build, glusterd: Add liburcu to build system

This patch adds liburcu related checks to the build system and updates
the spec file to require 'userspace-rcu'.

liburcu >= 0.7 is required to build GlusterFS, but 0.8 and above is
preferred. For cases when liburcu 0.7.x is the available version, some
function definitions (currently just one) from liburcu-0.8.6 have been
made available in /contrib/userspace-rcu/.

This change was developed on the git branch at [1]. This commit is a
combination of the following commits on the development branch.
  a5cd6bd Add userspace-rcu checks to configure.ac
  fe5ced3 Add URCU libs to glusterd libtool flags
  1e43302 Add local definition of cds_list_add_tail_rcu for
          liburcu-0.7
  98da755 Move local definition of cds_list_add_tail_rcu into contrib
  8c44dfd Update spec file to include userspace-rcu0466e33 Rename
  rculist-additional.h to rculist-extra.h
  947c7b3 Add rculist-extra.h to dist
  19f32ad Address review comments 9605/1

[1]: https://github.com/kshlm/glusterfs/tree/urcu

Change-Id: Ifbb617d0dacce8fa01214f894badb9d8cdcaf56f
BUG: 1191030
Signed-off-by: Kaushal M <kaushal@redhat.com>
Reviewed-on: http://review.gluster.org/9605
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Atin Mukherjee <amukherj@redhat.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Tested-by: Krishnan Parthasarathi <kparthas@redhat.com>

1 files changed, 42 insertions, 0 deletions

diff --git a/contrib/userspace-rcu/rculist-extra.h b/contrib/userspace-rcu/rculist-extra.h
new file mode 100644
index 00000000000..274cf9f9d7a
--- /dev/null
+++ b/contrib/userspace-rcu/rculist-extra.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2002 Free Software Foundation, Inc.
+ * (originally part of the GNU C Library)
+ * Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+ *
+ * Copyright (C) 2009 Pierre-Marc Fournier
+ * Conversion to RCU list.
+ * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef URCU_RCULIST_EXTRA_H
+#define URCU_RCULIST_EXTRA_H
+/* Copying this definition from liburcu-0.8 as liburcu-0.7 does not have this
+ * particular list api
+ */
+/* Add new element at the tail of the list. */
+
+static inline
+void cds_list_add_tail_rcu(struct cds_list_head *newp,
+                struct cds_list_head *head)
+{
+        newp->next = head;
+        newp->prev = head->prev;
+        rcu_assign_pointer(head->prev->next, newp);
+        head->prev = newp;
+}
+
+#endif