[PATCH 02/12] radix-tree: split struct radix_tree_root to <linux/radix-tree-root.h>

[Masahiro Yamada]

The idea is similar to the separation of <linux/spinlock_types.h>
and <linux/spinlock.h>.

The users of radix tree typically embed struct radix_tree_root in
their data structures, but those headers do not need to know anything
about the other radix tree stuff like radix_tree_node, accessors.

Including <linux/radix-tree.h> pulls in lots of bloat while struct
radix_tree_root only depends on <linux/types.h> for gfp_t, and
<linux/compiler.h> for __rcu.

To reduce the header dependency, split struct radix_tree_root out
to <linux/radix-tree-root.h>.

Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
---

 include/linux/radix-tree-root.h | 24 ++++++++++++++++++++++++
 include/linux/radix-tree.h      |  6 +-----
 2 files changed, 25 insertions(+), 5 deletions(-)
 create mode 100644 include/linux/radix-tree-root.h

diff --git a/include/linux/radix-tree-root.h b/include/linux/radix-tree-root.h
new file mode 100644
index 0000000..1726df0
--- /dev/null
+++ b/include/linux/radix-tree-root.h
@@ -0,0 +1,24 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2, or (at
+ * your option) any later version.
+ *
+ * This program 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
+ * General Public License for more details.
+ */
+
+#ifndef _LINUX_RADIX_TREE_ROOT_H
+#define _LINUX_RADIX_TREE_ROOT_H
+
+#include <linux/types.h>
+#include <linux/compiler.h>
+
+struct radix_tree_root {
+	gfp_t			gfp_mask;
+	struct radix_tree_node	__rcu *rnode;
+};
+
+#endif /* _LINUX_RADIX_TREE_ROOT_H */
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index 6df7fa9..db3fb1d 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -26,6 +26,7 @@
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/preempt.h>
+#include <linux/radix-tree-root.h>
 #include <linux/rcupdate.h>
 #include <linux/spinlock_types.h>
 #include <linux/types.h>
@@ -109,11 +110,6 @@ struct radix_tree_node {
 #define ROOT_IS_IDR	((__force gfp_t)(1 << __GFP_BITS_SHIFT))
 #define ROOT_TAG_SHIFT	(__GFP_BITS_SHIFT + 1)
 
-struct radix_tree_root {
-	gfp_t			gfp_mask;
-	struct radix_tree_node	__rcu *rnode;
-};
-
 #define RADIX_TREE_INIT(mask)	{					\
 	.gfp_mask = (mask),						\
 	.rnode = NULL,							\
-- 
2.7.4