106 строки
2.2 KiB
C
106 строки
2.2 KiB
C
#include <linux/slab.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/string.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/ceph/string_table.h>
|
|
|
|
static DEFINE_SPINLOCK(string_tree_lock);
|
|
static struct rb_root string_tree = RB_ROOT;
|
|
|
|
struct ceph_string *ceph_find_or_create_string(const char* str, size_t len)
|
|
{
|
|
struct ceph_string *cs, *exist;
|
|
struct rb_node **p, *parent;
|
|
int ret;
|
|
|
|
exist = NULL;
|
|
spin_lock(&string_tree_lock);
|
|
p = &string_tree.rb_node;
|
|
while (*p) {
|
|
exist = rb_entry(*p, struct ceph_string, node);
|
|
ret = ceph_compare_string(exist, str, len);
|
|
if (ret > 0)
|
|
p = &(*p)->rb_left;
|
|
else if (ret < 0)
|
|
p = &(*p)->rb_right;
|
|
else
|
|
break;
|
|
exist = NULL;
|
|
}
|
|
if (exist && !kref_get_unless_zero(&exist->kref)) {
|
|
rb_erase(&exist->node, &string_tree);
|
|
RB_CLEAR_NODE(&exist->node);
|
|
exist = NULL;
|
|
}
|
|
spin_unlock(&string_tree_lock);
|
|
if (exist)
|
|
return exist;
|
|
|
|
cs = kmalloc(sizeof(*cs) + len + 1, GFP_NOFS);
|
|
if (!cs)
|
|
return NULL;
|
|
|
|
kref_init(&cs->kref);
|
|
cs->len = len;
|
|
memcpy(cs->str, str, len);
|
|
cs->str[len] = 0;
|
|
|
|
retry:
|
|
exist = NULL;
|
|
parent = NULL;
|
|
p = &string_tree.rb_node;
|
|
spin_lock(&string_tree_lock);
|
|
while (*p) {
|
|
parent = *p;
|
|
exist = rb_entry(*p, struct ceph_string, node);
|
|
ret = ceph_compare_string(exist, str, len);
|
|
if (ret > 0)
|
|
p = &(*p)->rb_left;
|
|
else if (ret < 0)
|
|
p = &(*p)->rb_right;
|
|
else
|
|
break;
|
|
exist = NULL;
|
|
}
|
|
ret = 0;
|
|
if (!exist) {
|
|
rb_link_node(&cs->node, parent, p);
|
|
rb_insert_color(&cs->node, &string_tree);
|
|
} else if (!kref_get_unless_zero(&exist->kref)) {
|
|
rb_erase(&exist->node, &string_tree);
|
|
RB_CLEAR_NODE(&exist->node);
|
|
ret = -EAGAIN;
|
|
}
|
|
spin_unlock(&string_tree_lock);
|
|
if (ret == -EAGAIN)
|
|
goto retry;
|
|
|
|
if (exist) {
|
|
kfree(cs);
|
|
cs = exist;
|
|
}
|
|
|
|
return cs;
|
|
}
|
|
EXPORT_SYMBOL(ceph_find_or_create_string);
|
|
|
|
void ceph_release_string(struct kref *ref)
|
|
{
|
|
struct ceph_string *cs = container_of(ref, struct ceph_string, kref);
|
|
|
|
spin_lock(&string_tree_lock);
|
|
if (!RB_EMPTY_NODE(&cs->node)) {
|
|
rb_erase(&cs->node, &string_tree);
|
|
RB_CLEAR_NODE(&cs->node);
|
|
}
|
|
spin_unlock(&string_tree_lock);
|
|
|
|
kfree_rcu(cs, rcu);
|
|
}
|
|
EXPORT_SYMBOL(ceph_release_string);
|
|
|
|
bool ceph_strings_empty(void)
|
|
{
|
|
return RB_EMPTY_ROOT(&string_tree);
|
|
}
|