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// SPDX-License-Identifier: GPL-3.0-or-later
#ifndef NETDATA_DICTIONARY_LOCKS_H
#define NETDATA_DICTIONARY_LOCKS_H
#include "dictionary-internals.h"
// ----------------------------------------------------------------------------
// dictionary locks
static inline size_t dictionary_locks_init(DICTIONARY *dict) {
if(likely(!is_dictionary_single_threaded(dict))) {
rw_spinlock_init(&dict->index.rw_spinlock);
rw_spinlock_init(&dict->items.rw_spinlock);
}
return 0;
}
static inline size_t dictionary_locks_destroy(DICTIONARY *dict __maybe_unused) {
return 0;
}
static inline void ll_recursive_lock_set_thread_as_writer(DICTIONARY *dict) {
pid_t expected = 0, desired = gettid();
if(!__atomic_compare_exchange_n(&dict->items.writer_pid, &expected, desired, false, __ATOMIC_RELAXED, __ATOMIC_RELAXED))
fatal("DICTIONARY: Cannot set thread %d as exclusive writer, expected %d, desired %d, found %d.", gettid(), expected, desired, __atomic_load_n(&dict->items.writer_pid, __ATOMIC_RELAXED));
}
static inline void ll_recursive_unlock_unset_thread_writer(DICTIONARY *dict) {
pid_t expected = gettid(), desired = 0;
if(!__atomic_compare_exchange_n(&dict->items.writer_pid, &expected, desired, false, __ATOMIC_RELAXED, __ATOMIC_RELAXED))
fatal("DICTIONARY: Cannot unset thread %d as exclusive writer, expected %d, desired %d, found %d.", gettid(), expected, desired, __atomic_load_n(&dict->items.writer_pid, __ATOMIC_RELAXED));
}
static inline bool ll_recursive_lock_is_thread_the_writer(DICTIONARY *dict) {
pid_t tid = gettid();
return tid > 0 && tid == __atomic_load_n(&dict->items.writer_pid, __ATOMIC_RELAXED);
}
static inline void ll_recursive_lock(DICTIONARY *dict, char rw) {
if(unlikely(is_dictionary_single_threaded(dict)))
return;
if(ll_recursive_lock_is_thread_the_writer(dict)) {
dict->items.writer_depth++;
return;
}
if(rw == DICTIONARY_LOCK_READ || rw == DICTIONARY_LOCK_REENTRANT || rw == 'R') {
// read lock
rw_spinlock_read_lock(&dict->items.rw_spinlock);
}
else {
// write lock
rw_spinlock_write_lock(&dict->items.rw_spinlock);
ll_recursive_lock_set_thread_as_writer(dict);
}
}
static inline void ll_recursive_unlock(DICTIONARY *dict, char rw) {
if(unlikely(is_dictionary_single_threaded(dict)))
return;
if(ll_recursive_lock_is_thread_the_writer(dict) && dict->items.writer_depth > 0) {
dict->items.writer_depth--;
return;
}
if(rw == DICTIONARY_LOCK_READ || rw == DICTIONARY_LOCK_REENTRANT || rw == 'R') {
// read unlock
rw_spinlock_read_unlock(&dict->items.rw_spinlock);
}
else {
// write unlock
ll_recursive_unlock_unset_thread_writer(dict);
rw_spinlock_write_unlock(&dict->items.rw_spinlock);
}
}
static inline void dictionary_index_lock_rdlock(DICTIONARY *dict) {
if(unlikely(is_dictionary_single_threaded(dict)))
return;
rw_spinlock_read_lock(&dict->index.rw_spinlock);
}
static inline void dictionary_index_rdlock_unlock(DICTIONARY *dict) {
if(unlikely(is_dictionary_single_threaded(dict)))
return;
rw_spinlock_read_unlock(&dict->index.rw_spinlock);
}
static inline void dictionary_index_lock_wrlock(DICTIONARY *dict) {
if(unlikely(is_dictionary_single_threaded(dict)))
return;
rw_spinlock_write_lock(&dict->index.rw_spinlock);
}
static inline void dictionary_index_wrlock_unlock(DICTIONARY *dict) {
if(unlikely(is_dictionary_single_threaded(dict)))
return;
rw_spinlock_write_unlock(&dict->index.rw_spinlock);
}
#endif //NETDATA_DICTIONARY_LOCKS_H
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