#include #include #include #include #include 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); } td>
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