src/common/waiter.h

   1 /*
   2  * Copyright (C) 2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   3  *               2017 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU Lesser General Public License, version 2.1 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
  12  * for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public License
  15  * along with this program; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  *
  18  * This code is originally adapted from userspace-rcu's urcu-wait.h
  19  */
  20
  21 #ifndef LTTNG_WAITER_H
  22 #define LTTNG_WAITER_H
  23
  24 #define _LGPL_SOURCE
  25
  26 #include <stdint.h>
  27 #include <urcu/wfstack.h>
  28 #include <stdbool.h>
  29 #include "macros.h"
  30
  31 struct lttng_waiter {
  32         struct cds_wfs_node wait_queue_node;
  33         int32_t state;
  34 };
  35
  36 LTTNG_HIDDEN
  37 void lttng_waiter_init(struct lttng_waiter *waiter);
  38
  39 LTTNG_HIDDEN
  40 void lttng_waiter_wait(struct lttng_waiter *waiter);
  41
  42 /*
  43  * lttng_waiter_wake_up must only be called by a single waker.
  44  * It is invalid for multiple "wake" operations to be invoked
  45  * on a single waiter without re-initializing it before.
  46  */
  47 LTTNG_HIDDEN
  48 void lttng_waiter_wake_up(struct lttng_waiter *waiter);
  49
  50 #endif /* LTTNG_WAITER_H */