1 files changed, 84 insertions, 0 deletions
diff --git a/libglusterfs/src/glusterfs/locking.h b/libglusterfs/src/glusterfs/locking.h
new file mode 100644
index 00000000000..43cc87735d1
--- /dev/null
+++ b/libglusterfs/src/glusterfs/locking.h
@@ -0,0 +1,84 @@
+/*
+  Copyright (c) 2008-2012 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 _LOCKING_H
+#define _LOCKING_H
+
+#include <pthread.h>
+
+#if defined(GF_DARWIN_HOST_OS)
+#include <libkern/OSAtomic.h>
+#define pthread_spinlock_t OSSpinLock
+#define pthread_spin_lock(l) OSSpinLockLock(l)
+#define pthread_spin_unlock(l) OSSpinLockUnlock(l)
+#define pthread_spin_destroy(l) 0
+#define pthread_spin_init(l, v) (*l = v)
+#endif
+
+#if defined(HAVE_SPINLOCK)
+
+typedef union {
+    pthread_spinlock_t spinlock;
+    pthread_mutex_t mutex;
+} gf_lock_t;
+
+#if !defined(LOCKING_IMPL)
+extern int use_spinlocks;
+
+/*
+ * Using a dispatch table would be unpleasant because we're dealing with two
+ * different types.  If the dispatch contains direct pointers to pthread_xx
+ * or mutex_xxx then we have to hope that every possible union alternative
+ * starts at the same address as the union itself.  I'm old enough to remember
+ * compilers where this was not the case (for alignment reasons) so I'm a bit
+ * paranoid about that.  Also, I don't like casting arguments through "void *"
+ * which we'd also have to do to avoid type errors.  The other alternative would
+ * be to define actual functions which pick out the right union member, and put
+ * those in the dispatch tables.  Now we have a pointer dereference through the
+ * dispatch table plus a function call, which is likely to be worse than the
+ * branching here from the ?: construct.  If it were a clear win it might be
+ * worth the extra complexity, but for now this way seems preferable.
+ */
+
+#define LOCK_INIT(x)                                                           \
+    (use_spinlocks ? pthread_spin_init(&((x)->spinlock), 0)                    \
+                   : pthread_mutex_init(&((x)->mutex), 0))
+
+#define LOCK(x)                                                                \
+    (use_spinlocks ? pthread_spin_lock(&((x)->spinlock))                       \
+                   : pthread_mutex_lock(&((x)->mutex)))
+
+#define TRY_LOCK(x)                                                            \
+    (use_spinlocks ? pthread_spin_trylock(&((x)->spinlock))                    \
+                   : pthread_mutex_trylock(&((x)->mutex)))
+
+#define UNLOCK(x)                                                              \
+    (use_spinlocks ? pthread_spin_unlock(&((x)->spinlock))                     \
+                   : pthread_mutex_unlock(&((x)->mutex)))
+
+#define LOCK_DESTROY(x)                                                        \
+    (use_spinlocks ? pthread_spin_destroy(&((x)->spinlock))                    \
+                   : pthread_mutex_destroy(&((x)->mutex)))
+
+#endif
+
+#else
+
+typedef pthread_mutex_t gf_lock_t;
+
+#define LOCK_INIT(x) pthread_mutex_init(x, 0)
+#define LOCK(x) pthread_mutex_lock(x)
+#define TRY_LOCK(x) pthread_mutex_trylock(x)
+#define UNLOCK(x) pthread_mutex_unlock(x)
+#define LOCK_DESTROY(x) pthread_mutex_destroy(x)
+
+#endif /* HAVE_SPINLOCK */
+
+#endif /* _LOCKING_H */