Re: Calculating kernel logical address ..

Jesse Barnes
2002-09-09T18:10:02Z

On Mon, Sep 09, 2002 at 02:00:35PM -0400, Richard B. Johnson wrote:
> Well I just read Documentation/DMA-mapping.txt as advised by David
> and it seems as though it will no longer be possible to do what
> many programmers have been wanting to do, to wit:
>
> (1) In user-code, allocate a buffer.
> (2) Lock that buffer into memory.
> (3) Call some driver that DMAs data to/from that buffer.

It looks drivers/media/video/video-buf.c uses alloc_kiovec() and
map_user_kiobuf() to do it. And I think Ben LaHaise was talking about
removing these functions and creating some other, lightweight
interface for the same purpose? OTOH, it's been awhile since I looked
at this stuff, so I'm not sure how it works anymore, I'm sure someone
else could provide more useful info.

Jesse