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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 vectors as @set has queues. It will then query 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.
- */
- void 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;
- fallback:
- blk_mq_map_queues(qmap);
- }
- EXPORT_SYMBOL_GPL(blk_mq_virtio_map_queues);
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