[patch 05/38] btree: Initialize early when builtin

[Thomas Gleixner <tglx@linutronix.de>]

An upcoming user of btree needs it early on. Initialize it in
start_kernel().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/btree.h |    6 ++++++
 init/main.c           |    2 ++
 lib/btree.c           |    8 +++++++-
 3 files changed, 15 insertions(+), 1 deletion(-)

--- a/include/linux/btree.h
+++ b/include/linux/btree.h
@@ -5,6 +5,12 @@
 #include <linux/kernel.h>
 #include <linux/mempool.h>
 
+#if IS_BUILTIN(CONFIG_BTREE)
+extern void btree_cache_init(void);
+#else
+static inline void btree_cache_init(void) {}
+#endif
+
 /**
  * DOC: B+Tree basics
  *
--- a/init/main.c
+++ b/init/main.c
@@ -75,6 +75,7 @@
 #include <linux/signal.h>
 #include <linux/idr.h>
 #include <linux/kgdb.h>
+#include <linux/btree.h>
 #include <linux/ftrace.h>
 #include <linux/async.h>
 #include <linux/shmem_fs.h>
@@ -1125,6 +1126,7 @@ asmlinkage __visible void __init __no_sa
 	cgroup_init();
 	taskstats_init_early();
 	delayacct_init();
+	btree_cache_init();
 
 	poking_init();
 	check_bugs();
--- a/lib/btree.c
+++ b/lib/btree.c
@@ -787,15 +787,21 @@ static int __init btree_module_init(void
 	return 0;
 }
 
+#if IS_MODULE(CONFIG_BTREE)
 static void __exit btree_module_exit(void)
 {
 	kmem_cache_destroy(btree_cachep);
 }
 
-/* If core code starts using btree, initialization should happen even earlier */
 module_init(btree_module_init);
 module_exit(btree_module_exit);
 
 MODULE_AUTHOR("Joern Engel <joern@logfs.org>");
 MODULE_AUTHOR("Johannes Berg <johannes@sipsolutions.net>");
 MODULE_LICENSE("GPL");
+#else
+void __init btree_cache_init(void)
+{
+	BUG_ON(btree_module_init());
+}
+#endif