Merge /spare/repo/linux-2.6/
[linux-2.6/sactl.git] / drivers / scsi / hosts.c
blob5feb886c33921075ab728f8d6a072dedf9959a8c
1 /*
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
10 * <drew@colorado.edu>
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>
28 #include <linux/mm.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 = {
50 .name = "scsi_host",
51 .release = scsi_host_cls_release,
54 /**
55 * scsi_host_cancel - cancel outstanding IO to this host
56 * @shost: pointer to struct Scsi_Host
57 * recovery: recovery requested to run.
58 **/
59 static void scsi_host_cancel(struct Scsi_Host *shost, int recovery)
61 struct scsi_device *sdev;
63 set_bit(SHOST_CANCEL, &shost->shost_state);
64 shost_for_each_device(sdev, shost) {
65 scsi_device_cancel(sdev, recovery);
67 wait_event(shost->host_wait, (!test_bit(SHOST_RECOVERY,
68 &shost->shost_state)));
71 /**
72 * scsi_remove_host - remove a scsi host
73 * @shost: a pointer to a scsi host to remove
74 **/
75 void scsi_remove_host(struct Scsi_Host *shost)
77 scsi_forget_host(shost);
78 scsi_host_cancel(shost, 0);
79 scsi_proc_host_rm(shost);
81 set_bit(SHOST_DEL, &shost->shost_state);
83 transport_unregister_device(&shost->shost_gendev);
84 class_device_unregister(&shost->shost_classdev);
85 device_del(&shost->shost_gendev);
87 EXPORT_SYMBOL(scsi_remove_host);
89 /**
90 * scsi_add_host - add a scsi host
91 * @shost: scsi host pointer to add
92 * @dev: a struct device of type scsi class
94 * Return value:
95 * 0 on success / != 0 for error
96 **/
97 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
99 struct scsi_host_template *sht = shost->hostt;
100 int error = -EINVAL;
102 printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
103 sht->info ? sht->info(shost) : sht->name);
105 if (!shost->can_queue) {
106 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
107 sht->name);
108 goto out;
111 if (!shost->shost_gendev.parent)
112 shost->shost_gendev.parent = dev ? dev : &platform_bus;
114 error = device_add(&shost->shost_gendev);
115 if (error)
116 goto out;
118 set_bit(SHOST_ADD, &shost->shost_state);
119 get_device(shost->shost_gendev.parent);
121 error = class_device_add(&shost->shost_classdev);
122 if (error)
123 goto out_del_gendev;
125 get_device(&shost->shost_gendev);
127 if (shost->transportt->host_size &&
128 (shost->shost_data = kmalloc(shost->transportt->host_size,
129 GFP_KERNEL)) == NULL)
130 goto out_del_classdev;
132 if (shost->transportt->create_work_queue) {
133 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
134 shost->host_no);
135 shost->work_q = create_singlethread_workqueue(
136 shost->work_q_name);
137 if (!shost->work_q)
138 goto out_free_shost_data;
141 error = scsi_sysfs_add_host(shost);
142 if (error)
143 goto out_destroy_host;
145 scsi_proc_host_add(shost);
146 return error;
148 out_destroy_host:
149 if (shost->work_q)
150 destroy_workqueue(shost->work_q);
151 out_free_shost_data:
152 kfree(shost->shost_data);
153 out_del_classdev:
154 class_device_del(&shost->shost_classdev);
155 out_del_gendev:
156 device_del(&shost->shost_gendev);
157 out:
158 return error;
160 EXPORT_SYMBOL(scsi_add_host);
162 static void scsi_host_dev_release(struct device *dev)
164 struct Scsi_Host *shost = dev_to_shost(dev);
165 struct device *parent = dev->parent;
167 if (shost->ehandler) {
168 DECLARE_COMPLETION(sem);
169 shost->eh_notify = &sem;
170 shost->eh_kill = 1;
171 up(shost->eh_wait);
172 wait_for_completion(&sem);
173 shost->eh_notify = NULL;
176 if (shost->work_q)
177 destroy_workqueue(shost->work_q);
179 scsi_proc_hostdir_rm(shost->hostt);
180 scsi_destroy_command_freelist(shost);
181 kfree(shost->shost_data);
183 if (parent)
184 put_device(parent);
185 kfree(shost);
189 * scsi_host_alloc - register a scsi host adapter instance.
