[linux.git] / block / blk-mq-virtio.c

/*
 * 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 <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
 * @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);
Commit	Line	Data
73473427 CH	1	/*
	2	* Copyright (c) 2016 Christoph Hellwig.
	3	*
	4	* This program is free software; you can redistribute it and/or modify it
	5	* under the terms and conditions of the GNU General Public License,
	6	* version 2, as published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope it will be useful, but WITHOUT
	9	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	10	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	11	* more details.
	12	*/
	13	#include <linux/device.h>
	14	#include <linux/blk-mq.h>
	15	#include <linux/blk-mq-virtio.h>
	16	#include <linux/virtio_config.h>
	17	#include <linux/module.h>
	18	#include "blk-mq.h"
	19
	20	/**
	21	* blk_mq_virtio_map_queues - provide a default queue mapping for virtio device
	22	* @set: tagset to provide the mapping for
	23	* @vdev: virtio device associated with @set.
	24	* @first_vec: first interrupt vectors to use for queues (usually 0)
	25	*
	26	* This function assumes the virtio device @vdev has at least as many available
	27	* interrupt vetors as @set has queues. It will then queuery the vector
	28	* corresponding to each queue for it's affinity mask and built queue mapping
	29	* that maps a queue to the CPUs that have irq affinity for the corresponding
	30	* vector.
	31	*/
	32	int blk_mq_virtio_map_queues(struct blk_mq_tag_set *set,
	33	struct virtio_device *vdev, int first_vec)
	34	{
	35	const struct cpumask *mask;
	36	unsigned int queue, cpu;
	37
	38	if (!vdev->config->get_vq_affinity)
	39	goto fallback;
	40
	41	for (queue = 0; queue < set->nr_hw_queues; queue++) {
	42	mask = vdev->config->get_vq_affinity(vdev, first_vec + queue);
	43	if (!mask)
	44	goto fallback;
	45
	46	for_each_cpu(cpu, mask)
	47	set->mq_map[cpu] = queue;
	48	}
	49
	50	return 0;
	51	fallback:
	52	return blk_mq_map_queues(set);
	53	}
	54	EXPORT_SYMBOL_GPL(blk_mq_virtio_map_queues);