[PATCH 2/2] dma: remove unsupported gfp_mask...

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

From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: 2018-07-09 12:20:45

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>
---
 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

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

From: Vlastimil Babka <hidden>
Date: 2018-07-16 07:45:39

On 07/09/2018 02:19 PM, Marek Szyprowski 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: Vlastimil Babka <redacted>

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

From: Christoph Hellwig <hch@lst.de>
Date: 2018-07-17 15:06:03

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

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