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| author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-02-28 21:48:16 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-02-28 21:48:16 +0100 |
| commit | d4ab5487cc77a4053dc9070c5761ad94bf397825 (patch) | |
| tree | cd69e85b7cc3f45f10c3cf402c8a497be8da3944 /Documentation/core-api | |
| parent | tty: Reserve ldisc 29 for development purposes (diff) | |
| parent | Linux 5.17-rc6 (diff) | |
| download | linux-d4ab5487cc77a4053dc9070c5761ad94bf397825.tar.xz linux-d4ab5487cc77a4053dc9070c5761ad94bf397825.zip | |
Merge 5.17-rc6 into tty-next
We need the tty/serial fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/core-api')
| -rw-r--r-- | Documentation/core-api/dma-attributes.rst | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/core-api/dma-attributes.rst b/Documentation/core-api/dma-attributes.rst index 1887d92e8e92..17706dc91ec9 100644 --- a/Documentation/core-api/dma-attributes.rst +++ b/Documentation/core-api/dma-attributes.rst @@ -130,3 +130,11 @@ accesses to DMA buffers in both privileged "supervisor" and unprivileged subsystem that the buffer is fully accessible at the elevated privilege level (and ideally inaccessible or at least read-only at the lesser-privileged levels). + +DMA_ATTR_OVERWRITE +------------------ + +This is a hint to the DMA-mapping subsystem that the device is expected to +overwrite the entire mapped size, thus the caller does not require any of the +previous buffer contents to be preserved. This allows bounce-buffering +implementations to optimise DMA_FROM_DEVICE transfers. |