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  */
15 struct rcu_synchronize {
16 	struct rcu_head head;
17 	struct completion completion;
18 };
19 void wakeme_after_rcu(struct rcu_head *head);
20 
21 void __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, ...) \
25 do {									\
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  * The first argument tells Tiny RCU's _wait_rcu_gp() not to
46  * bother waiting for RCU.  The reason for this is because anywhere
47  * synchronize_rcu_mult() can be called is automatically already a full
48  * grace period.
49  */
50 #define synchronize_rcu_mult(...) \
51 	_wait_rcu_gp(IS_ENABLED(CONFIG_TINY_RCU), __VA_ARGS__)
52 
53 #endif /* _LINUX_SCHED_RCUPDATE_WAIT_H */
54