idr: create idr_layer_cache at boot time

Avoid a possible kmem_cache_create() failure by creating idr_layer_cache
unconditionary at boot time rather than creating it on-demand when idr_init()
is called the first time.

This change also enables us to eliminate the check every time idr_init() is
called.

[akpm@linux-foundation.org: rename init_id_cache() to idr_init_cache()]
[akpm@linux-foundation.org: fix alpha build]
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/idr.h b/include/linux/idr.h
index 0edda411959c..9a2d762124de 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -14,6 +14,7 @@
 
 #include <linux/types.h>
 #include <linux/bitops.h>
+#include <linux/init.h>
 
 #if BITS_PER_LONG == 32
 # define IDR_BITS 5
@@ -115,4 +116,6 @@ void ida_remove(struct ida *ida, int id);
 void ida_destroy(struct ida *ida);
 void ida_init(struct ida *ida);
 
+void __init idr_init_cache(void);
+
 #endif /* __IDR_H__ */