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Date:   Tue, 18 Feb 2020 09:14:54 -0800
From:   Christoph Hellwig <hch@infradead.org>
To:     Joerg Roedel <joro@8bytes.org>
Cc:     Lu Baolu <baolu.lu@linux.intel.com>,
        David Woodhouse <dwmw2@infradead.org>, jroedel@suse.de,
        iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/5] iommu/vt-d: Add attach_deferred() helper
Message-ID: <20200218171454.GA7067@infradead.org>
References: <20200217193858.26990-1-joro@8bytes.org>
 <20200217193858.26990-2-joro@8bytes.org>
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> +static bool attach_deferred(struct device *dev)
> +{
> +	return dev->archdata.iommu == DEFER_DEVICE_DOMAIN_INFO;
> +}

This is not a very useful helper.

> +
>  /**
>   * is_downstream_to_pci_bridge - test if a device belongs to the PCI
>   *				 sub-hierarchy of a candidate PCI-PCI bridge
> @@ -2510,8 +2515,7 @@ struct dmar_domain *find_domain(struct device *dev)
>  {
>  	struct device_domain_info *info;
>  
> -	if (unlikely(dev->archdata.iommu == DEFER_DEVICE_DOMAIN_INFO ||
> -		     dev->archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO))
> +	if (unlikely(attach_deferred(dev) || iommu_dummy(dev)))
>  		return NULL;

I'd rather kill the iommu_dummy helper as well.  And IIRC I have an
outstanding series somewhere that does just that..