linux/block/blk-mq-pci.c
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   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/kobject.h>
  14#include <linux/blkdev.h>
  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
  26 * interrupt vetors as @set has queues.  It will then queuery the vector
  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 */
  31int 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)
  39                        return -EINVAL;
  40
  41                for_each_cpu(cpu, mask)
  42                        set->mq_map[cpu] = queue;
  43        }
  44
  45        return 0;
  46}
  47EXPORT_SYMBOL_GPL(blk_mq_pci_map_queues);
  48