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  
blk_mq_map_queues(struct blk_mq_queue_map * qmap)18  void 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  }
36  EXPORT_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   */
blk_mq_hw_queue_to_node(struct blk_mq_queue_map * qmap,unsigned int index)46  int 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