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 99360b4c18
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>
This commit is contained in:
NeilBrown 2009-06-30 09:35:44 +02:00 committed by Jens Axboe
parent 018e044689
commit db64f680ba

View File

@ -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);