wrapper/rcu.h

   1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
   2  *
   3  * wrapper/rcu.h
   4  *
   5  * wrapper around linux/rcupdate.h and linux/rculist.h.
   6  *
   7  * Copyright (C) 2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  */
   9
  10 #ifndef _LTTNG_WRAPPER_RCU_H
  11 #define _LTTNG_WRAPPER_RCU_H
  12
  13 #include <linux/version.h>
  14 #include <linux/rculist.h>
  15 #include <linux/rcupdate.h>
  16 #include <wrapper/list.h>
  17
  18 #ifndef rcu_dereference_raw_notrace
  19 #define rcu_dereference_raw_notrace(p)  rcu_dereference_raw(p)
  20 #endif
  21
  22 #define lttng_rcu_dereference(p) rcu_dereference_raw_notrace(p)
  23
  24 /**
  25  * lttng_list_entry_rcu - get the struct for this entry
  26  * @ptr:        the &struct list_head pointer.
  27  * @type:       the type of the struct this is embedded in.
  28  * @member:     the name of the list_head within the struct.
  29  *
  30  * This primitive may safely run concurrently with the _rcu list-mutation
  31  * primitives such as list_add_rcu() as long as it's guarded by
  32  * rcu_read_lock_sched().
  33  * Can be used while tracing RCU.
  34  */
  35 #define lttng_list_entry_rcu(ptr, type, member) \
  36 ({ \
  37         typeof(*ptr) __rcu *__ptr = (typeof(*ptr) __rcu __force *)ptr; \
  38         container_of((typeof(ptr))lttng_rcu_dereference(__ptr), type, member); \
  39 })
  40
  41 /**
  42  * lttng_list_for_each_entry_rcu - iterate over rcu list of given type
  43  * @pos:        the type * to use as a loop cursor.
  44  * @head:       the head for your list.
  45  * @member:     the name of the list_head within the struct.
  46  *
  47  * This list-traversal primitive may safely run concurrently with
  48  * the _rcu list-mutation primitives such as list_add_rcu()
  49  * as long as the traversal is guarded by rcu_read_lock_sched().
  50  * Can be used while tracing RCU.
  51  */
  52 #define lttng_list_for_each_entry_rcu(pos, head, member) \
  53         for (pos = lttng_list_entry_rcu((head)->next, typeof(*pos), member); \
  54                 &pos->member != (head); \
  55                 pos = lttng_list_entry_rcu(pos->member.next, typeof(*pos), member))
  56
  57 /**
  58  * lttng_hlist_for_each_entry_rcu - iterate over rcu list of given type (for tracing)
  59  * @pos:        the type * to use as a loop cursor.
  60  * @head:       the head for your list.
  61  * @member:     the name of the hlist_node within the struct.
  62  *
  63  * This list-traversal primitive may safely run concurrently with
  64  * the _rcu list-mutation primitives such as hlist_add_head_rcu()
  65  * as long as the traversal is guarded by rcu_read_lock().
  66  *
  67  * This is the same as hlist_for_each_entry_rcu() except that it does
  68  * not do any RCU debugging or tracing.
  69  */
  70 #define lttng_hlist_for_each_entry_rcu(pos, head, member)       \
  71         for (pos = lttng_hlist_entry_safe (lttng_rcu_dereference(lttng_hlist_first_rcu(head)), \
  72                         typeof(*(pos)), member);                \
  73                 pos;                                            \
  74                 pos = lttng_hlist_entry_safe(lttng_rcu_dereference(lttng_hlist_next_rcu( \
  75                         &(pos)->member)), typeof(*(pos)), member))
  76
  77 #endif /* _LTTNG_WRAPPER_RCU_H */