blk-mq-rdma.c 1.3 KB

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