linux-kernel - Re: [PATCH v4 17/22] iommu/vt-d: Avoid duplicated code for PASID setup

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Date:   Mon, 24 Jun 2019 16:44:50 -0700
From:   Jacob Pan <jacob.jun.pan@...ux.intel.com>
To:     Jonathan Cameron <jonathan.cameron@...wei.com>
Cc:     <iommu@...ts.linux-foundation.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Joerg Roedel <joro@...tes.org>,
        David Woodhouse <dwmw2@...radead.org>,
        "Eric Auger" <eric.auger@...hat.com>,
        Alex Williamson <alex.williamson@...hat.com>,
        Jean-Philippe Brucker <jean-philippe.brucker@....com>,
        "Tian, Kevin" <kevin.tian@...el.com>,
        Raj Ashok <ashok.raj@...el.com>,
        Andriy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        jacob.jun.pan@...ux.intel.com
Subject: Re: [PATCH v4 17/22] iommu/vt-d: Avoid duplicated code for PASID
 setup

On Tue, 18 Jun 2019 17:03:35 +0100
Jonathan Cameron <jonathan.cameron@...wei.com> wrote:

> On Sun, 9 Jun 2019 06:44:17 -0700
> Jacob Pan <jacob.jun.pan@...ux.intel.com> wrote:
> 
> > After each setup for PASID entry, related translation caches must
> > be flushed. We can combine duplicated code into one function which
> > is less error prone.
> > 
> > Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>  
> Formatting nitpick below ;)
> 
> Otherwise it's cut and paste
> > ---
> >  drivers/iommu/intel-pasid.c | 48
> > +++++++++++++++++---------------------------- 1 file changed, 18
> > insertions(+), 30 deletions(-)
> > 
> > diff --git a/drivers/iommu/intel-pasid.c
> > b/drivers/iommu/intel-pasid.c index 1e25539..1ff2ecc 100644
> > --- a/drivers/iommu/intel-pasid.c
> > +++ b/drivers/iommu/intel-pasid.c
> > @@ -522,6 +522,21 @@ void intel_pasid_tear_down_entry(struct
> > intel_iommu *iommu, devtlb_invalidation_with_pasid(iommu, dev,
> > pasid); }
> >  
> > +static inline void pasid_flush_caches(struct intel_iommu *iommu,
> > +				struct pasid_entry *pte,
> > +				int pasid, u16 did)
> > +{
> > +	if (!ecap_coherent(iommu->ecap))
> > +		clflush_cache_range(pte, sizeof(*pte));
> > +
> > +	if (cap_caching_mode(iommu->cap)) {
> > +		pasid_cache_invalidation_with_pasid(iommu, did,
> > pasid);
> > +		iotlb_invalidation_with_pasid(iommu, did, pasid);
> > +	} else
> > +		iommu_flush_write_buffer(iommu);  
> 
> I have some vague recollection kernel style says use brackets around
> single lines if other blocks in an if / else stack have multiple
> lines..
> 
> I checked, this case is specifically called out
> 
> https://www.kernel.org/doc/html/v5.1/process/coding-style.html
> > +  
> This blank line doesn't add anything either ;)
indeed. i will add the braces and remove the blank line.

Thanks for looking it up.
> > +}
> > +
> >  /*
> >   * Set up the scalable mode pasid table entry for first only
> >   * translation type.
> > @@ -567,16 +582,7 @@ int intel_pasid_setup_first_level(struct
> > intel_iommu *iommu, /* Setup Present and PASID Granular Transfer
> > Type: */ pasid_set_translation_type(pte, 1);
> >  	pasid_set_present(pte);
> > -
> > -	if (!ecap_coherent(iommu->ecap))
> > -		clflush_cache_range(pte, sizeof(*pte));
> > -
> > -	if (cap_caching_mode(iommu->cap)) {
> > -		pasid_cache_invalidation_with_pasid(iommu, did,
> > pasid);
> > -		iotlb_invalidation_with_pasid(iommu, did, pasid);
> > -	} else {
> > -		iommu_flush_write_buffer(iommu);
> > -	}
> > +	pasid_flush_caches(iommu, pte, pasid, did);
> >  
> >  	return 0;
> >  }
> > @@ -640,16 +646,7 @@ int intel_pasid_setup_second_level(struct
> > intel_iommu *iommu, */
> >  	pasid_set_sre(pte);
> >  	pasid_set_present(pte);
> > -
> > -	if (!ecap_coherent(iommu->ecap))
> > -		clflush_cache_range(pte, sizeof(*pte));
> > -
> > -	if (cap_caching_mode(iommu->cap)) {
> > -		pasid_cache_invalidation_with_pasid(iommu, did,
> > pasid);
> > -		iotlb_invalidation_with_pasid(iommu, did, pasid);
> > -	} else {
> > -		iommu_flush_write_buffer(iommu);
> > -	}
> > +	pasid_flush_caches(iommu, pte, pasid, did);
> >  
> >  	return 0;
> >  }
> > @@ -683,16 +680,7 @@ int intel_pasid_setup_pass_through(struct
> > intel_iommu *iommu, */
> >  	pasid_set_sre(pte);
> >  	pasid_set_present(pte);
> > -
> > -	if (!ecap_coherent(iommu->ecap))
> > -		clflush_cache_range(pte, sizeof(*pte));
> > -
> > -	if (cap_caching_mode(iommu->cap)) {
> > -		pasid_cache_invalidation_with_pasid(iommu, did,
> > pasid);
> > -		iotlb_invalidation_with_pasid(iommu, did, pasid);
> > -	} else {
> > -		iommu_flush_write_buffer(iommu);
> > -	}
> > +	pasid_flush_caches(iommu, pte, pasid, did);
> >  
> >  	return 0;
> >  }  
> 
> 

[Jacob Pan]