sock: Use sock_owned_by_user_nocheck() instead of sk_lock.owned.

This patch moves sock_release_ownership() down in include/net/sock.h and
replaces some sk_lock.owned tests with sock_owned_by_user_nocheck().
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Link: https://lore.kernel.org/r/20211208062158.54132-1-kuniyu@amazon.co.jpSigned-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/sock.h

@@ -1635,16 +1635,6 @@ static inline void sk_mem_uncharge(struct sock *sk, int size)
 		__sk_mem_reclaim(sk, SK_RECLAIM_CHUNK);
 }
 
-static inline void sock_release_ownership(struct sock *sk)
-{
-	if (sk->sk_lock.owned) {
-		sk->sk_lock.owned = 0;
-
-		/* The sk_lock has mutex_unlock() semantics: */
-		mutex_release(&sk->sk_lock.dep_map, _RET_IP_);
-	}
-}
-
 /*
  * Macro so as to not evaluate some arguments when
  * lockdep is not enabled.
@@ -1771,12 +1761,23 @@ static inline bool sock_owned_by_user_nocheck(const struct sock *sk)
 	return sk->sk_lock.owned;
 }
 
+static inline void sock_release_ownership(struct sock *sk)
+{
+	if (sock_owned_by_user_nocheck(sk)) {
+		sk->sk_lock.owned = 0;
+
+		/* The sk_lock has mutex_unlock() semantics: */
+		mutex_release(&sk->sk_lock.dep_map, _RET_IP_);
+	}
+}
+
 /* no reclassification while locks are held */
 static inline bool sock_allow_reclassification(const struct sock *csk)
 {
 	struct sock *sk = (struct sock *)csk;
 
-	return !sk->sk_lock.owned && !spin_is_locked(&sk->sk_lock.slock);
+	return !sock_owned_by_user_nocheck(sk) &&
+		!spin_is_locked(&sk->sk_lock.slock);
 }
 
 struct sock *sk_alloc(struct net *net, int family, gfp_t priority,

net/core/sock.c

@@ -3292,7 +3292,7 @@ void lock_sock_nested(struct sock *sk, int subclass)
 
 	might_sleep();
 	spin_lock_bh(&sk->sk_lock.slock);
-	if (sk->sk_lock.owned)
+	if (sock_owned_by_user_nocheck(sk))
 		__lock_sock(sk);
 	sk->sk_lock.owned = 1;
 	spin_unlock_bh(&sk->sk_lock.slock);
@@ -3323,7 +3323,7 @@ bool __lock_sock_fast(struct sock *sk) __acquires(&sk->sk_lock.slock)
 	might_sleep();
 	spin_lock_bh(&sk->sk_lock.slock);
 
-	if (!sk->sk_lock.owned) {
+	if (!sock_owned_by_user_nocheck(sk)) {
 		/*
 		 * Fast path return with bottom halves disabled and
 		 * sock::sk_lock.slock held.

net/llc/llc_proc.c

@@ -195,7 +195,7 @@ static int llc_seq_core_show(struct seq_file *seq, void *v)
 		   timer_pending(&llc->pf_cycle_timer.timer),
 		   timer_pending(&llc->rej_sent_timer.timer),
 		   timer_pending(&llc->busy_state_timer.timer),
-		   !!sk->sk_backlog.tail, !!sk->sk_lock.owned);
+		   !!sk->sk_backlog.tail, sock_owned_by_user_nocheck(sk));
 out:
 	return 0;
 }