dma-direct: factor out a helper for DMA_ATTR_NO_KERNEL_MAPPING allocations

Split the code for DMA_ATTR_NO_KERNEL_MAPPING allocations into a separate
helper to make dma_direct_alloc a little more readable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: David Rientjes <rientjes@google.com>

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 3d1718d..0110466 100644 (file)
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -168,6 +168,24 @@ static void *dma_direct_alloc_from_pool(struct device *dev, size_t size,
        return ret;
 }
 
+static void *dma_direct_alloc_no_mapping(struct device *dev, size_t size,
+               dma_addr_t *dma_handle, gfp_t gfp)
+{
+       struct page *page;
+
+       page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO);
+       if (!page)
+               return NULL;
+
+       /* remove any dirty cache lines on the kernel alias */
+       if (!PageHighMem(page))
+               arch_dma_prep_coherent(page, size);
+
+       /* return the page pointer as the opaque cookie */
+       *dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
+       return page;
+}
+
 void *dma_direct_alloc(struct device *dev, size_t size,
                dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
 {
@@ -180,17 +198,8 @@ void *dma_direct_alloc(struct device *dev, size_t size,
                gfp |= __GFP_NOWARN;
 
        if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
-           !force_dma_unencrypted(dev) && !is_swiotlb_for_alloc(dev)) {
-               page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO);
-               if (!page)
-                       return NULL;
-               /* remove any dirty cache lines on the kernel alias */
-               if (!PageHighMem(page))
-                       arch_dma_prep_coherent(page, size);
-               *dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
-               /* return the page pointer as the opaque cookie */
-               return page;
-       }
+           !force_dma_unencrypted(dev) && !is_swiotlb_for_alloc(dev))
+               return dma_direct_alloc_no_mapping(dev, size, dma_handle, gfp);
 
        if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
            !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&