xref: /linux/drivers/scsi/raid_class.c (revision a1c613ae4c322ddd58d5a8539dbfba2a0380a8c0)
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 
22 struct 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 
32 struct 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 
raid_match(struct attribute_container * cont,struct device * dev)59 static 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 
raid_setup(struct transport_container * tc,struct device * dev,struct device * cdev)77 static 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 
raid_remove(struct transport_container * tc,struct device * dev,struct device * cdev)94 static 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 
111 static DECLARE_TRANSPORT_CLASS(raid_class,
112 			       "raid_devices",
113 			       raid_setup,
114 			       raid_remove,
115 			       NULL);
116 
117 static 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 
raid_state_name(enum raid_state state)128 static 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 
142 static 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 
raid_level_name(enum raid_level level)160 static 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)			\
175 static 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)				\
185 raid_attr_show_internal(attr, %s, name,					\
186 	const char *name;						\
187 	code								\
188 	name = raid_##states##_name(rd->attr);				\
189 )									\
190 static DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
191 
192 
193 #define raid_attr_ro_internal(attr, code)				\
194 raid_attr_show_internal(attr, %d, rd->attr, code)			\
195 static 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 
208 raid_attr_ro_state(level);
209 raid_attr_ro_fn(resync);
210 raid_attr_ro_state_fn(state);
211 
212 struct raid_template *
raid_class_attach(struct raid_function_template * ft)213 raid_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 }
239 EXPORT_SYMBOL(raid_class_attach);
240 
241 void
raid_class_release(struct raid_template * r)242 raid_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 }
250 EXPORT_SYMBOL(raid_class_release);
251 
raid_init(void)252 static __init int raid_init(void)
253 {
254 	return transport_class_register(&raid_class);
255 }
256 
raid_exit(void)257 static __exit void raid_exit(void)
258 {
259 	transport_class_unregister(&raid_class);
260 }
261 
262 MODULE_AUTHOR("James Bottomley");
263 MODULE_DESCRIPTION("RAID device class");
264 MODULE_LICENSE("GPL");
265 
266 module_init(raid_init);
267 module_exit(raid_exit);
268 
269