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/kthread.h>
28 #include <linux/string.h>
30 #include <linux/init.h>
31 #include <linux/completion.h>
32 #include <linux/transport_class.h>
34 #include <scsi/scsi_device.h>
35 #include <scsi/scsi_host.h>
36 #include <scsi/scsi_transport.h>
38 #include "scsi_priv.h"
39 #include "scsi_logging.h"
42 static int scsi_host_next_hn; /* host_no for next new host */
45 static void scsi_host_cls_release(struct class_device *class_dev)
47 put_device(&class_to_shost(class_dev)->shost_gendev);
50 static struct class shost_class = {
52 .release = scsi_host_cls_release,
56 * scsi_host_set_state - Take the given host through the host
58 * @shost: scsi host to change the state of.
59 * @state: state to change to.
61 * Returns zero if unsuccessful or an error if the requested
62 * transition is illegal.
64 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
66 enum scsi_host_state oldstate = shost->shost_state;
68 if (state == oldstate)
73 /* There are no legal states that come back to
74 * created. This is the manually initialised start
101 case SHOST_CANCEL_RECOVERY:
111 case SHOST_DEL_RECOVERY:
118 case SHOST_CANCEL_RECOVERY:
128 case SHOST_DEL_RECOVERY:
130 case SHOST_CANCEL_RECOVERY:
137 shost->shost_state = state;
141 SCSI_LOG_ERROR_RECOVERY(1,
142 dev_printk(KERN_ERR, &shost->shost_gendev,
143 "Illegal host state transition"
145 scsi_host_state_name(oldstate),
146 scsi_host_state_name(state)));
149 EXPORT_SYMBOL(scsi_host_set_state);
152 * scsi_remove_host - remove a scsi host
153 * @shost: a pointer to a scsi host to remove
155 void scsi_remove_host(struct Scsi_Host *shost)
158 down(&shost->scan_mutex);
159 spin_lock_irqsave(shost->host_lock, flags);
160 if (scsi_host_set_state(shost, SHOST_CANCEL))
161 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
162 spin_unlock_irqrestore(shost->host_lock, flags);
163 up(&shost->scan_mutex);
166 spin_unlock_irqrestore(shost->host_lock, flags);
167 up(&shost->scan_mutex);
168 scsi_forget_host(shost);
169 scsi_proc_host_rm(shost);
171 spin_lock_irqsave(shost->host_lock, flags);
172 if (scsi_host_set_state(shost, SHOST_DEL))
173 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
174 spin_unlock_irqrestore(shost->host_lock, flags);
176 transport_unregister_device(&shost->shost_gendev);
177 class_device_unregister(&shost->shost_classdev);
178 device_del(&shost->shost_gendev);
179 scsi_proc_hostdir_rm(shost->hostt);
181 EXPORT_SYMBOL(scsi_remove_host);
184 * scsi_add_host - add a scsi host
185 * @shost: scsi host pointer to add
186 * @dev: a struct device of type scsi class
189 * 0 on success / != 0 for error
191 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
193 struct scsi_host_template *sht = shost->hostt;
196 printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
197 sht->info ? sht->info(shost) : sht->name);
199 if (!shost->can_queue) {
200 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
205 if (!shost->shost_gendev.parent)
206 shost->shost_gendev.parent = dev ? dev : &platform_bus;
208 error = device_add(&shost->shost_gendev);
212 scsi_host_set_state(shost, SHOST_RUNNING);
213 get_device(shost->shost_gendev.parent);
215 error = class_device_add(&shost->shost_classdev);
219 get_device(&shost->shost_gendev);
221 if (shost->transportt->host_size &&
222 (shost->shost_data = kmalloc(shost->transportt->host_size,
223 GFP_KERNEL)) == NULL)
224 goto out_del_classdev;
226 if (shost->transportt->create_work_queue) {
227 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
229 shost->work_q = create_singlethread_workqueue(
232 goto out_free_shost_data;
235 error = scsi_sysfs_add_host(shost);
237 goto out_destroy_host;
239 scsi_proc_host_add(shost);
244 destroy_workqueue(shost->work_q);
246 kfree(shost->shost_data);
248 class_device_del(&shost->shost_classdev);
250 device_del(&shost->shost_gendev);
254 EXPORT_SYMBOL(scsi_add_host);
256 static void scsi_host_dev_release(struct device *dev)
258 struct Scsi_Host *shost = dev_to_shost(dev);
259 struct device *parent = dev->parent;
262 kthread_stop(shost->ehandler);
264 destroy_workqueue(shost->work_q);
266 scsi_destroy_command_freelist(shost);
267 kfree(shost->shost_data);
275 * scsi_host_alloc - register a scsi host adapter instance.
276 * @sht: pointer to scsi host template
277 * @privsize: extra bytes to allocate for driver
280 * Allocate a new Scsi_Host and perform basic initialization.
281 * The host is not published to the scsi midlayer until scsi_add_host
285 * Pointer to a new Scsi_Host
287 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
289 struct Scsi_Host *shost;
290 int gfp_mask = GFP_KERNEL, rval;
292 if (sht->unchecked_isa_dma && privsize)
293 gfp_mask |= __GFP_DMA;
295 /* Check to see if this host has any error handling facilities */
296 if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
297 !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
298 !sht->eh_host_reset_handler) {
299 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
300 "ERROR: This is not a safe way to run your "
302 "ERROR: The error handling must be added to "
303 "this driver\n", sht->proc_name);
307 shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
310 memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
312 spin_lock_init(&shost->default_lock);
313 scsi_assign_lock(shost, &shost->default_lock);
314 shost->shost_state = SHOST_CREATED;
315 INIT_LIST_HEAD(&shost->__devices);
316 INIT_LIST_HEAD(&shost->__targets);
317 INIT_LIST_HEAD(&shost->eh_cmd_q);
318 INIT_LIST_HEAD(&shost->starved_list);
319 init_waitqueue_head(&shost->host_wait);
321 init_MUTEX(&shost->scan_mutex);
323 shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
324 shost->dma_channel = 0xff;
326 /* These three are default values which can be overridden */
327 shost->max_channel = 0;
331 /* Give each shost a default transportt */
332 shost->transportt = &blank_transport_template;
335 * All drivers right now should be able to handle 12 byte
336 * commands. Every so often there are requests for 16 byte
337 * commands, but individual low-level drivers need to certify that
338 * they actually do something sensible with such commands.
