Commit bcf4b9c4 authored by Robin Murphy's avatar Robin Murphy Committed by Joerg Roedel
Browse files

iommu/dma: Refactor iommu_dma_free 



The freeing logic was made particularly horrible by part of it being
opaque to the arch wrapper, which led to a lot of convoluted repetition
to ensure each path did everything in the right order. Now that it's
all private, we can pick apart and consolidate the logically-distinct
steps of freeing the IOMMU mapping, the underlying pages, and the CPU
remap (if necessary) into something much more manageable.

Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
[various cosmetic changes to the code flow]
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent aa8ba227

drivers/iommu/dma-iommu.c

+33 −40
Original line number Diff line number Diff line
@@ -935,6 +935,39 @@ static void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle, 
	__iommu_dma_unmap(dev, handle, size);

}



static void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr,

		dma_addr_t handle, unsigned long attrs)

{

	size_t alloc_size = PAGE_ALIGN(size);

	int count = alloc_size >> PAGE_SHIFT;

	struct page *page = NULL, **pages = NULL;



	__iommu_dma_unmap(dev, handle, size);



	/* Non-coherent atomic allocation? Easy */

	if (dma_free_from_pool(cpu_addr, alloc_size))

		return;



	if (is_vmalloc_addr(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);

		if (!pages)

			page = vmalloc_to_page(cpu_addr);

		dma_common_free_remap(cpu_addr, alloc_size, VM_USERMAP);

	} else {

		/* Lowmem means a coherent atomic or CMA allocation */

		page = virt_to_page(cpu_addr);

	}



	if (pages)

		__iommu_dma_free_pages(pages, count);

	if (page && !dma_release_from_contiguous(dev, page, count))

		__free_pages(page, get_order(alloc_size));

}



static void *iommu_dma_alloc(struct device *dev, size_t size,

		dma_addr_t *handle, gfp_t gfp, unsigned long attrs)

{
@@ -1004,46 +1037,6 @@ static void *iommu_dma_alloc(struct device *dev, size_t size, 
	return addr;

}



static void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr,

		dma_addr_t handle, unsigned long attrs)

{

	size_t iosize = size;



	size = PAGE_ALIGN(size);

	/*

	 * @cpu_addr will be one of 4 things depending on how it was allocated:

	 * - A remapped array of pages for contiguous allocations.

	 * - A remapped array of pages from iommu_dma_alloc_remap(), for all

	 *   non-atomic allocations.

	 * - A non-cacheable alias from the atomic pool, for atomic

	 *   allocations by non-coherent devices.

	 * - A normal lowmem address, for atomic allocations by

	 *   coherent devices.

	 * Hence how dodgy the below logic looks...

	 */

	if (dma_in_atomic_pool(cpu_addr, size)) {

		__iommu_dma_unmap(dev, handle, iosize);

		dma_free_from_pool(cpu_addr, size);

	} else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {

		struct page *page = vmalloc_to_page(cpu_addr);



		__iommu_dma_unmap(dev, handle, iosize);

		dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);

		dma_common_free_remap(cpu_addr, size, VM_USERMAP);

	} else if (is_vmalloc_addr(cpu_addr)){

		struct page **pages = __iommu_dma_get_pages(cpu_addr);



		if (!pages)

			return;

		__iommu_dma_unmap(dev, handle, iosize);

		__iommu_dma_free_pages(pages, size >> PAGE_SHIFT);

		dma_common_free_remap(cpu_addr, size, VM_USERMAP);

	} else {

		__iommu_dma_unmap(dev, handle, iosize);

		__free_pages(virt_to_page(cpu_addr), get_order(size));

	}

}



static int __iommu_dma_mmap_pfn(struct vm_area_struct *vma,

			      unsigned long pfn, size_t size)

{

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