Re: [PATCH 2/2] dma: remove unsupported gfp_mask parameter from dma_alloc_from_contiguous()

["Michał Nazarewicz" <mina86@mina86.com>]

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On Mon, 9 Jul 2018 13:20 Marek Szyprowski, <m.szyprowski@samsung.com> wrote:

> The CMA memory allocator doesn't support standard gfp flags for memory
> allocation, so there is no point having it as a parameter for
> dma_alloc_from_contiguous() function. Replace it by a boolean no_warn
> argument, which covers all the underlaying cma_alloc() function supports.
>
> This will help to avoid giving false feeling that this function supports
> standard gfp flags and callers can pass __GFP_ZERO to get zeroed buffer,
> what has already been an issue: see commit dd65a941f6ba ("arm64:
> dma-mapping: clear buffers allocated with FORCE_CONTIGUOUS flag").
>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>

Acked-by: Michał Nazarewicz <mina86@mina86.com>

---
>  arch/arm/mm/dma-mapping.c      | 5 +++--
>  arch/arm64/mm/dma-mapping.c    | 4 ++--
>  arch/xtensa/kernel/pci-dma.c   | 2 +-
>  drivers/iommu/amd_iommu.c      | 2 +-
>  drivers/iommu/intel-iommu.c    | 3 ++-
>  include/linux/dma-contiguous.h | 4 ++--
>  kernel/dma/contiguous.c        | 7 +++----
>  kernel/dma/direct.c            | 3 ++-
>  8 files changed, 16 insertions(+), 14 deletions(-)
>
> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index be0fa7e39c26..121c6c3ba9e0 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -594,7 +594,7 @@ static void *__alloc_from_contiguous(struct device
> *dev, size_t size,
>         struct page *page;
>         void *ptr = NULL;
>
> -       page = dma_alloc_from_contiguous(dev, count, order, gfp);
> +       page = dma_alloc_from_contiguous(dev, count, order, gfp &
> __GFP_NOWARN);
>         if (!page)
>                 return NULL;
>
> @@ -1294,7 +1294,8 @@ static struct page **__iommu_alloc_buffer(struct
> device *dev, size_t size,
>                 unsigned long order = get_order(size);
>                 struct page *page;
>
> -               page = dma_alloc_from_contiguous(dev, count, order, gfp);
> +               page = dma_alloc_from_contiguous(dev, count, order,
> +                                                gfp & __GFP_NOWARN);
>                 if (!page)
>                         goto error;
>
> diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
> index 61e93f0b5482..072c51fb07d7 100644
> --- a/arch/arm64/mm/dma-mapping.c
> +++ b/arch/arm64/mm/dma-mapping.c
> @@ -355,7 +355,7 @@ static int __init atomic_pool_init(void)
>
>         if (dev_get_cma_area(NULL))
>                 page = dma_alloc_from_contiguous(NULL, nr_pages,
> -                                                pool_size_order,
> GFP_KERNEL);
> +                                                pool_size_order, false);
>         else
>                 page = alloc_pages(GFP_DMA32, pool_size_order);
>
> @@ -573,7 +573,7 @@ static void *__iommu_alloc_attrs(struct device *dev,
> size_t size,
>                 struct page *page;
>
>                 page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
> -                                                get_order(size), gfp);
> +                                       get_order(size), gfp &
> __GFP_NOWARN);
>                 if (!page)
>                         return NULL;
>
> diff --git a/arch/xtensa/kernel/pci-dma.c b/arch/xtensa/kernel/pci-dma.c
> index ba4640cc0093..b2c7ba91fb08 100644
> --- a/arch/xtensa/kernel/pci-dma.c
> +++ b/arch/xtensa/kernel/pci-dma.c
> @@ -137,7 +137,7 @@ static void *xtensa_dma_alloc(struct device *dev,
> size_t size,
>
>         if (gfpflags_allow_blocking(flag))
>                 page = dma_alloc_from_contiguous(dev, count,
> get_order(size),
> -                                                flag);
> +                                                flag & __GFP_NOWARN);
>
>         if (!page)
>                 page = alloc_pages(flag, get_order(size));
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 64cfe854e0f5..5ec97ffb561a 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -2622,7 +2622,7 @@ static void *alloc_coherent(struct device *dev,
> size_t size,
>                         return NULL;
>
>                 page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
