Re: [PATCH v3 02/20] iommu/apple-dart: Remove detach_dev callback

[Baolu Lu]

On 2022/12/1 1:00, Sven Peter wrote:
> On Mon, Nov 28, 2022, at 07:46, Lu Baolu wrote:
> > The IOMMU driver supports default domain, so the detach_dev op will never
> > be called. Remove it to avoid dead code.
> >
> > Signed-off-by: Lu Baolu<baolu.lu@xxxxxxxxxxxxxxx>
> > ---
> Reviewed-by: Sven Peter<sven@xxxxxxxxxxxxx>
>
> >   drivers/iommu/apple-dart.c | 17 -----------------
> >   1 file changed, 17 deletions(-)
> >
> > diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
> > index 4f4a323be0d0..6fbe6b275c79 100644
> > --- a/drivers/iommu/apple-dart.c
> > +++ b/drivers/iommu/apple-dart.c
> > @@ -535,22 +535,6 @@ static int apple_dart_attach_dev(struct
> > iommu_domain *domain,
> >   	return ret;
> >   }
> >
> > -static void apple_dart_detach_dev(struct iommu_domain *domain,
> > -				  struct device *dev)
> > -{
> Thanks for cleaning this entire API up!
>
> It actually turns out that this is slightly broken because I assumed that
> detach_dev would always be called for any attach_dev. I think the only
> consequence for a device that used to be assigned to domain A and is now moved to
> domain B is that any TLB flushes required for A will still flush the TLB for that
> device.
>
> That's not a big deal but I'll eventually send a fix.
>
> > -	int i;
> > -	struct apple_dart_stream_map *stream_map;
> > -	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
> > -	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
> > -
> > -	for_each_stream_map(i, cfg, stream_map)
> > -		apple_dart_hw_disable_dma(stream_map);
> > -
> > -	if (domain->type == IOMMU_DOMAIN_DMA ||
> > -	    domain->type == IOMMU_DOMAIN_UNMANAGED)
> > -		apple_dart_domain_remove_streams(dart_domain, cfg);
> Something might complain about unused apple_dart_domain_remove_streams now.
> Might make sense to drop that for now as well.

Done. Thanks!

Best regards,
baolu