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>
41 #include <scsi/scsi_cmnd.h>
43 #include "scsi_priv.h"
44 #include "scsi_logging.h"
47 static int shost_eh_deadline = -1;
49 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
50 MODULE_PARM_DESC(eh_deadline,
51 "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
53 static DEFINE_IDA(host_index_ida);
56 static void scsi_host_cls_release(struct device *dev)
58 put_device(&class_to_shost(dev)->shost_gendev);
61 static struct class shost_class = {
63 .dev_release = scsi_host_cls_release,
64 .dev_groups = scsi_shost_groups,
68 * scsi_host_set_state - Take the given host through the host state model.
69 * @shost: scsi host to change the state of.
70 * @state: state to change to.
72 * Returns zero if unsuccessful or an error if the requested
73 * transition is illegal.
75 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
77 enum scsi_host_state oldstate = shost->shost_state;
79 if (state == oldstate)
84 /* There are no legal states that come back to
85 * created. This is the manually initialised start
112 case SHOST_CANCEL_RECOVERY:
122 case SHOST_DEL_RECOVERY:
129 case SHOST_CANCEL_RECOVERY:
139 case SHOST_DEL_RECOVERY:
141 case SHOST_CANCEL_RECOVERY:
148 shost->shost_state = state;
152 SCSI_LOG_ERROR_RECOVERY(1,
153 shost_printk(KERN_ERR, shost,
154 "Illegal host state transition"
156 scsi_host_state_name(oldstate),
157 scsi_host_state_name(state)));
162 * scsi_remove_host - remove a scsi host
163 * @shost: a pointer to a scsi host to remove
165 void scsi_remove_host(struct Scsi_Host *shost)
169 mutex_lock(&shost->scan_mutex);
170 spin_lock_irqsave(shost->host_lock, flags);
171 if (scsi_host_set_state(shost, SHOST_CANCEL))
172 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
173 spin_unlock_irqrestore(shost->host_lock, flags);
174 mutex_unlock(&shost->scan_mutex);
177 spin_unlock_irqrestore(shost->host_lock, flags);
179 scsi_autopm_get_host(shost);
180 flush_workqueue(shost->tmf_work_q);
181 scsi_forget_host(shost);
182 mutex_unlock(&shost->scan_mutex);
183 scsi_proc_host_rm(shost);
184 scsi_proc_hostdir_rm(shost->hostt);
187 * New SCSI devices cannot be attached anymore because of the SCSI host
188 * state so drop the tag set refcnt. Wait until the tag set refcnt drops
189 * to zero because .exit_cmd_priv implementations may need the host
192 kref_put(&shost->tagset_refcnt, scsi_mq_free_tags);
193 wait_for_completion(&shost->tagset_freed);
195 spin_lock_irqsave(shost->host_lock, flags);
196 if (scsi_host_set_state(shost, SHOST_DEL))
197 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
198 spin_unlock_irqrestore(shost->host_lock, flags);
200 transport_unregister_device(&shost->shost_gendev);
201 device_unregister(&shost->shost_dev);
202 device_del(&shost->shost_gendev);
204 EXPORT_SYMBOL(scsi_remove_host);
207 * scsi_add_host_with_dma - add a scsi host with dma device
208 * @shost: scsi host pointer to add
209 * @dev: a struct device of type scsi class
210 * @dma_dev: dma device for the host
212 * Note: You rarely need to worry about this unless you're in a
213 * virtualised host environments, so use the simpler scsi_add_host()
217 * 0 on success / != 0 for error
219 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
220 struct device *dma_dev)
222 struct scsi_host_template *sht = shost->hostt;
225 shost_printk(KERN_INFO, shost, "%s\n",
226 sht->info ? sht->info(shost) : sht->name);
228 if (!shost->can_queue) {
229 shost_printk(KERN_ERR, shost,
230 "can_queue = 0 no longer supported\n");
234 /* Use min_t(int, ...) in case shost->can_queue exceeds SHRT_MAX */
235 shost->cmd_per_lun = min_t(int, shost->cmd_per_lun,
238 error = scsi_init_sense_cache(shost);
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 if (dma_dev->dma_mask) {
250 shost->max_sectors = min_t(unsigned int, shost->max_sectors,
251 dma_max_mapping_size(dma_dev) >> SECTOR_SHIFT);
254 error = scsi_mq_setup_tags(shost);
258 kref_init(&shost->tagset_refcnt);
259 init_completion(&shost->tagset_freed);
262 * Increase usage count temporarily here so that calling
263 * scsi_autopm_put_host() will trigger runtime idle if there is
264 * nothing else preventing suspending the device.
