1 files changed, 109 insertions, 0 deletions
diff --git a/libglusterfs/src/atomic.h b/libglusterfs/src/atomic.h
new file mode 100644
index 00000000000..71fcb1ee972
--- /dev/null
+++ b/libglusterfs/src/atomic.h
@@ -0,0 +1,109 @@
+/*
+  Copyright (c) 2017 Red Hat, Inc. <http://www.redhat.com>
+  This file is part of GlusterFS.
+
+  This file is licensed to you under your choice of the GNU Lesser
+  General Public License, version 3 or any later version (LGPLv3 or
+  later), or the GNU General Public License, version 2 (GPLv2), in all
+  cases as published by the Free Software Foundation.
+*/
+
+#ifndef _ATOMIC_H
+#define _ATOMIC_H
+
+#include <inttypes.h>
+
+#if defined(HAVE_ATOMIC_BUILTINS) || defined(HAVE_SYNC_BUILTINS)
+/* optimized implementation, macros only */
+
+typedef struct gf_atomic_t {
+        int64_t    cnt;
+} gf_atomic_t;
+
+#if defined(HAVE_ATOMIC_BUILTINS)
+
+/* all macros have a 'gf_atomic_t' as 1st argument */
+#define GF_ATOMIC_INIT(op, n)     __atomic_store (&(op.cnt), __ATOMIC_RELEASE)
+#define GF_ATOMIC_GET(op)         __atomic_load (&(op.cnt), __ATOMIC_ACQUIRE)
+#define GF_ATOMIC_INC(op)         __atomic_add_and_fetch (&(op.cnt), 1, \
+                                                          __ATOMIC_ACQ_REL)
+#define GF_ATOMIC_DEC(op)         __atomic_sub_and_fetch (&(op.cnt), 1, \
+                                                          __ATOMIC_ACQ_REL)
+#define GF_ATOMIC_ADD(op, n)      __atomic_add_and_fetch (&(op.cnt), n, \
+                                                          __ATOMIC_ACQ_REL)
+#define GF_ATOMIC_SUB(op, n)      __atomic_sub_and_fetch (&(op.cnt), n, \
+                                                          __ATOMIC_ACQ_REL)
+
+#else /* !HAVE_ATOMIC_BUILTINS, but HAVE_SYNC_BUILTINS */
+
+/* all macros have a 'gf_atomic_t' as 1st argument */
+#define GF_ATOMIC_INIT(op, n)     ({ op.cnt = n; __sync_synchronize (); })
+#define GF_ATOMIC_GET(op)         __sync_add_and_fetch (&(op.cnt), 0)
+#define GF_ATOMIC_INC(op)         __sync_add_and_fetch (&(op.cnt), 1)
+#define GF_ATOMIC_DEC(op)         __sync_sub_and_fetch (&(op.cnt), 1)
+#define GF_ATOMIC_ADD(op, n)      __sync_add_and_fetch (&(op.cnt), n)
+#define GF_ATOMIC_SUB(op, n)      __sync_sub_and_fetch (&(op.cnt), n)
+
+#endif /* HAVE_ATOMIC_BUILTINS || HAVE_SYNC_BUILTINS */
+
+#else /* no HAVE_(ATOMIC|SYNC)_BUILTINS */
+/* fallback implementation, using small inline functions to improve type
+ * checking while compiling */
+
+#include "locking.h"
+
+typedef struct gf_atomic_t {
+        int64_t    cnt;
+        gf_lock_t  lk;
+} gf_atomic_t;
+
+
+static inline void
+gf_atomic_init (gf_atomic_t *op, int64_t cnt)
+{
+        LOCK_INIT (&op->lk);
+        op->cnt = cnt;
+}
+
+
+static inline uint64_t
+gf_atomic_get (gf_atomic_t *op)
+{
+        uint64_t ret;
+
+        LOCK (&op->lk);
+        {
+               ret = op->cnt;
+        }
+        UNLOCK (&op->lk);
+
+        return ret;
+}
+
+
+static inline int64_t
+gf_atomic_add (gf_atomic_t *op, int64_t n)
+{
+        uint64_t ret;
+
+        LOCK (&op->lk);
+        {
+                op->cnt += n;
+                ret = op->cnt;
+        }
+        UNLOCK (&op->lk);
+
+        return ret;
+}
+
+
+#define GF_ATOMIC_INIT(op, cnt)   gf_atomic_init (&op, cnt)
+#define GF_ATOMIC_GET(op)         gf_atomic_get (&op)
+#define GF_ATOMIC_INC(op)         gf_atomic_add (&op, 1)
+#define GF_ATOMIC_DEC(op)         gf_atomic_add (&op, -1)
+#define GF_ATOMIC_ADD(op, n)      gf_atomic_add (&op, n)
+#define GF_ATOMIC_SUB(op, n)      gf_atomic_add (&op, -n)
+
+#endif /* HAVE_ATOMIC_SYNC_OPS */
+
+#endif /* _ATOMIC_H */