dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING in common code

DMA_ATTR_NO_KERNEL_MAPPING is generally implemented by allocating
normal cacheable pages or CMA memory, and then returning the page
pointer as the opaque handle.  Lift that code from the xtensa and
generic dma remapping implementations into the generic dma-direct
code so that we don't even call arch_dma_alloc for these allocations.

Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 14 insertions, 0 deletions

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index fc354f4f490b..b90e1aede743 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -138,6 +138,14 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
 	if (!page)
 		return NULL;
 
+	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {
+		/* 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 */
+		return page;
+	}
+
 	if (PageHighMem(page)) {
 		/*
 		 * Depending on the cma= arguments and per-arch setup
@@ -178,6 +186,12 @@ void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,
 {
 	unsigned int page_order = get_order(size);
 
+	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {
+		/* cpu_addr is a struct page cookie, not a kernel address */
+		__dma_direct_free_pages(dev, size, cpu_addr);
+		return;
+	}
+
 	if (force_dma_unencrypted())
 		set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);