1/*
2 * raid_class.c - implementation of a simple raid visualisation class
3 *
4 * Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com>
5 *
6 * This file is licensed under GPLv2
7 *
8 * This class is designed to allow raid attributes to be visualised and
9 * manipulated in a form independent of the underlying raid.  Ultimately this
10 * should work for both hardware and software raids.
11 */
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/list.h>
15#include <linux/slab.h>
16#include <linux/string.h>
17#include <linux/raid_class.h>
18#include <scsi/scsi_device.h>
19#include <scsi/scsi_host.h>
20
21#define RAID_NUM_ATTRS	3
22
23struct raid_internal {
24	struct raid_template r;
25	struct raid_function_template *f;
26	/* The actual attributes */
27	struct device_attribute private_attrs[RAID_NUM_ATTRS];
28	/* The array of null terminated pointers to attributes
29	 * needed by scsi_sysfs.c */
30	struct device_attribute *attrs[RAID_NUM_ATTRS + 1];
31};
32
33struct raid_component {
34	struct list_head node;
35	struct device dev;
36	int num;
37};
38
39#define to_raid_internal(tmpl)	container_of(tmpl, struct raid_internal, r)
40
41#define tc_to_raid_internal(tcont) ({					\
42	struct raid_template *r =					\
43		container_of(tcont, struct raid_template, raid_attrs);	\
44	to_raid_internal(r);						\
45})
46
47#define ac_to_raid_internal(acont) ({					\
48	struct transport_container *tc =				\
49		container_of(acont, struct transport_container, ac);	\
50	tc_to_raid_internal(tc);					\
51})
52
53#define device_to_raid_internal(dev) ({				\
54	struct attribute_container *ac =				\
55		attribute_container_classdev_to_container(dev);	\
56	ac_to_raid_internal(ac);					\
57})
58
59
60static int raid_match(struct attribute_container *cont, struct device *dev)
61{
62	/* We have to look for every subsystem that could house
63	 * emulated RAID devices, so start with SCSI */
64	struct raid_internal *i = ac_to_raid_internal(cont);
65
66#if defined(CONFIG_SCSI) || defined(CONFIG_SCSI_MODULE)
67	if (scsi_is_sdev_device(dev)) {
68		struct scsi_device *sdev = to_scsi_device(dev);
69
70		if (i->f->cookie != sdev->host->hostt)
71			return 0;
72
73		return i->f->is_raid(dev);
74	}
75#endif
76	/* FIXME: look at other subsystems too */
77	return 0;
78}
79
80static int raid_setup(struct transport_container *tc, struct device *dev,
81		       struct device *cdev)
82{
83	struct raid_data *rd;
84
85	BUG_ON(dev_get_drvdata(cdev));
86
87	rd = kzalloc(sizeof(*rd), GFP_KERNEL);
88	if (!rd)
89		return -ENOMEM;
90
91	INIT_LIST_HEAD(&rd->component_list);
92	dev_set_drvdata(cdev, rd);
93
94	return 0;
95}
96
97static int raid_remove(struct transport_container *tc, struct device *dev,
98		       struct device *cdev)
99{
100	struct raid_data *rd = dev_get_drvdata(cdev);
101	struct raid_component *rc, *next;
102	dev_printk(KERN_ERR, dev, "RAID REMOVE\n");
103	dev_set_drvdata(cdev, NULL);
104	list_for_each_entry_safe(rc, next, &rd->component_list, node) {
105		list_del(&rc->node);
106		dev_printk(KERN_ERR, rc->dev.parent, "RAID COMPONENT REMOVE\n");
107		device_unregister(&rc->dev);
108	}
109	dev_printk(KERN_ERR, dev, "RAID REMOVE DONE\n");
110	kfree(rd);
111	return 0;
112}
113
114static DECLARE_TRANSPORT_CLASS(raid_class,
115			       "raid_devices",
116			       raid_setup,
117			       raid_remove,
118			       NULL);
119
120static const struct {
121	enum raid_state	value;
122	char		*name;
123} raid_states[] = {
124	{ RAID_STATE_UNKNOWN, "unknown" },
125	{ RAID_STATE_ACTIVE, "active" },
126	{ RAID_STATE_DEGRADED, "degraded" },
127	{ RAID_STATE_RESYNCING, "resyncing" },
128	{ RAID_STATE_OFFLINE, "offline" },
129};
130
131static const char *raid_state_name(enum raid_state state)
132{
133	int i;
134	char *name = NULL;
135
136	for (i = 0; i < ARRAY_SIZE(raid_states); i++) {
137		if (raid_states[i].value == state) {
138			name = raid_states[i].name;
139			break;
140		}
141	}
142	return name;
143}
144
145static struct {
146	enum raid_level value;
147	char *name;
148} raid_levels[] = {
149	{ RAID_LEVEL_UNKNOWN, "unknown" },
150	{ RAID_LEVEL_LINEAR, "linear" },
151	{ RAID_LEVEL_0, "raid0" },
152	{ RAID_LEVEL_1, "raid1" },
153	{ RAID_LEVEL_10, "raid10" },
154	{ RAID_LEVEL_1E, "raid1e" },
155	{ RAID_LEVEL_3, "raid3" },
156	{ RAID_LEVEL_4, "raid4" },
157	{ RAID_LEVEL_5, "raid5" },
