[PATCH] make various thing static
[linux-2.6.git] / drivers / scsi / hosts.c
1 /*
2  *  hosts.c Copyright (C) 1992 Drew Eckhardt
3  *          Copyright (C) 1993, 1994, 1995 Eric Youngdale
4  *          Copyright (C) 2002-2003 Christoph Hellwig
5  *
6  *  mid to lowlevel SCSI driver interface
7  *      Initial versions: Drew Eckhardt
8  *      Subsequent revisions: Eric Youngdale
9  *
10  *  <drew@colorado.edu>
11  *
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
15  *
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>
19  *
20  *  Restructured scsi_host lists and associated functions.
21  *  September 04, 2002 Mike Anderson (andmike@us.ibm.com)
22  */
23
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>
32
33 #include <scsi/scsi_device.h>
34 #include <scsi/scsi_host.h>
35 #include <scsi/scsi_transport.h>
36
37 #include "scsi_priv.h"
38 #include "scsi_logging.h"
39
40
41 static int scsi_host_next_hn;           /* host_no for next new host */
42
43
44 static void scsi_host_cls_release(struct class_device *class_dev)
45 {
46         put_device(&class_to_shost(class_dev)->shost_gendev);
47 }
48
49 static struct class shost_class = {
50         .name           = "scsi_host",
51         .release        = scsi_host_cls_release,
52 };
53
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)
60 {
61         struct scsi_device *sdev;
62
63         set_bit(SHOST_CANCEL, &shost->shost_state);
64         shost_for_each_device(sdev, shost) {
65                 scsi_device_cancel(sdev, recovery);
66         }
67         wait_event(shost->host_wait, (!test_bit(SHOST_RECOVERY,
68                                                 &shost->shost_state)));
69 }
70
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)
76 {
77         scsi_forget_host(shost);
78         scsi_host_cancel(shost, 0);
79         scsi_proc_host_rm(shost);
80
81         set_bit(SHOST_DEL, &shost->shost_state);
82
83         transport_unregister_device(&shost->shost_gendev);
84         class_device_unregister(&shost->shost_classdev);
85         device_del(&shost->shost_gendev);
86 }
87 EXPORT_SYMBOL(scsi_remove_host);
88
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
93  *
94  * Return value: 
95  *      0 on success / != 0 for error
96  **/
97 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
98 {
99         struct scsi_host_template *sht = shost->hostt;
100         int error = -EINVAL;
101
102         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
103                         sht->info ? sht->info(shost) : sht->name);
104
105         if (!shost->can_queue) {
106                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
107                                 sht->name);
108                 goto out;
109         }
110
111         if (!shost->shost_gendev.parent)
112                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
113
114         error = device_add(&shost->shost_gendev);
115         if (error)
116                 goto out;
117
118         set_bit(SHOST_ADD, &shost->shost_state);
119         get_device(shost->shost_gendev.parent);
120
121         error = class_device_add(&shost->shost_classdev);
122         if (error)
123                 goto out_del_gendev;
124
125         get_device(&shost->shost_gendev);
126
127         if (shost->transportt->host_size &&
128             (shost->shost_data = kmalloc(shost->transportt->host_size,
129                                          GFP_KERNEL)) == NULL)
130                 goto out_del_classdev;
131
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;
139         }
140
141         error = scsi_sysfs_add_host(shost);
142         if (error)
143                 goto out_destroy_host;
144
145         scsi_proc_host_add(shost);
146         return error;
147
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;
159 }
160 EXPORT_SYMBOL(scsi_add_host);
161
162 static void scsi_host_dev_release(struct device *dev)
163 {
164         struct Scsi_Host *shost = dev_to_shost(dev);
165         struct device *parent = dev->parent;
166
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;
174         }
175
176         if (shost->work_q)
177                 destroy_workqueue(shost->work_q);
178
179         scsi_proc_hostdir_rm(shost->hostt);
180         scsi_destroy_command_freelist(shost);
181         kfree(shost->shost_data);
182
183         /*
184          * Some drivers (eg aha1542) do scsi_register()/scsi_unregister()
185          * during probing without performing a scsi_set_device() in between.
186          * In this case dev->parent is NULL.
