From 3d368ab87cf6681f928de1ddf804d69600671bb2 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 10 Feb 2021 06:41:44 -0800 Subject: net: initialize net->net_cookie at netns setup It is simpler to make net->net_cookie a plain u64 written once in setup_net() instead of looping and using atomic64 helpers. Lorenz Bauer wants to add SO_NETNS_COOKIE socket option and this patch would makes his patch series simpler. Signed-off-by: Eric Dumazet Cc: Daniel Borkmann Cc: Lorenz Bauer Acked-by: Daniel Borkmann Tested-by: Lorenz Bauer Signed-off-by: David S. Miller --- include/net/net_namespace.h | 4 +--- net/core/filter.c | 8 +++----- net/core/net_namespace.c | 19 +++---------------- 3 files changed, 7 insertions(+), 24 deletions(-) diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 29567875f428..dcaee24a4d87 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -165,7 +165,7 @@ struct net { struct netns_xfrm xfrm; #endif - atomic64_t net_cookie; /* written once */ + u64 net_cookie; /* written once */ #if IS_ENABLED(CONFIG_IP_VS) struct netns_ipvs *ipvs; @@ -224,8 +224,6 @@ extern struct list_head net_namespace_list; struct net *get_net_ns_by_pid(pid_t pid); struct net *get_net_ns_by_fd(int fd); -u64 __net_gen_cookie(struct net *net); - #ifdef CONFIG_SYSCTL void ipx_register_sysctl(void); void ipx_unregister_sysctl(void); diff --git a/net/core/filter.c b/net/core/filter.c index 9ab94e90d660..74bd401bf483 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4645,11 +4645,9 @@ static const struct bpf_func_proto bpf_get_socket_cookie_sock_ops_proto = { static u64 __bpf_get_netns_cookie(struct sock *sk) { -#ifdef CONFIG_NET_NS - return __net_gen_cookie(sk ? sk->sk_net.net : &init_net); -#else - return 0; -#endif + const struct net *net = sk ? sock_net(sk) : &init_net; + + return net->net_cookie; } BPF_CALL_1(bpf_get_netns_cookie_sock, struct sock *, ctx) diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 2ef3b4557f40..43b6ac4c4439 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -72,18 +72,6 @@ static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS; DEFINE_COOKIE(net_cookie); -u64 __net_gen_cookie(struct net *net) -{ - while (1) { - u64 res = atomic64_read(&net->net_cookie); - - if (res) - return res; - res = gen_cookie_next(&net_cookie); - atomic64_cmpxchg(&net->net_cookie, 0, res); - } -} - static struct net_generic *net_alloc_generic(void) { struct net_generic *ng; @@ -332,6 +320,9 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) refcount_set(&net->ns.count, 1); refcount_set(&net->passive, 1); get_random_bytes(&net->hash_mix, sizeof(u32)); + preempt_disable(); + net->net_cookie = gen_cookie_next(&net_cookie); + preempt_enable(); net->dev_base_seq = 1; net->user_ns = user_ns; idr_init(&net->netns_ids); @@ -1103,10 +1094,6 @@ static int __init net_ns_init(void) rcu_assign_pointer(init_net.gen, ng); - preempt_disable(); - __net_gen_cookie(&init_net); - preempt_enable(); - down_write(&pernet_ops_rwsem); if (setup_net(&init_net, &init_user_ns)) panic("Could not setup the initial network namespace"); -- cgit v1.2.3-58-ga151