On Mon, Mar 22, 2010 at 02:13:48AM +0100, Juan Quintela wrote: > "Michael S. Tsirkin" <m...@redhat.com> wrote: > > On Sun, Mar 21, 2010 at 06:11:43PM +0000, Jamie Lokier wrote: > >> Michael S. Tsirkin wrote: > >> > That's version 1 of my patch. Version 2 removed even need for macro > >> > completely by moving allocations to the caller. > >> > >> The downside of moving allocations are: (1) it's one more call in the > >> caller, to allocate the type, (2) it needs a virtual destructor for > >> each type to free the object, which can clutter the code if there is > >> no other reason for virtual destructors. > > > > BTW I don't understand why do you refer to virtual destructors here. > > When virtio-net.c allocates and frees structure of type VirtIONet > > this is analogous to regular destructur, not a virtual one. > > If you remove it in virtio-net.c, you are right. > > If your remove it in virtio.c, then you need the equivalent of a virtual > destructor (somehow you need to find a field that is an offset and do a > free(pointer- offset). > > If struct VirtIODevice is the 1st field of everything, then a simple > free(pointer) is enough and does the right thing. > > Notice that as just now there is no free call, you can put it in either > place.
We should remove it in virtio-net.c. We need to do cleanup there anyway. > > >> I don't think those are necessarily bad, but they can remove from the > >> neatness of existing code. Personally I favour an occasional macro > >> using sizeof/offsetof/container_of if the result is a natural and > >> sensible API to all of its callers. > >> > >> -- Jamie > > Later, Juan.