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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2016 Christoph Hellwig.
*/
#include <linux/device.h>
#include <linux/blk-mq.h>
#include <linux/blk-mq-virtio.h>
#include <linux/virtio_config.h>
#include <linux/module.h>
#include "blk-mq.h"
/**
* blk_mq_virtio_map_queues - provide a default queue mapping for virtio device
* @qmap: CPU to hardware queue map.
* @vdev: virtio device to provide a mapping for.
* @first_vec: first interrupt vectors to use for queues (usually 0)
*
* This function assumes the virtio device @vdev has at least as many available
* interrupt vetors as @set has queues. It will then queuery the vector
* corresponding to each queue for it's affinity mask and built queue mapping
* that maps a queue to the CPUs that have irq affinity for the corresponding
* vector.
*/
int blk_mq_virtio_map_queues(struct blk_mq_queue_map *qmap,
struct virtio_device *vdev, int first_vec)
{
const struct cpumask *mask;
unsigned int queue, cpu;
if (!vdev->config->get_vq_affinity)
goto fallback;
for (queue = 0; queue < qmap->nr_queues; queue++) {
mask = vdev->config->get_vq_affinity(vdev, first_vec + queue);
if (!mask)
goto fallback;
for_each_cpu(cpu, mask)
qmap->mq_map[cpu] = qmap->queue_offset + queue;
}
return 0;
fallback:
return blk_mq_map_queues(qmap);
}
EXPORT_SYMBOL_GPL(blk_mq_virtio_map_queues);
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