Le 24/09/2026 à 03:15, Yuyang Huang a écrit : > A multi-part RTM_GETMULTICAST dump of dev->mc resumes by position, so > entries added or removed between two dump rounds can be skipped or > repeated. The IPv4 and IPv6 dumps report that with NLM_F_DUMP_INTR by > stamping cb->seq from a per netns generation counter combined with > dev_base_seq, see inet_base_seq(). > > Add the equivalent for the device multicast lists: a per netns counter > bumped whenever an entry is added to or removed from any dev->mc. The > list helpers do not know which device a list belongs to, so give > netdev_hw_addr_list an owner set for dev->mc only and bump the counter > of dev_net(owner) where entries are created and freed. That covers the > dev_mc_* helpers, both lists of a sync, the hardware sync helpers > drivers call from their rx mode callbacks or their own workers and the > reconciliation after an asynchronous rx mode update, while snapshot > and other lists have no owner and are not tracked. It is atomic since > the writers only hold the address lock of their own device.
For IPv4 and IPv6, the generation counter was initially used to invalidate some caches; that's why it is global. Here, the goal is only to check the consistency of the netlink dump. I wonder if maintaining a counter per list would not be more straightforward. A helper could then manage list->count and list->genid, both evolving together.
