af_unix: Rename unlinked_skb in manage_oob().

When OOB skb has been already consumed, manage_oob() returns the next
skb if exists.  In such a case, we need to fall back to the else branch
below.

Then, we need to keep two skbs and free them later with consume_skb()
and kfree_skb().

Let's rename unlinked_skb accordingly.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20240905193240.17565-3-kuniyu@amazon.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/unix/af_unix.c

@@ -2654,7 +2654,7 @@ 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 sk_buff *read_skb = NULL, *unread_skb = NULL;
 	struct unix_sock *u = unix_sk(sk);
 
 	if (!unix_skb_len(skb)) {
@@ -2665,14 +2665,14 @@ static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
 		} else if (flags & MSG_PEEK) {
 			skb = skb_peek_next(skb, &sk->sk_receive_queue);
 		} else {
-			unlinked_skb = skb;
+			read_skb = skb;
 			skb = skb_peek_next(skb, &sk->sk_receive_queue);
-			__skb_unlink(unlinked_skb, &sk->sk_receive_queue);
+			__skb_unlink(read_skb, &sk->sk_receive_queue);
 		}
 
 		spin_unlock(&sk->sk_receive_queue.lock);
 
-		consume_skb(unlinked_skb);
+		consume_skb(read_skb);
 		return skb;
 	}
 
@@ -2688,7 +2688,7 @@ static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
 
 		if (!sock_flag(sk, SOCK_URGINLINE)) {
 			__skb_unlink(skb, &sk->sk_receive_queue);
-			unlinked_skb = skb;
+			unread_skb = skb;
 			skb = skb_peek(&sk->sk_receive_queue);
 		}
 	} else if (!sock_flag(sk, SOCK_URGINLINE)) {
@@ -2698,7 +2698,7 @@ static struct sk_buff *manage_oob(struct sk_buff *skb, struct sock *sk,
 unlock:
 	spin_unlock(&sk->sk_receive_queue.lock);
 
-	kfree_skb(unlinked_skb);
+	kfree_skb(unread_skb);
 
 	return skb;
 }