1 files changed, 25 insertions, 1 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 8e858744413..be68c956a66 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -2,11 +2,24 @@
 #include <linux/wait.h>
 #include <linux/backing-dev.h>
 #include <linux/fs.h>
+#include <linux/pagemap.h>
 #include <linux/sched.h>
 #include <linux/module.h>
 #include <linux/writeback.h>
 #include <linux/device.h>
 
+void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
+{
+}
+EXPORT_SYMBOL(default_unplug_io_fn);
+
+struct backing_dev_info default_backing_dev_info = {
+	.ra_pages	= VM_MAX_READAHEAD * 1024 / PAGE_CACHE_SIZE,
+	.state		= 0,
+	.capabilities	= BDI_CAP_MAP_COPY,
+	.unplug_io_fn	= default_unplug_io_fn,
+};
+EXPORT_SYMBOL_GPL(default_backing_dev_info);
 
 static struct class *bdi_class;
 
@@ -166,9 +179,20 @@ static __init int bdi_class_init(void)
 	bdi_debug_init();
 	return 0;
 }
-
 postcore_initcall(bdi_class_init);
 
+static int __init default_bdi_init(void)
+{
+	int err;
+
+	err = bdi_init(&default_backing_dev_info);
+	if (!err)
+		bdi_register(&default_backing_dev_info, NULL, "default");
+
+	return err;
+}
+subsys_initcall(default_bdi_init);
+
 int bdi_register(struct backing_dev_info *bdi, struct device *parent,
 		const char *fmt, ...)
 {