Commit f3c96222 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

dma-direct: clean up the remapping checks in dma_direct_alloc 



Add two local variables to track if we want to remap the returned
address using vmap or call dma_set_uncached and use that to simplify
the code flow.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarRobin Murphy <robin.murphy@arm.com>
parent a90cf304

kernel/dma/direct.c

+26 −22
Original line number Diff line number Diff line
@@ -171,6 +171,7 @@ static void *dma_direct_alloc_from_pool(struct device *dev, size_t size, 
void *dma_direct_alloc(struct device *dev, size_t size,

		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)

{

	bool remap = false, set_uncached = false;

	struct page *page;

	void *ret;
@@ -222,9 +223,25 @@ void *dma_direct_alloc(struct device *dev, size_t size, 
	if (!page)

		return NULL;



	if ((IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&

	     !dev_is_dma_coherent(dev)) ||

	    (IS_ENABLED(CONFIG_DMA_REMAP) && PageHighMem(page))) {

	if (!dev_is_dma_coherent(dev) && IS_ENABLED(CONFIG_DMA_DIRECT_REMAP)) {

		remap = true;

	} else if (PageHighMem(page)) {

		/*

		 * Depending on the cma= arguments and per-arch setup,

		 * dma_alloc_contiguous could return highmem pages.

		 * Without remapping there is no way to return them here, so

		 * log an error and fail.

		 */

		if (!IS_ENABLED(CONFIG_DMA_REMAP)) {

			dev_info(dev, "Rejecting highmem page from CMA.\n");

			goto out_free_pages;

		}

		remap = true;

	} else if (!dev_is_dma_coherent(dev) &&

		   IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED))

		set_uncached = true;



	if (remap) {

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

		arch_dma_prep_coherent(page, size);
@@ -234,34 +251,21 @@ void *dma_direct_alloc(struct device *dev, size_t size, 
				__builtin_return_address(0));

		if (!ret)

			goto out_free_pages;

		memset(ret, 0, size);

		goto done;

	}



	if (PageHighMem(page)) {

		/*

		 * Depending on the cma= arguments and per-arch setup

		 * dma_alloc_contiguous could return highmem pages.

		 * Without remapping there is no way to return them here,

		 * so log an error and fail.

		 */

		dev_info(dev, "Rejecting highmem page from CMA.\n");

		goto out_free_pages;

	}



	} else {

		ret = page_address(page);

		if (dma_set_decrypted(dev, ret, size))

			goto out_free_pages;

	}



	memset(ret, 0, size);



	if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&

	    !dev_is_dma_coherent(dev)) {

	if (set_uncached) {

		arch_dma_prep_coherent(page, size);

		ret = arch_dma_set_uncached(ret, size);

		if (IS_ERR(ret))

			goto out_encrypt_pages;

	}

done:



	*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));

	return ret;