aboutsummaryrefslogtreecommitdiff
path: root/block/blk-mq-rdma.c
blob: 14f968e58b8f7103bc81db1f42996d6853f70317 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2017 Sagi Grimberg.
 */
#include <linux/blk-mq.h>
#include <linux/blk-mq-rdma.h>
#include <rdma/ib_verbs.h>

/**
 * blk_mq_rdma_map_queues - provide a default queue mapping for rdma device
 * @map:	CPU to hardware queue map.
 * @dev:	rdma device to provide a mapping for.
 * @first_vec:	first interrupt vectors to use for queues (usually 0)
 *
 * This function assumes the rdma device @dev has at least as many available
 * interrupt vetors as @set has queues.  It will then query it's affinity mask
 * and built queue mapping that maps a queue to the CPUs that have irq affinity
 * for the corresponding vector.
 *
 * In case either the driver passed a @dev with less vectors than
 * @set->nr_hw_queues, or @dev does not provide an affinity mask for a
 * vector, we fallback to the naive mapping.
 */
int blk_mq_rdma_map_queues(struct blk_mq_queue_map *map,
		struct ib_device *dev, int first_vec)
{
	const struct cpumask *mask;
	unsigned int queue, cpu;

	for (queue = 0; queue < map->nr_queues; queue++) {
		mask = ib_get_vector_affinity(dev, first_vec + queue);
		if (!mask)
			goto fallback;

		for_each_cpu(cpu, mask)
			map->mq_map[cpu] = map->queue_offset + queue;
	}

	return 0;

fallback:
	return blk_mq_map_queues(map);
}
EXPORT_SYMBOL_GPL(blk_mq_rdma_map_queues);