[PATCH V2 3/6] scsi: add flag of .use_managed_irq to 'struct Scsi_Host'

[Ming Lei]

On Tue, Jul 06, 2021 at 07:37:19AM +0200, Christoph Hellwig wrote:
> On Mon, Jul 05, 2021 at 05:55:49PM +0800, Ming Lei wrote:
> > The thing is that blk_mq_pci_map_queues() is allowed to be called for
> > non-managed irqs. Also some managed irq consumers don't use blk_mq_pci_map_queues().
> > 
> > So this way just provides hint about managed irq uses, but we really
> > need to get this flag set if driver uses managed irq.
> 
> blk_mq_pci_map_queues is absolutely intended to only be used by
> managed irqs.  I wonder if we can enforce that somehow?

It may break some scsi drivers.

And blk_mq_pci_map_queues() just calls pci_irq_get_affinity() to
retrieve the irq's affinity, and the irq can be one non-managed irq,
which affinity is set via either irq_set_affinity_hint() from kernel
or /proc/irq/.


Thanks,
Ming