158	{ RAID_LEVEL_50, "raid50" },
159	{ RAID_LEVEL_6, "raid6" },
160};
161
162static const char *raid_level_name(enum raid_level level)
163{
164	int i;
165	char *name = NULL;
166
167	for (i = 0; i < ARRAY_SIZE(raid_levels); i++) {
168		if (raid_levels[i].value == level) {
169			name = raid_levels[i].name;
170			break;
171		}
172	}
173	return name;
174}
175
176#define raid_attr_show_internal(attr, fmt, var, code)			\
177static ssize_t raid_show_##attr(struct device *dev, 			\
178				struct device_attribute *attr, 		\
179				char *buf)				\
180{									\
181	struct raid_data *rd = dev_get_drvdata(dev);			\
182	code								\
183	return snprintf(buf, 20, #fmt "\n", var);			\
184}
185
186#define raid_attr_ro_states(attr, states, code)				\
187raid_attr_show_internal(attr, %s, name,					\
188	const char *name;						\
189	code								\
190	name = raid_##states##_name(rd->attr);				\
191)									\
192static DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
193
194
195#define raid_attr_ro_internal(attr, code)				\
196raid_attr_show_internal(attr, %d, rd->attr, code)			\
197static DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
198
199#define ATTR_CODE(attr)							\
200	struct raid_internal *i = device_to_raid_internal(dev);		\
201	if (i->f->get_##attr)						\
202		i->f->get_##attr(dev->parent);
203
204#define raid_attr_ro(attr)	raid_attr_ro_internal(attr, )
205#define raid_attr_ro_fn(attr)	raid_attr_ro_internal(attr, ATTR_CODE(attr))
206#define raid_attr_ro_state(attr)	raid_attr_ro_states(attr, attr, )
207#define raid_attr_ro_state_fn(attr)	raid_attr_ro_states(attr, attr, ATTR_CODE(attr))
208
209
210raid_attr_ro_state(level);
211raid_attr_ro_fn(resync);
212raid_attr_ro_state_fn(state);
213
214static void raid_component_release(struct device *dev)
215{
216	struct raid_component *rc =
217		container_of(dev, struct raid_component, dev);
218	dev_printk(KERN_ERR, rc->dev.parent, "COMPONENT RELEASE\n");
219	put_device(rc->dev.parent);
220	kfree(rc);
221}
222
223int raid_component_add(struct raid_template *r,struct device *raid_dev,
224		       struct device *component_dev)
225{
226	struct device *cdev =
227		attribute_container_find_class_device(&r->raid_attrs.ac,
228						      raid_dev);
229	struct raid_component *rc;
230	struct raid_data *rd = dev_get_drvdata(cdev);
231	int err;
232
233	rc = kzalloc(sizeof(*rc), GFP_KERNEL);
234	if (!rc)
235		return -ENOMEM;
236
237	INIT_LIST_HEAD(&rc->node);
238	device_initialize(&rc->dev);
239	rc->dev.release = raid_component_release;
240	rc->dev.parent = get_device(component_dev);
241	rc->num = rd->component_count++;
242
243	dev_set_name(&rc->dev, "component-%d", rc->num);
244	list_add_tail(&rc->node, &rd->component_list);
245	rc->dev.class = &raid_class.class;
246	err = device_add(&rc->dev);
247	if (err)
248		goto err_out;
249
250	return 0;
251
252err_out:
253	list_del(&rc->node);
254	rd->component_count--;
255	put_device(component_dev);
256	kfree(rc);
257	return err;
258}
259EXPORT_SYMBOL(raid_component_add);
260
261struct raid_template *
262raid_class_attach(struct raid_function_template *ft)
263{
264	struct raid_internal *i = kzalloc(sizeof(struct raid_internal),
265					  GFP_KERNEL);
266	int count = 0;
267
268	if (unlikely(!i))
269		return NULL;
270
271	i->f = ft;
272
273	i->r.raid_attrs.ac.class = &raid_class.class;
274	i->r.raid_attrs.ac.match = raid_match;
275	i->r.raid_attrs.ac.attrs = &i->attrs[0];
276
277	attribute_container_register(&i->r.raid_attrs.ac);
278
279	i->attrs[count++] = &dev_attr_level;
280	i->attrs[count++] = &dev_attr_resync;
281	i->attrs[count++] = &dev_attr_state;
282
283	i->attrs[count] = NULL;
284	BUG_ON(count > RAID_NUM_ATTRS);
285
286	return &i->r;
287}
288EXPORT_SYMBOL(raid_class_attach);
289
290void
291raid_class_release(struct raid_template *r)
292{
293	struct raid_internal *i = to_raid_internal(r);
294
295	BUG_ON(attribute_container_unregister(&i->r.raid_attrs.ac));
296
297	kfree(i);
298}
299EXPORT_SYMBOL(raid_class_release);
300
301static __init int raid_init(void)
302{
303	return transport_class_register(&raid_class);
304}
305
306static __exit void raid_exit(void)
307{
308	transport_class_unregister(&raid_class);
309}
310
311MODULE_AUTHOR("James Bottomley");
312MODULE_DESCRIPTION("RAID device class");
313MODULE_LICENSE("GPL");
314
315module_init(raid_init);
316module_exit(raid_exit);
317
318