-static void nfs_alloc_unique_id_locked(struct rb_root *root,
- struct nfs_unique_id *new,
- __u64 minval, int maxbits)
-{
- struct rb_node **p, *parent;
- struct nfs_unique_id *pos;
- __u64 mask = ~0ULL;
-
- if (maxbits < 64)
- mask = (1ULL << maxbits) - 1ULL;
-
- /* Ensure distribution is more or less flat */
- get_random_bytes(&new->id, sizeof(new->id));
- new->id &= mask;
- if (new->id < minval)
- new->id += minval;
-retry:
- p = &root->rb_node;
- parent = NULL;
-
- while (*p != NULL) {
- parent = *p;
- pos = rb_entry(parent, struct nfs_unique_id, rb_node);
-
- if (new->id < pos->id)
- p = &(*p)->rb_left;
- else if (new->id > pos->id)
- p = &(*p)->rb_right;
- else
- goto id_exists;
- }
- rb_link_node(&new->rb_node, parent, p);
- rb_insert_color(&new->rb_node, root);
- return;
-id_exists:
- for (;;) {
- new->id++;
- if (new->id < minval || (new->id & mask) != new->id) {
- new->id = minval;
- break;
- }
- parent = rb_next(parent);
- if (parent == NULL)
- break;
- pos = rb_entry(parent, struct nfs_unique_id, rb_node);
- if (new->id < pos->id)
- break;
- }
- goto retry;
-}
-
-static void nfs_free_unique_id(struct rb_root *root, struct nfs_unique_id *id)
-{
- rb_erase(&id->rb_node, root);
-}
-