| 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 | |
| 17 | #ifndef rcu_dereference_raw_notrace |
| 18 | #define rcu_dereference_raw_notrace(p) rcu_dereference_raw(p) |
| 19 | #endif |
| 20 | |
| 21 | #define lttng_rcu_dereference(p) rcu_dereference_raw_notrace(p) |
| 22 | |
| 23 | /** |
| 24 | * lttng_list_entry_rcu - get the struct for this entry |
| 25 | * @ptr: the &struct list_head pointer. |
| 26 | * @type: the type of the struct this is embedded in. |
| 27 | * @member: the name of the list_head within the struct. |
| 28 | * |
| 29 | * This primitive may safely run concurrently with the _rcu list-mutation |
| 30 | * primitives such as list_add_rcu() as long as it's guarded by |
| 31 | * rcu_read_lock_sched(). |
| 32 | * Can be used while tracing RCU. |
| 33 | */ |
| 34 | #define lttng_list_entry_rcu(ptr, type, member) \ |
| 35 | ({ \ |
| 36 | typeof(*ptr) __rcu *__ptr = (typeof(*ptr) __rcu __force *)ptr; \ |
| 37 | container_of((typeof(ptr))lttng_rcu_dereference(__ptr), type, member); \ |
| 38 | }) |
| 39 | |
| 40 | /** |
| 41 | * lttng_list_for_each_entry_rcu - iterate over rcu list of given type |
| 42 | * @pos: the type * to use as a loop cursor. |
| 43 | * @head: the head for your list. |
| 44 | * @member: the name of the list_head within the struct. |
| 45 | * |
| 46 | * This list-traversal primitive may safely run concurrently with |
| 47 | * the _rcu list-mutation primitives such as list_add_rcu() |
| 48 | * as long as the traversal is guarded by rcu_read_lock_sched(). |
| 49 | * Can be used while tracing RCU. |
| 50 | */ |
| 51 | #define lttng_list_for_each_entry_rcu(pos, head, member) \ |
| 52 | for (pos = lttng_list_entry_rcu((head)->next, typeof(*pos), member); \ |
| 53 | &pos->member != (head); \ |
| 54 | pos = lttng_list_entry_rcu(pos->member.next, typeof(*pos), member)) |
| 55 | |
| 56 | #endif /* _LTTNG_WRAPPER_RCU_H */ |