Commit 0a50ed05 authored by Daniel Wagner's avatar Daniel Wagner Committed by Jens Axboe
Browse files

virtio: blk/scsi: use block layer helpers to calculate num of queues 



The calculation of the upper limit for queues does not depend solely on
the number of possible CPUs; for example, the isolcpus kernel
command-line option must also be considered.

To account for this, the block layer provides a helper function to
retrieve the maximum number of queues. Use it to set an appropriate
upper queue number limit.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarDaniel Wagner <wagi@kernel.org>
Reviewed-by: default avatarChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20250617-isolcpus-queue-counters-v1-5-13923686b54b@kernel.org


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 94970cfb

drivers/block/virtio_blk.c

+2 −3
Original line number Diff line number Diff line
@@ -976,9 +976,8 @@ static int init_vq(struct virtio_blk *vblk) 
		return -EINVAL;

	}



	num_vqs = min_t(unsigned int,

			min_not_zero(num_request_queues, nr_cpu_ids),

			num_vqs);

	num_vqs = blk_mq_num_possible_queues(

			min_not_zero(num_request_queues, num_vqs));



	num_poll_vqs = min_t(unsigned int, poll_queues, num_vqs - 1);

drivers/scsi/virtio_scsi.c

+1 −0
Original line number Diff line number Diff line
@@ -919,6 +919,7 @@ static int virtscsi_probe(struct virtio_device *vdev) 
	/* We need to know how many queues before we allocate. */

	num_queues = virtscsi_config_get(vdev, num_queues) ? : 1;

	num_queues = min_t(unsigned int, nr_cpu_ids, num_queues);

	num_queues = blk_mq_num_possible_queues(num_queues);



	num_targets = virtscsi_config_get(vdev, max_target) + 1;