stable inclusion
from linux-4.19.200
commit db44d020633dad681cc234d0e04618b6b9049f9f

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

commit f4e65870 upstream.

We need this functionality for the io_uring file registration, but
we cannot rely on it since CONFIG_UNIX can be modular. Move the helpers
to a separate file, that's always builtin to the kernel if CONFIG_UNIX is
m/y.

No functional changes in this patch, just moving code around.
Reviewed-by: NHannes Reinecke <hare@suse.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
[ backported to older kernels to get access to unix_gc_lock - gregkh ]
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>