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>

1 files changed, 4 insertions, 5 deletions

diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index d22119d..ec24643 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -17,7 +17,7 @@
 #include <linux/highmem.h>
 #include <linux/mutex.h>
 #include <linux/radix-tree.h>
-#include <linux/buffer_head.h> /* invalidate_bh_lrus() */
+#include <linux/fs.h>
 #include <linux/slab.h>
 
 #include <asm/uaccess.h>
@@ -402,14 +402,13 @@ static int brd_ioctl(struct block_device *bdev, fmode_t mode,
 	error = -EBUSY;
 	if (bdev->bd_openers <= 1) {
 		/*
-		 * Invalidate the cache first, so it isn't written
-		 * back to the device.
+		 * Kill the cache first, so it isn't written back to the
+		 * device.
 		 *
 		 * Another thread might instantiate more buffercache here,
 		 * but there is not much we can do to close that race.
 		 */
-		invalidate_bh_lrus();
-		truncate_inode_pages(bdev->bd_inode->i_mapping, 0);
+		kill_bdev(bdev);
 		brd_free_pages(brd);
 		error = 0;
 	}