190 * @sht: pointer to scsi host template
191 * @privsize: extra bytes to allocate for driver
193 * Note:
194 * Allocate a new Scsi_Host and perform basic initialization.
195 * The host is not published to the scsi midlayer until scsi_add_host
196 * is called.
198 * Return value:
199 * Pointer to a new Scsi_Host
201 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
203 struct Scsi_Host *shost;
204 int gfp_mask = GFP_KERNEL, rval;
205 DECLARE_COMPLETION(complete);
207 if (sht->unchecked_isa_dma && privsize)
208 gfp_mask |= __GFP_DMA;
210 /* Check to see if this host has any error handling facilities */
211 if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
212 !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
213 !sht->eh_host_reset_handler) {
214 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
215 "ERROR: This is not a safe way to run your "
216 "SCSI host\n"
217 "ERROR: The error handling must be added to "
218 "this driver\n", sht->proc_name);
219 dump_stack();
222 shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
223 if (!shost)
224 return NULL;
225 memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
227 spin_lock_init(&shost->default_lock);
228 scsi_assign_lock(shost, &shost->default_lock);
229 INIT_LIST_HEAD(&shost->__devices);
230 INIT_LIST_HEAD(&shost->__targets);
231 INIT_LIST_HEAD(&shost->eh_cmd_q);
232 INIT_LIST_HEAD(&shost->starved_list);
233 init_waitqueue_head(&shost->host_wait);
235 init_MUTEX(&shost->scan_mutex);
237 shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
238 shost->dma_channel = 0xff;
240 /* These three are default values which can be overridden */
241 shost->max_channel = 0;
242 shost->max_id = 8;
243 shost->max_lun = 8;
245 /* Give each shost a default transportt */
246 shost->transportt = &blank_transport_template;
249 * All drivers right now should be able to handle 12 byte
250 * commands. Every so often there are requests for 16 byte
251 * commands, but individual low-level drivers need to certify that
252 * they actually do something sensible with such commands.
254 shost->max_cmd_len = 12;
255 shost->hostt = sht;
256 shost->this_id = sht->this_id;
257 shost->can_queue = sht->can_queue;
258 shost->sg_tablesize = sht->sg_tablesize;
259 shost->cmd_per_lun = sht->cmd_per_lun;
260 shost->unchecked_isa_dma = sht->unchecked_isa_dma;
261 shost->use_clustering = sht->use_clustering;
262 shost->ordered_flush = sht->ordered_flush;
263 shost->ordered_tag = sht->ordered_tag;
266 * hosts/devices that do queueing must support ordered tags
268 if (shost->can_queue > 1 && shost->ordered_flush) {
269 printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
270 shost->ordered_flush = 0;
273 if (sht->max_host_blocked)
274 shost->max_host_blocked = sht->max_host_blocked;
275 else
276 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
279 * If the driver imposes no hard sector transfer limit, start at
280 * machine infinity initially.
