linux/block/blk-mq-virtio.c
Christoph Hellwig 8c16567d86 block: switch all files cleared marked as GPLv2 to SPDX tags
All these files have some form of the usual GPLv2 boilerplate.  Switch
them to use SPDX tags instead.

Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-30 16:11:57 -06:00

47 lines
1.3 KiB
C

// 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
* @set: tagset to provide the mapping for
* @vdev: virtio device associated with @set.
* @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);