1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * linux/drivers/base/map.c
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * (C) Copyright Al Viro 2002,2003
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * NOTE: data structure needs to be changed. It works, but for large dev_t
8*4882a593Smuzhiyun * it will be too slow. It is isolated, though, so these changes will be
9*4882a593Smuzhiyun * local to that file.
10*4882a593Smuzhiyun */
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun #include <linux/module.h>
13*4882a593Smuzhiyun #include <linux/slab.h>
14*4882a593Smuzhiyun #include <linux/mutex.h>
15*4882a593Smuzhiyun #include <linux/kdev_t.h>
16*4882a593Smuzhiyun #include <linux/kobject.h>
17*4882a593Smuzhiyun #include <linux/kobj_map.h>
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun struct kobj_map {
20*4882a593Smuzhiyun struct probe {
21*4882a593Smuzhiyun struct probe *next;
22*4882a593Smuzhiyun dev_t dev;
23*4882a593Smuzhiyun unsigned long range;
24*4882a593Smuzhiyun struct module *owner;
25*4882a593Smuzhiyun kobj_probe_t *get;
26*4882a593Smuzhiyun int (*lock)(dev_t, void *);
27*4882a593Smuzhiyun void *data;
28*4882a593Smuzhiyun } *probes[255];
29*4882a593Smuzhiyun struct mutex *lock;
30*4882a593Smuzhiyun };
31*4882a593Smuzhiyun
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)32*4882a593Smuzhiyun int kobj_map(struct kobj_map *domain, dev_t dev, unsigned long range,
33*4882a593Smuzhiyun struct module *module, kobj_probe_t *probe,
34*4882a593Smuzhiyun int (*lock)(dev_t, void *), void *data)
35*4882a593Smuzhiyun {
36*4882a593Smuzhiyun unsigned n = MAJOR(dev + range - 1) - MAJOR(dev) + 1;
37*4882a593Smuzhiyun unsigned index = MAJOR(dev);
38*4882a593Smuzhiyun unsigned i;
39*4882a593Smuzhiyun struct probe *p;
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun if (n > 255)
42*4882a593Smuzhiyun n = 255;
43*4882a593Smuzhiyun
44*4882a593Smuzhiyun p = kmalloc_array(n, sizeof(struct probe), GFP_KERNEL);
45*4882a593Smuzhiyun if (p == NULL)
46*4882a593Smuzhiyun return -ENOMEM;
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun for (i = 0; i < n; i++, p++) {
49*4882a593Smuzhiyun p->owner = module;
50*4882a593Smuzhiyun p->get = probe;
51*4882a593Smuzhiyun p->lock = lock;
52*4882a593Smuzhiyun p->dev = dev;
53*4882a593Smuzhiyun p->range = range;
54*4882a593Smuzhiyun p->data = data;
55*4882a593Smuzhiyun }
56*4882a593Smuzhiyun mutex_lock(domain->lock);
57*4882a593Smuzhiyun for (i = 0, p -= n; i < n; i++, p++, index++) {
58*4882a593Smuzhiyun struct probe **s = &domain->probes[index % 255];
59*4882a593Smuzhiyun while (*s && (*s)->range < range)
60*4882a593Smuzhiyun s = &(*s)->next;
61*4882a593Smuzhiyun p->next = *s;
62*4882a593Smuzhiyun *s = p;
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun mutex_unlock(domain->lock);
65*4882a593Smuzhiyun return 0;
66*4882a593Smuzhiyun }
67*4882a593Smuzhiyun
kobj_unmap(struct kobj_map * domain,dev_t dev,unsigned long range)68*4882a593Smuzhiyun void kobj_unmap(struct kobj_map *domain, dev_t dev, unsigned long range)
69*4882a593Smuzhiyun {
70*4882a593Smuzhiyun unsigned n = MAJOR(dev + range - 1) - MAJOR(dev) + 1;
71*4882a593Smuzhiyun unsigned index = MAJOR(dev);
72*4882a593Smuzhiyun unsigned i;
73*4882a593Smuzhiyun struct probe *found = NULL;
74*4882a593Smuzhiyun
75*4882a593Smuzhiyun if (n > 255)
76*4882a593Smuzhiyun n = 255;
