The 'unplug on queued exceeding unplug threshold' logic only works for file
system requests currently, since it's in __make_request().  Move it where
it belongs, in elv_add_request().  This way it works for queued block sg
requests as well.
Signed-Off-By: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>