c005390374
While pci_irq_get_affinity should never fail for SMP kernel that implement the affinity mapping, it will always return NULL in the UP case, so provide a fallback mapping of all queues to CPU 0 in that case. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: stable@vger.kernel.org Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
53 lines
1.6 KiB
C
53 lines
1.6 KiB
C
/*
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* Copyright (c) 2016 Christoph Hellwig.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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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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/**
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* blk_mq_pci_map_queues - provide a default queue mapping for PCI device
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* @set: tagset to provide the mapping for
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* @pdev: PCI device associated with @set.
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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_tag_set *set, struct pci_dev *pdev)
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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 < set->nr_hw_queues; queue++) {
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mask = pci_irq_get_affinity(pdev, queue);
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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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set->mq_map[cpu] = queue;
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}
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return 0;
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fallback:
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WARN_ON_ONCE(set->nr_hw_queues > 1);
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for_each_possible_cpu(cpu)
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set->mq_map[cpu] = 0;
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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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