On Wed, Jan 27, 2021 at 6:41 PM Uwe Kleine-König [off-list ref] wrote:

The driver core ignores the return value of struct bus_type::remove()
because there is only little that can be done. To simplify the quest to
make this function return void, let struct vio_driver::remove() return
void, too. All users already unconditionally return 0, this commit makes
it obvious that returning an error code is a bad idea and makes it
obvious for future driver authors that returning an error code isn't
intended.

Note there are two nominally different implementations for a vio bus:
one in arch/sparc/kernel/vio.c and the other in
arch/powerpc/platforms/pseries/vio.c. I didn't care to check which
driver is using which of these busses (or if even some of them can be
used with both) and simply adapt all drivers and the two bus codes in
one go.

Note that for the powerpc implementation there is a semantical change:
Before this patch for a device that was bound to a driver without a
remove callback vio_cmo_bus_remove(viodev) wasn't called. As the device
core still considers the device unbound after vio_bus_remove() returns
calling this unconditionally is the consistent behaviour which is
implemented here.

Signed-off-by: Uwe Kleine-König <redacted>

Acked-by: Lijun Pan <redacted>