LXR linux/block/blk-mq-virtio.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   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 device
  13 * @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 available
  18 * interrupt vectors as @set has queues.  It will then query the vector
  19 * 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 */
  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