RE: [PATCH 02/12] iommu/vt-d: Remove for_each_device_domain()

[Tian, Kevin]

> From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Sent: Friday, May 27, 2022 2:30 PM
> 
> The per-device device_domain_info data could be retrieved from the
> device itself. There's no need to search a global list.
> 
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>

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

> ---
>  drivers/iommu/intel/iommu.h |  2 --
>  drivers/iommu/intel/iommu.c | 25 -------------------------
>  drivers/iommu/intel/pasid.c | 37 +++++++++++--------------------------
>  3 files changed, 11 insertions(+), 53 deletions(-)
> 
> diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
> index 8a6d64d726c0..2f4a5b9509c0 100644
> --- a/drivers/iommu/intel/iommu.h
> +++ b/drivers/iommu/intel/iommu.h
> @@ -727,8 +727,6 @@ extern int dmar_ir_support(void);
>  void *alloc_pgtable_page(int node);
>  void free_pgtable_page(void *vaddr);
>  struct intel_iommu *domain_get_iommu(struct dmar_domain *domain);
> -int for_each_device_domain(int (*fn)(struct device_domain_info *info,
> -				     void *data), void *data);
>  void iommu_flush_write_buffer(struct intel_iommu *iommu);
>  int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device
> *dev);
>  struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8
> *devfn);
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index cacae8bdaa65..6549b09d7f32 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -316,31 +316,6 @@ static int iommu_skip_te_disable;
> 
>  static DEFINE_SPINLOCK(device_domain_lock);
>  static LIST_HEAD(device_domain_list);
> -
> -/*
> - * Iterate over elements in device_domain_list and call the specified
> - * callback @fn against each element.
> - */
> -int for_each_device_domain(int (*fn)(struct device_domain_info *info,
> -				     void *data), void *data)
> -{
> -	int ret = 0;
> -	unsigned long flags;
> -	struct device_domain_info *info;
> -
> -	spin_lock_irqsave(&device_domain_lock, flags);
> -	list_for_each_entry(info, &device_domain_list, global) {
> -		ret = fn(info, data);
> -		if (ret) {
> -			spin_unlock_irqrestore(&device_domain_lock, flags);
> -			return ret;
> -		}
> -	}
> -	spin_unlock_irqrestore(&device_domain_lock, flags);
> -
> -	return 0;
> -}
> -
>  const struct iommu_ops intel_iommu_ops;
> 
>  static bool translation_pre_enabled(struct intel_iommu *iommu)
> diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
> index b2ac5869286f..0627d6465f25 100644
> --- a/drivers/iommu/intel/pasid.c
> +++ b/drivers/iommu/intel/pasid.c
> @@ -103,36 +103,20 @@ device_detach_pasid_table(struct
> device_domain_info *info,
>  }
> 
>  struct pasid_table_opaque {
> -	struct pasid_table	**pasid_table;
> -	int			segment;
> -	int			bus;
> -	int			devfn;
> +	struct pasid_table	*pasid_table;
>  };
> 
> -static int search_pasid_table(struct device_domain_info *info, void *opaque)
> -{
> -	struct pasid_table_opaque *data = opaque;
> -
> -	if (info->iommu->segment == data->segment &&
> -	    info->bus == data->bus &&
> -	    info->devfn == data->devfn &&
> -	    info->pasid_table) {
> -		*data->pasid_table = info->pasid_table;
> -		return 1;
> -	}
> -
> -	return 0;
> -}
> -
>  static int get_alias_pasid_table(struct pci_dev *pdev, u16 alias, void
> *opaque)
>  {
>  	struct pasid_table_opaque *data = opaque;
> +	struct device_domain_info *info;
> 
> -	data->segment = pci_domain_nr(pdev->bus);
> -	data->bus = PCI_BUS_NUM(alias);
> -	data->devfn = alias & 0xff;
> +	info = dev_iommu_priv_get(&pdev->dev);
> +	if (!info || !info->pasid_table)
> +		return 0;
> 
> -	return for_each_device_domain(&search_pasid_table, data);
> +	data->pasid_table = info->pasid_table;
> +	return 1;
>  }
> 
>  /*
> @@ -141,9 +125,9 @@ static int get_alias_pasid_table(struct pci_dev *pdev,
> u16 alias, void *opaque)
>   */
>  int intel_pasid_alloc_table(struct device *dev)
>  {
> +	struct pasid_table_opaque data = { NULL };
>  	struct device_domain_info *info;
>  	struct pasid_table *pasid_table;
> -	struct pasid_table_opaque data;
>  	struct page *pages;
>  	u32 max_pasid = 0;
>  	int ret, order;
> @@ -155,11 +139,12 @@ int intel_pasid_alloc_table(struct device *dev)
>  		return -EINVAL;
> 
>  	/* DMA alias device already has a pasid table, use it: */
> -	data.pasid_table = &pasid_table;
>  	ret = pci_for_each_dma_alias(to_pci_dev(dev),
>  				     &get_alias_pasid_table, &data);
> -	if (ret)
> +	if (ret) {
> +		pasid_table = data.pasid_table;
>  		goto attach_out;
> +	}
> 
>  	pasid_table = kzalloc(sizeof(*pasid_table), GFP_KERNEL);
>  	if (!pasid_table)
> --
> 2.25.1