Commit 5cf45379 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

dma-mapping: introduce a dma_common_find_pages helper 



A helper to find the backing page array based on a virtual address.
This also ensures we do the same vm_flags check everywhere instead
of slightly different or missing ones in a few places.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 51231740

arch/arm/mm/dma-mapping.c

+1 −6
Original line number Diff line number Diff line
@@ -1439,18 +1439,13 @@ static struct page **__atomic_get_pages(void *addr) 


static struct page **__iommu_get_pages(void *cpu_addr, unsigned long attrs)

{

	struct vm_struct *area;



	if (__in_atomic_pool(cpu_addr, PAGE_SIZE))

		return __atomic_get_pages(cpu_addr);



	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING)

		return cpu_addr;



	area = find_vm_area(cpu_addr);

	if (area && (area->flags & VM_DMA_COHERENT))

		return area->pages;

	return NULL;

	return dma_common_find_pages(cpu_addr);

}



static void *__iommu_alloc_simple(struct device *dev, size_t size, gfp_t gfp,

drivers/iommu/dma-iommu.c

+3 −12
Original line number Diff line number Diff line
@@ -541,15 +541,6 @@ static struct page **__iommu_dma_alloc_pages(struct device *dev, 
	return pages;

}



static struct page **__iommu_dma_get_pages(void *cpu_addr)

{

	struct vm_struct *area = find_vm_area(cpu_addr);



	if (!area || !area->pages)

		return NULL;

	return area->pages;

}



/**

 * iommu_dma_alloc_remap - Allocate and map a buffer contiguous in IOVA space

 * @dev: Device to allocate memory for. Must be a real device
@@ -938,7 +929,7 @@ static void __iommu_dma_free(struct device *dev, size_t size, void *cpu_addr) 
		 * If it the address is remapped, then it's either non-coherent

		 * or highmem CMA, or an iommu_dma_alloc_remap() construction.

		 */

		pages = __iommu_dma_get_pages(cpu_addr);

		pages = dma_common_find_pages(cpu_addr);

		if (!pages)

			page = vmalloc_to_page(cpu_addr);

		dma_common_free_remap(cpu_addr, alloc_size);
@@ -1045,7 +1036,7 @@ static int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma, 
		return -ENXIO;



	if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) {

		struct page **pages = __iommu_dma_get_pages(cpu_addr);

		struct page **pages = dma_common_find_pages(cpu_addr);



		if (pages)

			return __iommu_dma_mmap(pages, size, vma);
@@ -1067,7 +1058,7 @@ static int iommu_dma_get_sgtable(struct device *dev, struct sg_table *sgt, 
	int ret;



	if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) {

		struct page **pages = __iommu_dma_get_pages(cpu_addr);

		struct page **pages = dma_common_find_pages(cpu_addr);



		if (pages) {

			return sg_alloc_table_from_pages(sgt, pages,

include/linux/dma-mapping.h

+1 −0
Original line number Diff line number Diff line
@@ -626,6 +626,7 @@ extern int dma_common_mmap(struct device *dev, struct vm_area_struct *vma, 
		void *cpu_addr, dma_addr_t dma_addr, size_t size,

		unsigned long attrs);



struct page **dma_common_find_pages(void *cpu_addr);

void *dma_common_contiguous_remap(struct page *page, size_t size,

			pgprot_t prot, const void *caller);

kernel/dma/remap.c

+11 −2
Original line number Diff line number Diff line
@@ -11,6 +11,15 @@ 
#include <linux/slab.h>

#include <linux/vmalloc.h>



struct page **dma_common_find_pages(void *cpu_addr)

{

	struct vm_struct *area = find_vm_area(cpu_addr);



	if (!area || area->flags != VM_DMA_COHERENT)

		return NULL;

	return area->pages;

}



static struct vm_struct *__dma_common_pages_remap(struct page **pages,

			size_t size, pgprot_t prot, const void *caller)

{
@@ -78,9 +87,9 @@ void *dma_common_contiguous_remap(struct page *page, size_t size, 
 */

void dma_common_free_remap(void *cpu_addr, size_t size)

{

	struct vm_struct *area = find_vm_area(cpu_addr);

	struct page **pages = dma_common_find_pages(cpu_addr);



	if (!area || area->flags != VM_DMA_COHERENT) {

	if (!pages) {

		WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);

		return;

	}