include/linux/rcupdate_wait.h

   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 */