Allow elevators to sort/merge discard requests
But blkdev_issue_discard() still emits requests which are interpreted as
soft barriers, because naïve callers might otherwise issue subsequent
writes to those same sectors, which might cross on the queue (if they're
reallocated quickly enough).
Callers still _can_ issue non-barrier discard requests, but they have to
take care of queue ordering for themselves.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/ioctl.c b/block/ioctl.c
index 342298b..375c579 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -161,7 +161,7 @@
bio->bi_size = len << 9;
len = 0;
}
- submit_bio(WRITE_DISCARD, bio);
+ submit_bio(DISCARD_NOBARRIER, bio);
wait_for_completion(&wait);