io_uring: move common poll bits

io_uring: move common poll bits

[ upstream commmit 5641897a5e8fb8abeb07e89c71a788d3db3ec75e ]

Move some poll helpers/etc up, we'll need them there shortly

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6c5c3dba24c86aad5cd389a54a8c7412e6a0621d.1639605189.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[pavel: backport]
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit a85d7ac14f2215a0ea90d836115ca63dce13203a linux-5.15.y)
CVE-2022-3176
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>