[patches][RFC] situation with csum_and_copy_... API

On Tue, Nov 18, 2014 at 08:47:45AM +0000, Al Viro wrote:

I do have a patch doing just that; the question is what to do with csum-and-copy
primitives.  Originally I planned to simply strip those access_ok() from those
(both the explicit calls and use of copy_from_user() where we ought to use
__copy_from_user(), etc.), but that's not nice to potential out-of-tree callers
of those suckers.  If any of those exist and manage to cope with the wonderful
calling conventions, that is.  As it is, we have the total of 4 callers of
csum_and_copy_from_user() and 2 callers of csum_and_copy_to_user(), all in
networking code.  Do we care about potential out-of-tree users existing and
getting screwed by such change?  Davem, Linus?

FWIW, the beginning of series in question follows; removal of those
access_ok() is 3/5.  The series is longer than that (see vfs.git#iov_iter-net
for a bit more, and there's more stuff in local queue still too much in flux
to push them out), but all the stuff relevant to validating iovecs on
sendmsg/recvmsg and getting rid of excessive access_ok() is in the first 5
commits.