On Mon, Jun 12, 2023 at 02:29:05PM +0200, Paolo Bonzini wrote: > On 6/12/23 14:18, Greg KH wrote: > > Yeah, it's a pain, but you are trying to hand-roll code that is not a > > "normal" path for a struct device, sorry. > > > > I don't know if you really can encode all of that crazy logic in the > > cleanup api, UNLESS you can "switch" the cleanup function at a point in > > time (i.e. after device_add() is successful). Is that possible? > > What _could_ make sense is that device_add() completely takes ownership of > the given pointer, and takes care of calling put_device() on failure. I think we tried that decades ago :) Problem is that the caller wants to clean stuff up associted with that struct device-embedded structure _before_ the final put_device() is called which would usually free the memory of the overall structure. So device_add() can't call put_device() on the error path within it, you need the caller to unwind it's local stuff before that happens. > Then you can have > > struct device *dev_struct __free(put_device) = > kzalloc(sizeof(struct device), GFP_KERNEL); > > struct device *dev __free(device_del) = > device_add(no_free_ptr(dev_struct)); > > /* dev_struct is NULL now */ > > pmu->dev = no_free_ptr(dev); I don't see how that works properly, what am I missing? thanks, greg k-h
