blk-mq: provide a default queue mapping for PCI device

obj-$(CONFIG_BLOCK_COMPAT)	+= compat_ioctl.o

obj-$(CONFIG_BLK_CMDLINE_PARSER)	+= cmdline-parser.o

obj-$(CONFIG_BLK_DEV_INTEGRITY) += bio-integrity.o blk-integrity.o t10-pi.o

obj-$(CONFIG_PCI)		+= blk-mq-pci.o

/*

 * 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/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 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_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)

			return -EINVAL;

		for_each_cpu(cpu, mask)

			set->mq_map[cpu] = queue;

	}

	return 0;

}

EXPORT_SYMBOL_GPL(blk_mq_pci_map_queues);

#ifndef _LINUX_BLK_MQ_PCI_H

#define _LINUX_BLK_MQ_PCI_H

struct blk_mq_tag_set;

struct pci_dev;

int blk_mq_pci_map_queues(struct blk_mq_tag_set *set, struct pci_dev *pdev);

#endif /* _LINUX_BLK_MQ_PCI_H */