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun mutex_lock(domain->lock);
79*4882a593Smuzhiyun for (i = 0; i < n; i++, index++) {
80*4882a593Smuzhiyun struct probe **s;
81*4882a593Smuzhiyun for (s = &domain->probes[index % 255]; *s; s = &(*s)->next) {
82*4882a593Smuzhiyun struct probe *p = *s;
83*4882a593Smuzhiyun if (p->dev == dev && p->range == range) {
84*4882a593Smuzhiyun *s = p->next;
85*4882a593Smuzhiyun if (!found)
86*4882a593Smuzhiyun found = p;
87*4882a593Smuzhiyun break;
88*4882a593Smuzhiyun }
89*4882a593Smuzhiyun }
90*4882a593Smuzhiyun }
91*4882a593Smuzhiyun mutex_unlock(domain->lock);
92*4882a593Smuzhiyun kfree(found);
93*4882a593Smuzhiyun }
94*4882a593Smuzhiyun
kobj_lookup(struct kobj_map * domain,dev_t dev,int * index)95*4882a593Smuzhiyun struct kobject *kobj_lookup(struct kobj_map *domain, dev_t dev, int *index)
96*4882a593Smuzhiyun {
97*4882a593Smuzhiyun struct kobject *kobj;
98*4882a593Smuzhiyun struct probe *p;
99*4882a593Smuzhiyun unsigned long best = ~0UL;
100*4882a593Smuzhiyun
101*4882a593Smuzhiyun retry:
102*4882a593Smuzhiyun mutex_lock(domain->lock);
103*4882a593Smuzhiyun for (p = domain->probes[MAJOR(dev) % 255]; p; p = p->next) {
104*4882a593Smuzhiyun struct kobject *(*probe)(dev_t, int *, void *);
105*4882a593Smuzhiyun struct module *owner;
106*4882a593Smuzhiyun void *data;
107*4882a593Smuzhiyun
108*4882a593Smuzhiyun if (p->dev > dev || p->dev + p->range - 1 < dev)
109*4882a593Smuzhiyun continue;
110*4882a593Smuzhiyun if (p->range - 1 >= best)
111*4882a593Smuzhiyun break;
112*4882a593Smuzhiyun if (!try_module_get(p->owner))
113*4882a593Smuzhiyun continue;
114*4882a593Smuzhiyun owner = p->owner;
115*4882a593Smuzhiyun data = p->data;
116*4882a593Smuzhiyun probe = p->get;
117*4882a593Smuzhiyun best = p->range - 1;
118*4882a593Smuzhiyun *index = dev - p->dev;
119*4882a593Smuzhiyun if (p->lock && p->lock(dev, data) < 0) {
120*4882a593Smuzhiyun module_put(owner);
121*4882a593Smuzhiyun continue;
122*4882a593Smuzhiyun }
123*4882a593Smuzhiyun mutex_unlock(domain->lock);
124*4882a593Smuzhiyun kobj = probe(dev, index, data);
125*4882a593Smuzhiyun /* Currently ->owner protects _only_ ->probe() itself. */
126*4882a593Smuzhiyun module_put(owner);
127*4882a593Smuzhiyun if (kobj)
128*4882a593Smuzhiyun return kobj;
129*4882a593Smuzhiyun goto retry;
130*4882a593Smuzhiyun }
131*4882a593Smuzhiyun mutex_unlock(domain->lock);
132*4882a593Smuzhiyun return NULL;
133*4882a593Smuzhiyun }
134*4882a593Smuzhiyun
kobj_map_init(kobj_probe_t * base_probe,struct mutex * lock)135*4882a593Smuzhiyun struct kobj_map *kobj_map_init(kobj_probe_t *base_probe, struct mutex *lock)
136*4882a593Smuzhiyun {
137*4882a593Smuzhiyun struct kobj_map *p = kmalloc(sizeof(struct kobj_map), GFP_KERNEL);
138*4882a593Smuzhiyun struct probe *base = kzalloc(sizeof(*base), GFP_KERNEL);
139*4882a593Smuzhiyun int i;
140*4882a593Smuzhiyun
141*4882a593Smuzhiyun if ((p == NULL) || (base == NULL)) {
142*4882a593Smuzhiyun kfree(p);
143*4882a593Smuzhiyun kfree(base);
144*4882a593Smuzhiyun return NULL;
145*4882a593Smuzhiyun }
146*4882a593Smuzhiyun
147*4882a593Smuzhiyun base->dev = 1;
148*4882a593Smuzhiyun base->range = ~0;
149*4882a593Smuzhiyun base->get = base_probe;
150*4882a593Smuzhiyun for (i = 0; i < 255; i++)
151*4882a593Smuzhiyun p->probes[i] = base;
152*4882a593Smuzhiyun p->lock = lock;
153*4882a593Smuzhiyun return p;
154*4882a593Smuzhiyun }
155