blob: ee9d3d958fbe1a16eab68256e9e1dadff87b07e1
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 | */ |
31 | int 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 | goto fallback; |
40 | |
41 | for_each_cpu(cpu, mask) |
42 | set->mq_map[cpu] = queue; |
43 | } |
44 | |
45 | return 0; |
46 | |
47 | fallback: |
48 | WARN_ON_ONCE(set->nr_hw_queues > 1); |
49 | for_each_possible_cpu(cpu) |
50 | set->mq_map[cpu] = 0; |
51 | return 0; |
52 | } |
53 | EXPORT_SYMBOL_GPL(blk_mq_pci_map_queues); |
54 |