Re: atomic copy_from_user?

[William Lee Irwin III <wli@holomorphy.com>]

On Sun, Dec 21, 2003 at 07:48:20PM -0500, Albert Cahalan wrote:
> Surely I'm not the only one wanting such a beast...?
> From some naughty place in the code where might_sleep
> would trigger, I'd like to read from user memory.
> I'll pretty much assume that mlockall() has been
> called. Suppose that "current" is correct as well.
> I'd just use a pointer directly, except that:
> a. it isn't OK for the 4g/4g feature, s390, or sparc64
> b. it causes the "sparse" type checker to complain
> c. it will oops or worse if the user screwed up
> If the page is swapped out, I want a failed copy.

c.f. kmap_atomic() usage in mm/filemap.c


-- wli