fs: remove default_backing_dev_info

Now that default_backing_dev_info is not used for writeback purposes we can
git rid of it easily:

 - instead of using it's name for tracing unregistered bdi we just use
   "unknown"
 - btrfs and ceph can just assign the default read ahead window themselves
   like several other filesystems already do.
 - we can assign noop_backing_dev_info as the default one in alloc_super.
   All filesystems already either assigned their own or
   noop_backing_dev_info.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Christoph Hellwig 2015-01-14 10:42:41 +01:00 committed by Jens Axboe
parent c4db59d31e
commit df0ce26cb4
6 changed files with 6 additions and 22 deletions

View file

@ -156,10 +156,8 @@ DECLARE_EVENT_CLASS(writeback_work_class,
__field(int, reason)
),
TP_fast_assign(
struct device *dev = bdi->dev;
if (!dev)
dev = default_backing_dev_info.dev;
strncpy(__entry->name, dev_name(dev), 32);
strncpy(__entry->name,
bdi->dev ? dev_name(bdi->dev) : "(unknown)", 32);
__entry->nr_pages = work->nr_pages;
__entry->sb_dev = work->sb ? work->sb->s_dev : 0;
__entry->sync_mode = work->sync_mode;