Re: [PATCH v2 10/12] iommu/vt-d: Fold __dmar_remove_one_dev_info() into its caller

[Baolu Lu]

On 2022/6/14 15:07, Tian, Kevin wrote:
> > From: Lu Baolu<baolu.lu@xxxxxxxxxxxxxxx>
> > Sent: Tuesday, June 14, 2022 10:52 AM
> >
> > Fold __dmar_remove_one_dev_info() into dmar_remove_one_dev_info()
> > which
> > is its only caller. Make the spin lock critical range only cover the
> > device list change code and remove some unnecessary checks.
> >
> > Signed-off-by: Lu Baolu<baolu.lu@xxxxxxxxxxxxxxx>
> > ---
> >   drivers/iommu/intel/iommu.c | 34 +++++++++-------------------------
> >   1 file changed, 9 insertions(+), 25 deletions(-)
> >
> > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> > index af22690f44c8..8345e0c0824c 100644
> > --- a/drivers/iommu/intel/iommu.c
> > +++ b/drivers/iommu/intel/iommu.c
> > @@ -295,7 +295,6 @@ static LIST_HEAD(dmar_satc_units);
> >   static int g_num_of_iommus;
> >
> >   static void dmar_remove_one_dev_info(struct device *dev);
> > -static void __dmar_remove_one_dev_info(struct device_domain_info *info);
> >
> >   int dmar_disabled = !IS_ENABLED(CONFIG_INTEL_IOMMU_DEFAULT_ON);
> >   int intel_iommu_sm =
> > IS_ENABLED(CONFIG_INTEL_IOMMU_SCALABLE_MODE_DEFAULT_ON);
> > @@ -4141,20 +4140,14 @@ static void domain_context_clear(struct
> > device_domain_info *info)
> >   			       &domain_context_clear_one_cb, info);
> >   }
> >
> > -static void __dmar_remove_one_dev_info(struct device_domain_info *info)
> > +static void dmar_remove_one_dev_info(struct device *dev)
> >   {
> > -	struct dmar_domain *domain;
> > -	struct intel_iommu *iommu;
> > -
> > -	assert_spin_locked(&device_domain_lock);
> > -
> > -	if (WARN_ON(!info))
> > -		return;
> > -
> > -	iommu = info->iommu;
> > -	domain = info->domain;
> > +	struct device_domain_info *info = dev_iommu_priv_get(dev);
> > +	struct dmar_domain *domain = info->domain;
> this local variable is not required as there is just one reference
> to info->domain.

Yes. It could be removed and use info->domain directly.

> btw I didn't see info->domain is cleared in this path. Is it correct?

It's better to clear here. I will make this change in my in-process
blocking domain series.

But it doesn't cause any real problems because the Intel IOMMU driver
supports default domain, hence the logic here is info->domain is
replaced, but not cleared.

Best regards,
baolu