io_uring/rsrc: disallow multi-source reg buffers

stable inclusion
from stable-v5.10.173
commit 72783d2af89b622282f7d83b166052292b70c87b
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8BFR3

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=72783d2af89b622282f7d83b166052292b70c87b



--------------------------------

commit edd47826 upstream.

If two or more mappings go back to back to each other they can be passed
into io_uring to be registered as a single registered buffer. That would
even work if mappings came from different sources, e.g. it's possible to
mix in this way anon pages and pages from shmem or hugetlb. That is not
a problem but it'd rather be less prone if we forbid such mixing.

Cc: <stable@vger.kernel.org>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>