fs: move code out of buffer.c

Move invalidate_bdev, block_sync_page into fs/block_dev.c.  Export
kill_bdev as well, so brd doesn't have to open code it.  Reduce
buffer_head.h requirement accordingly.

Removed a rather large comment from invalidate_bdev, as it looked a bit
obsolete to bother moving.  The small comment replacing it says enough.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 1 insertions, 3 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 4720f68f817e..b89c548ec3f8 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -14,7 +14,6 @@
 #include <linux/moduleparam.h>
 #include <linux/blkpg.h>
 #include <linux/bio.h>
-#include <linux/buffer_head.h>
 #include <linux/mempool.h>
 #include <linux/slab.h>
 #include <linux/idr.h>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index f47f1f8ac44b..5d1b6762f108 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -36,8 +36,7 @@
 #include <linux/blkdev.h>
 #include <linux/sysctl.h>
 #include <linux/seq_file.h>
-#include <linux/mutex.h>
-#include <linux/buffer_head.h> /* for invalidate_bdev */
+#include <linux/fs.h>
 #include <linux/poll.h>
 #include <linux/ctype.h>
 #include <linux/string.h>