Commit d98849af authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING in common code 



DMA_ATTR_NO_KERNEL_MAPPING is generally implemented by allocating
normal cacheable pages or CMA memory, and then returning the page
pointer as the opaque handle.  Lift that code from the xtensa and
generic dma remapping implementations into the generic dma-direct
code so that we don't even call arch_dma_alloc for these allocations.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent c2f2124e

arch/xtensa/kernel/pci-dma.c

+1 −7
Original line number Diff line number Diff line
@@ -167,10 +167,6 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, 


	*handle = phys_to_dma(dev, page_to_phys(page));



	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {

		return page;

	}



#ifdef CONFIG_MMU

	if (PageHighMem(page)) {

		void *p;
@@ -196,9 +192,7 @@ void arch_dma_free(struct device *dev, size_t size, void *vaddr, 
	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;

	struct page *page;



	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {

		page = vaddr;

	} else if (platform_vaddr_uncached(vaddr)) {

	if (platform_vaddr_uncached(vaddr)) {

		page = virt_to_page(platform_vaddr_to_cached(vaddr));

	} else {

#ifdef CONFIG_MMU

include/linux/dma-noncoherent.h

+2 −0
Original line number Diff line number Diff line
@@ -28,6 +28,8 @@ static inline bool dma_alloc_need_uncached(struct device *dev, 
{

	if (dev_is_dma_coherent(dev))

		return false;

	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING)

		return false;

	if (IS_ENABLED(CONFIG_DMA_NONCOHERENT_CACHE_SYNC) &&

	    (attrs & DMA_ATTR_NON_CONSISTENT))

		return false;

kernel/dma/direct.c

+14 −0
Original line number Diff line number Diff line
@@ -138,6 +138,14 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size, 
	if (!page)

		return NULL;



	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {

		/* remove any dirty cache lines on the kernel alias */

		if (!PageHighMem(page))

			arch_dma_prep_coherent(page, size);

		/* return the page pointer as the opaque cookie */

		return page;

	}



	if (PageHighMem(page)) {

		/*

		 * Depending on the cma= arguments and per-arch setup
@@ -178,6 +186,12 @@ void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr, 
{

	unsigned int page_order = get_order(size);



	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {

		/* cpu_addr is a struct page cookie, not a kernel address */

		__dma_direct_free_pages(dev, size, cpu_addr);

		return;

	}



	if (force_dma_unencrypted())

		set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);

kernel/dma/remap.c

+2 −11
Original line number Diff line number Diff line
@@ -202,8 +202,7 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, 


	size = PAGE_ALIGN(size);



	if (!gfpflags_allow_blocking(flags) &&

	    !(attrs & DMA_ATTR_NO_KERNEL_MAPPING)) {

	if (!gfpflags_allow_blocking(flags)) {

		ret = dma_alloc_from_pool(size, &page, flags);

		if (!ret)

			return NULL;
@@ -217,11 +216,6 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, 
	/* remove any dirty cache lines on the kernel alias */

	arch_dma_prep_coherent(page, size);



	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {

		ret = page; /* opaque cookie */

		goto done;

	}



	/* create a coherent mapping */

	ret = dma_common_contiguous_remap(page, size, VM_USERMAP,

			arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs),
@@ -240,10 +234,7 @@ done: 
void arch_dma_free(struct device *dev, size_t size, void *vaddr,

		dma_addr_t dma_handle, unsigned long attrs)

{

	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {

		/* vaddr is a struct page cookie, not a kernel address */

		__dma_direct_free_pages(dev, size, vaddr);

	} else if (!dma_free_from_pool(vaddr, PAGE_ALIGN(size))) {

	if (!dma_free_from_pool(vaddr, PAGE_ALIGN(size))) {

		phys_addr_t phys = dma_to_phys(dev, dma_handle);

		struct page *page = pfn_to_page(__phys_to_pfn(phys));

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