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/string.h>
29 #include <linux/init.h>
30 #include <linux/completion.h>
31 #include <linux/transport_class.h>
33 #include <scsi/scsi_device.h>
34 #include <scsi/scsi_host.h>
35 #include <scsi/scsi_transport.h>
37 #include "scsi_priv.h"
38 #include "scsi_logging.h"
41 static int scsi_host_next_hn; /* host_no for next new host */
44 static void scsi_host_cls_release(struct class_device *class_dev)
46 put_device(&class_to_shost(class_dev)->shost_gendev);
49 static struct class shost_class = {
51 .release = scsi_host_cls_release,
55 * scsi_host_set_state - Take the given host through the host
57 * @shost: scsi host to change the state of.
58 * @state: state to change to.
60 * Returns zero if unsuccessful or an error if the requested
61 * transition is illegal.
63 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
65 enum scsi_host_state oldstate = shost->shost_state;
67 if (state == oldstate)
72 /* There are no legal states that come back to
73 * created. This is the manually initialised start
116 shost->shost_state = state;
120 SCSI_LOG_ERROR_RECOVERY(1,
121 dev_printk(KERN_ERR, &shost->shost_gendev,
122 "Illegal host state transition"
124 scsi_host_state_name(oldstate),
125 scsi_host_state_name(state)));
128 EXPORT_SYMBOL(scsi_host_set_state);
131 * scsi_host_cancel - cancel outstanding IO to this host
132 * @shost: pointer to struct Scsi_Host
133 * recovery: recovery requested to run.
135 static void scsi_host_cancel(struct Scsi_Host *shost, int recovery)
137 struct scsi_device *sdev;
139 scsi_host_set_state(shost, SHOST_CANCEL);
140 shost_for_each_device(sdev, shost) {
141 scsi_device_cancel(sdev, recovery);
143 wait_event(shost->host_wait, (shost->shost_state != SHOST_RECOVERY));
147 * scsi_remove_host - remove a scsi host
148 * @shost: a pointer to a scsi host to remove
150 void scsi_remove_host(struct Scsi_Host *shost)
152 scsi_forget_host(shost);
153 scsi_host_cancel(shost, 0);
154 scsi_proc_host_rm(shost);
156 scsi_host_set_state(shost, SHOST_DEL);
158 transport_unregister_device(&shost->shost_gendev);
159 class_device_unregister(&shost->shost_classdev);
160 device_del(&shost->shost_gendev);
162 EXPORT_SYMBOL(scsi_remove_host);
165 * scsi_add_host - add a scsi host
166 * @shost: scsi host pointer to add
167 * @dev: a struct device of type scsi class
170 * 0 on success / != 0 for error
172 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
174 struct scsi_host_template *sht = shost->hostt;
177 printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
178 sht->info ? sht->info(shost) : sht->name);
180 if (!shost->can_queue) {
181 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
186 if (!shost->shost_gendev.parent)
187 shost->shost_gendev.parent = dev ? dev : &platform_bus;
189 error = device_add(&shost->shost_gendev);
193 scsi_host_set_state(shost, SHOST_RUNNING);
194 get_device(shost->shost_gendev.parent);
196 error = class_device_add(&shost->shost_classdev);
200 get_device(&shost->shost_gendev);
202 if (shost->transportt->host_size &&
203 (shost->shost_data = kmalloc(shost->transportt->host_size,
204 GFP_KERNEL)) == NULL)
205 goto out_del_classdev;
207 if (shost->transportt->create_work_queue) {
208 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
210 shost->work_q = create_singlethread_workqueue(
213 goto out_free_shost_data;
216 error = scsi_sysfs_add_host(shost);
218 goto out_destroy_host;
220 scsi_proc_host_add(shost);
225 destroy_workqueue(shost->work_q);
227 kfree(shost->shost_data);
229 class_device_del(&shost->shost_classdev);
231 device_del(&shost->shost_gendev);
235 EXPORT_SYMBOL(scsi_add_host);
237 static void scsi_host_dev_release(struct device *dev)
239 struct Scsi_Host *shost = dev_to_shost(dev);
240 struct device *parent = dev->parent;
242 if (shost->ehandler) {
243 DECLARE_COMPLETION(sem);
244 shost->eh_notify = &sem;
247 wait_for_completion(&sem);
248 shost->eh_notify = NULL;
252 destroy_workqueue(shost->work_q);
254 scsi_proc_hostdir_rm(shost->hostt);
255 scsi_destroy_command_freelist(shost);
256 kfree(shost->shost_data);
264 * scsi_host_alloc - register a scsi host adapter instance.
265 * @sht: pointer to scsi host template
266 * @privsize: extra bytes to allocate for driver
269 * Allocate a new Scsi_Host and perform basic initialization.
270 * The host is not published to the scsi midlayer until scsi_add_host
274 * Pointer to a new Scsi_Host
276 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
278 struct Scsi_Host *shost;
279 int gfp_mask = GFP_KERNEL, rval;
280 DECLARE_COMPLETION(complete);
282 if (sht->unchecked_isa_dma && privsize)
283 gfp_mask |= __GFP_DMA;
285 /* Check to see if this host has any error handling facilities */
286 if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
287 !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
288 !sht->eh_host_reset_handler) {
289 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
290 "ERROR: This is not a safe way to run your "
292 "ERROR: The error handling must be added to "
293 "this driver\n", sht->proc_name);
297 shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
300 memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
302 spin_lock_init(&shost->default_lock);
303 scsi_assign_lock(shost, &shost->default_lock);
304 shost->shost_state = SHOST_CREATED;
305 INIT_LIST_HEAD(&shost->__devices);
306 INIT_LIST_HEAD(&shost->__targets);
307 INIT_LIST_HEAD(&shost->eh_cmd_q);
308 INIT_LIST_HEAD(&shost->starved_list);
309 init_waitqueue_head(&shost->host_wait);
311 init_MUTEX(&shost->scan_mutex);
313 shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
314 shost->dma_channel = 0xff;
316 /* These three are default values which can be overridden */
317 shost->max_channel = 0;
321 /* Give each shost a default transportt */
322 shost->transportt = &blank_transport_template;
325 * All drivers right now should be able to handle 12 byte
326 * commands. Every so often there are requests for 16 byte
327 * commands, but individual low-level drivers need to certify that
328 * they actually do something sensible with such commands.
