Re: [PATCH 13/13] blk-mq: get rid of the cpumask in struct blk_mq_tags

+static int blk_mq_create_mq_map(struct blk_mq_tag_set *set,
+		const struct cpumask *affinity_mask)
 {
+	int queue = -1, cpu = 0;
+
+	set->mq_map = kzalloc_node(sizeof(*set->mq_map) * nr_cpu_ids,
+			GFP_KERNEL, set->numa_node);
+	if (!set->mq_map)
+		return -ENOMEM;
+
+	if (!affinity_mask)
+		return 0;	/* map all cpus to queue 0 */
+
+	/* If cpus are offline, map them to first hctx */
+	for_each_online_cpu(cpu) {
+		if (cpumask_test_cpu(cpu, affinity_mask))
+			queue++;
+		if (queue >= 0)
+			set->mq_map[cpu] = queue;
+	}
+
+	return 0;
 }