On Thu, Jan 5, 2023 at 10:08 PM Steven Rostedt [off-list ref] wrote:

On Thu,  5 Jan 2023 18:00:14 +0800
Yunhui Cui [off-list ref] wrote:

quoted

@@ -715,6 +716,10 @@ static inline int sock_sendmsg_nosec(struct socket *sock, struct msghdr *msg)
                                   inet_sendmsg, sock, msg,
                                   msg_data_left(msg));
      BUG_ON(ret == -EIOCBQUEUED);
+
+     trace_sock_sendmsg_length(sock->sk, sock->sk->sk_family,
+                               sock->sk->sk_protocol,
+                               ret > 0 ? ret : 0, ret > 0 ? 0 : ret, 0);

The length and error seem confusing. Basically, length is ret > 0 and error
is ret < 0, right?

That means we don't need both. We could simply have:

quoted

+     TP_ARGS(sk, family, protocol, length, error, flags),

        TP_ARGS(sk, family, protocol, ret, flags)

Hi Steve, thank you for your advice，i'll modify it on v3.

quoted

@@ -992,9 +997,17 @@ INDIRECT_CALLABLE_DECLARE(int inet6_recvmsg(struct socket *, struct msghdr *,
 static inline int sock_recvmsg_nosec(struct socket *sock, struct msghdr *msg,
                                   int flags)
 {
-     return INDIRECT_CALL_INET(sock->ops->recvmsg, inet6_recvmsg,
+     int ret = INDIRECT_CALL_INET(sock->ops->recvmsg, inet6_recvmsg,
                                inet_recvmsg, sock, msg, msg_data_left(msg),
                                flags);
+
+     trace_sock_recvmsg_length(sock->sk, sock->sk->sk_family,
+                               sock->sk->sk_protocol,
+                               (ret > 0 && !(flags & MSG_PEEK)) ?
+                               ret : 0,
+                               (ret > 0 && !(flags & MSG_PEEK)) ? 0 : ret,

Since both length and error are zero when flags has MSG_PEEK set:

        trace_sock_recvmsg_length(sock->sk, sock->sk->sk_family,
                                  sock->sk->sk_protocol,
                                  !(flags & MSG_PEEK) ? ret : 0,

-- Steve

Regardless of whether the MSG_PEEK flag is set or not, it is possible
to return -errno,
but based on your suggestion, I plan to modify it like this:

trace_sock_recvmsg_length(sock->sk, sock->sk->sk_family,
                          sock->sk->sk_protocol,
                          !(flags & MSG_PEEK) ? ret : (ret < 0 ? ret : 0),

what do you think?

Thanks,
Yunhui