1 files changed, 155 insertions, 0 deletions

diff --git a/drivers/base/map.c b/drivers/base/map.c
new file mode 100644
index 000000000000..2f455d86793c
--- /dev/null
+++ b/drivers/base/map.c
@@ -0,0 +1,155 @@
+/*
+ *  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 = kmalloc(sizeof(struct probe), GFP_KERNEL);
+        int i;
+
+        if ((p == NULL) || (base == NULL)) {
+                kfree(p);
+                kfree(base);
+                return NULL;
+        }
+
+        memset(base, 0, sizeof(struct probe));
+        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;
+}