[Linaro-mm-sig] [PATCH] dma-buf: document fd flags and O_CLOEXEC requirement
ville.syrjala at linux.intel.com
Mon Mar 19 15:44:33 UTC 2012
On Mon, Mar 19, 2012 at 04:41:55PM +0100, Daniel Vetter wrote:
> Otherwise subsystems will get this wrong and end up with a second
> export ioctl with the flag and O_CLOEXEC support added.
> v2: Fixup the function name and caution exporters to limit the flags
> to only O_CLOEXEC. Noted by Dave Airlie.
> Cc: Dave Airlie <airlied at gmail.com>
> Signed-Off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> Documentation/dma-buf-sharing.txt | 6 ++++++
> 1 files changed, 6 insertions(+), 0 deletions(-)
> diff --git a/Documentation/dma-buf-sharing.txt b/Documentation/dma-buf-sharing.txt
> index 9f3aeef..a6d4c37 100644
> --- a/Documentation/dma-buf-sharing.txt
> +++ b/Documentation/dma-buf-sharing.txt
> @@ -319,6 +319,12 @@ Miscellaneous notes
> - Any exporters or users of the dma-buf buffer sharing framework must have
> a 'select DMA_SHARED_BUFFER' in their respective Kconfigs.
> +- To avoid the wrath of userspace library writers exporting subsystems must have
> + a flag parameter in the ioctl that creates the dma-buf fd which needs to
> + support at least the O_CLOEXEC fd flag. This needs to be passed in the flag
> + parameter of dma_buf_fd. Without any other reasons applying it is recommended
> + that exporters limit the flags passed to dma_buf_fd to only O_CLOEXEC.
Difficult to parse. Needs more punctuation.
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