LXR linux/block/blk-mq-rdma.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (c) 2017 Sagi Grimberg.
   4 */
   5#include <linux/blk-mq.h>
   6#include <linux/blk-mq-rdma.h>
   7#include <rdma/ib_verbs.h>
   8
   9/**
  10 * blk_mq_rdma_map_queues - provide a default queue mapping for rdma device
  11 * @map:        CPU to hardware queue map.
  12 * @dev:        rdma device to provide a mapping for.
  13 * @first_vec:  first interrupt vectors to use for queues (usually 0)
  14 *
  15 * This function assumes the rdma device @dev has at least as many available
  16 * interrupt vetors as @set has queues.  It will then query it's affinity mask
  17 * and built queue mapping that maps a queue to the CPUs that have irq affinity
  18 * for the corresponding vector.
  19 *
  20 * In case either the driver passed a @dev with less vectors than
  21 * @set->nr_hw_queues, or @dev does not provide an affinity mask for a
  22 * vector, we fallback to the naive mapping.
  23 */
  24int blk_mq_rdma_map_queues(struct blk_mq_queue_map *map,
  25                struct ib_device *dev, int first_vec)
  26{
  27        const struct cpumask *mask;
  28        unsigned int queue, cpu;
  29
  30        for (queue = 0; queue < map->nr_queues; queue++) {
  31                mask = ib_get_vector_affinity(dev, first_vec + queue);
  32                if (!mask)
  33                        goto fallback;
  34
  35                for_each_cpu(cpu, mask)
  36                        map->mq_map[cpu] = map->queue_offset + queue;
  37        }
  38
  39        return 0;
  40
  41fallback:
  42        return blk_mq_map_queues(map);
  43}
  44EXPORT_SYMBOL_GPL(blk_mq_rdma_map_queues);
  45