1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2016 Christoph Hellwig. 4 */ 5 #include <linux/kobject.h> 6 #include <linux/blkdev.h> 7 #include <linux/blk-mq-pci.h> 8 #include <linux/pci.h> 9 #include <linux/module.h> 10 11 #include "blk-mq.h" 12 13 /** 14 * blk_mq_pci_map_queues - provide a default queue mapping for PCI device 15 * @qmap: CPU to hardware queue map. 16 * @pdev: PCI device associated with @set. 17 * @offset: Offset to use for the pci irq vector 18 * 19 * This function assumes the PCI device @pdev has at least as many available 20 * interrupt vectors as @set has queues. It will then query the vector 21 * corresponding to each queue for it's affinity mask and built queue mapping 22 * that maps a queue to the CPUs that have irq affinity for the corresponding 23 * vector. 24 */ 25 void blk_mq_pci_map_queues(struct blk_mq_queue_map *qmap, struct pci_dev *pdev, 26 int offset) 27 { 28 const struct cpumask *mask; 29 unsigned int queue, cpu; 30 31 for (queue = 0; queue < qmap->nr_queues; queue++) { 32 mask = pci_irq_get_affinity(pdev, queue + offset); 33 if (!mask) 34 goto fallback; 35 36 for_each_cpu(cpu, mask) 37 qmap->mq_map[cpu] = qmap->queue_offset + queue; 38 } 39 40 return; 41 42 fallback: 43 WARN_ON_ONCE(qmap->nr_queues > 1); 44 blk_mq_clear_mq_map(qmap); 45 } 46 EXPORT_SYMBOL_GPL(blk_mq_pci_map_queues); 47