summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/base/map.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/drivers/base/map.c')
-rw-r--r--kernel/drivers/base/map.c154
1 files changed, 154 insertions, 0 deletions
diff --git a/kernel/drivers/base/map.c b/kernel/drivers/base/map.c
new file mode 100644
index 000000000..c1d38234d
--- /dev/null
+++ b/kernel/drivers/base/map.c
@@ -0,0 +1,154 @@
+/*
+ * 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/mutex.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 mutex *lock;
+};
+
+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_array(n, sizeof(struct probe), 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;
+ }
+ mutex_lock(domain->lock);
+ 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;
+ }
+ mutex_unlock(domain->lock);
+ 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;
+
+ mutex_lock(domain->lock);
+ 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;
+ }
+ }
+ }
+ mutex_unlock(domain->lock);
+ 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:
+ mutex_lock(domain->lock);
+ 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;
+ }
+ mutex_unlock(domain->lock);
+ kobj = probe(dev, index, data);
+ /* Currently ->owner protects _only_ ->probe() itself. */
+ module_put(owner);
+ if (kobj)
+ return kobj;
+ goto retry;
+ }
+ mutex_unlock(domain->lock);
+ return NULL;
+}
+
+struct kobj_map *kobj_map_init(kobj_probe_t *base_probe, struct mutex *lock)
+{
+ 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->lock = lock;
+ return p;
+}