155 lines
3.3 KiB
C
155 lines
3.3 KiB
C
/*
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* linux/drivers/base/map.c
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*
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* (C) Copyright Al Viro 2002,2003
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* Released under GPL v2.
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*
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* NOTE: data structure needs to be changed. It works, but for large dev_t
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* it will be too slow. It is isolated, though, so these changes will be
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* local to that file.
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*/
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/mutex.h>
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#include <linux/kdev_t.h>
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#include <linux/kobject.h>
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#include <linux/kobj_map.h>
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struct kobj_map {
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struct probe {
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struct probe *next;
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dev_t dev;
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unsigned long range;
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struct module *owner;
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kobj_probe_t *get;
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int (*lock)(dev_t, void *);
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void *data;
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} *probes[255];
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struct mutex *lock;
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};
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int kobj_map(struct kobj_map *domain, dev_t dev, unsigned long range,
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struct module *module, kobj_probe_t *probe,
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int (*lock)(dev_t, void *), void *data)
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{
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unsigned n = MAJOR(dev + range - 1) - MAJOR(dev) + 1;
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unsigned index = MAJOR(dev);
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unsigned i;
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struct probe *p;
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if (n > 255)
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n = 255;
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p = kmalloc_array(n, sizeof(struct probe), GFP_KERNEL);
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if (p == NULL)
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return -ENOMEM;
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for (i = 0; i < n; i++, p++) {
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p->owner = module;
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p->get = probe;
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p->lock = lock;
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p->dev = dev;
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p->range = range;
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p->data = data;
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}
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mutex_lock(domain->lock);
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for (i = 0, p -= n; i < n; i++, p++, index++) {
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struct probe **s = &domain->probes[index % 255];
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while (*s && (*s)->range < range)
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s = &(*s)->next;
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p->next = *s;
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*s = p;
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}
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mutex_unlock(domain->lock);
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return 0;
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}
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void kobj_unmap(struct kobj_map *domain, dev_t dev, unsigned long range)
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{
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unsigned n = MAJOR(dev + range - 1) - MAJOR(dev) + 1;
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unsigned index = MAJOR(dev);
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unsigned i;
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struct probe *found = NULL;
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if (n > 255)
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n = 255;
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mutex_lock(domain->lock);
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for (i = 0; i < n; i++, index++) {
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struct probe **s;
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for (s = &domain->probes[index % 255]; *s; s = &(*s)->next) {
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struct probe *p = *s;
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if (p->dev == dev && p->range == range) {
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*s = p->next;
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if (!found)
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found = p;
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break;
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}
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}
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}
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mutex_unlock(domain->lock);
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kfree(found);
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}
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struct kobject *kobj_lookup(struct kobj_map *domain, dev_t dev, int *index)
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{
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struct kobject *kobj;
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struct probe *p;
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unsigned long best = ~0UL;
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retry:
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mutex_lock(domain->lock);
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for (p = domain->probes[MAJOR(dev) % 255]; p; p = p->next) {
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struct kobject *(*probe)(dev_t, int *, void *);
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struct module *owner;
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void *data;
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if (p->dev > dev || p->dev + p->range - 1 < dev)
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continue;
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if (p->range - 1 >= best)
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break;
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if (!try_module_get(p->owner))
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continue;
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owner = p->owner;
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data = p->data;
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probe = p->get;
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best = p->range - 1;
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*index = dev - p->dev;
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if (p->lock && p->lock(dev, data) < 0) {
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module_put(owner);
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continue;
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}
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mutex_unlock(domain->lock);
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kobj = probe(dev, index, data);
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/* Currently ->owner protects _only_ ->probe() itself. */
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module_put(owner);
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if (kobj)
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return kobj;
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goto retry;
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}
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mutex_unlock(domain->lock);
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return NULL;
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}
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struct kobj_map *kobj_map_init(kobj_probe_t *base_probe, struct mutex *lock)
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{
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struct kobj_map *p = kmalloc(sizeof(struct kobj_map), GFP_KERNEL);
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struct probe *base = kzalloc(sizeof(*base), GFP_KERNEL);
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int i;
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if ((p == NULL) || (base == NULL)) {
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kfree(p);
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kfree(base);
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return NULL;
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}
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base->dev = 1;
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base->range = ~0;
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base->get = base_probe;
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for (i = 0; i < 255; i++)
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p->probes[i] = base;
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p->lock = lock;
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return p;
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}
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