1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * raid_class.c - implementation of a simple raid visualisation class
4 *
5 * Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com>
6 *
7 * This class is designed to allow raid attributes to be visualised and
8 * manipulated in a form independent of the underlying raid.  Ultimately this
9 * should work for both hardware and software raids.
10 */
11#include <linux/init.h>
12#include <linux/module.h>
13#include <linux/list.h>
14#include <linux/slab.h>
15#include <linux/string.h>
16#include <linux/raid_class.h>
17#include <scsi/scsi_device.h>
18#include <scsi/scsi_host.h>
19
20#define RAID_NUM_ATTRS	3
21
22struct raid_internal {
23	struct raid_template r;
24	struct raid_function_template *f;
25	/* The actual attributes */
26	struct device_attribute private_attrs[RAID_NUM_ATTRS];
27	/* The array of null terminated pointers to attributes
28	 * needed by scsi_sysfs.c */
29	struct device_attribute *attrs[RAID_NUM_ATTRS + 1];
30};
31
32struct raid_component {
33	struct list_head node;
34	struct device dev;
35	int num;
36};
37
38#define to_raid_internal(tmpl)	container_of(tmpl, struct raid_internal, r)
39
40#define tc_to_raid_internal(tcont) ({					\
41	struct raid_template *r =					\
42		container_of(tcont, struct raid_template, raid_attrs);	\
43	to_raid_internal(r);						\
44})
45
46#define ac_to_raid_internal(acont) ({					\
47	struct transport_container *tc =				\
48		container_of(acont, struct transport_container, ac);	\
49	tc_to_raid_internal(tc);					\
50})
51
52#define device_to_raid_internal(dev) ({				\
53	struct attribute_container *ac =				\
54		attribute_container_classdev_to_container(dev);	\
55	ac_to_raid_internal(ac);					\
56})
57
58
59static int raid_match(struct attribute_container *cont, struct device *dev)
60{
61	/* We have to look for every subsystem that could house
62	 * emulated RAID devices, so start with SCSI */
63	struct raid_internal *i = ac_to_raid_internal(cont);
64
65	if (IS_ENABLED(CONFIG_SCSI) && scsi_is_sdev_device(dev)) {
66		struct scsi_device *sdev = to_scsi_device(dev);
67
68		if (i->f->cookie != sdev->host->hostt)
69			return 0;
70
71		return i->f->is_raid(dev);
72	}
73	/* FIXME: look at other subsystems too */
74	return 0;
75}
76
77static int raid_setup(struct transport_container *tc, struct device *dev,
78		       struct device *cdev)
79{
80	struct raid_data *rd;
81
82	BUG_ON(dev_get_drvdata(cdev));
83
84	rd = kzalloc(sizeof(*rd), GFP_KERNEL);
85	if (!rd)
86		return -ENOMEM;
87
88	INIT_LIST_HEAD(&rd->component_list);
89	dev_set_drvdata(cdev, rd);
90
91	return 0;
92}
93
94static int raid_remove(struct transport_container *tc, struct device *dev,
95		       struct device *cdev)
96{
97	struct raid_data *rd = dev_get_drvdata(cdev);
98	struct raid_component *rc, *next;
99	dev_printk(KERN_ERR, dev, "RAID REMOVE\n");
100	dev_set_drvdata(cdev, NULL);
101	list_for_each_entry_safe(rc, next, &rd->component_list, node) {
102		list_del(&rc->node);
103		dev_printk(KERN_ERR, rc->dev.parent, "RAID COMPONENT REMOVE\n");
104		device_unregister(&rc->dev);
105	}
106	dev_printk(KERN_ERR, dev, "RAID REMOVE DONE\n");
107	kfree(rd);
108	return 0;
109}
110
111static DECLARE_TRANSPORT_CLASS(raid_class,
112			       "raid_devices",
113			       raid_setup,
114			       raid_remove,
115			       NULL);
116
117static const struct {
118	enum raid_state	value;
119	char		*name;
120} raid_states[] = {
121	{ RAID_STATE_UNKNOWN, "unknown" },
122	{ RAID_STATE_ACTIVE, "active" },
123	{ RAID_STATE_DEGRADED, "degraded" },
124	{ RAID_STATE_RESYNCING, "resyncing" },
125	{ RAID_STATE_OFFLINE, "offline" },
126};
127
128static const char *raid_state_name(enum raid_state state)
129{
