From 14451467014b4c8aff6570b44b6d0ee68cd49bc0 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 15 Mar 2019 17:56:43 +0100 Subject: dma-mapping: move the dma_get_sgtable API comments from arm to common code The comments are spot on and should be near the central API, not just near a single implementation. Signed-off-by: Christoph Hellwig --- arch/arm/mm/dma-mapping.c | 11 ----------- 1 file changed, 11 deletions(-) (limited to 'arch/arm/mm/dma-mapping.c') diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index d27b12f61737..0189a757a8f2 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -877,17 +877,6 @@ static void arm_coherent_dma_free(struct device *dev, size_t size, void *cpu_add __arm_dma_free(dev, size, cpu_addr, handle, attrs, true); } -/* - * The whole dma_get_sgtable() idea is fundamentally unsafe - it seems - * that the intention is to allow exporting memory allocated via the - * coherent DMA APIs through the dma_buf API, which only accepts a - * scattertable. This presents a couple of problems: - * 1. Not all memory allocated via the coherent DMA APIs is backed by - * a struct page - * 2. Passing coherent DMA memory into the streaming APIs is not allowed - * as we will try to flush the memory through a different alias to that - * actually being used (and the flushes are redundant.) - */ int arm_dma_get_sgtable(struct device *dev, struct sg_table *sgt, void *cpu_addr, dma_addr_t handle, size_t size, unsigned long attrs) -- cgit