On Wed, Sep 14, 2022 at 10:49:42AM +0100, Jean-Philippe Brucker wrote: > External email: Use caution opening links or attachments > > > On Wed, Sep 14, 2022 at 06:11:06AM -0300, Jason Gunthorpe wrote: > > On Tue, Sep 13, 2022 at 01:27:03PM +0100, Jean-Philippe Brucker wrote: > > > I think in the future it will be too easy to forget about the constrained > > > return value of attach() while modifying some other part of the driver, > > > and let an external helper return EINVAL. So I'd rather not propagate ret > > > from outside of viommu_domain_attach() and finalise(). > > > > Fortunately, if -EINVAL is wrongly returned it only creates an > > inefficiency, not a functional problem. So we do not need to be > > precise here. > > Ah fair. In that case the attach_dev() documentation should indicate that > EINVAL is a hint, so that callers don't rely on it (currently words "must" > and "exclusively" indicate that returning EINVAL for anything other than > device-domain incompatibility is unacceptable). The virtio-iommu > implementation may well return EINVAL from the virtio stack or from the > host response. How about this? + * * EINVAL - mainly, device and domain are incompatible, or something went + * wrong with the domain. It's suggested to avoid kernel prints + * along with this errno. And it's better to convert any EINVAL + * returned from kAPIs to ENODEV if it is device-specific, or to + * some other reasonable errno being listed below > > > Since we can't guarantee that APIs like virtio or ida won't ever return > > > EINVAL, we should set all return values: > > > > I dislike this alot, it squashes all return codes to try to optimize > > an obscure failure path :( Hmm...should I revert all the driver changes back to this version?
