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Christoph Hellwig8c165672019-04-30 14:42:39 -04001// SPDX-License-Identifier: GPL-2.0
Christoph Hellwig73473422017-02-05 18:15:24 +01002/*
3 * Copyright (c) 2016 Christoph Hellwig.
Christoph Hellwig73473422017-02-05 18:15:24 +01004 */
5#include <linux/device.h>
Christoph Hellwig73473422017-02-05 18:15:24 +01006#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 device
Bart Van Assche0542cd52019-05-30 17:00:49 -070013 * @qmap: CPU to hardware queue map.
14 * @vdev: virtio device to provide a mapping for.
Christoph Hellwig73473422017-02-05 18:15:24 +010015 * @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 available
Gabriela Bittencourt7901b6e2019-10-29 19:35:56 -030018 * interrupt vectors as @set has queues. It will then query the vector
Christoph Hellwig73473422017-02-05 18:15:24 +010019 * corresponding to each queue for it's affinity mask and built queue mapping
20 * that maps a queue to the CPUs that have irq affinity for the corresponding
21 * vector.
22 */
Bart Van Asschea4e1d0b2022-08-15 10:00:43 -070023void blk_mq_virtio_map_queues(struct blk_mq_queue_map *qmap,
Christoph Hellwig73473422017-02-05 18:15:24 +010024 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
Jens Axboeed76e322018-10-29 13:06:14 -060032 for (queue = 0; queue < qmap->nr_queues; queue++) {
Christoph Hellwig73473422017-02-05 18:15:24 +010033 mask = vdev->config->get_vq_affinity(vdev, first_vec + queue);
34 if (!mask)
35 goto fallback;
36
37 for_each_cpu(cpu, mask)
Jens Axboe843477d2018-10-24 13:16:11 -060038 qmap->mq_map[cpu] = qmap->queue_offset + queue;
Christoph Hellwig73473422017-02-05 18:15:24 +010039 }
40
Bart Van Asschea4e1d0b2022-08-15 10:00:43 -070041 return;
42
Christoph Hellwig73473422017-02-05 18:15:24 +010043fallback:
Bart Van Asschea4e1d0b2022-08-15 10:00:43 -070044 blk_mq_map_queues(qmap);
Christoph Hellwig73473422017-02-05 18:15:24 +010045}
46EXPORT_SYMBOL_GPL(blk_mq_virtio_map_queues);