UPSTREAM: io_uring: correct pinned_vm accounting

[ upstream commit 42b6419d ]

->mm_account should be released only after we free all registered
buffers, otherwise __io_sqe_buffers_unregister() will see a NULL
->mm_account and skip locked_vm accounting.

Cc: <Stable@vger.kernel.org>
Change-Id: If057ab39e422d6a637d2d97b0098532d99cc0606
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6d798f65ed4ab8db3664c4d3397d4af16ca98846.1664849932.git.asml.silence@gmail.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit cd148d4e)
Bug: 268174392
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>