netdev - [PATCH v4 net-next 10/11] af_unix: Remove put_pid()/put_cred() in copy

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Date: Thu, 20 Jun 2024 13:56:22 -0700
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: "David S. Miller" <davem@...emloft.net>, Eric Dumazet
	<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
	<pabeni@...hat.com>
CC: Kent Overstreet <kent.overstreet@...ux.dev>, Kuniyuki Iwashima
	<kuniyu@...zon.com>, Kuniyuki Iwashima <kuni1840@...il.com>,
	<netdev@...r.kernel.org>
Subject: [PATCH v4 net-next 10/11] af_unix: Remove put_pid()/put_cred() in copy_peercred().

When (AF_UNIX, SOCK_STREAM) socket connect()s to a listening socket,
the listener's sk_peer_pid/sk_peer_cred are copied to the client in
copy_peercred().

Then, the client's sk_peer_pid and sk_peer_cred are always NULL, so
we need not call put_pid() and put_cred() there.

Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
---
 net/unix/af_unix.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index d11664c2faad..3d0ace7ca017 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -772,9 +772,6 @@ static void update_peercred(struct sock *sk)
 
 static void copy_peercred(struct sock *sk, struct sock *peersk)
 {
-	const struct cred *old_cred;
-	struct pid *old_pid;
-
 	if (sk < peersk) {
 		spin_lock(&sk->sk_peer_lock);
 		spin_lock_nested(&peersk->sk_peer_lock, SINGLE_DEPTH_NESTING);
@@ -782,16 +779,12 @@ static void copy_peercred(struct sock *sk, struct sock *peersk)
 		spin_lock(&peersk->sk_peer_lock);
 		spin_lock_nested(&sk->sk_peer_lock, SINGLE_DEPTH_NESTING);
 	}
-	old_pid = sk->sk_peer_pid;
-	old_cred = sk->sk_peer_cred;
+
 	sk->sk_peer_pid  = get_pid(peersk->sk_peer_pid);
 	sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
 
 	spin_unlock(&sk->sk_peer_lock);
 	spin_unlock(&peersk->sk_peer_lock);
-
-	put_pid(old_pid);
-	put_cred(old_cred);
 }
 
 static int unix_listen(struct socket *sock, int backlog)
-- 
2.30.2