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 #include <linux/device/bus.h> 15 16 #include "blk.h" 17 #include "blk-mq.h" 18 19 void blk_mq_map_queues(struct blk_mq_queue_map *qmap) 20 { 21 const struct cpumask *masks; 22 unsigned int queue, cpu; 23 24 masks = group_cpus_evenly(qmap->nr_queues); 25 if (!masks) { 26 for_each_possible_cpu(cpu) 27 qmap->mq_map[cpu] = qmap->queue_offset; 28 return; 29 } 30 31 for (queue = 0; queue < qmap->nr_queues; queue++) { 32 for_each_cpu(cpu, &masks[queue]) 33 qmap->mq_map[cpu] = qmap->queue_offset + queue; 34 } 35 kfree(masks); 36 } 37 EXPORT_SYMBOL_GPL(blk_mq_map_queues); 38 39 /** 40 * blk_mq_hw_queue_to_node - Look up the memory node for a hardware queue index 41 * @qmap: CPU to hardware queue map. 42 * @index: hardware queue index. 43 * 44 * We have no quick way of doing reverse lookups. This is only used at 45 * queue init time, so runtime isn't important. 46 */ 47 int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int index) 48 { 49 int i; 50 51 for_each_possible_cpu(i) { 52 if (index == qmap->mq_map[i]) 53 return cpu_to_node(i); 54 } 55 56 return NUMA_NO_NODE; 57 } 58 59 /** 60 * blk_mq_map_hw_queues - Create CPU to hardware queue mapping 61 * @qmap: CPU to hardware queue map 62 * @dev: The device to map queues 63 * @offset: Queue offset to use for the device 64 * 65 * Create a CPU to hardware queue mapping in @qmap. The struct bus_type 66 * irq_get_affinity callback will be used to retrieve the affinity. 67 */ 68 void blk_mq_map_hw_queues(struct blk_mq_queue_map *qmap, 69 struct device *dev, unsigned int offset) 70 71 { 72 const struct cpumask *mask; 73 unsigned int queue, cpu; 74 75 if (!dev->bus->irq_get_affinity) 76 goto fallback; 77 78 for (queue = 0; queue < qmap->nr_queues; queue++) { 79 mask = dev->bus->irq_get_affinity(dev, queue + offset); 80 if (!mask) 81 goto fallback; 82 83 for_each_cpu(cpu, mask) 84 qmap->mq_map[cpu] = qmap->queue_offset + queue; 85 } 86 87 return; 88 89 fallback: 90 WARN_ON_ONCE(qmap->nr_queues > 1); 91 blk_mq_clear_mq_map(qmap); 92 } 93 EXPORT_SYMBOL_GPL(blk_mq_map_hw_queues); 94