On Mon, Jun 02, 2014 at 10:01:17PM +0100, Mark Brown wrote: > On Mon, Jun 02, 2014 at 10:01:43AM +0100, Charles Keepax wrote: > > Sometimes MFD children will have interdependancies. For example an MFD > > device might contain a regulator cell and another cell which requires > > that regulator to function. Probe deferral will ensure that these > > devices probe in the correct order, however currently nothing ensures > > they are destroyed in the correct order. As such it is possible for a > > cell to be destroyed whilst another cell still expects it to exist. For > > example the cell mentioned earlier would attempt to do a regulator_put > > as part of its own tear-down but the regulator may have already been > > destroyed. > > Probe deferral is supposed to handle removal too, we're supposed to be > able to walk the device list in reverse order and everything just work.
I had considered this approach but was perhaps incorrectly too nervous about it. I was slightly concerned about breaking other MFD devices by changing the order things destroy in. Also the way the child devices are iterated with device_for_each_child, there is lack of helpers to process the klist in reverse and it felt like code I probably shouldn't be modifying. I am happy to do a version that removes devices in reverse probe order, if that is preferrable? But any pointers if I am missing the obvious way to do that would be appreciated. Thanks, Charles -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
