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