From: Jens Axboe <axboe@kernel.dk>
Date: Thu, 26 Aug 2021 14:46:36 +0000 (-0600)
Subject: Merge branch 'wip-cxx' of https://github.com/tchaikov/fio
X-Git-Tag: fio-3.28~21
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=7f02f21f53ccd5e2448086f8e9015489693dd2dc;hp=15ce99bb71e7c289f62ddee94e0149f6c81549de;p=fio.git

Merge branch 'wip-cxx' of https://github.com/tchaikov/fio

* 'wip-cxx' of https://github.com/tchaikov/fio:
  arch,lib/seqlock: implement seqlock with C++ atomic if compiled with C++
---

diff --git a/arch/arch.h b/arch/arch.h
index a25779d4..fca003be 100644
--- a/arch/arch.h
+++ b/arch/arch.h
@@ -1,7 +1,11 @@
 #ifndef ARCH_H
 #define ARCH_H
 
+#ifdef __cplusplus
+#include <atomic>
+#else
 #include <stdatomic.h>
+#endif
 
 #include "../lib/types.h"
 
@@ -36,6 +40,21 @@ extern unsigned long arch_flags;
 
 #define ARCH_CPU_CLOCK_WRAPS
 
+#ifdef __cplusplus
+#define atomic_add(p, v)						\
+	std::atomic_fetch_add(p, (v))
+#define atomic_sub(p, v)						\
+	std::atomic_fetch_sub(p, (v))
+#define atomic_load_relaxed(p)					\
+	std::atomic_load_explicit(p,				\
+			     std::memory_order_relaxed)
+#define atomic_load_acquire(p)					\
+	std::atomic_load_explicit(p,				\
+			     std::memory_order_acquire)
+#define atomic_store_release(p, v)				\
+	std::atomic_store_explicit(p, (v),			\
+			     std::memory_order_release)
+#else
 #define atomic_add(p, v)					\
 	atomic_fetch_add((_Atomic typeof(*(p)) *)(p), v)
 #define atomic_sub(p, v)					\
@@ -49,6 +68,7 @@ extern unsigned long arch_flags;
 #define atomic_store_release(p, v)				\
 	atomic_store_explicit((_Atomic typeof(*(p)) *)(p), (v),	\
 			      memory_order_release)
+#endif
 
 /* IWYU pragma: begin_exports */
 #if defined(__i386__)
diff --git a/lib/seqlock.h b/lib/seqlock.h
index 56f3e37d..ef3aa091 100644
--- a/lib/seqlock.h
+++ b/lib/seqlock.h
@@ -5,7 +5,11 @@
 #include "../arch/arch.h"
 
 struct seqlock {
+#ifdef __cplusplus
+	std::atomic<unsigned int> sequence;
+#else
 	volatile unsigned int sequence;
+#endif
 };
 
 static inline void seqlock_init(struct seqlock *s)