Re: inverse mmap() available?

Tommy Reynolds (
Fri, 28 Sep 2001 10:28:36 -0500

Norbert Roos <> was pleased to say:

> Hello!
> Is there a way to map user space memory into kernel address space, e.g.
> that i don't have to call get_user(var,...) but simply use var =
> *user_space_ptr?
> What i intend to do (as the next step) is to DMA-transfer data directly
> between a PCI device and user space memory. The buffer in user space
> should be allocated with malloc(), so allocating a buffer in kernel and
> mmap()-ping it to user space is not the solution..
> I guess this has been asked before, any links to further information
> would be great.

Look at the KIOBUF stuff in <linux/iobuf.h> for how to do this.

Tommy Reynolds | mailto: <>
Red Hat, Inc., Embedded Development Services | Phone: +1.256.704.9286
307 Wynn Drive NW, Huntsville, AL 35805 USA | FAX: +1.236.837.3839
Senior Software Developer | Mobile: +1.919.641.2923
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at