serdev: fix receive_buf return value when no callback

[ Upstream commit fd00cf81a9 ]

The receive_buf callback is supposed to return the number of bytes
processed and should specifically not return a negative errno.

Due to missing sanity checks in the serdev tty-port controller, a driver
not providing a receive_buf callback could cause the flush_to_ldisc()
worker to spin in a tight loop when the tty buffer pointers are
incremented with -EINVAL (-22).

The missing sanity checks have now been added to the tty-port
controller, but let's fix up the serdev-controller helper as well.

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johan Hovold 2017-11-03 15:30:53 +01:00 committed by Greg Kroah-Hartman
parent 371cf4043b
commit 2ba11e4309
1 changed files with 1 additions and 1 deletions

View File

@ -184,7 +184,7 @@ static inline int serdev_controller_receive_buf(struct serdev_controller *ctrl,
struct serdev_device *serdev = ctrl->serdev;
if (!serdev || !serdev->ops->receive_buf)
return -EINVAL;
return 0;
return serdev->ops->receive_buf(serdev, data, count);
}