Re: [PATCH v3 1/8] iommu/arm-smmu: Refactor context bank allocation

[Jordan Crouse]

On Tue, Sep 08, 2020 at 06:42:06PM +0000, Jordan Crouse wrote:
> On Fri, Sep 04, 2020 at 03:55:06PM +0000, Bjorn Andersson wrote:
> > Extract the conditional invocation of the platform defined
> > alloc_context_bank() to a separate function to keep
> > arm_smmu_init_domain_context() cleaner.
> > 
> > Instead pass a reference to the arm_smmu_device as parameter to the
> > call. Also remove the count parameter, as this can be read from the
> > newly passed object.
> > 
> > This allows us to not assign smmu_domain->smmu before attempting to
> > allocate the context bank and as such we don't need to roll back this
> > assignment on failure.
> 
> Much nicer.
> 
> Reviewed-by: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>

I didn't notice that Rob had grabbed this one for his stack. That's fine too.

> > Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> > ---
> > 
> > Note that this series applies ontop of:
> > https://lore.kernel.org/linux-arm-msm/20200901164707.2645413-1-robdclark@xxxxxxxxx/
> > 
> > This could either go on its own, or be squashed with "[PATCH v16 14/20]
> > iommu/arm-smmu: Prepare for the adreno-smmu implementation" from Rob's series.
> > 
> > Changes since v2:
> > - New patch
> > 
> >  drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c |  6 ++++--
> >  drivers/iommu/arm/arm-smmu/arm-smmu.c      | 23 ++++++++++++----------
> >  drivers/iommu/arm/arm-smmu/arm-smmu.h      |  3 ++-
> >  3 files changed, 19 insertions(+), 13 deletions(-)
> > 
> > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> > index 2aa6249050ff..0663d7d26908 100644
> > --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> > @@ -91,9 +91,10 @@ static int qcom_adreno_smmu_set_ttbr0_cfg(const void *cookie,
> >  }
> >  
> >  static int qcom_adreno_smmu_alloc_context_bank(struct arm_smmu_domain *smmu_domain,
> > -		struct device *dev, int start, int count)
> > +					       struct arm_smmu_device *smmu,
> > +					       struct device *dev, int start)
> >  {
> > -	struct arm_smmu_device *smmu = smmu_domain->smmu;
> > +	int count;
> >  
> >  	/*
> >  	 * Assign context bank 0 to the GPU device so the GPU hardware can
> > @@ -104,6 +105,7 @@ static int qcom_adreno_smmu_alloc_context_bank(struct arm_smmu_domain *smmu_doma
> >  		count = 1;
> >  	} else {
> >  		start = 1;
> > +		count = smmu->num_context_banks;
> >  	}
> >  
> >  	return __arm_smmu_alloc_bitmap(smmu->context_map, start, count);
> > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > index bbec5793faf8..e19d7bdc7674 100644
> > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > @@ -623,6 +623,16 @@ void arm_smmu_write_context_bank(struct arm_smmu_device *smmu, int idx)
> >  	arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_SCTLR, reg);
> >  }
> >  
> > +static int arm_smmu_alloc_context_bank(struct arm_smmu_domain *smmu_domain,
> > +				       struct arm_smmu_device *smmu,
> > +				       struct device *dev, unsigned int start)
> > +{
> > +	if (smmu->impl && smmu->impl->alloc_context_bank)
> > +		return smmu->impl->alloc_context_bank(smmu_domain, smmu, dev, start);
> > +
> > +	return __arm_smmu_alloc_bitmap(smmu->context_map, start, smmu->num_context_banks);
> > +}
> > +
> >  static int arm_smmu_init_domain_context(struct iommu_domain *domain,
> >  					struct arm_smmu_device *smmu,
> >  					struct device *dev)
> > @@ -741,20 +751,13 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
> >  		goto out_unlock;
> >  	}
> >  
> > -	smmu_domain->smmu = smmu;
> > -
> > -	if (smmu->impl && smmu->impl->alloc_context_bank)
> > -		ret = smmu->impl->alloc_context_bank(smmu_domain, dev,
> > -				start, smmu->num_context_banks);
> > -	else
> > -		ret = __arm_smmu_alloc_bitmap(smmu->context_map, start,
> > -				      smmu->num_context_banks);
> > -
> > +	ret = arm_smmu_alloc_context_bank(smmu_domain, smmu, dev, start);
> >  	if (ret < 0) {
> > -		smmu_domain->smmu = NULL;
> >  		goto out_unlock;
> >  	}
> >  
> > +	smmu_domain->smmu = smmu;
> > +
> >  	cfg->cbndx = ret;
> >  	if (smmu->version < ARM_SMMU_V2) {
> >  		cfg->irptndx = atomic_inc_return(&smmu->irptndx);
> > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h b/drivers/iommu/arm/arm-smmu/arm-smmu.h
> > index 2df3a70a8a41..ddf2ca4c923d 100644
> > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.h
> > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h
> > @@ -437,7 +437,8 @@ struct arm_smmu_impl {
> >  	irqreturn_t (*global_fault)(int irq, void *dev);
> >  	irqreturn_t (*context_fault)(int irq, void *dev);
> >  	int (*alloc_context_bank)(struct arm_smmu_domain *smmu_domain,
> > -			struct device *dev, int start, int max);
> > +				  struct arm_smmu_device *smmu,
> > +				  struct device *dev, int start);
> >  };
> >  
> >  #define INVALID_SMENDX			-1
> > -- 
> > 2.28.0
> > 
> 
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