diff options
| author | Christoph Hellwig | 2019-03-15 17:56:43 +0100 |
|---|---|---|
| committer | Christoph Hellwig | 2019-09-04 11:13:17 +0200 |
| commit | 14451467014b4c8aff6570b44b6d0ee68cd49bc0 (patch) | |
| tree | 66eec34dfcf1db31d85ebc9b1387e4ec43fe8a58 | |
| parent | 392e879a445008e8e96b872dabaaf5b1eca58729 (diff) | |
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 <hch@lst.de>
| -rw-r--r-- | arch/arm/mm/dma-mapping.c | 11 | ||||
| -rw-r--r-- | kernel/dma/mapping.c | 11 |
2 files changed, 11 insertions, 11 deletions
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) diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 72c825c1788e..a136932b8e6d 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -136,6 +136,17 @@ int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt, return ret; } +/* + * 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 dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr, dma_addr_t dma_addr, size_t size, unsigned long attrs) |