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>
diff --git a/mm/madvise.c b/mm/madvise.c
index d551475..64bb8a2 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -17,6 +17,7 @@
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/blkdev.h>
+#include <linux/backing-dev.h>
#include <linux/swap.h>
#include <linux/swapops.h>