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SubjectRe: [PATCH 1/2] iommu: Fix iommu_unmap and iommu_unmap_fast return type
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Hi Suravee,

On 31/01/18 01:48, Suravee Suthikulpanit wrote:
> Currently, iommu_unmap and iommu_unmap_fast return unmapped
> pages with size_t. However, the actual value returned could
> be error codes (< 0), which can be misinterpreted as large
> number of unmapped pages. Therefore, change the return type to ssize_t.
>
> Cc: Joerg Roedel <joro@8bytes.org>
> Cc: Alex Williamson <alex.williamson@redhat.com>
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> ---
> drivers/iommu/amd_iommu.c | 6 +++---
> drivers/iommu/intel-iommu.c | 4 ++--

Er, there are a few more drivers than that implementing iommu_ops ;)

It seems like it might be more sensible to fix the single instance of a
driver returning -EINVAL (which appears to be a "should never happen if
used correctly" kinda thing anyway) and leave the API-internal callback
prototype as-is. I do agree the inconsistency of iommu_unmap() itself
wants sorting, though (particularly the !IOMMU_API stubs which are wrong
either way).

Robin.

> drivers/iommu/iommu.c | 16 ++++++++--------
> include/linux/iommu.h | 20 ++++++++++----------
> 4 files changed, 23 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 7d5eb00..3609f51 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -3030,11 +3030,11 @@ static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova,
> return ret;
> }
>
> -static size_t amd_iommu_unmap(struct iommu_domain *dom, unsigned long iova,
> - size_t page_size)
> +static ssize_t amd_iommu_unmap(struct iommu_domain *dom, unsigned long iova,
> + size_t page_size)
> {
> struct protection_domain *domain = to_pdomain(dom);
> - size_t unmap_size;
> + ssize_t unmap_size;
>
> if (domain->mode == PAGE_MODE_NONE)
> return -EINVAL;
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 4a2de34..15ba866 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -5068,8 +5068,8 @@ static int intel_iommu_map(struct iommu_domain *domain,
> return ret;
> }
>
> -static size_t intel_iommu_unmap(struct iommu_domain *domain,
> - unsigned long iova, size_t size)
> +static ssize_t intel_iommu_unmap(struct iommu_domain *domain,
> + unsigned long iova, size_t size)
> {
> struct dmar_domain *dmar_domain = to_dmar_domain(domain);
> struct page *freelist = NULL;
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 3de5c0b..8f7da8a 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -1557,12 +1557,12 @@ int iommu_map(struct iommu_domain *domain, unsigned long iova,
> }
> EXPORT_SYMBOL_GPL(iommu_map);
>
> -static size_t __iommu_unmap(struct iommu_domain *domain,
> - unsigned long iova, size_t size,
> - bool sync)
> +static ssize_t __iommu_unmap(struct iommu_domain *domain,
> + unsigned long iova, size_t size,
> + bool sync)
> {
> const struct iommu_ops *ops = domain->ops;
> - size_t unmapped_page, unmapped = 0;
> + ssize_t unmapped_page, unmapped = 0;
> unsigned long orig_iova = iova;
> unsigned int min_pagesz;
>
> @@ -1617,15 +1617,15 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
> return unmapped;
> }
>
> -size_t iommu_unmap(struct iommu_domain *domain,
> - unsigned long iova, size_t size)
> +ssize_t iommu_unmap(struct iommu_domain *domain,
> + unsigned long iova, size_t size)
> {
> return __iommu_unmap(domain, iova, size, true);
> }
> EXPORT_SYMBOL_GPL(iommu_unmap);
>
> -size_t iommu_unmap_fast(struct iommu_domain *domain,
> - unsigned long iova, size_t size)
> +ssize_t iommu_unmap_fast(struct iommu_domain *domain,
> + unsigned long iova, size_t size)
> {
> return __iommu_unmap(domain, iova, size, false);
> }
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index 41b8c57..78df048 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -199,8 +199,8 @@ struct iommu_ops {
> void (*detach_dev)(struct iommu_domain *domain, struct device *dev);
> int (*map)(struct iommu_domain *domain, unsigned long iova,
> phys_addr_t paddr, size_t size, int prot);
> - size_t (*unmap)(struct iommu_domain *domain, unsigned long iova,
> - size_t size);
> + ssize_t (*unmap)(struct iommu_domain *domain, unsigned long iova,
> + size_t size);
> size_t (*map_sg)(struct iommu_domain *domain, unsigned long iova,
> struct scatterlist *sg, unsigned int nents, int prot);
> void (*flush_iotlb_all)(struct iommu_domain *domain);
> @@ -299,10 +299,10 @@ extern void iommu_detach_device(struct iommu_domain *domain,
> extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev);
> extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
> phys_addr_t paddr, size_t size, int prot);
> -extern size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova,
> - size_t size);
> -extern size_t iommu_unmap_fast(struct iommu_domain *domain,
> - unsigned long iova, size_t size);
> +extern ssize_t iommu_unmap(struct iommu_domain *domain, unsigned long iova,
> + size_t size);
> +extern ssize_t iommu_unmap_fast(struct iommu_domain *domain,
> + unsigned long iova, size_t size);
> extern size_t default_iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
> struct scatterlist *sg,unsigned int nents,
> int prot);
> @@ -465,14 +465,14 @@ static inline int iommu_map(struct iommu_domain *domain, unsigned long iova,
> return -ENODEV;
> }
>
> -static inline int iommu_unmap(struct iommu_domain *domain, unsigned long iova,
> - size_t size)
> +static inline ssize_t iommu_unmap(struct iommu_domain *domain,
> + unsigned long iova, size_t size)
> {
> return -ENODEV;
> }
>
> -static inline int iommu_unmap_fast(struct iommu_domain *domain, unsigned long iova,
> - int gfp_order)
> +static inline ssize_t iommu_unmap_fast(struct iommu_domain *domain,
> + unsigned long iova, int gfp_order)
> {
> return -ENODEV;
> }
>

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