Johan Hovold
9e782cac2b
[ Upstream commitdd5619582d] TIOCSSERIAL is a horrid, underspecified, legacy interface which for most serial devices is only useful for setting the close_delay and closing_wait parameters. A non-privileged user has only ever been able to set the since long deprecated ASYNC_SPD flags and trying to change any other *supported* feature should result in -EPERM being returned. Setting the current values for any supported features should return success. Fix the cdc-acm implementation which instead indicated that the TIOCSSERIAL ioctl was not even implemented when a non-privileged user set the current values. Fixes:ba2d8ce9db("cdc-acm: implement TIOCSSERIAL to avoid blocking close(2)") Acked-by: Oliver Neukum <oneukum@suse.com> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20210408131602.27956-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>