1// SPDX-License-Identifier: GPL-2.0
2/*
3 * CPU <-> hardware queue mapping helpers
4 *
5 * Copyright (C) 2013-2014 Jens Axboe
6 */
7#include <linux/kernel.h>
8#include <linux/threads.h>
9#include <linux/module.h>
10#include <linux/mm.h>
11#include <linux/smp.h>
12#include <linux/cpu.h>
13#include <linux/group_cpus.h>
14
15#include "blk.h"
16#include "blk-mq.h"
17
18void blk_mq_map_queues(struct blk_mq_queue_map *qmap)
19{
20	const struct cpumask *masks;
21	unsigned int queue, cpu;
22
23	masks = group_cpus_evenly(qmap->nr_queues);
24	if (!masks) {
25		for_each_possible_cpu(cpu)
26			qmap->mq_map[cpu] = qmap->queue_offset;
27		return;
28	}
29
30	for (queue = 0; queue < qmap->nr_queues; queue++) {
31		for_each_cpu(cpu, &masks[queue])
32			qmap->mq_map[cpu] = qmap->queue_offset + queue;
33	}
34	kfree(masks);
35}
36EXPORT_SYMBOL_GPL(blk_mq_map_queues);
37
38/**
39 * blk_mq_hw_queue_to_node - Look up the memory node for a hardware queue index
40 * @qmap: CPU to hardware queue map.
41 * @index: hardware queue index.
42 *
43 * We have no quick way of doing reverse lookups. This is only used at
44 * queue init time, so runtime isn't important.
45 */
46int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int index)
47{
48	int i;
49
50	for_each_possible_cpu(i) {
51		if (index == qmap->mq_map[i])
52			return cpu_to_node(i);
53	}
54
55	return NUMA_NO_NODE;
56}
57