1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
/*
* linux/drivers/base/map.c
*
* (C) Copyright Al Viro 2002,2003
* Released under GPL v2.
*
* NOTE: data structure needs to be changed. It works, but for large dev_t
* it will be too slow. It is isolated, though, so these changes will be
* local to that file.
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/kdev_t.h>
#include <linux/kobject.h>
#include <linux/kobj_map.h>
struct kobj_map {
struct probe {
struct probe *next;
dev_t dev;
unsigned long range;
struct module *owner;
kobj_probe_t *get;
int (*lock)(dev_t, void *);
void *data;
} *probes[255];
struct semaphore *sem;
};
int kobj_map(struct kobj_map *domain, dev_t dev, unsigned long range,
struct module *module, kobj_probe_t *probe,
int (*lock)(dev_t, void *), void *data)
{
unsigned n = MAJOR(dev + range - 1) - MAJOR(dev) + 1;
unsigned index = MAJOR(dev);
unsigned i;
struct probe *p;
if (n > 255)
n = 255;
p = kmalloc(sizeof(struct probe) * n, GFP_KERNEL);
if (p == NULL)
return -ENOMEM;
for (i = 0; i < n; i++, p++) {
p->owner = module;
p->get = probe;
p->lock = lock;
p->dev = dev;
p->range = range;
p->data = data;
}
down(domain->sem);
for (i = 0, p -= n; i < n; i++, p++, index++) {
struct probe **s = &domain->probes[index % 255];
while (*s && (*s)->range < range)
s = &(*s)->next;
p->next = *s;
*s = p;
}
up(domain->sem);
return 0;
}
void kobj_unmap(struct kobj_map *domain, dev_t dev, unsigned long range)
{
unsigned n = MAJOR(dev + range - 1) - MAJOR(dev) + 1;
unsigned index = MAJOR(dev);
unsigned i;
struct probe *found = NULL;
if (n > 255)
n = 255;
down(domain->sem);
for (i = 0; i < n; i++, index++) {
struct probe **s;
for (s = &domain->probes[index % 255]; *s; s = &(*s)->next) {
struct probe *p = *s;
if (p->dev == dev && p->range == range) {
*s = p->next;
if (!found)
found = p;
break;
}
}
}
up(domain->sem);
kfree(found);
}
struct kobject *kobj_lookup(struct kobj_map *domain, dev_t dev, int *index)
{
struct kobject *kobj;
struct probe *p;
unsigned long best = ~0UL;
retry:
down(domain->sem);
for (p = domain->probes[MAJOR(dev) % 255]; p; p = p->next) {
struct kobject *(*probe)(dev_t, int *, void *);
struct module *owner;
void *data;
if (p->dev > dev || p->dev + p->range - 1 < dev)
continue;
if (p->range - 1 >= best)
break;
if (!try_module_get(p->owner))
continue;
owner = p->owner;
data = p->data;
probe = p->get;
best = p->range - 1;
*index = dev - p->dev;
if (p->lock && p->lock(dev, data) < 0) {
module_put(owner);
continue;
}
up(domain->sem);
kobj = probe(dev, index, data);
/* Currently ->owner protects _only_ ->probe() itself. */
module_put(owner);
if (kobj)
return kobj;
goto retry;
}
up(domain->sem);
return NULL;
}
struct kobj_map *kobj_map_init(kobj_probe_t *base_probe, struct semaphore *sem)
{
struct kobj_map *p = kmalloc(sizeof(struct kobj_map), GFP_KERNEL);
struct probe *base = kzalloc(sizeof(*base), GFP_KERNEL);
int i;
if ((p == NULL) || (base == NULL)) {
kfree(p);
kfree(base);
return NULL;
}
base->dev = 1;
base->range = ~0;
base->get = base_probe;
for (i = 0; i < 255; i++)
p->probes[i] = base;
p->sem = sem;
return p;
}
|
