Commit db64f680 authored Jun 30, 2009 by NeilBrown Committed by Jens Axboe Jul 01, 2009

blocK: Restore barrier support for md and probably other virtual devices.



The next_ordered flag is only meaningful for devices that use __make_request.
So move the test against next_ordered out of generic code and in to
__make_request

Since this test was added, barriers have not worked on md or any
devices that don't use __make_request and so don't bother to set
next_ordered.  (dm explicitly sets something other than
QUEUE_ORDERED_NONE since
  commit 99360b4c
but notes in the comments that it is otherwise meaningless).

Cc: Ken Milmore <ken.milmore@googlemail.com>
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

parent 018e0446

block/blk-core.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -1170,6 +1170,11 @@ static int __make_request(struct request_queue q, struct bio bio)
		const int unplug = bio_unplug(bio);
		int rw_flags;

		if (bio_barrier(bio) && bio_has_data(bio) &&
		(q->next_ordered == QUEUE_ORDERED_NONE)) {
		bio_endio(bio, -EOPNOTSUPP);
		return 0;
		}
		/*
		* low level driver can indicate that it wants pages above a
		* certain limit bounced to low memory (ie for highmem, or even
		@@ -1470,11 +1475,6 @@ static inline void __generic_make_request(struct bio *bio)
		err = -EOPNOTSUPP;
		goto end_io;
		}
		if (bio_barrier(bio) && bio_has_data(bio) &&
		(q->next_ordered == QUEUE_ORDERED_NONE)) {
		err = -EOPNOTSUPP;
		goto end_io;
		}

		ret = q->make_request_fn(q, bio);
		} while (ret);