There's an issue with bio_uncopy_user() in that it expects ->bv_len to
be untouched from io submission to io completion, which it wont be for
some transfer lengths on some hardware. So we end up not copying all the
data back to user space, not so good. This patch adds a bio_map_data
local structure to track the io_vec.
Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>