I have a PPC405GPr system with an image processing device, that
is creating potentially huge amounts of data. In one setup I
have a 256Meg system, and I'm trying to map a 192Meg destination
buffer using map_user_kiovec and an array of kiobufs.
I'm finding, however, that I'm getting an Oops in map_user_kiovec
when it tries this, and I'm wondering where I need to look for
any limits I might be overrunning.
Also, I've been considering skipping kiobufs all together and
instead using code like this (lifted from map_user_kiobuf)
/* Try to fault in all of the necessary pages */
down_read(&mm->mmap_sem);
/* rw==READ means read from disk, write into memory area */
err = get_user_pages(current, mm, va, pgcount,
(rw==READ), 0, iobuf->maplist, NULL);
up_read(&mm->mmap_sem);
to get the user pages directly. This is really what I want, and
I do not need the other functionality of kiobufs. Is the
get_user_pages function kosher for use by drivers? Is there
a limit to what get_user_pages may map?
--
Steve Williams "The woods are lovely, dark and deep.
steve at icarus.com But I have promises to keep,
http://www.icarus.com and lines to code before I sleep,
http://www.picturel.com And lines to code before I sleep."
