On Fri, Jul 07, 2017 at 04:58:17PM +0200, Igor Mammedov wrote: > On Fri, 7 Jul 2017 10:13:00 -0300 > "Eduardo Habkost" <ehabk...@redhat.com> wrote: [...] > > I don't disagree with adding the assert(), but it looks like > > making fw_cfg_find() return NULL if there are multiple devices > > can be useful for realize. > > > > In this case, it looks like Mark is relying on that in > > fw_cfg_common_realize(): if multiple devices are created, > > fw_cfg_find() will return NULL, and realize will fail. This > > sounds like a more graceful way to handle multiple-device > > creation than crashing on fw_cfg_find(). This is the solution > > used by find_vmgenid_dev()/vmgenid_realize(), BTW. > > I suspect that find_vmgenid_dev() works by luck as it could be > placed only as /machine/peripheral-anon/foo1 or /machine/peripheral/foo2 > object_resolve_partial_path() : machine > object_resolve_partial_path() : peripheral-anon => foo1 > object_resolve_partial_path() : peripheral => foo2 > if (found /* foo2 */) { > if (obj /* foo1 */) { > return NULL;
I don't think this is luck: object_resolve_partial_path() is explicitly documented to always return NULL if multiple matches are found, and I don't see any bug in its implementation that would break that functionality. -- Eduardo