kernel: dma: disallow altering logical map for non-CMA allocs

DMA_ATTR_STRONGLY_ORDERED and DMA_ATTR_NO_KERNEL_MAPPING alters
the logical mapping of allocated memory. This works only for CMA
allocations where the pages are PAGE_SIZE mapped.
Disallow fallback to buddy alloc if above attrs are set.

Change-Id: I25c632d3c9179e22bc5061fd5f7e9ab6e7847322
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>

kernel/dma/direct.c

@@ -85,7 +85,8 @@ again:
 			page = NULL;
 		}
 	}
-	if (!page)
+	if (!page && !(attrs & (DMA_ATTR_STRONGLY_ORDERED |
+				DMA_ATTR_NO_KERNEL_MAPPING)))
 		page = alloc_pages_node(dev_to_node(dev), gfp, page_order);
 
 	if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {

kernel/dma/swiotlb.c

@@ -1026,7 +1026,8 @@ void *swiotlb_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 	gfp |= __GFP_NOWARN;
 
 	vaddr = dma_direct_alloc(dev, size, dma_handle, gfp, attrs);
-	if (!vaddr)
+	if (!vaddr && !(attrs & (DMA_ATTR_STRONGLY_ORDERED |
+				DMA_ATTR_NO_KERNEL_MAPPING)))
 		vaddr = swiotlb_alloc_buffer(dev, size, dma_handle, attrs);
 	return vaddr;
 }