From: Andreas Dilger <adilger@whamcloud.com>
Date: Fri, 14 Dec 2018 22:49:36 +0000 (-0700)
Subject: LU-11453 misc: add compat for INIT_LIST_HEAD_RCU
X-Git-Tag: 2.12.51~102
X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=commitdiff_plain;h=773e60669b53b0ca2fb48723a21dcddba592af9a

LU-11453 misc: add compat for INIT_LIST_HEAD_RCU

Add a compat version of INIT_LIST_HEAD_RCU() if unavailable.

Fixes: 68bc3984975bb72f730d8a8ab7aa2d836e50abe5

Test-Parameters: trivial
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I9c1296206e002b895bb6bdf55ddd0d8ec70cab07
Reviewed-on: https://review.whamcloud.com/33875
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Yang Sheng <ys@whamcloud.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
---

diff --git a/lustre/autoconf/lustre-core.m4 b/lustre/autoconf/lustre-core.m4
index 735d0dc..f4d6a25 100644
--- a/lustre/autoconf/lustre-core.m4
+++ b/lustre/autoconf/lustre-core.m4
@@ -1676,6 +1676,27 @@ kiocb_ki_left, [
 ]) # LC_KIOCB_KI_LEFT
 
 #
+# LC_INIT_LIST_HEAD_RCU
+#
+# 3.12 added INIT_LIST_HEAD_RCU in commit 2a855b644c310d5db5
+# which is unfortunately an inline function and not a macro
+# that can be tested directly, so it needs a configure check.
+#
+AC_DEFUN([LC_INIT_LIST_HEAD_RCU], [
+LB_CHECK_COMPILE([if 'INIT_LIST_HEAD_RCU' exists],
+init_list_head_rcu, [
+	#include <linux/list.h>
+	#include <linux/rculist.h>
+],[
+	struct list_head list;
+	INIT_LIST_HEAD_RCU(&list);
+],[
+	AC_DEFINE(HAVE_INIT_LIST_HEAD_RCU, 1,
+		  [INIT_LIST_HEAD_RCU exists])
+])
+]) # LC_INIT_LIST_HEAD_RCU
+
+#
 # LC_VFS_RENAME_5ARGS
 #
 # 3.13 has vfs_rename with 5 args
@@ -3099,6 +3120,7 @@ AC_DEFUN([LC_PROG_LINUX], [
 	LC_OLDSIZE_TRUNCATE_PAGECACHE
 	LC_PTR_ERR_OR_ZERO_MISSING
 	LC_KIOCB_KI_LEFT
+	LC_INIT_LIST_HEAD_RCU
 
 	# 3.13
 	LC_VFS_RENAME_5ARGS
diff --git a/lustre/include/lustre_compat.h b/lustre/include/lustre_compat.h
index fdb2010..34465f1 100644
--- a/lustre/include/lustre_compat.h
+++ b/lustre/include/lustre_compat.h
@@ -148,6 +148,14 @@ static inline void ll_set_fs_pwd(struct fs_struct *fs, struct vfsmount *mnt,
 #define SLAB_DESTROY_BY_RCU 0
 #endif
 
+#ifndef HAVE_INIT_LIST_HEAD_RCU
+static inline void INIT_LIST_HEAD_RCU(struct list_head *list)
+{
+	WRITE_ONCE(list->next, list);
+	WRITE_ONCE(list->prev, list);
+}
+#endif
+
 #ifndef HAVE_DQUOT_SUSPEND
 # define ll_vfs_dq_init             vfs_dq_init
 # define ll_vfs_dq_drop             vfs_dq_drop