diff options
| author | Sakari Ailus <sakari.ailus@iki.fi> | 2015-09-23 13:41:09 +0200 |
|---|---|---|
| committer | Jonathan Corbet <corbet@lwn.net> | 2015-09-24 23:50:06 +0200 |
| commit | 7bc590b2fc057f3c48b618c739517bf1af9a28fe (patch) | |
| tree | ff8516085cd5098e5e0fcf83e3d72fe6564cc40c | |
| parent | Documentation: Update the default value of crashkernel low (diff) | |
| download | linux-7bc590b2fc057f3c48b618c739517bf1af9a28fe.tar.xz linux-7bc590b2fc057f3c48b618c739517bf1af9a28fe.zip | |
Documentation: DMA API: Be more explicit that nents is always the same
The nents argument to the DMA API functions operating on scatterlists is
always the same. The documentation used different argument names and the
matter was not mentioned in Documentation/DMA-API-HOWTO.txt at all. Fix
these.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
| -rw-r--r-- | Documentation/DMA-API-HOWTO.txt | 5 | ||||
| -rw-r--r-- | Documentation/DMA-API.txt | 6 |
2 files changed, 8 insertions, 3 deletions
diff --git a/Documentation/DMA-API-HOWTO.txt b/Documentation/DMA-API-HOWTO.txt index 55b70b903ead..d69b3fc64e14 100644 --- a/Documentation/DMA-API-HOWTO.txt +++ b/Documentation/DMA-API-HOWTO.txt @@ -681,6 +681,11 @@ or: as appropriate. +PLEASE NOTE: The 'nents' argument to dma_sync_sg_for_cpu() and + dma_sync_sg_for_device() must be the same passed to + dma_map_sg(). It is _NOT_ the count returned by + dma_map_sg(). + After the last DMA transfer call one of the DMA unmap routines dma_unmap_{single,sg}(). If you don't touch the data from the first dma_map_*() call till dma_unmap_*(), then you don't have to call the diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index edccacd4f048..8d065d6ec956 100644 --- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt @@ -340,7 +340,7 @@ accessed sg->address and sg->length as shown above. void dma_unmap_sg(struct device *dev, struct scatterlist *sg, - int nhwentries, enum dma_data_direction direction) + int nents, enum dma_data_direction direction) Unmap the previously mapped scatter/gather list. All the parameters must be the same as those and passed in to the scatter/gather mapping @@ -356,10 +356,10 @@ void dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle, size_t size, enum dma_data_direction direction) void -dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nelems, +dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction direction) void -dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nelems, +dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction direction) Synchronise a single contiguous or scatter/gather mapping for the CPU |