[PATCH 7/8] staging: unisys: stop device registration before visorbus registration

[Jes Sorensen]

Sudip Mukherjee <sudipm.mukherjee at gmail.com> writes:
> On Tue, Aug 18, 2015 at 03:14:02PM -0400, Benjamin Romer wrote:
>> In cases where visorbus is compiled directly into the kernel, if
>> visorbus registration fails for any reason, it is still possible for
>> other drivers to call visorbus_register_visor_driver(), which could
>> cause an oops. Prevent this by returning an error code when the bus
>> hasn't been registered.
>> 
>> Signed-off-by: Benjamin Romer <benjamin.romer at unisys.com>
>> ---
>>  drivers/staging/unisys/visorbus/visorbus_main.c | 3 +++
>>  1 file changed, 3 insertions(+)
>> 
>> diff --git a/drivers/staging/unisys/visorbus/visorbus_main.c b/drivers/staging/unisys/visorbus/visorbus_main.c
>> index 7905ea9..ad2b1ac 100644
>> --- a/drivers/staging/unisys/visorbus/visorbus_main.c
>> +++ b/drivers/staging/unisys/visorbus/visorbus_main.c
>> @@ -863,6 +863,9 @@ int visorbus_register_visor_driver(struct visor_driver *drv)
>>  {
>>  	int rc = 0;
>>  
>> +	if (!visorbus_type.p)
>> +		return -ENODEV; /*can't register on a nonexistent bus*/
>> +
> IIRC, Greg once told that we should not be working with the internal
> data structures of struct bus_type.

If you looked at the code you would have noticed this is in fact the bus
driver, and visorbus_type is defined in this file. I guess we could tell
visorbus_main.c to not touch visorbus_type by deleting the file
completely .....