From 42ed64524d846b96afaa8b3f9ba045bcaf11ab0f Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 2 Feb 2018 09:51:14 +0100 Subject: [PATCH] dma-direct: comment the dma_direct_free calling convention Signed-off-by: Christoph Hellwig --- lib/dma-direct.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/lib/dma-direct.c b/lib/dma-direct.c index fdc733cf9e30..c9e8e21cb334 100644 --- a/lib/dma-direct.c +++ b/lib/dma-direct.c @@ -84,6 +84,10 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, return page_address(page); } +/* + * NOTE: this function must never look at the dma_addr argument, because we want + * to be able to use it as a helper for iommu implementations as well. + */ void dma_direct_free(struct device *dev, size_t size, void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs) {