| 1 | /* |
| 2 | * Copyright (C) 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 3 | * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com> |
| 4 | * |
| 5 | * SPDX-License-Identifier: LGPL-2.1-only |
| 6 | * |
| 7 | * This code is originally adapted from userspace-rcu's urcu-wait.h |
| 8 | */ |
| 9 | |
| 10 | #ifndef LTTNG_WAITER_H |
| 11 | #define LTTNG_WAITER_H |
| 12 | |
| 13 | #define _LGPL_SOURCE |
| 14 | |
| 15 | #include "macros.hpp" |
| 16 | |
| 17 | #include <stdbool.h> |
| 18 | #include <stdint.h> |
| 19 | #include <urcu/wfstack.h> |
| 20 | |
| 21 | struct lttng_waiter { |
| 22 | struct cds_wfs_node wait_queue_node; |
| 23 | int32_t state; |
| 24 | }; |
| 25 | |
| 26 | struct lttng_wait_queue { |
| 27 | struct cds_wfs_stack stack; |
| 28 | }; |
| 29 | |
| 30 | void lttng_waiter_init(struct lttng_waiter *waiter); |
| 31 | |
| 32 | void lttng_waiter_wait(struct lttng_waiter *waiter); |
| 33 | |
| 34 | /* |
| 35 | * lttng_waiter_wake must only be called by a single waker. |
| 36 | * It is invalid for multiple "wake" operations to be invoked |
| 37 | * on a single waiter without re-initializing it before. |
| 38 | */ |
| 39 | void lttng_waiter_wake(struct lttng_waiter *waiter); |
| 40 | |
| 41 | void lttng_wait_queue_init(struct lttng_wait_queue *queue); |
| 42 | |
| 43 | /* |
| 44 | * Atomically add a waiter to a wait queue. |
| 45 | * A full memory barrier is issued before being added to the wait queue. |
| 46 | */ |
| 47 | void lttng_wait_queue_add(struct lttng_wait_queue *queue, struct lttng_waiter *waiter); |
| 48 | |
| 49 | /* |
| 50 | * Wake every waiter present in the wait queue and remove them from |
| 51 | * the queue. |
| 52 | */ |
| 53 | void lttng_wait_queue_wake_all(struct lttng_wait_queue *queue); |
| 54 | |
| 55 | #endif /* LTTNG_WAITER_H */ |