[linux.git] / block / blk-mq-pci.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/kobject.h>
#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/blk-mq-pci.h>
#include <linux/pci.h>
#include <linux/module.h>

/**
 * blk_mq_pci_map_queues - provide a default queue mapping for PCI device
 * @set:	tagset to provide the mapping for
 * @pdev:	PCI device associated with @set.
 *
 * This function assumes the PCI device @pdev 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.
 */
int blk_mq_pci_map_queues(struct blk_mq_tag_set *set, struct pci_dev *pdev)
{
	const struct cpumask *mask;
	unsigned int queue, cpu;

	for (queue = 0; queue < set->nr_hw_queues; queue++) {
		mask = pci_irq_get_affinity(pdev, queue);
		if (!mask)
			goto fallback;

		for_each_cpu(cpu, mask)
			set->mq_map[cpu] = queue;
	}

	return 0;

fallback:
	WARN_ON_ONCE(set->nr_hw_queues > 1);
	for_each_possible_cpu(cpu)
		set->mq_map[cpu] = 0;
	return 0;
}
EXPORT_SYMBOL_GPL(blk_mq_pci_map_queues);
Commit	Line	Data
973c4e37 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	*/
8ec2ef2b SR	13	#include <linux/kobject.h>
8ec2ef2b SR	14	#include <linux/blkdev.h>
973c4e37 CH	15	#include <linux/blk-mq.h>
	16	#include <linux/blk-mq-pci.h>
	17	#include <linux/pci.h>
	18	#include <linux/module.h>
	19
	20	/**
	21	* blk_mq_pci_map_queues - provide a default queue mapping for PCI device
	22	* @set: tagset to provide the mapping for
	23	* @pdev: PCI device associated with @set.
	24	*
	25	* This function assumes the PCI device @pdev has at least as many available
018c259b	26	* interrupt vectors as @set has queues. It will then query the vector
973c4e37 CH	27	* corresponding to each queue for it's affinity mask and built queue mapping
	28	* that maps a queue to the CPUs that have irq affinity for the corresponding
	29	* vector.
	30	*/
	31	int blk_mq_pci_map_queues(struct blk_mq_tag_set set, struct pci_dev pdev)
	32	{
	33	const struct cpumask *mask;
	34	unsigned int queue, cpu;
	35
	36	for (queue = 0; queue < set->nr_hw_queues; queue++) {
	37	mask = pci_irq_get_affinity(pdev, queue);
	38	if (!mask)
c0053903	39	goto fallback;
973c4e37 CH	40
	41	for_each_cpu(cpu, mask)
	42	set->mq_map[cpu] = queue;
	43	}
	44
	45	return 0;
c0053903 CH	46
	47	fallback:
	48	WARN_ON_ONCE(set->nr_hw_queues > 1);
	49	for_each_possible_cpu(cpu)
	50	set->mq_map[cpu] = 0;
	51	return 0;
973c4e37 CH	52	}
973c4e37 CH	53	EXPORT_SYMBOL_GPL(blk_mq_pci_map_queues);