Line data    Source code

       1             : // SPDX-License-Identifier: GPL-2.0
       2             : /*
       3             :  * Copyright (c) 2016 Christoph Hellwig.
       4             :  */
       5             : #include <linux/device.h>
       6             : #include <linux/blk-mq.h>
       7             : #include <linux/blk-mq-virtio.h>
       8             : #include <linux/virtio_config.h>
       9             : #include <linux/module.h>
      10             : #include "blk-mq.h"
      11             : 
      12             : /**
      13             :  * blk_mq_virtio_map_queues - provide a default queue mapping for virtio device
      14             :  * @qmap:       CPU to hardware queue map.
      15             :  * @vdev:       virtio device to provide a mapping for.
      16             :  * @first_vec:  first interrupt vectors to use for queues (usually 0)
      17             :  *
      18             :  * This function assumes the virtio device @vdev has at least as many available
      19             :  * interrupt vectors as @set has queues.  It will then query the vector
      20             :  * corresponding to each queue for it's affinity mask and built queue mapping
      21             :  * that maps a queue to the CPUs that have irq affinity for the corresponding
      22             :  * vector.
      23             :  */
      24           1 : int blk_mq_virtio_map_queues(struct blk_mq_queue_map *qmap,
      25             :                 struct virtio_device *vdev, int first_vec)
      26             : {
      27           1 :         const struct cpumask *mask;
      28           1 :         unsigned int queue, cpu;
      29             : 
      30           1 :         if (!vdev->config->get_vq_affinity)
      31           1 :                 goto fallback;
      32             : 
      33           0 :         for (queue = 0; queue < qmap->nr_queues; queue++) {
      34           0 :                 mask = vdev->config->get_vq_affinity(vdev, first_vec + queue);
      35           0 :                 if (!mask)
      36           0 :                         goto fallback;
      37             : 
      38           0 :                 for_each_cpu(cpu, mask)
      39           0 :                         qmap->mq_map[cpu] = qmap->queue_offset + queue;
      40             :         }
      41             : 
      42             :         return 0;
      43           1 : fallback:
      44           1 :         return blk_mq_map_queues(qmap);
      45             : }
      46             : EXPORT_SYMBOL_GPL(blk_mq_virtio_map_queues);