[PATCH 21/25] iommu/dma: Refactor iommu_dma_mmap

Christoph Hellwig
2019-04-30T10:52:10Z

Inline __iommu_dma_mmap_pfn into the main function, and use the
fact that __iommu_dma_get_pages return NULL for remapped contigous
allocations to simplify the code flow a bit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
---
drivers/iommu/dma-iommu.c | 46 ++++++++++-----------------------------
1 file changed, 11 insertions(+), 35 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 5d4013ffd068..9ace9ad73e10 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1023,31 +1023,12 @@ static void *iommu_dma_alloc(struct device *dev, size_t size,
return cpu_addr;
}

-static int __iommu_dma_mmap_pfn(struct vm_area_struct *vma,
- unsigned long pfn, size_t size)
-{
- int ret = -ENXIO;
- unsigned long nr_vma_pages = vma_pages(vma);
- unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
- unsigned long off = vma->vm_pgoff;
-
- if (off < nr_pages && nr_vma_pages <= (nr_pages - off)) {
- ret = remap_pfn_range(vma, vma->vm_start,
- pfn + off,
- vma->vm_end - vma->vm_start,
- vma->vm_page_prot);
- }
-
- return ret;
-}
-
static int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs)
{
unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
- unsigned long off = vma->vm_pgoff;
- struct page **pages;
+ unsigned long pfn, off = vma->vm_pgoff;
int ret;

vma->vm_page_prot = arch_dma_mmap_pgprot(dev, vma->vm_page_prot, attrs);
@@ -1058,24 +1039,19 @@ static int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,
if (off >= nr_pages || vma_pages(vma) > nr_pages - off)
return -ENXIO;

- if (!is_vmalloc_addr(cpu_addr)) {
- unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
- return __iommu_dma_mmap_pfn(vma, pfn, size);
- }
+ if (is_vmalloc_addr(cpu_addr)) {
+ struct page **pages = __iommu_dma_get_pages(cpu_addr);

- if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
- /*
- * DMA_ATTR_FORCE_CONTIGUOUS allocations are always remapped,
- * hence in the vmalloc space.
- */
- unsigned long pfn = vmalloc_to_pfn(cpu_addr);
- return __iommu_dma_mmap_pfn(vma, pfn, size);
+ if (pages)
+ return __iommu_dma_mmap(pages, size, vma);
+ pfn = vmalloc_to_pfn(cpu_addr);
+ } else {
+ pfn = page_to_pfn(virt_to_page(cpu_addr));
}

- pages = __iommu_dma_get_pages(cpu_addr);
- if (!pages)
- return -ENXIO;
- return __iommu_dma_mmap(pages, size, vma);
+ return remap_pfn_range(vma, vma->vm_start, pfn + off,
+ vma->vm_end - vma->vm_start,
+ vma->vm_page_prot);
}

static int iommu_dma_get_sgtable(struct device *dev, struct sg_table *sgt,
--
2.20.1