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1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (c) 2016 Christoph Hellwig.4 */5#include <linux/device.h>6#include <linux/blk-mq-virtio.h>7#include <linux/virtio_config.h>8#include <linux/module.h>9#include "blk-mq.h"10 11/**12 * blk_mq_virtio_map_queues - provide a default queue mapping for virtio device13 * @qmap: CPU to hardware queue map.14 * @vdev: virtio device to provide a mapping for.15 * @first_vec: first interrupt vectors to use for queues (usually 0)16 *17 * This function assumes the virtio device @vdev has at least as many available18 * interrupt vectors as @set has queues. It will then query the vector19 * corresponding to each queue for it's affinity mask and built queue mapping20 * that maps a queue to the CPUs that have irq affinity for the corresponding21 * vector.22 */23void blk_mq_virtio_map_queues(struct blk_mq_queue_map *qmap,24 struct virtio_device *vdev, int first_vec)25{26 const struct cpumask *mask;27 unsigned int queue, cpu;28 29 if (!vdev->config->get_vq_affinity)30 goto fallback;31 32 for (queue = 0; queue < qmap->nr_queues; queue++) {33 mask = vdev->config->get_vq_affinity(vdev, first_vec + queue);34 if (!mask)35 goto fallback;36 37 for_each_cpu(cpu, mask)38 qmap->mq_map[cpu] = qmap->queue_offset + queue;39 }40 41 return;42 43fallback:44 blk_mq_map_queues(qmap);45}46EXPORT_SYMBOL_GPL(blk_mq_virtio_map_queues);47