blkcg: pass @q and @blkcg into blkcg_pol_alloc_pd_fn()

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: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 0fff7b5..46fa644 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -934,11 +934,13 @@ static size_t iolatency_pd_stat(struct blkg_policy_data *pd, char *buf,
 }
 
 
-static struct blkg_policy_data *iolatency_pd_alloc(gfp_t gfp, int node)
+static struct blkg_policy_data *iolatency_pd_alloc(gfp_t gfp,
+						   struct request_queue *q,
+						   struct blkcg *blkcg)
 {
 	struct iolatency_grp *iolat;
 
-	iolat = kzalloc_node(sizeof(*iolat), gfp, node);
+	iolat = kzalloc_node(sizeof(*iolat), gfp, q->node);
 	if (!iolat)
 		return NULL;
 	iolat->stats = __alloc_percpu_gfp(sizeof(struct latency_stat),