266 pm_runtime_get_noresume(&shost->shost_gendev);
267 pm_runtime_set_active(&shost->shost_gendev);
268 pm_runtime_enable(&shost->shost_gendev);
269 device_enable_async_suspend(&shost->shost_gendev);
271 error = device_add(&shost->shost_gendev);
273 goto out_disable_runtime_pm;
275 scsi_host_set_state(shost, SHOST_RUNNING);
276 get_device(shost->shost_gendev.parent);
278 device_enable_async_suspend(&shost->shost_dev);
280 get_device(&shost->shost_gendev);
281 error = device_add(&shost->shost_dev);
285 if (shost->transportt->host_size) {
286 shost->shost_data = kzalloc(shost->transportt->host_size,
288 if (shost->shost_data == NULL) {
294 if (shost->transportt->create_work_queue) {
295 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
296 "scsi_wq_%d", shost->host_no);
297 shost->work_q = alloc_workqueue("%s",
298 WQ_SYSFS | __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_UNBOUND,
299 1, shost->work_q_name);
301 if (!shost->work_q) {
307 error = scsi_sysfs_add_host(shost);
311 scsi_proc_host_add(shost);
312 scsi_autopm_put_host(shost);
316 * Any host allocation in this function will be freed in
317 * scsi_host_dev_release().
320 device_del(&shost->shost_dev);
323 * Host state is SHOST_RUNNING so we have to explicitly release
326 put_device(&shost->shost_dev);
327 device_del(&shost->shost_gendev);
328 out_disable_runtime_pm:
329 device_disable_async_suspend(&shost->shost_gendev);
330 pm_runtime_disable(&shost->shost_gendev);
331 pm_runtime_set_suspended(&shost->shost_gendev);
332 pm_runtime_put_noidle(&shost->shost_gendev);
333 kref_put(&shost->tagset_refcnt, scsi_mq_free_tags);
337 EXPORT_SYMBOL(scsi_add_host_with_dma);
339 static void scsi_host_dev_release(struct device *dev)
341 struct Scsi_Host *shost = dev_to_shost(dev);
342 struct device *parent = dev->parent;
344 /* Wait for functions invoked through call_rcu(&scmd->rcu, ...) */
347 if (shost->tmf_work_q)
348 destroy_workqueue(shost->tmf_work_q);
350 kthread_stop(shost->ehandler);
352 destroy_workqueue(shost->work_q);
354 if (shost->shost_state == SHOST_CREATED) {
356 * Free the shost_dev device name here if scsi_host_alloc()
357 * and scsi_host_put() have been called but neither
358 * scsi_host_add() nor scsi_host_remove() has been called.
359 * This avoids that the memory allocated for the shost_dev
362 kfree(dev_name(&shost->shost_dev));
365 kfree(shost->shost_data);
367 ida_free(&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;
397 shost = kzalloc(sizeof(struct Scsi_Host) + privsize, GFP_KERNEL);
401 shost->host_lock = &shost->default_lock;
402 spin_lock_init(shost->host_lock);
403 shost->shost_state = SHOST_CREATED;
404 INIT_LIST_HEAD(&shost->__devices);
405 INIT_LIST_HEAD(&shost->__targets);
406 INIT_LIST_HEAD(&shost->eh_abort_list);
407 INIT_LIST_HEAD(&shost->eh_cmd_q);
408 INIT_LIST_HEAD(&shost->starved_list);
409 init_waitqueue_head(&shost->host_wait);
410 mutex_init(&shost->scan_mutex);
412 index = ida_alloc(&host_index_ida, GFP_KERNEL);
417 shost->host_no = index;
419 shost->dma_channel = 0xff;
421 /* These three are default values which can be overridden */
422 shost->max_channel = 0;
426 /* Give each shost a default transportt */
427 shost->transportt = &blank_transport_template;
430 * All drivers right now should be able to handle 12 byte
431 * commands. Every so often there are requests for 16 byte
432 * commands, but individual low-level drivers need to certify that
433 * they actually do something sensible with such commands.