130	int i;
131	char *name = NULL;
132
133	for (i = 0; i < ARRAY_SIZE(raid_states); i++) {
134		if (raid_states[i].value == state) {
135			name = raid_states[i].name;
136			break;
137		}
138	}
139	return name;
140}
141
142static struct {
143	enum raid_level value;
144	char *name;
145} raid_levels[] = {
146	{ RAID_LEVEL_UNKNOWN, "unknown" },
147	{ RAID_LEVEL_LINEAR, "linear" },
148	{ RAID_LEVEL_0, "raid0" },
149	{ RAID_LEVEL_1, "raid1" },
150	{ RAID_LEVEL_10, "raid10" },
151	{ RAID_LEVEL_1E, "raid1e" },
152	{ RAID_LEVEL_3, "raid3" },
153	{ RAID_LEVEL_4, "raid4" },
154	{ RAID_LEVEL_5, "raid5" },
155	{ RAID_LEVEL_50, "raid50" },
156	{ RAID_LEVEL_6, "raid6" },
157	{ RAID_LEVEL_JBOD, "jbod" },
158};
159
160static const char *raid_level_name(enum raid_level level)
161{
162	int i;
163	char *name = NULL;
164
165	for (i = 0; i < ARRAY_SIZE(raid_levels); i++) {
166		if (raid_levels[i].value == level) {
167			name = raid_levels[i].name;
168			break;
169		}
170	}
171	return name;
172}
173
174#define raid_attr_show_internal(attr, fmt, var, code)			\
175static ssize_t raid_show_##attr(struct device *dev, 			\
176				struct device_attribute *attr, 		\
177				char *buf)				\
178{									\
179	struct raid_data *rd = dev_get_drvdata(dev);			\
180	code								\
181	return snprintf(buf, 20, #fmt "\n", var);			\
182}
183
184#define raid_attr_ro_states(attr, states, code)				\
185raid_attr_show_internal(attr, %s, name,					\
186	const char *name;						\
187	code								\
188	name = raid_##states##_name(rd->attr);				\
189)									\
190static DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
191
192
193#define raid_attr_ro_internal(attr, code)				\
194raid_attr_show_internal(attr, %d, rd->attr, code)			\
195static DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
196
197#define ATTR_CODE(attr)							\
198	struct raid_internal *i = device_to_raid_internal(dev);		\
199	if (i->f->get_##attr)						\
200		i->f->get_##attr(dev->parent);
201
202#define raid_attr_ro(attr)	raid_attr_ro_internal(attr, )
203#define raid_attr_ro_fn(attr)	raid_attr_ro_internal(attr, ATTR_CODE(attr))
204#define raid_attr_ro_state(attr)	raid_attr_ro_states(attr, attr, )
205#define raid_attr_ro_state_fn(attr)	raid_attr_ro_states(attr, attr, ATTR_CODE(attr))
206
207
208raid_attr_ro_state(level);
209raid_attr_ro_fn(resync);
210raid_attr_ro_state_fn(state);
211
212struct raid_template *
213raid_class_attach(struct raid_function_template *ft)
214{
215	struct raid_internal *i = kzalloc(sizeof(struct raid_internal),
216					  GFP_KERNEL);
217	int count = 0;
218
219	if (unlikely(!i))
220		return NULL;
221
222	i->f = ft;
223
224	i->r.raid_attrs.ac.class = &raid_class.class;
225	i->r.raid_attrs.ac.match = raid_match;
226	i->r.raid_attrs.ac.attrs = &i->attrs[0];
227
228	attribute_container_register(&i->r.raid_attrs.ac);
229
230	i->attrs[count++] = &dev_attr_level;
231	i->attrs[count++] = &dev_attr_resync;
232	i->attrs[count++] = &dev_attr_state;
233
234	i->attrs[count] = NULL;
235	BUG_ON(count > RAID_NUM_ATTRS);
236
237	return &i->r;
238}
239EXPORT_SYMBOL(raid_class_attach);
240
241void
242raid_class_release(struct raid_template *r)
243{
244	struct raid_internal *i = to_raid_internal(r);
245
246	BUG_ON(attribute_container_unregister(&i->r.raid_attrs.ac));
247
248	kfree(i);
249}
250EXPORT_SYMBOL(raid_class_release);
251
252static __init int raid_init(void)
253{
254	return transport_class_register(&raid_class);
255}
256
257static __exit void raid_exit(void)
258{
259	transport_class_unregister(&raid_class);
260}
261
262MODULE_AUTHOR("James Bottomley");
263MODULE_DESCRIPTION("RAID device class");
264MODULE_LICENSE("GPL");
265
266module_init(raid_init);
267module_exit(raid_exit);
268
269