commit cf09a8ee19ad1f78b4e18cdde9f2a61133efacf5 upstream.

Instead of @node, pass in @q and @blkcg so that the alloc function has
more context.  This doesn't cause any behavior change and will be used
by io.weight implementation.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
[Joseph: resolve conflicts for cfq]
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: NJiufei Xue <jiufei.xue@linux.alibaba.com>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>