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Message-ID: <20230921133021.1995349-5-edumazet@google.com>
Date: Thu, 21 Sep 2023 13:30:17 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>
Cc: David Ahern <dsahern@...nel.org>, netdev@...r.kernel.org, eric.dumazet@...il.com,
Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH net-next 4/8] inet: lockless getsockopt(IP_OPTIONS)
inet->inet_opt being RCU protected, we can use RCU instead
of locking the socket.
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
net/ipv4/ip_sockglue.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 50c008efbb6de7303621dd30b178c90cb3f5a2fc..45d89487914a12061f05c192004ad79f0abbf756 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1591,27 +1591,20 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
case IP_TOS:
val = READ_ONCE(inet->tos);
goto copyval;
- }
-
- if (needs_rtnl)
- rtnl_lock();
- sockopt_lock_sock(sk);
-
- switch (optname) {
case IP_OPTIONS:
{
unsigned char optbuf[sizeof(struct ip_options)+40];
struct ip_options *opt = (struct ip_options *)optbuf;
struct ip_options_rcu *inet_opt;
- inet_opt = rcu_dereference_protected(inet->inet_opt,
- lockdep_sock_is_held(sk));
+ rcu_read_lock();
+ inet_opt = rcu_dereference(inet->inet_opt);
opt->optlen = 0;
if (inet_opt)
memcpy(optbuf, &inet_opt->opt,
sizeof(struct ip_options) +
inet_opt->opt.optlen);
- sockopt_release_sock(sk);
+ rcu_read_unlock();
if (opt->optlen == 0) {
len = 0;
@@ -1627,6 +1620,13 @@ int do_ip_getsockopt(struct sock *sk, int level, int optname,
return -EFAULT;
return 0;
}
+ }
+
+ if (needs_rtnl)
+ rtnl_lock();
+ sockopt_lock_sock(sk);
+
+ switch (optname) {
case IP_MTU:
{
struct dst_entry *dst;
--
2.42.0.459.ge4e396fd5e-goog
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