From 3af3df905fb43dd3a3957f3daea7777a434fee05 Mon Sep 17 00:00:00 2001
From: Richard Yao <ryao@gentoo.org>
Date: Wed, 30 Apr 2014 13:12:27 -0400
Subject: libspl: Implement LWP rwlock interface

This implements a subset of the LWP rwlock interface by wrapping the
equivalent POSIX thread interface. It is a superset of the features
needed by ztest.

The missing bits are {,_}rw_read_held() and {,_}rw_write_held().

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1970
---
 include/sys/zfs_context.h  |  1 +
 lib/libspl/include/synch.h | 51 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/include/sys/zfs_context.h b/include/sys/zfs_context.h
index 1861b845d..ec2a7dea0 100644
--- a/include/sys/zfs_context.h
+++ b/include/sys/zfs_context.h
@@ -90,6 +90,7 @@
 #include <string.h>
 #include <strings.h>
 #include <pthread.h>
+#include <synch.h>
 #include <assert.h>
 #include <alloca.h>
 #include <umem.h>
diff --git a/lib/libspl/include/synch.h b/lib/libspl/include/synch.h
index 7ce2a53d4..93d231498 100644
--- a/lib/libspl/include/synch.h
+++ b/lib/libspl/include/synch.h
@@ -21,10 +21,61 @@
  */
 /*
  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2014 Zettabyte Software, LLC.  All rights reserved.
  * Use is subject to license terms.
  */
 
 #ifndef _LIBSPL_SYNCH_H
 #define	_LIBSPL_SYNCH_H
 
+#ifndef __sun__
+
+#include <assert.h>
+#include <pthread.h>
+
+/*
+ * Definitions of synchronization types.
+ */
+#define	USYNC_THREAD	0x00		/* private to a process */
+#define	USYNC_PROCESS	0x01		/* shared by processes */
+
+typedef pthread_rwlock_t rwlock_t;
+
+#define	DEFAULTRWLOCK		PTHREAD_RWLOCK_INITIALIZER
+
+static inline int
+rwlock_init(rwlock_t *rwlp, int type, void *arg)
+{
+	pthread_rwlockattr_t attr;
+	int err = 0;
+
+	VERIFY0(pthread_rwlockattr_init(&attr));
+	switch (type) {
+	case USYNC_THREAD:
+		VERIFY0(pthread_rwlockattr_setpshared(&attr,
+			PTHREAD_PROCESS_PRIVATE));
+		break;
+	case USYNC_PROCESS:
+		VERIFY0(pthread_rwlockattr_setpshared(&attr,
+			PTHREAD_PROCESS_SHARED));
+		break;
+	default:
+		VERIFY0(1);
+	}
+
+	err = pthread_rwlock_init(rwlp, &attr);
+	VERIFY0(pthread_rwlockattr_destroy(&attr));
+
+	return (err);
+}
+
+#define	rwlock_destroy(x)	pthread_rwlock_destroy((x))
+#define	rw_rdlock(x)		pthread_rwlock_rdlock((x))
+#define	rw_wrlock(x)		pthread_rwlock_wrlock((x))
+#define	rw_unlock(x)		pthread_rwlock_unlock((x))
+#define	rw_tryrdlock(x)		pthread_rwlock_tryrdlock((x))
+#define	rw_trywrlock(x)		pthread_rwlock_trywrlock((x))
+
+#endif /* __sun__ */
+
 #endif
-- 
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