Re: [PATCH v4 19/19] iommu: Remove detach_dev callback

[Baolu Lu]

On 2023/1/4 21:22, Jason Gunthorpe wrote:
> On Wed, Jan 04, 2023 at 08:57:25PM +0800, Lu Baolu wrote:
> > The detach_dev callback of domain ops is not called in the IOMMU core.
> > Remove this callback to avoid dead code. The trace event for detaching
> > domain from device is removed accordingly.
> >
> > Signed-off-by: Lu Baolu<baolu.lu@xxxxxxxxxxxxxxx>
> > ---
> >   include/linux/iommu.h        |  2 --
> >   include/trace/events/iommu.h |  7 -------
> >   drivers/iommu/iommu-traces.c |  1 -
> >   drivers/iommu/iommu.c        | 29 +++++------------------------
> >   4 files changed, 5 insertions(+), 34 deletions(-)
> >
> > diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> > index 0d10566b3cb2..a8063f26ff69 100644
> > --- a/include/linux/iommu.h
> > +++ b/include/linux/iommu.h
> > @@ -299,7 +299,6 @@ struct iommu_ops {
> >    * * EBUSY	- device is attached to a domain and cannot be changed
> >    * * ENODEV	- device specific errors, not able to be attached
> >    * * <others>	- treated as ENODEV by the caller. Use is discouraged
> > - * @detach_dev: detach an iommu domain from a device
> >    * @set_dev_pasid: set an iommu domain to a pasid of device
> >    * @map: map a physically contiguous memory region to an iommu domain
> >    * @map_pages: map a physically contiguous set of pages of the same size to
> > @@ -320,7 +319,6 @@ struct iommu_ops {
> >    */
> >   struct iommu_domain_ops {
> >   	int (*attach_dev)(struct iommu_domain *domain, struct device *dev);
> > -	void (*detach_dev)(struct iommu_domain *domain, struct device *dev);
> >   	int (*set_dev_pasid)(struct iommu_domain *domain, struct device *dev,
> >   			     ioasid_t pasid);
> >   
> > diff --git a/include/trace/events/iommu.h b/include/trace/events/iommu.h
> > index 29096fe12623..70743db1fb75 100644
> > --- a/include/trace/events/iommu.h
> > +++ b/include/trace/events/iommu.h
> > @@ -76,13 +76,6 @@ DEFINE_EVENT(iommu_device_event, attach_device_to_domain,
> >   	TP_ARGS(dev)
> >   );
> >   
> > -DEFINE_EVENT(iommu_device_event, detach_device_from_domain,
> > -
> > -	TP_PROTO(struct device *dev),
> > -
> > -	TP_ARGS(dev)
> > -);
> > -
> did you want to add a trace for the set_platform_dma_ops in the
> earlier patch?

If necessary, we can add such a trace event. But I do hope to further
evolve the iommu drivers that need this callback. Finally, we should
remove it totally.

--
Best regards,
baolu