Willem de Bruijn <willemdebruijn.ker...@gmail.com> wrote: >On Fri, Aug 14, 2020 at 9:20 AM linmiaohe <linmia...@huawei.com> wrote: >> >> Willem de Bruijn <willemdebruijn.ker...@gmail.com> wrote: >> >On Thu, Aug 13, 2020 at 2:16 PM Miaohe Lin <linmia...@huawei.com> wrote: >> >> >> >> If the skb is zcopied, we should increase the skb_uarg refcount >> >> before we involve skb_release_data(). See pskb_expand_head() as a >> >> reference. >> > >> >Did you manage to observe a bug through this datapath in practice? >> > >> >pskb_carve_inside_header is called >> > from pskb_carve >> > from pskb_extract >> > from rds_tcp_data_recv >> > >> >That receive path should not see any packets with zerocopy state associated. >> > >> >> This works fine yet as its caller is limited. But we should take care of the >> skb_uarg refcount for future use. > >If a new application of this interface is proposed, the author will have to >make sure that it is exercised correctly.
Sure. Let the author make sure that it is exercised correctly if a new application of this interface is proposed. >> On the other hand, because this codepath should not see any packets >> with zerocopy state associated, then we should not call skb_orphan_frags >> here. >I'm also not convinced that the skb_orphan_frags here are needed, given the >only path is from tcp_read_sock. Maybe just keep it here as it doesn't hurt even if it's really not needed. Many thanks.