435 shost->max_cmd_len = 12;
437 shost->this_id = sht->this_id;
438 shost->can_queue = sht->can_queue;
439 shost->sg_tablesize = sht->sg_tablesize;
440 shost->sg_prot_tablesize = sht->sg_prot_tablesize;
441 shost->cmd_per_lun = sht->cmd_per_lun;
442 shost->no_write_same = sht->no_write_same;
443 shost->host_tagset = sht->host_tagset;
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;
475 if (sht->max_segment_size)
476 shost->max_segment_size = sht->max_segment_size;
478 shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
481 * assume a 4GB boundary, if not set
483 if (sht->dma_boundary)
484 shost->dma_boundary = sht->dma_boundary;
486 shost->dma_boundary = 0xffffffff;
488 if (sht->virt_boundary_mask)
489 shost->virt_boundary_mask = sht->virt_boundary_mask;
491 device_initialize(&shost->shost_gendev);
492 dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
493 shost->shost_gendev.bus = &scsi_bus_type;
494 shost->shost_gendev.type = &scsi_host_type;
495 scsi_enable_async_suspend(&shost->shost_gendev);
497 device_initialize(&shost->shost_dev);
498 shost->shost_dev.parent = &shost->shost_gendev;
499 shost->shost_dev.class = &shost_class;
500 dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
501 shost->shost_dev.groups = sht->shost_groups;
503 shost->ehandler = kthread_run(scsi_error_handler, shost,
504 "scsi_eh_%d", shost->host_no);
505 if (IS_ERR(shost->ehandler)) {
506 shost_printk(KERN_WARNING, shost,
507 "error handler thread failed to spawn, error = %ld\n",
508 PTR_ERR(shost->ehandler));
509 shost->ehandler = NULL;
513 shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
514 WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS,
516 if (!shost->tmf_work_q) {
517 shost_printk(KERN_WARNING, shost,
518 "failed to create tmf workq\n");
521 scsi_proc_hostdir_add(shost->hostt);
525 * Host state is still SHOST_CREATED and that is enough to release
526 * ->shost_gendev. scsi_host_dev_release() will free
527 * dev_name(&shost->shost_dev).
529 put_device(&shost->shost_gendev);
533 EXPORT_SYMBOL(scsi_host_alloc);
535 static int __scsi_host_match(struct device *dev, const void *data)
538 const unsigned short *hostnum = data;
540 p = class_to_shost(dev);
541 return p->host_no == *hostnum;
545 * scsi_host_lookup - get a reference to a Scsi_Host by host no
546 * @hostnum: host number to locate
549 * A pointer to located Scsi_Host or NULL.
551 * The caller must do a scsi_host_put() to drop the reference
552 * that scsi_host_get() took. The put_device() below dropped
553 * the reference from class_find_device().
555 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
558 struct Scsi_Host *shost = NULL;
560 cdev = class_find_device(&shost_class, NULL, &hostnum,
563 shost = scsi_host_get(class_to_shost(cdev));
568 EXPORT_SYMBOL(scsi_host_lookup);
571 * scsi_host_get - inc a Scsi_Host ref count
572 * @shost: Pointer to Scsi_Host to inc.
574 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
576 if ((shost->shost_state == SHOST_DEL) ||
577 !get_device(&shost->shost_gendev))
581 EXPORT_SYMBOL(scsi_host_get);
583 static bool scsi_host_check_in_flight(struct request *rq, void *data)
586 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
588 if (test_bit(SCMD_STATE_INFLIGHT, &cmd->state))
595 * scsi_host_busy - Return the host busy counter
596 * @shost: Pointer to Scsi_Host to inc.
