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.h> 8 #include <linux/blk-mq-pci.h> 9 #include <linux/pci.h> 10 #include <linux/module.h> 11 12 #include "blk-mq.h" 13 14 /** 15 * blk_mq_pci_map_queues - provide a default queue mapping for PCI device 16 * @set: tagset to provide the mapping for 17 * @pdev: PCI device associated with @set. 18 * @offset: Offset to use for the pci irq vector 19 * 20 * This function assumes the PCI device @pdev has at least as many available 21 * interrupt vectors as @set has queues. It will then query the vector 22 * corresponding to each queue for it's affinity mask and built queue mapping 23 * that maps a queue to the CPUs that have irq affinity for the corresponding 24 * vector. 25 */ 26 int blk_mq_pci_map_queues(struct blk_mq_queue_map *qmap, struct pci_dev *pdev, 27 int offset) 28 { 29 const struct cpumask *mask; 30 unsigned int queue, cpu; 31 32 for (queue = 0; queue < qmap->nr_queues; queue++) { 33 mask = pci_irq_get_affinity(pdev, queue + offset); 34 if (!mask) 35 goto fallback; 36 37 for_each_cpu(cpu, mask) 38 qmap->mq_map[cpu] = qmap->queue_offset + queue; 39 } 40 41 return 0; 42 43 fallback: 44 WARN_ON_ONCE(qmap->nr_queues > 1); 45 blk_mq_clear_mq_map(qmap); 46 return 0; 47 } 48 EXPORT_SYMBOL_GPL(blk_mq_pci_map_queues); 49