On Fri, Jan 10, 2025 at 10:51:49AM -0400, Jason Gunthorpe wrote: > On Fri, Jan 10, 2025 at 07:12:46AM +0000, Tian, Kevin wrote: > > > > + if (!viommu) > > > + return -ENODEV; > > > + if (WARN_ON_ONCE(!viommu->ops || !viommu->ops- > > > >supports_veventq || > > > + !viommu->ops->supports_veventq(type))) > > > + return -EOPNOTSUPP; > > > > Hmm the driver knows which type is supported by itself before > > calling this helper. Why bother having the helper calling into > > the driver again to verify? > > Indeed, it might make sense to protect this with > > if (IS_ENABLED(CONFIG_IOMMUFD_TEST)) > > As a compiled out assertion > > Or drop it > > We shouldn't have unnecessary argument validation on fast paths, > !viommu should go too. Ack. I will drop those two if-statments. Nicolin