Cregit: Linux 5.9: blk-mq-pci.c

Contributors: 6
Author	Tokens	Token Proportion	Commits	Commit Proportion
Christoph Hellwig	107	78.68%	3	33.33%
Jens Axboe	12	8.82%	2	22.22%
Stephen Rothwell	6	4.41%	1	11.11%
Keith Busch	5	3.68%	1	11.11%
Minwoo Im	5	3.68%	1	11.11%
Bart Van Assche	1	0.74%	1	11.11%
Total	136		9

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2016 Christoph Hellwig.
 */
#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>

#include "blk-mq.h"

/**
 * blk_mq_pci_map_queues - provide a default queue mapping for PCI device
 * @qmap:	CPU to hardware queue map.
 * @pdev:	PCI device associated with @set.
 * @offset:	Offset to use for the pci irq vector
 *
 * 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_queue_map *qmap, struct pci_dev *pdev,
			    int offset)
{
	const struct cpumask *mask;
	unsigned int queue, cpu;

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

		for_each_cpu(cpu, mask)
			qmap->mq_map[cpu] = qmap->queue_offset + queue;
	}

	return 0;

fallback:
	WARN_ON_ONCE(qmap->nr_queues > 1);
	blk_mq_clear_mq_map(qmap);
	return 0;
}
EXPORT_SYMBOL_GPL(blk_mq_pci_map_queues);