[20/26] iommu/dma: Refactor iommu_dma_alloc, part 2
diff mbox series

Message ID 20190422175942.18788-21-hch@lst.de
State New
Headers show
Series
  • [01/26] arm64/iommu: handle non-remapped addresses in ->mmap and ->get_sgtable
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Commit Message

Christoph Hellwig April 22, 2019, 5:59 p.m. UTC
From: Robin Murphy <robin.murphy@arm.com>

Apart from the iommu_dma_alloc_remap() case which remains sufficiently
different that it's better off being self-contained, the rest of the
logic can now be consolidated into a single flow which separates the
logcially-distinct steps of allocating pages, getting the CPU address,
and finally getting the IOMMU address.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
[hch: split the page allocation into a new helper to simplify the flow]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/iommu/dma-iommu.c | 65 +++++++++++++++++++++------------------
 1 file changed, 35 insertions(+), 30 deletions(-)

Comments

Robin Murphy April 29, 2019, 2:45 p.m. UTC | #1
On 22/04/2019 18:59, Christoph Hellwig wrote:
> From: Robin Murphy <robin.murphy@arm.com>

Honestly I don't think anything left of my patch here...

> Apart from the iommu_dma_alloc_remap() case which remains sufficiently
> different that it's better off being self-contained, the rest of the
> logic can now be consolidated into a single flow which separates the
> logcially-distinct steps of allocating pages, getting the CPU address,
> and finally getting the IOMMU address.

...and it certainly doesn't do that any more.

It's clear that we have fundamentally different ways of reading code, so 
I don't think it's productive to keep arguing personal preference - I 
still find the end result here a fair bit more tolerable than before, so 
if you update the commit message to reflect the actual change (at which 
point there's really nothing left of my authorship) I can live with it.

Robin.

> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> [hch: split the page allocation into a new helper to simplify the flow]
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   drivers/iommu/dma-iommu.c | 65 +++++++++++++++++++++------------------
>   1 file changed, 35 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index 9b269f0792f3..acdfe866cb29 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -955,35 +955,14 @@ static void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr,
>   	__iommu_dma_free(dev, size, cpu_addr);
>   }
>   
> -static void *iommu_dma_alloc(struct device *dev, size_t size,
> -		dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
> +static void *iommu_dma_alloc_pages(struct device *dev, size_t size,
> +		struct page **pagep, gfp_t gfp, unsigned long attrs)
>   {
>   	bool coherent = dev_is_dma_coherent(dev);
> -	int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
>   	size_t alloc_size = PAGE_ALIGN(size);
>   	struct page *page = NULL;
>   	void *cpu_addr;
>   
> -	gfp |= __GFP_ZERO;
> -
> -	if (gfpflags_allow_blocking(gfp) &&
> -	    !(attrs & DMA_ATTR_FORCE_CONTIGUOUS))
> -		return iommu_dma_alloc_remap(dev, size, handle, gfp, attrs);
> -
> -	if (!gfpflags_allow_blocking(gfp) && !coherent) {
> -		cpu_addr = dma_alloc_from_pool(alloc_size, &page, gfp);
> -		if (!cpu_addr)
> -			return NULL;
> -
> -		*handle = __iommu_dma_map(dev, page_to_phys(page), size,
> -					  ioprot);
> -		if (*handle == DMA_MAPPING_ERROR) {
> -			dma_free_from_pool(cpu_addr, alloc_size);
> -			return NULL;
> -		}
> -		return cpu_addr;
> -	}
> -
>   	if (gfpflags_allow_blocking(gfp))
>   		page = dma_alloc_from_contiguous(dev, alloc_size >> PAGE_SHIFT,
>   						 get_order(alloc_size),
> @@ -993,33 +972,59 @@ static void *iommu_dma_alloc(struct device *dev, size_t size,
>   	if (!page)
>   		return NULL;
>   
> -	*handle = __iommu_dma_map(dev, page_to_phys(page), size, ioprot);
> -	if (*handle == DMA_MAPPING_ERROR)
> -		goto out_free_pages;
> -
>   	if (!coherent || PageHighMem(page)) {
>   		pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
>   
>   		cpu_addr = dma_common_contiguous_remap(page, alloc_size,
>   				VM_USERMAP, prot, __builtin_return_address(0));
>   		if (!cpu_addr)
> -			goto out_unmap;
> +			goto out_free_pages;
>   
>   		if (!coherent)
>   			arch_dma_prep_coherent(page, size);
>   	} else {
>   		cpu_addr = page_address(page);
>   	}
> +
> +	*pagep = page;
>   	memset(cpu_addr, 0, alloc_size);
>   	return cpu_addr;
> -out_unmap:
> -	__iommu_dma_unmap(dev, *handle, size);
>   out_free_pages:
>   	if (!dma_release_from_contiguous(dev, page, alloc_size >> PAGE_SHIFT))
>   		__free_pages(page, get_order(alloc_size));
>   	return NULL;
>   }
>   
> +static void *iommu_dma_alloc(struct device *dev, size_t size,
> +		dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
> +{
> +	bool coherent = dev_is_dma_coherent(dev);
> +	int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
> +	struct page *page = NULL;
> +	void *cpu_addr;
> +
> +	gfp |= __GFP_ZERO;
> +
> +	if (gfpflags_allow_blocking(gfp) &&
> +	    !(attrs & DMA_ATTR_FORCE_CONTIGUOUS))
> +		return iommu_dma_alloc_remap(dev, size, handle, gfp, attrs);
> +
> +	if (!gfpflags_allow_blocking(gfp) && !coherent)
> +		cpu_addr = dma_alloc_from_pool(PAGE_ALIGN(size), &page, gfp);
> +	else
> +		cpu_addr = iommu_dma_alloc_pages(dev, size, &page, gfp, attrs);
> +	if (!cpu_addr)
> +		return NULL;
> +
> +	*handle = __iommu_dma_map(dev, page_to_phys(page), size, ioprot);
> +	if (*handle == DMA_MAPPING_ERROR) {
> +		__iommu_dma_free(dev, size, cpu_addr);
> +		return NULL;
> +	}
> +
> +	return cpu_addr;
> +}
> +
>   static int __iommu_dma_mmap_pfn(struct vm_area_struct *vma,
>   			      unsigned long pfn, size_t size)
>   {
>