> -                                                get_order(size), flag);
> +                                       get_order(size), flag &
> __GFP_NOWARN);
>                 if (!page)
>                         return NULL;
>         }
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 869321c594e2..dd2d343428ab 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -3746,7 +3746,8 @@ static void *intel_alloc_coherent(struct device
> *dev, size_t size,
>         if (gfpflags_allow_blocking(flags)) {
>                 unsigned int count = size >> PAGE_SHIFT;
>
> -               page = dma_alloc_from_contiguous(dev, count, order, flags);
> +               page = dma_alloc_from_contiguous(dev, count, order,
> +                                                flags & __GFP_NOWARN);
>                 if (page && iommu_no_mapping(dev) &&
>                     page_to_phys(page) + size > dev->coherent_dma_mask) {
>                         dma_release_from_contiguous(dev, page, count);
> diff --git a/include/linux/dma-contiguous.h
> b/include/linux/dma-contiguous.h
> index 3c5a4cb3eb95..f247e8aa5e3d 100644
> --- a/include/linux/dma-contiguous.h
> +++ b/include/linux/dma-contiguous.h
> @@ -112,7 +112,7 @@ static inline int dma_declare_contiguous(struct device
> *dev, phys_addr_t size,
>  }
>
>  struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
> -                                      unsigned int order, gfp_t gfp_mask);
> +                                      unsigned int order, bool no_warn);
>  bool dma_release_from_contiguous(struct device *dev, struct page *pages,
>                                  int count);
>
> @@ -145,7 +145,7 @@ int dma_declare_contiguous(struct device *dev,
> phys_addr_t size,
>
>  static inline
>  struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
> -                                      unsigned int order, gfp_t gfp_mask)
> +                                      unsigned int order, bool no_warn)
>  {
>         return NULL;
>  }
> diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
> index 19ea5d70150c..286d82329eb0 100644
> --- a/kernel/dma/contiguous.c
> +++ b/kernel/dma/contiguous.c
> @@ -178,7 +178,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t
> size, phys_addr_t base,
>   * @dev:   Pointer to device for which the allocation is performed.
>   * @count: Requested number of pages.
>   * @align: Requested alignment of pages (in PAGE_SIZE order).
> - * @gfp_mask: GFP flags to use for this allocation.
> + * @no_warn: Avoid printing message about failed allocation.
>   *
>   * This function allocates memory buffer for specified device. It uses
>   * device specific contiguous memory area if available or the default
> @@ -186,13 +186,12 @@ int __init dma_contiguous_reserve_area(phys_addr_t
> size, phys_addr_t base,
>   * function.
>   */
>  struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
> -                                      unsigned int align, gfp_t gfp_mask)
> +                                      unsigned int align, bool no_warn)
>  {
>         if (align > CONFIG_CMA_ALIGNMENT)
>                 align = CONFIG_CMA_ALIGNMENT;
>
> -       return cma_alloc(dev_get_cma_area(dev), count, align,
> -                        gfp_mask & __GFP_NOWARN);
> +       return cma_alloc(dev_get_cma_area(dev), count, align, no_warn);
>  }
>
>  /**
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> index 8be8106270c2..e0241beeb645 100644
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -78,7 +78,8 @@ void *dma_direct_alloc(struct device *dev, size_t size,
> dma_addr_t *dma_handle,
>  again:
>         /* CMA can be used only in the context which permits sleeping */
>         if (gfpflags_allow_blocking(gfp)) {
> -               page = dma_alloc_from_contiguous(dev, count, page_order,
> gfp);
> +               page = dma_alloc_from_contiguous(dev, count, page_order,
> +                                                gfp & __GFP_NOWARN);
>                 if (page && !dma_coherent_ok(dev, page_to_phys(page),
> size)) {
>                         dma_release_from_contiguous(dev, page, count);
>                         page = NULL;
> --
> 2.17.1
>
>

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