330 shost->max_cmd_len = 12;
332 shost->this_id = sht->this_id;
333 shost->can_queue = sht->can_queue;
334 shost->sg_tablesize = sht->sg_tablesize;
335 shost->cmd_per_lun = sht->cmd_per_lun;
336 shost->unchecked_isa_dma = sht->unchecked_isa_dma;
337 shost->use_clustering = sht->use_clustering;
338 shost->ordered_flush = sht->ordered_flush;
339 shost->ordered_tag = sht->ordered_tag;
342 * hosts/devices that do queueing must support ordered tags
344 if (shost->can_queue > 1 && shost->ordered_flush) {
345 printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
346 shost->ordered_flush = 0;
349 if (sht->max_host_blocked)
350 shost->max_host_blocked = sht->max_host_blocked;
352 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
355 * If the driver imposes no hard sector transfer limit, start at
356 * machine infinity initially.
358 if (sht->max_sectors)
359 shost->max_sectors = sht->max_sectors;
361 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
364 * assume a 4GB boundary, if not set
366 if (sht->dma_boundary)
367 shost->dma_boundary = sht->dma_boundary;
369 shost->dma_boundary = 0xffffffff;
371 rval = scsi_setup_command_freelist(shost);
375 device_initialize(&shost->shost_gendev);
376 snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
378 shost->shost_gendev.release = scsi_host_dev_release;
380 class_device_initialize(&shost->shost_classdev);
381 shost->shost_classdev.dev = &shost->shost_gendev;
382 shost->shost_classdev.class = &shost_class;
383 snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
386 shost->eh_notify = &complete;
387 rval = kernel_thread(scsi_error_handler, shost, 0);
389 goto fail_destroy_freelist;
390 wait_for_completion(&complete);
391 shost->eh_notify = NULL;
393 scsi_proc_hostdir_add(shost->hostt);
396 fail_destroy_freelist:
397 scsi_destroy_command_freelist(shost);
402 EXPORT_SYMBOL(scsi_host_alloc);
404 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
406 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
409 printk(KERN_WARNING "scsi_register() called on new-style "
410 "template for driver %s\n", sht->name);
415 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
418 EXPORT_SYMBOL(scsi_register);
420 void scsi_unregister(struct Scsi_Host *shost)
422 list_del(&shost->sht_legacy_list);
423 scsi_host_put(shost);
425 EXPORT_SYMBOL(scsi_unregister);
428 * scsi_host_lookup - get a reference to a Scsi_Host by host no
430 * @hostnum: host number to locate
433 * A pointer to located Scsi_Host or NULL.
435 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
437 struct class *class = &shost_class;
438 struct class_device *cdev;
439 struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
441 down_read(&class->subsys.rwsem);
442 list_for_each_entry(cdev, &class->children, node) {
443 p = class_to_shost(cdev);
444 if (p->host_no == hostnum) {
445 shost = scsi_host_get(p);
449 up_read(&class->subsys.rwsem);
453 EXPORT_SYMBOL(scsi_host_lookup);
456 * scsi_host_get - inc a Scsi_Host ref count
457 * @shost: Pointer to Scsi_Host to inc.
459 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
461 if ((shost->shost_state == SHOST_DEL) ||
462 !get_device(&shost->shost_gendev))
466 EXPORT_SYMBOL(scsi_host_get);
469 * scsi_host_put - dec a Scsi_Host ref count
470 * @shost: Pointer to Scsi_Host to dec.
472 void scsi_host_put(struct Scsi_Host *shost)
474 put_device(&shost->shost_gendev);
476 EXPORT_SYMBOL(scsi_host_put);
478 int scsi_init_hosts(void)
480 return class_register(&shost_class);
483 void scsi_exit_hosts(void)
485 class_unregister(&shost_class);
488 int scsi_is_host_device(const struct device *dev)
490 return dev->release == scsi_host_dev_release;
492 EXPORT_SYMBOL(scsi_is_host_device);
495 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
496 * @shost: Pointer to Scsi_Host.
497 * @work: Work to queue for execution.
500 * 0 on success / != 0 for error
502 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
504 if (unlikely(!shost->work_q)) {
506 "ERROR: Scsi host '%s' attempted to queue scsi-work, "
507 "when no workqueue created.\n", shost->hostt->name);
513 return queue_work(shost->work_q, work);
515 EXPORT_SYMBOL_GPL(scsi_queue_work);
518 * scsi_flush_work - Flush a Scsi_Host's workqueue.
519 * @shost: Pointer to Scsi_Host.
521 void scsi_flush_work(struct Scsi_Host *shost)
523 if (!shost->work_q) {
525 "ERROR: Scsi host '%s' attempted to flush scsi-work, "
526 "when no workqueue created.\n", shost->hostt->name);
531 flush_workqueue(shost->work_q);
533 EXPORT_SYMBOL_GPL(scsi_flush_work);