1 // SPDX-License-Identifier: GPL-2.0-only
3  * klist.c - Routines for manipulating klists.
20  * It works using a 3rd object type - struct klist_iter - that is declared
50 		((unsigned long)knode->n_klist & KNODE_KLIST_MASK);  in knode_klist()
55 	return (unsigned long)knode->n_klist & KNODE_DEAD;  in knode_dead()
60 	knode->n_klist = klist;  in knode_set_klist()
67 	/* and no knode should die twice ever either, see we're very humane */  in knode_kill()
69 	*(unsigned long *)&knode->n_klist |= KNODE_DEAD;  in knode_kill()
73  * klist_init - Initialize a klist structure.
74  * @k: The klist we're initializing.
87 	INIT_LIST_HEAD(&k->k_list);  in klist_init()
88 	spin_lock_init(&k->k_lock);  in klist_init()
89 	k->get = get;  in klist_init()
90 	k->put = put;  in klist_init()
96 	spin_lock(&k->k_lock);  in add_head()
97 	list_add(&n->n_node, &k->k_list);  in add_head()
98 	spin_unlock(&k->k_lock);  in add_head()
103 	spin_lock(&k->k_lock);  in add_tail()
104 	list_add_tail(&n->n_node, &k->k_list);  in add_tail()
105 	spin_unlock(&k->k_lock);  in add_tail()
110 	INIT_LIST_HEAD(&n->n_node);  in klist_node_init()
111 	kref_init(&n->n_ref);  in klist_node_init()
113 	if (k->get)  in klist_node_init()
114 		k->get(n);  in klist_node_init()
118  * klist_add_head - Initialize a klist_node and add it to front.
119  * @n: node we're adding.
130  * klist_add_tail - Initialize a klist_node and add it to back.
131  * @n: node we're adding.
142  * klist_add_behind - Init a klist_node and add it after an existing node
143  * @n: node we're adding.
151 	spin_lock(&k->k_lock);  in klist_add_behind()
152 	list_add(&n->n_node, &pos->n_node);  in klist_add_behind()
153 	spin_unlock(&k->k_lock);  in klist_add_behind()
158  * klist_add_before - Init a klist_node and add it before an existing node
159  * @n: node we're adding.
167 	spin_lock(&k->k_lock);  in klist_add_before()
168 	list_add_tail(&n->n_node, &pos->n_node);  in klist_add_before()
169 	spin_unlock(&k->k_lock);  in klist_add_before()
189 	list_del(&n->n_node);  in klist_release()
192 		if (waiter->node != n)  in klist_release()
195 		list_del(&waiter->list);  in klist_release()
196 		waiter->woken = 1;  in klist_release()
198 		wake_up_process(waiter->process);  in klist_release()
206 	return kref_put(&n->n_ref, klist_release);  in klist_dec_and_del()
212 	void (*put)(struct klist_node *) = k->put;  in klist_put()
214 	spin_lock(&k->k_lock);  in klist_put()
219 	spin_unlock(&k->k_lock);  in klist_put()
225  * klist_del - Decrement the reference count of node and try to remove.
226  * @n: node we're deleting.
235  * klist_remove - Decrement the refcount of node and wait for it to go away.
236  * @n: node we're removing.
262  * klist_node_attached - Say whether a node is bound to a list or not.
263  * @n: Node that we're testing.
267 	return (n->n_klist != NULL);  in klist_node_attached()
272  * klist_iter_init_node - Initialize a klist_iter structure.
273  * @k: klist we're iterating.
274  * @i: klist_iter we're filling.
283 	i->i_klist = k;  in klist_iter_init_node()
284 	i->i_cur = NULL;  in klist_iter_init_node()
285 	if (n && kref_get_unless_zero(&n->n_ref))  in klist_iter_init_node()
286 		i->i_cur = n;  in klist_iter_init_node()
291  * klist_iter_init - Iniitalize a klist_iter structure.
292  * @k: klist we're iterating.
293  * @i: klist_iter structure we're filling.
304  * klist_iter_exit - Finish a list iteration.
313 	if (i->i_cur) {  in klist_iter_exit()
314 		klist_put(i->i_cur, false);  in klist_iter_exit()
315 		i->i_cur = NULL;  in klist_iter_exit()
326  * klist_prev - Ante up prev node in list.
335 	void (*put)(struct klist_node *) = i->i_klist->put;  in klist_prev()
336 	struct klist_node *last = i->i_cur;  in klist_prev()
340 	spin_lock_irqsave(&i->i_klist->k_lock, flags);  in klist_prev()
343 		prev = to_klist_node(last->n_node.prev);  in klist_prev()
347 		prev = to_klist_node(i->i_klist->k_list.prev);  in klist_prev()
349 	i->i_cur = NULL;  in klist_prev()
350 	while (prev != to_klist_node(&i->i_klist->k_list)) {  in klist_prev()
352 			kref_get(&prev->n_ref);  in klist_prev()
353 			i->i_cur = prev;  in klist_prev()
356 		prev = to_klist_node(prev->n_node.prev);  in klist_prev()
359 	spin_unlock_irqrestore(&i->i_klist->k_lock, flags);  in klist_prev()
363 	return i->i_cur;  in klist_prev()
368  * klist_next - Ante up next node in list.
377 	void (*put)(struct klist_node *) = i->i_klist->put;  in klist_next()
378 	struct klist_node *last = i->i_cur;  in klist_next()
382 	spin_lock_irqsave(&i->i_klist->k_lock, flags);  in klist_next()
385 		next = to_klist_node(last->n_node.next);  in klist_next()
389 		next = to_klist_node(i->i_klist->k_list.next);  in klist_next()
391 	i->i_cur = NULL;  in klist_next()
392 	while (next != to_klist_node(&i->i_klist->k_list)) {  in klist_next()
394 			kref_get(&next->n_ref);  in klist_next()
395 			i->i_cur = next;  in klist_next()
398 		next = to_klist_node(next->n_node.next);  in klist_next()
401 	spin_unlock_irqrestore(&i->i_klist->k_lock, flags);  in klist_next()
405 	return i->i_cur;  in klist_next()