1 // SPDX-License-Identifier: GPL-2.0
3  * CPU <-> hardware queue mapping helpers
5  * Copyright (C) 2013-2014 Jens Axboe
12 #include <linux/cpu.h>
14 #include <linux/blk-mq.h>
16 #include "blk-mq.h"
21 	return qmap->queue_offset + (q % nr_queues);  in queue_index()
24 static int get_first_sibling(unsigned int cpu)  in get_first_sibling()  argument
28 	ret = cpumask_first(topology_sibling_cpumask(cpu));  in get_first_sibling()
32 	return cpu;  in get_first_sibling()
37 	unsigned int *map = qmap->mq_map;  in blk_mq_map_queues()  local
38 	unsigned int nr_queues = qmap->nr_queues;  in blk_mq_map_queues()
39 	unsigned int cpu, first_sibling, q = 0;  in blk_mq_map_queues()  local
41 	for_each_possible_cpu(cpu)  in blk_mq_map_queues()
42 		map[cpu] = -1;  in blk_mq_map_queues()
46 	 * count of dead queues which are mapped by all un-present CPUs  in blk_mq_map_queues()
48 	for_each_present_cpu(cpu) {  in blk_mq_map_queues()
51 		map[cpu] = queue_index(qmap, nr_queues, q++);  in blk_mq_map_queues()
54 	for_each_possible_cpu(cpu) {  in blk_mq_map_queues()
55 		if (map[cpu] != -1)  in blk_mq_map_queues()
59 		 * In case we still have CPUs to map, and we have some number of  in blk_mq_map_queues()
60 		 * threads per cores then map sibling threads to the same queue  in blk_mq_map_queues()
64 			map[cpu] = queue_index(qmap, nr_queues, q++);  in blk_mq_map_queues()
66 			first_sibling = get_first_sibling(cpu);  in blk_mq_map_queues()
67 			if (first_sibling == cpu)  in blk_mq_map_queues()
68 				map[cpu] = queue_index(qmap, nr_queues, q++);  in blk_mq_map_queues()
70 				map[cpu] = map[first_sibling];  in blk_mq_map_queues()
77  * blk_mq_hw_queue_to_node - Look up the memory node for a hardware queue index
78  * @qmap: CPU to hardware queue map.
89 		if (index == qmap->mq_map[i])  in blk_mq_hw_queue_to_node()