340 shost->max_cmd_len = 12;
342 shost->this_id = sht->this_id;
343 shost->can_queue = sht->can_queue;
344 shost->sg_tablesize = sht->sg_tablesize;
345 shost->cmd_per_lun = sht->cmd_per_lun;
346 shost->unchecked_isa_dma = sht->unchecked_isa_dma;
347 shost->use_clustering = sht->use_clustering;
348 shost->ordered_flush = sht->ordered_flush;
349 shost->ordered_tag = sht->ordered_tag;
352 * hosts/devices that do queueing must support ordered tags
354 if (shost->can_queue > 1 && shost->ordered_flush) {
355 printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
356 shost->ordered_flush = 0;
359 if (sht->max_host_blocked)
360 shost->max_host_blocked = sht->max_host_blocked;
362 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
365 * If the driver imposes no hard sector transfer limit, start at
366 * machine infinity initially.
368 if (sht->max_sectors)
369 shost->max_sectors = sht->max_sectors;
371 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
374 * assume a 4GB boundary, if not set
376 if (sht->dma_boundary)
377 shost->dma_boundary = sht->dma_boundary;
379 shost->dma_boundary = 0xffffffff;
381 rval = scsi_setup_command_freelist(shost);
385 device_initialize(&shost->shost_gendev);
386 snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
388 shost->shost_gendev.release = scsi_host_dev_release;
390 class_device_initialize(&shost->shost_classdev);
391 shost->shost_classdev.dev = &shost->shost_gendev;
392 shost->shost_classdev.class = &shost_class;
393 snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
396 shost->ehandler = kthread_run(scsi_error_handler, shost,
397 "scsi_eh_%d", shost->host_no);
398 if (IS_ERR(shost->ehandler)) {
399 rval = PTR_ERR(shost->ehandler);
400 goto fail_destroy_freelist;
403 scsi_proc_hostdir_add(shost->hostt);
406 fail_destroy_freelist:
407 scsi_destroy_command_freelist(shost);
412 EXPORT_SYMBOL(scsi_host_alloc);
414 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
416 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
419 printk(KERN_WARNING "scsi_register() called on new-style "
420 "template for driver %s\n", sht->name);
425 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
428 EXPORT_SYMBOL(scsi_register);
430 void scsi_unregister(struct Scsi_Host *shost)
432 list_del(&shost->sht_legacy_list);
433 scsi_host_put(shost);
435 EXPORT_SYMBOL(scsi_unregister);
438 * scsi_host_lookup - get a reference to a Scsi_Host by host no
440 * @hostnum: host number to locate
443 * A pointer to located Scsi_Host or NULL.
445 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
447 struct class *class = &shost_class;
448 struct class_device *cdev;
449 struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
451 down_read(&class->subsys.rwsem);
452 list_for_each_entry(cdev, &class->children, node) {
453 p = class_to_shost(cdev);
454 if (p->host_no == hostnum) {
455 shost = scsi_host_get(p);
459 up_read(&class->subsys.rwsem);
463 EXPORT_SYMBOL(scsi_host_lookup);
466 * scsi_host_get - inc a Scsi_Host ref count
467 * @shost: Pointer to Scsi_Host to inc.
469 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
471 if ((shost->shost_state == SHOST_DEL) ||
472 !get_device(&shost->shost_gendev))
476 EXPORT_SYMBOL(scsi_host_get);
479 * scsi_host_put - dec a Scsi_Host ref count
480 * @shost: Pointer to Scsi_Host to dec.
482 void scsi_host_put(struct Scsi_Host *shost)
484 put_device(&shost->shost_gendev);
486 EXPORT_SYMBOL(scsi_host_put);
488 int scsi_init_hosts(void)
490 return class_register(&shost_class);
493 void scsi_exit_hosts(void)
495 class_unregister(&shost_class);
498 int scsi_is_host_device(const struct device *dev)
500 return dev->release == scsi_host_dev_release;
502 EXPORT_SYMBOL(scsi_is_host_device);
505 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
506 * @shost: Pointer to Scsi_Host.
507 * @work: Work to queue for execution.
510 * 0 on success / != 0 for error
512 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
514 if (unlikely(!shost->work_q)) {
516 "ERROR: Scsi host '%s' attempted to queue scsi-work, "
517 "when no workqueue created.\n", shost->hostt->name);
523 return queue_work(shost->work_q, work);
525 EXPORT_SYMBOL_GPL(scsi_queue_work);
528 * scsi_flush_work - Flush a Scsi_Host's workqueue.
529 * @shost: Pointer to Scsi_Host.
531 void scsi_flush_work(struct Scsi_Host *shost)
533 if (!shost->work_q) {
535 "ERROR: Scsi host '%s' attempted to flush scsi-work, "
536 "when no workqueue created.\n", shost->hostt->name);
541 flush_workqueue(shost->work_q);
543 EXPORT_SYMBOL_GPL(scsi_flush_work);