Re: [PATCH v3 6/6] iommu: Propagate ret for a potential soft failure EINVAL

[Nicolin Chen]

On Tue, Sep 20, 2022 at 06:50:22AM +0000, Tian, Kevin wrote:
> External email: Use caution opening links or attachments
> 
> 
> > From: Nicolin Chen <nicolinc@xxxxxxxxxx>
> > Sent: Thursday, September 15, 2022 3:59 PM
> >
> > Following the new rules in include/linux/iommu.h kdocs, EINVAL now can be
> > used to indicate that domain and device are incompatible by a caller that
> > treats it as a soft failure and tries attaching to another domain.
> >
> > Either mtk_iommu or virtio driver has a place that returns a hard failure
> > instead of the return value from the function call, where an incompatible
> > errno EINVAL could potentially occur.
> 
> in both cases there is no EINVAL returned from the calling stack
> 
> IMHO error propagation is the right way even w/o talking about EINVAL
> otherwise we may miss ENOMEM etc.

OK. I changed to:

The mtk_iommu and virtio drivers have places in the ->attach_dev callback
functions that return hardcode errnos instead of the returned values, but
callers of these ->attach_dv callback functions may care. Propagate them
directly without the extra conversions.

> > Propagate the real return value to not miss a potential soft failure.
> >
> > Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
> 
> Apart from that comment,
> 
> Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>

Added this too. Thanks!