Re: DMA to/from user buffers

Gerd Knorr (kraxel@bytesex.org)
4 Sep 2001 19:30:49 GMT

Sebastian Heidl wrote:
>
> Hi,
>
> two questions about using an user-supplied buffer (e.g. malloced
> in user space) for DMA transfers:
>
> 1. Is it possible ?
> 2. What restrictions/requirements apply for the buffer (alignment...) ?
>
> Documentation/DMA-mapping.txt only talks about buffers allocated in
> kernel space.

Lock down the user pages using kiobufs (see include/linux/iobufs.h),
then feed these pages to the pci_* functions.

Gerd

-- 
Damn lot people confuse usability and eye-candy.
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