187          */
188         if (parent)
189                 put_device(parent);
190         kfree(shost);
191 }
192
193 /**
194  * scsi_host_alloc - register a scsi host adapter instance.
195  * @sht:        pointer to scsi host template
196  * @privsize:   extra bytes to allocate for driver
197  *
198  * Note:
199  *      Allocate a new Scsi_Host and perform basic initialization.
200  *      The host is not published to the scsi midlayer until scsi_add_host
201  *      is called.
202  *
203  * Return value:
204  *      Pointer to a new Scsi_Host
205  **/
206 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
207 {
208         struct Scsi_Host *shost;
209         int gfp_mask = GFP_KERNEL, rval;
210         DECLARE_COMPLETION(complete);
211
212         if (sht->unchecked_isa_dma && privsize)
213                 gfp_mask |= __GFP_DMA;
214
215         /* Check to see if this host has any error handling facilities */
216         if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
217             !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
218             !sht->eh_host_reset_handler) {
219                 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
220                                 "ERROR: This is not a safe way to run your "
221                                         "SCSI host\n"
222                                 "ERROR: The error handling must be added to "
223                                 "this driver\n", sht->proc_name);
224                 dump_stack();
225         }
226
227         shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
228         if (!shost)
229                 return NULL;
230         memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
231
232         spin_lock_init(&shost->default_lock);
233         scsi_assign_lock(shost, &shost->default_lock);
234         INIT_LIST_HEAD(&shost->__devices);
235         INIT_LIST_HEAD(&shost->__targets);
236         INIT_LIST_HEAD(&shost->eh_cmd_q);
237         INIT_LIST_HEAD(&shost->starved_list);
238         init_waitqueue_head(&shost->host_wait);
239
240         init_MUTEX(&shost->scan_mutex);
241
242         shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
243         shost->dma_channel = 0xff;
244
245         /* These three are default values which can be overridden */
246         shost->max_channel = 0;
247         shost->max_id = 8;
248         shost->max_lun = 8;
249
250         /* Give each shost a default transportt */
251         shost->transportt = &blank_transport_template;
252
253         /*
254          * All drivers right now should be able to handle 12 byte
255          * commands.  Every so often there are requests for 16 byte
256          * commands, but individual low-level drivers need to certify that
257          * they actually do something sensible with such commands.
258          */
259         shost->max_cmd_len = 12;
260         shost->hostt = sht;
261         shost->this_id = sht->this_id;
262         shost->can_queue = sht->can_queue;
263         shost->sg_tablesize = sht->sg_tablesize;
264         shost->cmd_per_lun = sht->cmd_per_lun;
265         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
266         shost->use_clustering = sht->use_clustering;
267         shost->ordered_flush = sht->ordered_flush;
268         shost->ordered_tag = sht->ordered_tag;
269
270         /*
271          * hosts/devices that do queueing must support ordered tags
272          */
273         if (shost->can_queue > 1 && shost->ordered_flush) {
274                 printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
275                 shost->ordered_flush = 0;
276         }
277
278         if (sht->max_host_blocked)
279                 shost->max_host_blocked = sht->max_host_blocked;
280         else
281                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
282
283         /*
284          * If the driver imposes no hard sector transfer limit, start at
285          * machine infinity initially.
