Our current implementation has a generic set of barrier functions that
go through the SCSI driver model.  Realistically, this is unnecessary,
because the only device that can use barriers (sd) can set the flush
functions up at probe or revalidate time.  This patch pulls the barrier
functions out of the mid layer and scsi driver model and relocates them
directly in sd.
Acked-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

All ordered request related stuff delegated to HLD.  Midlayer
now doens't deal with ordered setting or prepare_flush
callback.  sd.c updated to deal with blk_queue_ordered
setting.  Currently, ordered tag isn't used as SCSI midlayer
cannot guarantee request ordering.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJens Axboe <axboe@suse.de>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!