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authorEric Dumazet <edumazet@google.com>2021-02-10 17:41:44 +0300
committerDavid S. Miller <davem@davemloft.net>2021-02-12 01:10:07 +0300
commit3d368ab87cf6681f928de1ddf804d69600671bb2 (patch)
tree87071c9aa3fd53cdbadadd99deaefec3100d270b
parent06e56697bd98d33ab101920bb5380fcd7efed4df (diff)
downloadlinux-3d368ab87cf6681f928de1ddf804d69600671bb2.tar.xz
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 <edumazet@google.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Lorenz Bauer <lmb@cloudflare.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/net_namespace.h4
-rw-r--r--net/core/filter.c8
-rw-r--r--net/core/net_namespace.c19
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");