\n", shost->hostt->name);
638 return queue_work(shost->work_q, work);
640 EXPORT_SYMBOL_GPL(scsi_queue_work);
643 * scsi_flush_work - Flush a Scsi_Host's workqueue.
644 * @shost: Pointer to Scsi_Host.
646 void scsi_flush_work(struct Scsi_Host *shost)
648 if (!shost->work_q) {
649 shost_printk(KERN_ERR, shost,
650 "ERROR: Scsi host '%s' attempted to flush scsi-work, "
651 "when no workqueue created.\n", shost->hostt->name);
656 flush_workqueue(shost->work_q);
658 EXPORT_SYMBOL_GPL(scsi_flush_work);