writeback: separate out include/linux/backing-dev-defs.h

With the planned cgroup writeback support, backing-dev related
declarations will be more widely used across block and cgroup;
unfortunately, including backing-dev.h from include/linux/blkdev.h
makes cyclic include dependency quite likely.

This patch separates out backing-dev-defs.h which only has the
essential definitions and updates blkdev.h to include it.  c files
which need access to more backing-dev details now include
backing-dev.h directly.  This takes backing-dev.h off the common
include dependency chain making it a lot easier to use it across block
and cgroup.

v2: fs/fat build failure fixed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <axboe@fb.com>

block/blk-integrity.c

@@ -21,6 +21,7 @@
  */
 
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/mempool.h>
 #include <linux/bio.h>
 #include <linux/scatterlist.h>

block/blk-sysfs.c

@@ -6,6 +6,7 @@
 #include <linux/module.h>
 #include <linux/bio.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/blktrace_api.h>
 #include <linux/blk-mq.h>
 #include <linux/blk-cgroup.h>

block/bounce.c

@@ -13,6 +13,7 @@
 #include <linux/pagemap.h>
 #include <linux/mempool.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/init.h>
 #include <linux/hash.h>
 #include <linux/highmem.h>

block/genhd.c

@@ -8,6 +8,7 @@
 #include <linux/kdev_t.h>
 #include <linux/kernel.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/init.h>
 #include <linux/spinlock.h>
 #include <linux/proc_fs.h>

drivers/block/drbd/drbd_int.h

@@ -38,6 +38,7 @@
 #include <linux/mutex.h>
 #include <linux/major.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/genhd.h>
 #include <linux/idr.h>
 #include <net/tcp.h>

drivers/block/pktcdvd.c

@@ -61,6 +61,7 @@
 #include <linux/freezer.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
+#include <linux/backing-dev.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_ioctl.h>
 #include <scsi/scsi.h>

drivers/char/raw.c

@@ -12,6 +12,7 @@
 #include <linux/fs.h>
 #include <linux/major.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/module.h>
 #include <linux/raw.h>
 #include <linux/capability.h>

drivers/md/bcache/request.c

@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/hash.h>
 #include <linux/random.h>
+#include <linux/backing-dev.h>
 
 #include <trace/events/bcache.h>
 

drivers/md/dm.h

@@ -14,6 +14,7 @@
 #include <linux/device-mapper.h>
 #include <linux/list.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/hdreg.h>
 #include <linux/completion.h>
 #include <linux/kobject.h>

drivers/md/md.h

@@ -16,6 +16,7 @@
 #define _MD_MD_H
 
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/kobject.h>
 #include <linux/list.h>
 #include <linux/mm.h>

drivers/mtd/devices/block2mtd.c

@@ -20,6 +20,7 @@
 #include <linux/delay.h>
 #include <linux/fs.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/bio.h>
 #include <linux/pagemap.h>
 #include <linux/list.h>

fs/block_dev.c

@@ -14,6 +14,7 @@
 #include <linux/device_cgroup.h>
 #include <linux/highmem.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/module.h>
 #include <linux/blkpg.h>
 #include <linux/magic.h>

fs/ext4/extents.c

@@ -39,6 +39,7 @@
 #include <linux/slab.h>
 #include <asm/uaccess.h>
 #include <linux/fiemap.h>
+#include <linux/backing-dev.h>
 #include "ext4_jbd2.h"
 #include "ext4_extents.h"
 #include "xattr.h"

fs/ext4/mballoc.c

@@ -26,6 +26,7 @@
 #include <linux/log2.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/backing-dev.h>
 #include <trace/events/ext4.h>
 
 #ifdef CONFIG_EXT4_DEBUG

fs/ext4/super.c

@@ -24,6 +24,7 @@
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/parser.h>
 #include <linux/buffer_head.h>
 #include <linux/exportfs.h>

fs/f2fs/segment.h

@@ -9,6 +9,7 @@
  * published by the Free Software Foundation.
  */
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 
 /* constant macro */
 #define NULL_SEGNO			((unsigned int)(~0))

fs/fat/file.c

@@ -11,6 +11,7 @@
 #include <linux/compat.h>
 #include <linux/mount.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/fsnotify.h>
 #include <linux/security.h>
 #include "fat.h"

fs/fat/inode.c

@@ -18,6 +18,7 @@
 #include <linux/parser.h>
 #include <linux/uio.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <asm/unaligned.h>
 #include "fat.h"
 

fs/hfs/super.c

@@ -14,6 +14,7 @@
 
 #include <linux/module.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/mount.h>
 #include <linux/init.h>
 #include <linux/nls.h>

fs/hfsplus/super.c

@@ -11,6 +11,7 @@
 #include <linux/init.h>
 #include <linux/pagemap.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/fs.h>
 #include <linux/slab.h>
 #include <linux/vfs.h>