Messages in this thread | | | Date | Sun, 14 Nov 1999 12:43:41 +0000 | From | Jeff Garzik <> | Subject | Re: locking user memory and kiobuf |
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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
swap_in_and_lock_page(page); 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"
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