1 files changed, 30 insertions, 6 deletions

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 8e8587444132..493b468a5035 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, ...)
 {
@@ -260,12 +284,12 @@ static wait_queue_head_t congestion_wqh[2] = {
         };
 
 
-void clear_bdi_congested(struct backing_dev_info *bdi, int rw)
+void clear_bdi_congested(struct backing_dev_info *bdi, int sync)
 {
         enum bdi_state bit;
-        wait_queue_head_t *wqh = &congestion_wqh[rw];
+        wait_queue_head_t *wqh = &congestion_wqh[sync];
 
-        bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested;
+        bit = sync ? BDI_sync_congested : BDI_async_congested;
         clear_bit(bit, &bdi->state);
         smp_mb__after_clear_bit();
         if (waitqueue_active(wqh))
@@ -273,11 +297,11 @@ void clear_bdi_congested(struct backing_dev_info *bdi, int rw)
 }
 EXPORT_SYMBOL(clear_bdi_congested);
 
-void set_bdi_congested(struct backing_dev_info *bdi, int rw)
+void set_bdi_congested(struct backing_dev_info *bdi, int sync)
 {
         enum bdi_state bit;
 
-        bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested;
+        bit = sync ? BDI_sync_congested : BDI_async_congested;
         set_bit(bit, &bdi->state);
 }
 EXPORT_SYMBOL(set_bdi_congested);