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inet: lockless getsockopt(IP_OPTIONS)

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inet->inet_opt being RCU protected, we can use RCU instead
of locking the socket.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2023-09-22 03:42:17 +00:00
committed by David S. Miller
parent e08d0b3d17
commit a4725d0d89
1 changed files with 10 additions and 10 deletions
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20
net/ipv4/ip_sockglue.c
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@@ -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;