On Tue, Nov 12, 2024 at 02:26:19PM +0100, Daniel Wagner wrote:
> blk_mq_pci_map_queues and blk_mq_virtio_map_queues will create a CPU to
> hardware queue mapping based on affinity information. These two function
> share common code and only differ on how the affinity information is
> retrieved. Also, those functions are located in the block subsystem
> where it doesn't really fit in. They are virtio and pci subsystem
> specific.
>
> Thus introduce provide a generic mapping function which uses the
> irq_get_affinity callback from bus_type.
>
> Originally idea from Ming Lei <ming.lei@xxxxxxxxxx>
>
> Signed-off-by: Daniel Wagner <wagi@xxxxxxxxxx>
> ---
> block/blk-mq-cpumap.c | 37 +++++++++++++++++++++++++++++++++++++
> include/linux/blk-mq.h | 2 ++
> 2 files changed, 39 insertions(+)
>
> diff --git a/block/blk-mq-cpumap.c b/block/blk-mq-cpumap.c
> index 9638b25fd52124f0173e968ebdca5f1fe0b42ad9..db22a7d523a2762b76398fdd768f55efd1d6d669 100644
> --- a/block/blk-mq-cpumap.c
> +++ b/block/blk-mq-cpumap.c
> @@ -11,6 +11,7 @@
> #include <linux/smp.h>
> #include <linux/cpu.h>
> #include <linux/group_cpus.h>
> +#include <linux/device/bus.h>
>
> #include "blk.h"
> #include "blk-mq.h"
> @@ -54,3 +55,39 @@ int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int index)
>
> return NUMA_NO_NODE;
> }
> +
> +/**
> + * blk_mq_hctx_map_queues - Create CPU to hardware queue mapping
> + * @qmap: CPU to hardware queue map.
> + * @dev: The device to map queues.
> + * @offset: Queue offset to use for the device.
> + *
> + * Create a CPU to hardware queue mapping in @qmap. The struct bus_type
> + * irq_get_affinity callback will be used to retrieve the affinity.
> + */
> +void blk_mq_hctx_map_queues(struct blk_mq_queue_map *qmap,
> + struct device *dev, unsigned int offset)
> +
> +{
> + const struct cpumask *mask;
> + unsigned int queue, cpu;
> +
> + if (!dev->bus->irq_get_affinity)
> + goto fallback;
I think this is better than hard-coding it, but are you sure that the
bus will always be bound to the device here so that you have a valid
bus-> pointer?
thanks,
greg k-h
