Adding upstream version 3.4.0.upstream/3.4.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 14 insertions, 66 deletions

diff --git a/src/contrib/spinlock.h b/src/contrib/spinlock.h
index 837f500..a7ec5ec 100644
--- a/src/contrib/spinlock.h
+++ b/src/contrib/spinlock.h
@@ -1,4 +1,4 @@
-/*  Copyright (C) 2021 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+/*  Copyright (C) 2023 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -15,48 +15,23 @@
  */
 
 /*!
- * \brief Multiplatform spinlock.
+ * \brief A C11 spinlock (POSIX pthread spinlock as a fallback).
  */
 
 #pragma once
 
 #if (__STDC_VERSION__ >= 201112L) && !defined(__STDC_NO_ATOMICS__)
-/* Not tested and activated yet. */
-/* #define HAVE_STDATOMIC */
-#endif
-
-#if defined(__APPLE__)
-#  if defined(MAC_OS_X_VERSION_10_12) || \
-      MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_12
-#    define APPLE_SPIN_NEW
-#  else
-#    define APPLE_SPIN_OLD
-#  endif	/* MAC_OS_X_VERSION_10_12 ... */
-#endif	/* __APPLE__ */
-
-#if defined(HAVE_SYNC_ATOMIC) || defined(HAVE_ATOMIC)
-#  include <stdbool.h>
-#elif defined(HAVE_STDATOMIC)
-#  include <stdbool.h>
-#  include <stdatomic.h>
-#elif defined(APPLE_SPIN_NEW)
-#  include <os/lock.h>
-#elif defined(APPLE_SPIN_OLD)
-#  include <libkern/OSAtomic.h>
+  #define HAVE_STDATOMIC
+  #include <stdatomic.h>
+  #include <stdbool.h>
 #else	/* POSIX pthread spinlock. */
-#  include <pthread.h>
+  #include <pthread.h>
 #endif
 
 /*! \brief Spinlock lock variable type. */
 typedef
-#if defined(HAVE_SYNC_ATOMIC) || defined(HAVE_ATOMIC)
-	bool			/*!< Spinlock lock - a simple & fast atomic version. */
-#elif defined(HAVE_STDATOMIC)
+#if defined(HAVE_STDATOMIC)
 	atomic_bool		/*!< Spinlock lock - a simple & fast atomic version, C11 */
-#elif defined(APPLE_SPIN_NEW)
-	os_unfair_lock		/*!< Spinlock lock - a newer macOS version (macOS >= 10.12). */
-#elif defined(APPLE_SPIN_OLD)
-	OSSpinLock		/*!< Spinlock lock - an older macOS version (macOS < 10.12). */
 #else	/* POSIX */
 	pthread_spinlock_t	/*!< Spinlock lock - a POSIX pthread version. */
 #endif
@@ -65,14 +40,8 @@ typedef
 /*! \brief Initialize the spinlock pointed to by the parameter "lock". */
 static inline void knot_spin_init(knot_spin_t *lock)
 {
-#if defined(HAVE_SYNC_ATOMIC) || defined(HAVE_ATOMIC)
-	*lock = false;
-#elif defined(HAVE_STDATOMIC)
+#if defined(HAVE_STDATOMIC)
 	atomic_init(lock, false);
-#elif defined(APPLE_SPIN_NEW)
-	*lock = OS_UNFAIR_LOCK_INIT;
-#elif defined(APPLE_SPIN_OLD)
-	*lock = OS_SPINLOCK_INIT;
 #else	/* POSIX */
 	pthread_spin_init(lock, PTHREAD_PROCESS_PRIVATE);
 #endif
@@ -81,8 +50,7 @@ static inline void knot_spin_init(knot_spin_t *lock)
 /*! \brief Destroy the spinlock pointed to by the parameter "lock". */
 static inline void knot_spin_destroy(knot_spin_t *lock)
 {
-#if defined(HAVE_SYNC_ATOMIC) || defined(HAVE_ATOMIC) || defined(HAVE_STDATOMIC) || \
-    defined(APPLE_SPIN_NEW) || defined(APPLE_SPIN_OLD)
+#if defined(HAVE_STDATOMIC)
 	/* Nothing needed here. */
 #else	/* POSIX */
 	pthread_spin_destroy(lock);
@@ -92,23 +60,11 @@ static inline void knot_spin_destroy(knot_spin_t *lock)
 /*! \brief Lock the spinlock pointed to by the parameter "lock". */
 static inline void knot_spin_lock(knot_spin_t *lock)
 {
-#if defined(HAVE_SYNC_ATOMIC)
-	while (__sync_lock_test_and_set(lock, 1)) {
-	}
-#elif defined(HAVE_ATOMIC)
-	int expected = 0;
-        while (!__atomic_compare_exchange_n(lock, &expected, 1, false, __ATOMIC_RELAXED, __ATOMIC_RELAXED)) {
-		expected = 0;
-	}
-#elif defined(HAVE_STDATOMIC)
-	int expected = 0;
-	while (!atomic_compare_exchange_strong(lock, &expected, false)) {
-		expected = 0;
+#if defined(HAVE_STDATOMIC)
+	bool expected = false;
+	while (!atomic_compare_exchange_strong(lock, &expected, true)) {
+		expected = false;
 	}
-#elif defined(APPLE_SPIN_NEW)
-	os_unfair_lock_lock(lock);
-#elif defined(APPLE_SPIN_OLD)
-	OSSpinLockLock(lock);
 #else	/* POSIX */
 	pthread_spin_lock(lock);
 #endif
@@ -117,16 +73,8 @@ static inline void knot_spin_lock(knot_spin_t *lock)
 /*! \brief Unlock the spinlock pointed to by the parameter "lock". */
 static inline void knot_spin_unlock(knot_spin_t *lock)
 {
-#if defined(HAVE_SYNC_ATOMIC)
-	__sync_lock_release(lock);
-#elif defined(HAVE_ATOMIC)
-	__atomic_clear(lock, __ATOMIC_RELAXED);
-#elif defined(HAVE_STDATOMIC)
+#if defined(HAVE_STDATOMIC)
 	atomic_store(lock, false);
-#elif defined(APPLE_SPIN_NEW)
-	os_unfair_lock_unlock(lock);
-#elif defined(APPLE_SPIN_OLD)
-	OSSpinLockUnlock(lock);
 #else	/* POSIX */
 	pthread_spin_unlock(lock);
 #endif