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iommu/dma: Refactor iommu_dma_free

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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: Robin Murphy <robin.murphy@arm.com>
[various cosmetic changes to the code flow]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Robin Murphy 2019-05-20 09:29:36 +02:00 committed by Joerg Roedel
parent aa8ba22757
commit bcf4b9c4c2
1 changed files with 33 additions and 40 deletions
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73
drivers/iommu/dma-iommu.c
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@ -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)
{