Support custom build directories and move includes

One of the neat tricks an autoconf style project is capable of
is allow configurion/building in a directory other than the
source directory.  The major advantage to this is that you can
build the project various different ways while making changes
in a single source tree.

For example, this project is designed to work on various different
Linux distributions each of which work slightly differently.  This
means that changes need to verified on each of those supported
distributions perferably before the change is committed to the
public git repo.

Using nfs and custom build directories makes this much easier.
I now have a single source tree in nfs mounted on several different
systems each running a supported distribution.  When I make a
change to the source base I suspect may break things I can
concurrently build from the same source on all the systems each
in their own subdirectory.

wget -c http://github.com/downloads/behlendorf/zfs/zfs-x.y.z.tar.gz
tar -xzf zfs-x.y.z.tar.gz
cd zfs-x-y-z

------------------------- run concurrently ----------------------
<ubuntu system>  <fedora system>  <debian system>  <rhel6 system>
mkdir ubuntu     mkdir fedora     mkdir debian     mkdir rhel6
cd ubuntu        cd fedora        cd debian        cd rhel6
../configure     ../configure     ../configure     ../configure
make             make             make             make
make check       make check       make check       make check

This change also moves many of the include headers from individual
incude/sys directories under the modules directory in to a single
top level include directory.  This has the advantage of making
the build rules cleaner and logically it makes a bit more sense.

1 files changed, 107 insertions, 0 deletions

diff --git a/include/sys/refcount.h b/include/sys/refcount.h
new file mode 100644
index 000000000..1752c64e3
--- /dev/null
+++ b/include/sys/refcount.h
@@ -0,0 +1,107 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ */
+
+#ifndef	_SYS_REFCOUNT_H
+#define	_SYS_REFCOUNT_H
+
+#include <sys/inttypes.h>
+#include <sys/list.h>
+#include <sys/zfs_context.h>
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+/*
+ * If the reference is held only by the calling function and not any
+ * particular object, use FTAG (which is a string) for the holder_tag.
+ * Otherwise, use the object that holds the reference.
+ */
+#define	FTAG ((char *)__func__)
+
+#ifdef	ZFS_DEBUG
+typedef struct reference {
+	list_node_t ref_link;
+	void *ref_holder;
+	uint64_t ref_number;
+	uint8_t *ref_removed;
+} reference_t;
+
+typedef struct refcount {
+	kmutex_t rc_mtx;
+	list_t rc_list;
+	list_t rc_removed;
+	int64_t rc_count;
+	int64_t rc_removed_count;
+} refcount_t;
+
+/* Note: refcount_t must be initialized with refcount_create() */
+
+void refcount_create(refcount_t *rc);
+void refcount_destroy(refcount_t *rc);
+void refcount_destroy_many(refcount_t *rc, uint64_t number);
+int refcount_is_zero(refcount_t *rc);
+int64_t refcount_count(refcount_t *rc);
+int64_t refcount_add(refcount_t *rc, void *holder_tag);
+int64_t refcount_remove(refcount_t *rc, void *holder_tag);
+int64_t refcount_add_many(refcount_t *rc, uint64_t number, void *holder_tag);
+int64_t refcount_remove_many(refcount_t *rc, uint64_t number, void *holder_tag);
+void refcount_transfer(refcount_t *dst, refcount_t *src);
+
+void refcount_init(void);
+void refcount_fini(void);
+
+#else	/* ZFS_DEBUG */
+
+typedef struct refcount {
+	uint64_t rc_count;
+} refcount_t;
+
+#define	refcount_create(rc) ((rc)->rc_count = 0)
+#define	refcount_destroy(rc) ((rc)->rc_count = 0)
+#define	refcount_destroy_many(rc, number) ((rc)->rc_count = 0)
+#define	refcount_is_zero(rc) ((rc)->rc_count == 0)
+#define	refcount_count(rc) ((rc)->rc_count)
+#define	refcount_add(rc, holder) atomic_add_64_nv(&(rc)->rc_count, 1)
+#define	refcount_remove(rc, holder) atomic_add_64_nv(&(rc)->rc_count, -1)
+#define	refcount_add_many(rc, number, holder) \
+	atomic_add_64_nv(&(rc)->rc_count, number)
+#define	refcount_remove_many(rc, number, holder) \
+	atomic_add_64_nv(&(rc)->rc_count, -number)
+#define	refcount_transfer(dst, src) { \
+	uint64_t __tmp = (src)->rc_count; \
+	atomic_add_64(&(src)->rc_count, -__tmp); \
+	atomic_add_64(&(dst)->rc_count, __tmp); \
+}
+
+#define	refcount_init()
+#define	refcount_fini()
+
+#endif	/* ZFS_DEBUG */
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif /* _SYS_REFCOUNT_H */