On Mon, Nov 11, 2024 at 07:02:09PM +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.
>
> Introduce a new callback in struct bus_type to get the affinity mask.
> The callbacks can then be populated by the subsystem directly.
>
> All but one driver use the subsystem default affinity masks. hisi_sas v2
> depends on a driver specific mapping, thus use the optional argument
> get_queue_affinity to retrieve the mapping.
This seems to mix up a few different things:
1) adding a new bus operation
2) implementations of that operation for PCI and virtio
3) a block layer consumer of the operation
all these really should be separate per-subsystem patches.
You'll also need to Cc the driver model maintainers.
> +void blk_mq_hctx_map_queues(struct blk_mq_queue_map *qmap,
> + struct device *dev, unsigned int offset,
> + get_queue_affinity_fn *get_irq_affinity)
> +{
> + const struct cpumask *mask = NULL;
> + unsigned int queue, cpu;
> +
> + for (queue = 0; queue < qmap->nr_queues; queue++) {
> + if (get_irq_affinity)
> + mask = get_irq_affinity(dev, queue + offset);
> + else if (dev->bus->irq_get_affinity)
> + mask = dev->bus->irq_get_affinity(dev, queue + offset);
> +
> + if (!mask)
> + goto fallback;
> +
> + for_each_cpu(cpu, mask)
> + qmap->mq_map[cpu] = qmap->queue_offset + queue;
> + }
This does different things with a NULL argument vs not. Please split it
into two separate helpers. The non-NULL case is only uses in hisi_sas,
so it might be worth just open coding it there as well.
> +static const struct cpumask *pci_device_irq_get_affinity(struct device *dev,
> + unsigned int irq_vec)
> +{
> + struct pci_dev *pdev = to_pci_dev(dev);
> +
> + return pci_irq_get_affinity(pdev, irq_vec);
Nit: this could be shortened to:
return pci_irq_get_affinity(to_pci_dev(dev), irq_vec);