598 int scsi_host_busy(struct Scsi_Host *shost)
602 blk_mq_tagset_busy_iter(&shost->tag_set,
603 scsi_host_check_in_flight, &cnt);
606 EXPORT_SYMBOL(scsi_host_busy);
609 * scsi_host_put - dec a Scsi_Host ref count
610 * @shost: Pointer to Scsi_Host to dec.
612 void scsi_host_put(struct Scsi_Host *shost)
614 put_device(&shost->shost_gendev);
616 EXPORT_SYMBOL(scsi_host_put);
618 int scsi_init_hosts(void)
620 return class_register(&shost_class);
623 void scsi_exit_hosts(void)
625 class_unregister(&shost_class);
626 ida_destroy(&host_index_ida);
629 int scsi_is_host_device(const struct device *dev)
631 return dev->type == &scsi_host_type;
633 EXPORT_SYMBOL(scsi_is_host_device);
636 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
637 * @shost: Pointer to Scsi_Host.
638 * @work: Work to queue for execution.
641 * 1 - work queued for execution
642 * 0 - work is already queued
643 * -EINVAL - work queue doesn't exist
645 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
647 if (unlikely(!shost->work_q)) {
648 shost_printk(KERN_ERR, shost,
649 "ERROR: Scsi host '%s' attempted to queue scsi-work, "
650 "when no workqueue created.\n", shost->hostt->name);
656 return queue_work(shost->work_q, work);
658 EXPORT_SYMBOL_GPL(scsi_queue_work);
661 * scsi_flush_work - Flush a Scsi_Host's workqueue.
662 * @shost: Pointer to Scsi_Host.
664 void scsi_flush_work(struct Scsi_Host *shost)
666 if (!shost->work_q) {
667 shost_printk(KERN_ERR, shost,
668 "ERROR: Scsi host '%s' attempted to flush scsi-work, "
669 "when no workqueue created.\n", shost->hostt->name);
674 flush_workqueue(shost->work_q);
676 EXPORT_SYMBOL_GPL(scsi_flush_work);
678 static bool complete_all_cmds_iter(struct request *rq, void *data)
680 struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
681 enum scsi_host_status status = *(enum scsi_host_status *)data;
683 scsi_dma_unmap(scmd);
685 set_host_byte(scmd, status);
691 * scsi_host_complete_all_commands - Terminate all running commands
692 * @shost: Scsi Host on which commands should be terminated
693 * @status: Status to be set for the terminated commands
695 * There is no protection against modification of the number
696 * of outstanding commands. It is the responsibility of the
697 * caller to ensure that concurrent I/O submission and/or
698 * completion is stopped when calling this function.
700 void scsi_host_complete_all_commands(struct Scsi_Host *shost,
701 enum scsi_host_status status)
703 blk_mq_tagset_busy_iter(&shost->tag_set, complete_all_cmds_iter,
706 EXPORT_SYMBOL_GPL(scsi_host_complete_all_commands);
708 struct scsi_host_busy_iter_data {
709 bool (*fn)(struct scsi_cmnd *, void *);
713 static bool __scsi_host_busy_iter_fn(struct request *req, void *priv)
715 struct scsi_host_busy_iter_data *iter_data = priv;
716 struct scsi_cmnd *sc = blk_mq_rq_to_pdu(req);
718 return iter_data->fn(sc, iter_data->priv);
722 * scsi_host_busy_iter - Iterate over all busy commands
723 * @shost: Pointer to Scsi_Host.
724 * @fn: Function to call on each busy command
725 * @priv: Data pointer passed to @fn
727 * If locking against concurrent command completions is required
728 * ithas to be provided by the caller
730 void scsi_host_busy_iter(struct Scsi_Host *shost,
731 bool (*fn)(struct scsi_cmnd *, void *),
734 struct scsi_host_busy_iter_data iter_data = {
739 blk_mq_tagset_busy_iter(&shost->tag_set, __scsi_host_busy_iter_fn,
742 EXPORT_SYMBOL_GPL(scsi_host_busy_iter);