diff options
| author | Jakub Kicinski <kuba@kernel.org> | 2025-02-06 16:14:34 -0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-02-06 16:14:35 -0800 |
| commit | 3da81cb9a4ac26ac6bc7ef48508b3ebea714eb1a (patch) | |
| tree | eab90221e224204ce7115a0f8031043c8ee533b0 /include | |
| parent | 3cf0a98fea776adb09087e521fe150c295a4b031 (diff) | |
| parent | b768294d449da6d7dc0667c1ec92dc4af6ef766b (diff) | |
Merge branch 'net-first-round-to-use-dev_net_rcu'
Eric Dumazet says:
====================
net: first round to use dev_net_rcu()
dev_net(dev) should either be protected by RTNL or RCU.
There is no LOCKDEP support yet for this helper.
Adding it would trigger too many splats.
Instead, add dev_net_rcu() for rcu_read_lock() contexts
and start to use it to fix bugs and clearly document the
safety requirements.
v4: https://lore.kernel.org/CANn89i+AozhFhZNK0Y4e_EqXV1=yKjGuvf43Wa6JJKWMOixWQQ@mail.gmail.com
v3: https://lore.kernel.org/20250203153633.46ce0337@kernel.org/
====================
Link: https://patch.msgid.link/20250205155120.1676781-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/netdevice.h | 6 | ||||
| -rw-r--r-- | include/net/ip.h | 13 | ||||
| -rw-r--r-- | include/net/net_namespace.h | 2 | ||||
| -rw-r--r-- | include/net/route.h | 9 |
4 files changed, 24 insertions, 6 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 03bb584c62cf..c0a86afb85da 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2664,6 +2664,12 @@ struct net *dev_net(const struct net_device *dev) } static inline +struct net *dev_net_rcu(const struct net_device *dev) +{ + return read_pnet_rcu(&dev->nd_net); +} + +static inline void dev_net_set(struct net_device *dev, struct net *net) { write_pnet(&dev->nd_net, net); diff --git a/include/net/ip.h b/include/net/ip.h index 9f5e33e371fc..ba7b43447775 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -471,9 +471,12 @@ static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst, bool forwarding) { const struct rtable *rt = dst_rtable(dst); - struct net *net = dev_net(dst->dev); - unsigned int mtu; + unsigned int mtu, res; + struct net *net; + + rcu_read_lock(); + net = dev_net_rcu(dst->dev); if (READ_ONCE(net->ipv4.sysctl_ip_fwd_use_pmtu) || ip_mtu_locked(dst) || !forwarding) { @@ -497,7 +500,11 @@ static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst, out: mtu = min_t(unsigned int, mtu, IP_MAX_MTU); - return mtu - lwtunnel_headroom(dst->lwtstate, mtu); + res = mtu - lwtunnel_headroom(dst->lwtstate, mtu); + + rcu_read_unlock(); + + return res; } static inline unsigned int ip_skb_dst_mtu(struct sock *sk, diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 0f5eb9db0c62..7ba1402ca779 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -398,7 +398,7 @@ static inline struct net *read_pnet(const possible_net_t *pnet) #endif } -static inline struct net *read_pnet_rcu(possible_net_t *pnet) +static inline struct net *read_pnet_rcu(const possible_net_t *pnet) { #ifdef CONFIG_NET_NS return rcu_dereference(pnet->net); diff --git a/include/net/route.h b/include/net/route.h index f86775be3e29..c605fd5ec0c0 100644 --- a/include/net/route.h +++ b/include/net/route.h @@ -382,10 +382,15 @@ static inline int inet_iif(const struct sk_buff *skb) static inline int ip4_dst_hoplimit(const struct dst_entry *dst) { int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT); - struct net *net = dev_net(dst->dev); - if (hoplimit == 0) + if (hoplimit == 0) { + const struct net *net; + + rcu_read_lock(); + net = dev_net_rcu(dst->dev); hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl); + rcu_read_unlock(); + } return hoplimit; } |