| // 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); |
| |
| MODULE_DESCRIPTION("Virtio Device Default Queue Mapping"); |
| MODULE_LICENSE("GPL v2"); |