[lkml]   [1999]   [Nov]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: locking user memory and kiobuf
Alan Cox wrote:
> > kiobuf sounds perfect for a problem we have. Currently I use mmap() to map
> > pages from __get_free_pages() into user space for dma. This is not totally
> > satisfactory, tho, in part because the resulting group of pages is not mapped
> > contiguously into kernel.
> If you have a situation where that is hard to handle you can vmalloc a block
> of memory then map that into user space. drivers/char/bttv.c does it. Its
> ugly and bttv needs to switch to kiovecs in 2.3.x if I get time.

On a tangent issue, is there an example somewhere of driver code storing
and retrieving objects from VM? something along the lines of

ptr = page_address(page);
/* access ptr */
unlock_pack(page); /* page can now be swapped out if necessary */

Jeff Garzik | Just once, I wish we would encounter
Building 1024 | an alien menace that wasn't immune to
MandrakeSoft, Inc. | bullets. -- The Brigadier, "Dr. Who"

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
Please read the FAQ at

 \ /
  Last update: 2005-03-22 13:55    [W:0.073 / U:1.708 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site