openssl/include/internal/rcu.h
Neil Horman d0e1a0ae70 RCU lock implementation
Introduce an RCU lock implementation as an alternative locking mechanism
to openssl.  The api is documented in the ossl_rcu.pod
file

Read side implementaiton is comparable to that of RWLOCKS:
ossl_rcu_read_lock(lock);
<
critical section in which data can be accessed via
ossl_derefrence
>
ossl_rcu_read_unlock(lock);

Write side implementation is:
ossl_rcu_write_lock(lock);
<
critical section in which data can be updated via
ossl_assign_pointer
and stale data can optionally be scheduled for removal
via ossl_rcu_call
>
ossl_rcu_write_unlock(lock);
...
ossl_synchronize_rcu(lock);

ossl_rcu_call fixup

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/22729)
2024-02-01 08:33:25 -05:00

32 lines
1.1 KiB
C

/*
* Copyright 2023 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#ifndef OPENSSL_RCU_H
# define OPENSSL_RCU_H
# pragma once
typedef void (*rcu_cb_fn)(void *data);
typedef struct rcu_lock_st CRYPTO_RCU_LOCK;
CRYPTO_RCU_LOCK *ossl_rcu_lock_new(int num_writers);
void ossl_rcu_lock_free(CRYPTO_RCU_LOCK *lock);
void ossl_rcu_read_lock(CRYPTO_RCU_LOCK *lock);
void ossl_rcu_write_lock(CRYPTO_RCU_LOCK *lock);
void ossl_rcu_write_unlock(CRYPTO_RCU_LOCK *lock);
void ossl_rcu_read_unlock(CRYPTO_RCU_LOCK *lock);
void ossl_synchronize_rcu(CRYPTO_RCU_LOCK *lock);
int ossl_rcu_call(CRYPTO_RCU_LOCK *lock, rcu_cb_fn cb, void *data);
void *ossl_rcu_uptr_deref(void **p);
void ossl_rcu_assign_uptr(void **p, void **v);
#define ossl_rcu_deref(p) ossl_rcu_uptr_deref((void **)p)
#define ossl_rcu_assign_ptr(p,v) ossl_rcu_assign_uptr((void **)p, (void **)v)
#endif