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#include <linux/sched.h> 12 13/* 14 * Structure allowing asynchronous waiting on RCU. 15 */ 16struct rcu_synchronize { 17 struct rcu_head head; 18 struct completion completion; 19}; 20void wakeme_after_rcu(struct rcu_head *head); 21 22void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array, 23 struct rcu_synchronize *rs_array); 24 25#define _wait_rcu_gp(checktiny, ...) \ 26do { \ 27 call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \ 28 struct rcu_synchronize __rs_array[ARRAY_SIZE(__crcu_array)]; \ 29 __wait_rcu_gp(checktiny, ARRAY_SIZE(__crcu_array), \ 30 __crcu_array, __rs_array); \ 31} while (0) 32 33#define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__) 34 35/** 36 * synchronize_rcu_mult - Wait concurrently for multiple grace periods 37 * @...: List of call_rcu() functions for different grace periods to wait on 38 * 39 * This macro waits concurrently for multiple types of RCU grace periods. 40 * For example, synchronize_rcu_mult(call_rcu, call_rcu_tasks) would wait 41 * on concurrent RCU and RCU-tasks grace periods. Waiting on a given SRCU 42 * domain requires you to write a wrapper function for that SRCU domain's 43 * call_srcu() function, with this wrapper supplying the pointer to the 44 * corresponding srcu_struct. 45 * 46 * Note that call_rcu_hurry() should be used instead of call_rcu() 47 * because in kernels built with CONFIG_RCU_LAZY=y the delay between the 48 * invocation of call_rcu() and that of the corresponding RCU callback 49 * can be multiple seconds. 50 * 51 * The first argument tells Tiny RCU's _wait_rcu_gp() not to 52 * bother waiting for RCU. The reason for this is because anywhere 53 * synchronize_rcu_mult() can be called is automatically already a full 54 * grace period. 55 */ 56#define synchronize_rcu_mult(...) \ 57 _wait_rcu_gp(IS_ENABLED(CONFIG_TINY_RCU), __VA_ARGS__) 58 59static inline void cond_resched_rcu(void) 60{ 61#if defined(CONFIG_DEBUG_ATOMIC_SLEEP) || !defined(CONFIG_PREEMPT_RCU) 62 rcu_read_unlock(); 63 cond_resched(); 64 rcu_read_lock(); 65#endif 66} 67 68#endif /* _LINUX_SCHED_RCUPDATE_WAIT_H */ 69