1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_SCHED_RCUPDATE_WAIT_H
3#define _LINUX_SCHED_RCUPDATE_WAIT_H
4
5/*
6 * RCU synchronization types and methods:
7 */
8
9#include <linux/rcupdate.h>
10#include <linux/completion.h>
11
12/*
13 * Structure allowing asynchronous waiting on RCU.
14 */
15struct rcu_synchronize {
16 struct rcu_head head;
17 struct completion completion;
18};
19void wakeme_after_rcu(struct rcu_head *head);
20
21void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
22 struct rcu_synchronize *rs_array);
23
24#define _wait_rcu_gp(checktiny, ...) \
25do { \
26 call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \
27 struct rcu_synchronize __rs_array[ARRAY_SIZE(__crcu_array)]; \
28 __wait_rcu_gp(checktiny, ARRAY_SIZE(__crcu_array), \
29 __crcu_array, __rs_array); \
30} while (0)
31
32#define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__)
33
34/**
35 * synchronize_rcu_mult - Wait concurrently for multiple grace periods
36 * @...: List of call_rcu() functions for different grace periods to wait on
37 *
38 * This macro waits concurrently for multiple types of RCU grace periods.
39 * For example, synchronize_rcu_mult(call_rcu, call_rcu_tasks) would wait
40 * on concurrent RCU and RCU-tasks grace periods. Waiting on a given SRCU
41 * domain requires you to write a wrapper function for that SRCU domain's
42 * call_srcu() function, with this wrapper supplying the pointer to the
43 * corresponding srcu_struct.
44 *
45 * Note that call_rcu_hurry() should be used instead of call_rcu()
46 * because in kernels built with CONFIG_RCU_LAZY=y the delay between the
47 * invocation of call_rcu() and that of the corresponding RCU callback
48 * can be multiple seconds.
49 *
50 * The first argument tells Tiny RCU's _wait_rcu_gp() not to
51 * bother waiting for RCU. The reason for this is because anywhere
52 * synchronize_rcu_mult() can be called is automatically already a full
53 * grace period.
54 */
55#define synchronize_rcu_mult(...) \
56 _wait_rcu_gp(IS_ENABLED(CONFIG_TINY_RCU), __VA_ARGS__)
57
58#endif /* _LINUX_SCHED_RCUPDATE_WAIT_H */
59

source code of linux/include/linux/rcupdate_wait.h