286          */
287         if (sht->max_sectors)
288                 shost->max_sectors = sht->max_sectors;
289         else
290                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
291
292         /*
293          * assume a 4GB boundary, if not set
294          */
295         if (sht->dma_boundary)
296                 shost->dma_boundary = sht->dma_boundary;
297         else
298                 shost->dma_boundary = 0xffffffff;
299
300         rval = scsi_setup_command_freelist(shost);
301         if (rval)
302                 goto fail_kfree;
303
304         device_initialize(&shost->shost_gendev);
305         snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
306                 shost->host_no);
307         shost->shost_gendev.release = scsi_host_dev_release;
308
309         class_device_initialize(&shost->shost_classdev);
310         shost->shost_classdev.dev = &shost->shost_gendev;
311         shost->shost_classdev.class = &shost_class;
312         snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
313                   shost->host_no);
314
315         shost->eh_notify = &complete;
316         rval = kernel_thread(scsi_error_handler, shost, 0);
317         if (rval < 0)
318                 goto fail_destroy_freelist;
319         wait_for_completion(&complete);
320         shost->eh_notify = NULL;
321
322         scsi_proc_hostdir_add(shost->hostt);
323         return shost;
324
325  fail_destroy_freelist:
326         scsi_destroy_command_freelist(shost);
327  fail_kfree:
328         kfree(shost);
329         return NULL;
330 }
331 EXPORT_SYMBOL(scsi_host_alloc);
332
333 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
334 {
335         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
336
337         if (!sht->detect) {
338                 printk(KERN_WARNING "scsi_register() called on new-style "
339                                     "template for driver %s\n", sht->name);
340                 dump_stack();
341         }
342
343         if (shost)
344                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
345         return shost;
346 }
347 EXPORT_SYMBOL(scsi_register);
348
349 void scsi_unregister(struct Scsi_Host *shost)
350 {
351         list_del(&shost->sht_legacy_list);
352         scsi_host_put(shost);
353 }
354 EXPORT_SYMBOL(scsi_unregister);
355
356 /**
357  * scsi_host_lookup - get a reference to a Scsi_Host by host no
358  *
359  * @hostnum:    host number to locate
360  *
361  * Return value:
362  *      A pointer to located Scsi_Host or NULL.
363  **/
364 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
365 {
366         struct class *class = &shost_class;
367         struct class_device *cdev;
368         struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
369
370         down_read(&class->subsys.rwsem);
371         list_for_each_entry(cdev, &class->children, node) {
372                 p = class_to_shost(cdev);
373                 if (p->host_no == hostnum) {
374                         shost = scsi_host_get(p);
375                         break;
376                 }
377         }
378         up_read(&class->subsys.rwsem);
379
380         return shost;
381 }
382 EXPORT_SYMBOL(scsi_host_lookup);
383
384 /**
385  * scsi_host_get - inc a Scsi_Host ref count
386  * @shost:      Pointer to Scsi_Host to inc.
387  **/
388 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
389 {
390         if (test_bit(SHOST_DEL, &shost->shost_state) ||
391                 !get_device(&shost->shost_gendev))
392                 return NULL;
393         return shost;
394 }
395 EXPORT_SYMBOL(scsi_host_get);
396
397 /**
398  * scsi_host_put - dec a Scsi_Host ref count
399  * @shost:      Pointer to Scsi_Host to dec.
400  **/
401 void scsi_host_put(struct Scsi_Host *shost)
402 {
403         put_device(&shost->shost_gendev);
404 }
405 EXPORT_SYMBOL(scsi_host_put);
406
407 int scsi_init_hosts(void)
408 {
409         return class_register(&shost_class);
410 }
411
412 void scsi_exit_hosts(void)
413 {
414         class_unregister(&shost_class);
415 }
416
417 int scsi_is_host_device(const struct device *dev)
418 {
419         return dev->release == scsi_host_dev_release;
420 }
421 EXPORT_SYMBOL(scsi_is_host_device);
422
423 /**
424  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
425  * @shost:      Pointer to Scsi_Host.
426  * @work:       Work to queue for execution.
427  *
428  * Return value:
429  *      0 on success / != 0 for error
430  **/
431 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
432 {
433         if (unlikely(!shost->work_q)) {
434                 printk(KERN_ERR
435                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
436                         "when no workqueue created.\n", shost->hostt->name);
437                 dump_stack();
438
439                 return -EINVAL;
440         }
441
442         return queue_work(shost->work_q, work);
443 }
444 EXPORT_SYMBOL_GPL(scsi_queue_work);
445
446 /**
447  * scsi_flush_work - Flush a Scsi_Host's workqueue.
448  * @shost:      Pointer to Scsi_Host.
449  **/
450 void scsi_flush_work(struct Scsi_Host *shost)
451 {
452         if (!shost->work_q) {
453                 printk(KERN_ERR
454                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
455                         "when no workqueue created.\n", shost->hostt->name);
456                 dump_stack();
457                 return;
458         }
459
460         flush_workqueue(shost->work_q);
461 }
462 EXPORT_SYMBOL_GPL(scsi_flush_work);