On Thu, 2013-09-19 at 12:59 +0530, Bharat Bhushan wrote:
> This api return the iommu domain to which the device is attached.
> The iommu_domain is required for making API calls related to iommu.
> Follow up patches which use this API to know iommu maping.
>
> Signed-off-by: Bharat Bhushan <bharat.bhus...@freescale.com>
> ---
> drivers/iommu/iommu.c | 10 ++++++++++
> include/linux/iommu.h | 7 +++++++
> 2 files changed, 17 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index fbe9ca7..6ac5f50 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -696,6 +696,16 @@ void iommu_detach_device(struct iommu_domain *domain,
> struct device *dev)
> }
> EXPORT_SYMBOL_GPL(iommu_detach_device);
>
> +struct iommu_domain *iommu_get_dev_domain(struct device *dev)
> +{
> + struct iommu_ops *ops = dev->bus->iommu_ops;
> +
> + if (unlikely(ops == NULL || ops->get_dev_iommu_domain == NULL))
> + return NULL;
> +
> + return ops->get_dev_iommu_domain(dev);
> +}
> +EXPORT_SYMBOL_GPL(iommu_get_dev_domain);
What prevents this from racing iommu_domain_free()? There's no
references acquired, so there's no reason for the caller to assume the
pointer is valid.
> /*
> * IOMMU groups are really the natrual working unit of the IOMMU, but
> * the IOMMU API works on domains and devices. Bridge that gap by
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index 7ea319e..fa046bd 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -127,6 +127,7 @@ struct iommu_ops {
> int (*domain_set_windows)(struct iommu_domain *domain, u32 w_count);
> /* Get the numer of window per domain */
> u32 (*domain_get_windows)(struct iommu_domain *domain);
> + struct iommu_domain *(*get_dev_iommu_domain)(struct device *dev);
>
> unsigned long pgsize_bitmap;
> };
> @@ -190,6 +191,7 @@ extern int iommu_domain_window_enable(struct iommu_domain
> *domain, u32 wnd_nr,
> phys_addr_t offset, u64 size,
> int prot);
> extern void iommu_domain_window_disable(struct iommu_domain *domain, u32
> wnd_nr);
> +extern struct iommu_domain *iommu_get_dev_domain(struct device *dev);
> /**
> * report_iommu_fault() - report about an IOMMU fault to the IOMMU framework
> * @domain: the iommu domain where the fault has happened
> @@ -284,6 +286,11 @@ static inline void iommu_domain_window_disable(struct
> iommu_domain *domain,
> {
> }
>
> +static inline struct iommu_domain *iommu_get_dev_domain(struct device *dev)
> +{
> + return NULL;
> +}
> +
> static inline phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain,
> dma_addr_t iova)
> {
> return 0;
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