On 1/16/19 11:16 AM, Jerome Glisse wrote: >> We *could* also simply truncate the existing top-level >> "Persistent Memory" resource and take over the released address >> space. But, this means that if we ever decide to hot-unplug the >> "RAM" and give it back, we need to recreate the original setup, >> which may mean going back to the BIOS tables. >> >> This should have no real effect on the existing collision >> detection because the areas that truly conflict should be marked >> IORESOURCE_BUSY. > > Still i am worrying that this might allow device private to register > itself as a child of some un-busy resource as this patch obviously > change the behavior of register_memory_resource() > > What about instead explicitly providing parent resource to add_memory() > and then to register_memory_resource() so if it is provided as an > argument (!NULL) then you can __request_region(arg_res, ...) otherwise > you keep existing code intact ? We don't have the locking to do this, do we? For instance, all the locking is done below register_memory_resource(), so any previous resource lookup is invalid by the time we get to register_memory_resource().
