• K
    net: Convert pernet_subsys, registered from inet_init() · f84c6821
    Kirill Tkhai 提交于
    arp_net_ops just addr/removes /proc entry.
    
    devinet_ops allocates and frees duplicate of init_net tables
    and (un)registers sysctl entries.
    
    fib_net_ops allocates and frees pernet tables, creates/destroys
    netlink socket and (un)initializes /proc entries. Foreign
    pernet_operations do not touch them.
    
    ip_rt_proc_ops only modifies pernet /proc entries.
    
    xfrm_net_ops creates/destroys /proc entries, allocates/frees
    pernet statistics, hashes and tables, and (un)initializes
    sysctl files. These are not touched by foreigh pernet_operations
    
    xfrm4_net_ops allocates/frees private pernet memory, and
    configures sysctls.
    
    sysctl_route_ops creates/destroys sysctls.
    
    rt_genid_ops only initializes fields of just allocated net.
    
    ipv4_inetpeer_ops allocated/frees net private memory.
    
    igmp_net_ops just creates/destroys /proc files and socket,
    noone else interested in.
    
    tcp_sk_ops seems to be safe, because tcp_sk_init() does not
    depend on any other pernet_operations modifications. Iteration
    over hash table in inet_twsk_purge() is made under RCU lock,
    and it's safe to iterate the table this way. Removing from
    the table happen from inet_twsk_deschedule_put(), but this
    function is safe without any extern locks, as it's synchronized
    inside itself. There are many examples, it's used in different
    context. So, it's safe to leave tcp_sk_exit_batch() unlocked.
    
    tcp_net_metrics_ops is synchronized on tcp_metrics_lock and safe.
    
    udplite4_net_ops only creates/destroys pernet /proc file.
    
    icmp_sk_ops creates percpu sockets, not touched by foreign
    pernet_operations.
    
    ipmr_net_ops creates/destroys pernet fib tables, (un)registers
    fib rules and /proc files. This seem to be safe to execute
    in parallel with foreign pernet_operations.
    
    af_inet_ops just sets up default parameters of newly created net.
    
    ipv4_mib_ops creates and destroys pernet percpu statistics.
    
    raw_net_ops, tcp4_net_ops, udp4_net_ops, ping_v4_net_ops
    and ip_proc_ops only create/destroy pernet /proc files.
    
    ip4_frags_ops creates and destroys sysctl file.
    
    So, it's safe to make the pernet_operations async.
    Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com>
    Acked-by: NAndrei Vagin <avagin@virtuozzo.com>
    Signed-off-by: NDavid S. Miller <davem@davemloft.net>
    f84c6821
udp.c 72.3 KB