dma-direct: comment the dma_direct_free calling convention

Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-02-02 09:51:14 +01:00 · 2018-02-02 09:51:14 +01:00 · 42ed64524d
parent f25e6f6b4e
commit 42ed64524d
1 changed files with 4 additions and 0 deletions
--- 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)
 {