Re: [PATCH v2 05/13] iommufd: Add IOMMUFD_OBJ_EVENTQ_VIRQ and IOMMUFD_CMD_VIRQ_ALLOC

[Nicolin Chen <nicolinc@nvidia.com>]

On Wed, Dec 11, 2024 at 07:55:53AM +0000, Tian, Kevin wrote:
> > From: Nicolin Chen <nicolinc@nvidia.com>
> > Sent: Wednesday, December 4, 2024 6:10 AM
> > +
> > +/* An iommufd_virq represents a vIOMMU interrupt in an eventq_virq
> > queue */
> > +struct iommufd_virq {
> > +	struct iommufd_eventq_virq *eventq_virq;
> > +	struct list_head node;
> > +	ssize_t irq_len;
> > +	void *irq_data;
> > +};
> 
> looks the only use of eventq_virq is in below:
> 
> > +
> > +static inline int iommufd_eventq_virq_handler(struct iommufd_virq *virq)
> > +{
> > +	return iommufd_eventq_notify(&virq->eventq_virq->common,
> > &virq->node);
> > +}
> 
> If there is no other intended usages upon that field, it's simpler to
> remove it and directly pass the pointer in when the handler is 
> called. Anyway iommufd_viommu_report_irq() needs to find the
> eventq first before calling it.

OK.

> > +/**
> > + * struct iommu_virq_alloc - ioctl(IOMMU_VIRQ_ALLOC)
> > + * @size: sizeof(struct iommu_virq_alloc)
> > + * @flags: Must be 0
> > + * @viommu: virtual IOMMU ID to associate the virtual IRQ with
> > + * @type: Type of the virtual IRQ. Must be defined in enum
> > iommu_virq_type
> > + * @out_virq_id: The ID of the new virtual IRQ
> > + * @out_fault_fd: The fd of the new virtual IRQ. User space must close the
> > + *                successfully returned fd after using it
> 
> s/out_fault_fd/out_virq_fd/
> 
> > + *
> > + * Explicitly allocate a virtual IRQ handler for a vIOMMU. A vIOMMU can
> > have
> > + * multiple FDs for different @type, but is confined to one FD per @type.
> > + */
> 
> s/handler/interface/
> 
> > +
> > +	eventq_virq->irq_wq = alloc_workqueue("viommu_irq/%d",
> > WQ_UNBOUND, 0,
> > +					      eventq_virq->common.obj.id);
> > +	if (!eventq_virq->irq_wq) {
> > +		rc = -ENOMEM;
> > +		goto out_put_fdno;
> > +	}
> 
> there is no use of this wq

Oops. Looks like I forgot to clean it up.

> > @@ -335,6 +335,8 @@ static const struct iommufd_ioctl_op
> > iommufd_ioctl_ops[] = {
> >  	IOCTL_OP(IOMMU_DESTROY, iommufd_destroy, struct
> > iommu_destroy, id),
> >  	IOCTL_OP(IOMMU_FAULT_QUEUE_ALLOC,
> > iommufd_eventq_iopf_alloc,
> >  		 struct iommu_fault_alloc, out_fault_fd),
> > +	IOCTL_OP(IOMMU_VIRQ_ALLOC, iommufd_eventq_virq_alloc,
> > +		 struct iommu_virq_alloc, out_virq_fd),
> 
> sort it in alphabetical order.

Ack.

Thanks
Nic