dma-iommu: remove __iommu_dma_mmap

The function has a single caller, so open code it there and take
advantage of the precalculated page count variable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20201209112019.2625029-1-hch@lst.de
Signed-off-by: Will Deacon <will@kernel.org>

drivers/iommu/dma-iommu.c

@@ -752,21 +752,6 @@ 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)
 {
@@ -1287,7 +1272,7 @@ static int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,
 		struct page **pages = dma_common_find_pages(cpu_addr);
 
 		if (pages)
-			return __iommu_dma_mmap(pages, size, vma);
+			return vm_map_pages(vma, pages, nr_pages);
 		pfn = vmalloc_to_pfn(cpu_addr);
 	} else {
 		pfn = page_to_pfn(virt_to_page(cpu_addr));