md: unplug writes to external bitmaps.
When writing to an 'external' bitmap we don't currently unplug the
device before waiting, so we can get a 3msec delay each time;
So use REQ_UNPLUG to force and unplug.
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index fdde027..5a1ffe3 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -343,7 +343,7 @@
atomic_inc(&bitmap->pending_writes);
set_buffer_locked(bh);
set_buffer_mapped(bh);
- submit_bh(WRITE, bh);
+ submit_bh(WRITE | REQ_UNPLUG | REQ_SYNC, bh);
bh = bh->b_this_page;
}