af_unix: Remove single nest in manage_oob().

This is a prep for the later fix.

No functional change intended.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20240905193240.17565-2-kuniyu@amazon.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/unix/af_unix.c

@@ -2654,11 +2654,10 @@ static int unix_stream_recv_urg(struct unix_stream_read_state *state)
 static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
 				  int flags, int copied)
 {
+	struct sk_buff *unlinked_skb = NULL;
 	struct unix_sock *u = unix_sk(sk);
 
 	if (!unix_skb_len(skb)) {
-		struct sk_buff *unlinked_skb = NULL;
-
 		spin_lock(&sk->sk_receive_queue.lock);
 
 		if (copied && (!u->oob_skb || skb == u->oob_skb)) {
@@ -2674,31 +2673,33 @@ static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
 		spin_unlock(&sk->sk_receive_queue.lock);
 
 		consume_skb(unlinked_skb);
-	} else {
-		struct sk_buff *unlinked_skb = NULL;
+		return skb;
+	}
 
-		spin_lock(&sk->sk_receive_queue.lock);
+	spin_lock(&sk->sk_receive_queue.lock);
 
-		if (skb == u->oob_skb) {
-			if (copied) {
-				skb = NULL;
-			} else if (!(flags & MSG_PEEK)) {
-				WRITE_ONCE(u->oob_skb, NULL);
-
-				if (!sock_flag(sk, SOCK_URGINLINE)) {
-					__skb_unlink(skb, &sk->sk_receive_queue);
-					unlinked_skb = skb;
-					skb = skb_peek(&sk->sk_receive_queue);
-				}
-			} else if (!sock_flag(sk, SOCK_URGINLINE)) {
-				skb = skb_peek_next(skb, &sk->sk_receive_queue);
-			}
-		}
+	if (skb != u->oob_skb)
+		goto unlock;
 
-		spin_unlock(&sk->sk_receive_queue.lock);
+	if (copied) {
+		skb = NULL;
+	} else if (!(flags & MSG_PEEK)) {
+		WRITE_ONCE(u->oob_skb, NULL);
 
-		kfree_skb(unlinked_skb);
+		if (!sock_flag(sk, SOCK_URGINLINE)) {
+			__skb_unlink(skb, &sk->sk_receive_queue);
+			unlinked_skb = skb;
+			skb = skb_peek(&sk->sk_receive_queue);
+		}
+	} else if (!sock_flag(sk, SOCK_URGINLINE)) {
+		skb = skb_peek_next(skb, &sk->sk_receive_queue);
 	}
+
+unlock:
+	spin_unlock(&sk->sk_receive_queue.lock);
+
+	kfree_skb(unlinked_skb);
+
 	return skb;
 }
 #endif