bpf: Use sk_is_inet() and sk_is_unix() in __cgroup_bpf_run_filter_sock_addr().

sk->sk_family should be read with READ_ONCE() in
__cgroup_bpf_run_filter_sock_addr() due to IPV6_ADDRFORM.

Also, the comment there is a bit stale since commit 859051d
("bpf: Implement cgroup sockaddr hooks for unix sockets"), and the
kdoc has the same comment.

Let's use sk_is_inet() and sk_is_unix() and remove the comment.

Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260203213442.682838-2-kuniyu@google.com

Author: q2ven

kernel/bpf/cgroup.c

@@ -1680,11 +1680,7 @@ int __cgroup_bpf_run_filter_sock_addr(struct sock *sk,
 	struct cgroup *cgrp;
 	int ret;
 
-	/* Check socket family since not all sockets represent network
-	 * endpoint (e.g. AF_UNIX).
-	 */
-	if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6 &&
-	    sk->sk_family != AF_UNIX)
+	if (!sk_is_inet(sk) && !sk_is_unix(sk))
 		return 0;
 
 	if (!ctx.uaddr) {