// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2016 Christoph Hellwig.
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*/
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#include <linux/kobject.h>
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#include <linux/blkdev.h>
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#include <linux/blk-mq.h>
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#include <linux/blk-mq-pci.h>
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#include <linux/pci.h>
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#include <linux/module.h>
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#include "blk-mq.h"
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/**
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* blk_mq_pci_map_queues - provide a default queue mapping for PCI device
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* @qmap: CPU to hardware queue map.
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* @pdev: PCI device associated with @set.
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* @offset: Offset to use for the pci irq vector
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*
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* This function assumes the PCI device @pdev has at least as many available
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* interrupt vectors as @set has queues. It will then query the vector
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* corresponding to each queue for it's affinity mask and built queue mapping
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* that maps a queue to the CPUs that have irq affinity for the corresponding
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* vector.
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*/
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int blk_mq_pci_map_queues(struct blk_mq_queue_map *qmap, struct pci_dev *pdev,
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int offset)
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{
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const struct cpumask *mask;
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unsigned int queue, cpu;
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for (queue = 0; queue < qmap->nr_queues; queue++) {
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mask = pci_irq_get_affinity(pdev, queue + offset);
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if (!mask)
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goto fallback;
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for_each_cpu(cpu, mask)
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qmap->mq_map[cpu] = qmap->queue_offset + queue;
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}
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return 0;
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fallback:
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WARN_ON_ONCE(qmap->nr_queues > 1);
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blk_mq_clear_mq_map(qmap);
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return 0;
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}
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EXPORT_SYMBOL_GPL(blk_mq_pci_map_queues);
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