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973c4e37 CH |
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 | */ | |
8ec2ef2b SR |
13 | #include <linux/kobject.h> |
14 | #include <linux/blkdev.h> | |
973c4e37 CH |
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. | |
f23f5bec | 24 | * @offset: Offset to use for the pci irq vector |
973c4e37 CH |
25 | * |
26 | * This function assumes the PCI device @pdev has at least as many available | |
018c259b | 27 | * interrupt vectors as @set has queues. It will then query the vector |
973c4e37 CH |
28 | * corresponding to each queue for it's affinity mask and built queue mapping |
29 | * that maps a queue to the CPUs that have irq affinity for the corresponding | |
30 | * vector. | |
31 | */ | |
f23f5bec KB |
32 | int blk_mq_pci_map_queues(struct blk_mq_tag_set *set, struct pci_dev *pdev, |
33 | int offset) | |
973c4e37 CH |
34 | { |
35 | const struct cpumask *mask; | |
36 | unsigned int queue, cpu; | |
37 | ||
38 | for (queue = 0; queue < set->nr_hw_queues; queue++) { | |
f23f5bec | 39 | mask = pci_irq_get_affinity(pdev, queue + offset); |
973c4e37 | 40 | if (!mask) |
c0053903 | 41 | goto fallback; |
973c4e37 CH |
42 | |
43 | for_each_cpu(cpu, mask) | |
44 | set->mq_map[cpu] = queue; | |
45 | } | |
46 | ||
47 | return 0; | |
c0053903 CH |
48 | |
49 | fallback: | |
50 | WARN_ON_ONCE(set->nr_hw_queues > 1); | |
51 | for_each_possible_cpu(cpu) | |
52 | set->mq_map[cpu] = 0; | |
53 | return 0; | |
973c4e37 CH |
54 | } |
55 | EXPORT_SYMBOL_GPL(blk_mq_pci_map_queues); |