Patch
diff mbox series

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 9b269f0792f3..acdfe866cb29 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -955,35 +955,14 @@  static void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr,
 	__iommu_dma_free(dev, size, cpu_addr);
 }
 
-static void *iommu_dma_alloc(struct device *dev, size_t size,
-		dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
+static void *iommu_dma_alloc_pages(struct device *dev, size_t size,
+		struct page **pagep, gfp_t gfp, unsigned long attrs)
 {
 	bool coherent = dev_is_dma_coherent(dev);
-	int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
 	size_t alloc_size = PAGE_ALIGN(size);
 	struct page *page = NULL;
 	void *cpu_addr;
 
-	gfp |= __GFP_ZERO;
-
-	if (gfpflags_allow_blocking(gfp) &&
-	    !(attrs & DMA_ATTR_FORCE_CONTIGUOUS))
-		return iommu_dma_alloc_remap(dev, size, handle, gfp, attrs);
-
-	if (!gfpflags_allow_blocking(gfp) && !coherent) {
-		cpu_addr = dma_alloc_from_pool(alloc_size, &page, gfp);
-		if (!cpu_addr)
-			return NULL;
-
-		*handle = __iommu_dma_map(dev, page_to_phys(page), size,
-					  ioprot);
-		if (*handle == DMA_MAPPING_ERROR) {
-			dma_free_from_pool(cpu_addr, alloc_size);
-			return NULL;
-		}
-		return cpu_addr;
-	}
-
 	if (gfpflags_allow_blocking(gfp))
 		page = dma_alloc_from_contiguous(dev, alloc_size >> PAGE_SHIFT,
 						 get_order(alloc_size),
@@ -993,33 +972,59 @@  static void *iommu_dma_alloc(struct device *dev, size_t size,
 	if (!page)
 		return NULL;
 
-	*handle = __iommu_dma_map(dev, page_to_phys(page), size, ioprot);
-	if (*handle == DMA_MAPPING_ERROR)
-		goto out_free_pages;
-
 	if (!coherent || PageHighMem(page)) {
 		pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
 
 		cpu_addr = dma_common_contiguous_remap(page, alloc_size,
 				VM_USERMAP, prot, __builtin_return_address(0));
 		if (!cpu_addr)
-			goto out_unmap;
+			goto out_free_pages;
 
 		if (!coherent)
 			arch_dma_prep_coherent(page, size);
 	} else {
 		cpu_addr = page_address(page);
 	}
+
+	*pagep = page;
 	memset(cpu_addr, 0, alloc_size);
 	return cpu_addr;
-out_unmap:
-	__iommu_dma_unmap(dev, *handle, size);
 out_free_pages:
 	if (!dma_release_from_contiguous(dev, page, alloc_size >> PAGE_SHIFT))
 		__free_pages(page, get_order(alloc_size));
 	return NULL;
 }
 
+static void *iommu_dma_alloc(struct device *dev, size_t size,
+		dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
+{
+	bool coherent = dev_is_dma_coherent(dev);
+	int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
+	struct page *page = NULL;
+	void *cpu_addr;
+
+	gfp |= __GFP_ZERO;
+
+	if (gfpflags_allow_blocking(gfp) &&
+	    !(attrs & DMA_ATTR_FORCE_CONTIGUOUS))
+		return iommu_dma_alloc_remap(dev, size, handle, gfp, attrs);
+
+	if (!gfpflags_allow_blocking(gfp) && !coherent)
+		cpu_addr = dma_alloc_from_pool(PAGE_ALIGN(size), &page, gfp);
+	else
+		cpu_addr = iommu_dma_alloc_pages(dev, size, &page, gfp, attrs);
+	if (!cpu_addr)
+		return NULL;
+
+	*handle = __iommu_dma_map(dev, page_to_phys(page), size, ioprot);
+	if (*handle == DMA_MAPPING_ERROR) {
+		__iommu_dma_free(dev, size, cpu_addr);
+		return NULL;
+	}
+
+	return cpu_addr;
+}
+
 static int __iommu_dma_mmap_pfn(struct vm_area_struct *vma,
 			      unsigned long pfn, size_t size)
 {