From 73473427bb551686e4b68ecd99bfd27e6635286a Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sun, 5 Feb 2017 18:15:24 +0100 Subject: blk-mq: provide a default queue mapping for virtio device Similar to the PCI version, just calling into virtio instead. Signed-off-by: Christoph Hellwig Signed-off-by: Michael S. Tsirkin --- block/blk-mq-virtio.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 block/blk-mq-virtio.c (limited to 'block/blk-mq-virtio.c') diff --git a/block/blk-mq-virtio.c b/block/blk-mq-virtio.c new file mode 100644 index 000000000000..c3afbca11299 --- /dev/null +++ b/block/blk-mq-virtio.c @@ -0,0 +1,54 @@ +/* + * Copyright (c) 2016 Christoph Hellwig. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ +#include +#include +#include +#include +#include +#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_tag_set *set, + 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 < set->nr_hw_queues; queue++) { + mask = vdev->config->get_vq_affinity(vdev, first_vec + queue); + if (!mask) + goto fallback; + + for_each_cpu(cpu, mask) + set->mq_map[cpu] = queue; + } + + return 0; +fallback: + return blk_mq_map_queues(set); +} +EXPORT_SYMBOL_GPL(blk_mq_virtio_map_queues); -- cgit