[PATCH 19/23] iommu/dma: Refactor iommu_dma_mmap

Christoph Hellwig
2019-05-23T07:01:31Z

Inline __iommu_dma_mmap and __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 | 60 +++++++--------------------------------
1 file changed, 11 insertions(+), 49 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index b56bd8e7d5f9..ea2797d10070 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -650,21 +650,6 @@ static void *iommu_dma_alloc_remap(struct device *dev, size_t size,
return NULL;
}

-/**
- * __iommu_dma_mmap - Map a buffer into provided user VMA
- * @pages: Array representing buffer from __iommu_dma_alloc()
- * @size: Size of buffer in bytes
- * @vma: VMA describing requested userspace mapping
- *
- * Maps the pages of the buffer in @pages into @vma. The caller is responsible
- * for verifying the correct size and protection of @vma beforehand.
- */
-static int __iommu_dma_mmap(struct page **pages, size_t size,
- struct vm_area_struct *vma)
-{
- return vm_map_pages(vma, pages, PAGE_ALIGN(size) >> PAGE_SHIFT);
-}
-
static void iommu_dma_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
{
@@ -1042,31 +1027,13 @@ 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;
int ret;

vma->vm_page_prot = arch_dma_mmap_pgprot(dev, vma->vm_page_prot, attrs);
@@ -1077,24 +1044,19 @@ 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 vm_map_pages(vma, pages, nr_pages);
+ 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