From: Jeff Barnhill <0xeff...@gmail.com> Date: Tue, 30 Oct 2018 07:10:58 -0400
> I originally started implementing it the way you suggested; however, > it seemed to complicate management of that structure because it isn't > currently using rcu. Also, assuming that can be worked out, where > would I get the net from? Would I need to store a copy in ifcaddr6, > or is there some way to access it during ipv6_chk_acast_addr()? It > seems that if I don't add a copy of net, but instead access it through > aca_rt(?), then freeing the ifcaddr6 memory becomes problematic > (detaching it from idev, while read_rcu may still be accessing it). > On Mon, Oct 29, 2018 at 11:32 PM David Miller <da...@davemloft.net> wrote: I don't think converting the structure over to RCU, especially because all of the read paths (everything leading to ipv6_chk_acast_dev()) are taking RCU locks already. And I cannot understand how having _two_ structures to manage a piece of information can be less complicated than just one. You can add a backpointer to the 'idev' in ifacaddr6 to get at the network namespace. You don't even need to do additional reference counting because the idev->ac_list is always purged before an idev is destroyed.
