linux-kernel - RE: [PATCH 04/12] iommu/vt-d: Use pci_get_domain_bus_and_slot() in pgtable

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Message-ID: <BN9PR11MB52760466E3E4AAD92DB0F91B8CDF9@BN9PR11MB5276.namprd11.prod.outlook.com>
Date:   Wed, 1 Jun 2022 08:56:23 +0000
From:   "Tian, Kevin" <kevin.tian@...el.com>
To:     Lu Baolu <baolu.lu@...ux.intel.com>,
        Joerg Roedel <joro@...tes.org>,
        "Raj, Ashok" <ashok.raj@...el.com>,
        Christoph Hellwig <hch@...radead.org>,
        "Jason Gunthorpe" <jgg@...dia.com>
CC:     Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>,
        "Liu, Yi L" <yi.l.liu@...el.com>,
        "Pan, Jacob jun" <jacob.jun.pan@...el.com>,
        "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 04/12] iommu/vt-d: Use pci_get_domain_bus_and_slot() in
 pgtable_walk()

> From: Lu Baolu <baolu.lu@...ux.intel.com>
> Sent: Friday, May 27, 2022 2:30 PM
> 
> Use pci_get_domain_bus_and_slot() instead of searching the global list
> to retrieve the pci device pointer. This removes device_domain_list
> global list as there are no consumers anymore.
> 
> Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>

Reviewed-by: Kevin Tian <kevin.tian@...el.com>

> ---
>  drivers/iommu/intel/iommu.h |  1 -
>  drivers/iommu/intel/iommu.c | 33 ++++++---------------------------
>  2 files changed, 6 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
> index 2f4a5b9509c0..6724703d573b 100644
> --- a/drivers/iommu/intel/iommu.h
> +++ b/drivers/iommu/intel/iommu.h
> @@ -609,7 +609,6 @@ struct intel_iommu {
>  /* PCI domain-device relationship */
>  struct device_domain_info {
>  	struct list_head link;	/* link to domain siblings */
> -	struct list_head global; /* link to global list */
>  	struct list_head table;	/* link to pasid table */
>  	u32 segment;		/* PCI segment number */
>  	u8 bus;			/* PCI bus number */
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 25d4c5200526..bbdd3417a1b1 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -131,8 +131,6 @@ static struct intel_iommu **g_iommus;
> 
>  static void __init check_tylersburg_isoch(void);
>  static int rwbf_quirk;
> -static inline struct device_domain_info *
> -dmar_search_domain_by_dev_info(int segment, int bus, int devfn);
> 
>  /*
>   * set to 1 to panic kernel if can't successfully enable VT-d
> @@ -315,7 +313,6 @@ static int iommu_skip_te_disable;
>  #define IDENTMAP_AZALIA		4
> 
>  static DEFINE_SPINLOCK(device_domain_lock);
> -static LIST_HEAD(device_domain_list);
>  const struct iommu_ops intel_iommu_ops;
> 
>  static bool translation_pre_enabled(struct intel_iommu *iommu)
> @@ -845,9 +842,14 @@ static void pgtable_walk(struct intel_iommu
> *iommu, unsigned long pfn, u8 bus, u
>  	struct device_domain_info *info;
>  	struct dma_pte *parent, *pte;
>  	struct dmar_domain *domain;
> +	struct pci_dev *pdev;
>  	int offset, level;
> 
> -	info = dmar_search_domain_by_dev_info(iommu->segment, bus,
> devfn);
> +	pdev = pci_get_domain_bus_and_slot(iommu->segment, bus, devfn);
> +	if (!pdev)
> +		return;
> +
> +	info = dev_iommu_priv_get(&pdev->dev);
>  	if (!info || !info->domain) {
>  		pr_info("device [%02x:%02x.%d] not probed\n",
>  			bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
> @@ -2348,19 +2350,6 @@ static void domain_remove_dev_info(struct
> dmar_domain *domain)
>  	spin_unlock_irqrestore(&device_domain_lock, flags);
>  }
> 
> -static inline struct device_domain_info *
> -dmar_search_domain_by_dev_info(int segment, int bus, int devfn)
> -{
> -	struct device_domain_info *info;
> -
> -	list_for_each_entry(info, &device_domain_list, global)
> -		if (info->segment == segment && info->bus == bus &&
> -		    info->devfn == devfn)
> -			return info;
> -
> -	return NULL;
> -}
> -
>  static int domain_setup_first_level(struct intel_iommu *iommu,
>  				    struct dmar_domain *domain,
>  				    struct device *dev,
> @@ -4564,7 +4553,6 @@ static struct iommu_device
> *intel_iommu_probe_device(struct device *dev)
>  	struct pci_dev *pdev = dev_is_pci(dev) ? to_pci_dev(dev) : NULL;
>  	struct device_domain_info *info;
>  	struct intel_iommu *iommu;
> -	unsigned long flags;
>  	u8 bus, devfn;
> 
>  	iommu = device_to_iommu(dev, &bus, &devfn);
> @@ -4607,10 +4595,7 @@ static struct iommu_device
> *intel_iommu_probe_device(struct device *dev)
>  		}
>  	}
> 
> -	spin_lock_irqsave(&device_domain_lock, flags);
> -	list_add(&info->global, &device_domain_list);
>  	dev_iommu_priv_set(dev, info);
> -	spin_unlock_irqrestore(&device_domain_lock, flags);
> 
>  	return &iommu->iommu;
>  }
> @@ -4618,15 +4603,9 @@ static struct iommu_device
> *intel_iommu_probe_device(struct device *dev)
>  static void intel_iommu_release_device(struct device *dev)
>  {
>  	struct device_domain_info *info = dev_iommu_priv_get(dev);
> -	unsigned long flags;
> 
>  	dmar_remove_one_dev_info(dev);
> -
> -	spin_lock_irqsave(&device_domain_lock, flags);
>  	dev_iommu_priv_set(dev, NULL);
> -	list_del(&info->global);
> -	spin_unlock_irqrestore(&device_domain_lock, flags);
> -
>  	kfree(info);
>  	set_dma_ops(dev, NULL);
>  }
> --
> 2.25.1