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 */ 23 void 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 43 fallback: 44 blk_mq_map_queues(qmap); 45 } 46 EXPORT_SYMBOL_GPL(blk_mq_virtio_map_queues); 47