commit 9e5c353510b26500bd6b8309823ac9ef2837b761
author Slava Pestov <sp@daterainc.com> Thu May 01 13:48:57 2014 -0700
committer Kent Overstreet <kmo@daterainc.com> Mon Aug 04 15:23:03 2014 -0700
tree ff1ff3500ed20d3b9ac2dc3338e1d6ad87e9e0ea
parent c5aa4a3157b55bdca18dd2a9d9f43314470b6d32

bcache: fix uninterruptible sleep in writeback thread

There were two issues here:

- writeback thread did not start until the device first became dirty
- writeback thread used uninterruptible sleep once running

Without this patch I see kernel warnings printed and a load average of
1.52 after booting my test VM. With this patch the warnings are gone and
the load average is near 0.00 as expected.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

drivers/md/bcache/writeback.h

diff --git a/drivers/md/bcache/writeback.h b/drivers/md/bcache/writeback.h
index e2f8598..0a9dab1 100644
--- a/drivers/md/bcache/writeback.h
+++ b/drivers/md/bcache/writeback.h
@@ -85,6 +85,7 @@
 void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int);
 
 void bch_sectors_dirty_init(struct cached_dev *dc);
-int bch_cached_dev_writeback_init(struct cached_dev *);
+void bch_cached_dev_writeback_init(struct cached_dev *);
+int bch_cached_dev_writeback_start(struct cached_dev *);
 
 #endif