282 if (sht->max_sectors)
283 shost->max_sectors = sht->max_sectors;
284 else
285 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
288 * assume a 4GB boundary, if not set
290 if (sht->dma_boundary)
291 shost->dma_boundary = sht->dma_boundary;
292 else
293 shost->dma_boundary = 0xffffffff;
295 rval = scsi_setup_command_freelist(shost);
296 if (rval)
297 goto fail_kfree;
299 device_initialize(&shost->shost_gendev);
300 snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
301 shost->host_no);
302 shost->shost_gendev.release = scsi_host_dev_release;
304 class_device_initialize(&shost->shost_classdev);
305 shost->shost_classdev.dev = &shost->shost_gendev;
306 shost->shost_classdev.class = &shost_class;
307 snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
308 shost->host_no);
310 shost->eh_notify = &complete;
311 rval = kernel_thread(scsi_error_handler, shost, 0);
312 if (rval < 0)
313 goto fail_destroy_freelist;
314 wait_for_completion(&complete);
315 shost->eh_notify = NULL;
317 scsi_proc_hostdir_add(shost->hostt);
318 return shost;
320 fail_destroy_freelist:
321 scsi_destroy_command_freelist(shost);
322 fail_kfree:
323 kfree(shost);
324 return NULL;
326 EXPORT_SYMBOL(scsi_host_alloc);
328 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
330 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
332 if (!sht->detect) {
333 printk(KERN_WARNING "scsi_register() called on new-style "
334 "template for driver %s\n", sht->name);
335 dump_stack();
338 if (shost)
339 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
340 return shost;
342 EXPORT_SYMBOL(scsi_register);
344 void scsi_unregister(struct Scsi_Host *shost)
346 list_del(&shost->sht_legacy_list);
347 scsi_host_put(shost);
349 EXPORT_SYMBOL(scsi_unregister);
352 * scsi_host_lookup - get a reference to a Scsi_Host by host no
354 * @hostnum: host number to locate
356 * Return value:
357 * A pointer to located Scsi_Host or NULL.
359 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
361 struct class *class = &shost_class;
362 struct class_device *cdev;
363 struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
365 down_read(&class->subsys.rwsem);
366 list_for_each_entry(cdev, &class->children, node) {
367 p = class_to_shost(cdev);
368 if (p->host_no == hostnum) {
369 shost = scsi_host_get(p);
370 break;
373 up_read(&class->subsys.rwsem);
375 return shost;
377 EXPORT_SYMBOL(scsi_host_lookup);
380 * scsi_host_get - inc a Scsi_Host ref count
381 * @shost: Pointer to Scsi_Host to inc.
383 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
385 if (test_bit(SHOST_DEL, &shost->shost_state) ||
386 !get_device(&shost->shost_gendev))
387 return NULL;
388 return shost;
390 EXPORT_SYMBOL(scsi_host_get);
393 * scsi_host_put - dec a Scsi_Host ref count
394 * @shost: Pointer to Scsi_Host to dec.
396 void scsi_host_put(struct Scsi_Host *shost)
398 put_device(&shost->shost_gendev);
400 EXPORT_SYMBOL(scsi_host_put);
402 int scsi_init_hosts(void)
404 return class_register(&shost_class);
407 void scsi_exit_hosts(void)
409 class_unregister(&shost_class);
412 int scsi_is_host_device(const struct device *dev)
414 return dev->release == scsi_host_dev_release;
416 EXPORT_SYMBOL(scsi_is_host_device);
419 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
420 * @shost: Pointer to Scsi_Host.
421 * @work: Work to queue for execution.
423 * Return value:
424 * 0 on success / != 0 for error
426 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
428 if (unlikely(!shost->work_q)) {
429 printk(KERN_ERR
430 "ERROR: Scsi host '%s' attempted to queue scsi-work, "
431 "when no workqueue created.\n", shost->hostt->name);
432 dump_stack();
434 return -EINVAL;
437 return queue_work(shost->work_q, work);
439 EXPORT_SYMBOL_GPL(scsi_queue_work);
442 * scsi_flush_work - Flush a Scsi_Host's workqueue.
443 * @shost: Pointer to Scsi_Host.
445 void scsi_flush_work(struct Scsi_Host *shost)
447 if (!shost->work_q) {
448 printk(KERN_ERR
449 "ERROR: Scsi host '%s' attempted to flush scsi-work, "
450 "when no workqueue created.\n", shost->hostt->name);
451 dump_stack();
452 return;
455 flush_workqueue(shost->work_q);
457 EXPORT_SYMBOL_GPL(scsi_flush_work);