af_unix: Pass struct sock to unix_autobind().

We do not use struct socket in unix_autobind() and pass struct sock to
unix_bind_bsd() and unix_bind_abstract().  Let's pass it to unix_autobind()
as well.

Also, this patch fixes these errors by checkpatch.pl.

  ERROR: do not use assignment in if condition
  #1795: FILE: net/unix/af_unix.c:1795:
  +	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr

  CHECK: Logical continuations should be on the previous line
  #1796: FILE: net/unix/af_unix.c:1796:
  +	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
  +	    && (err = unix_autobind(sock)) != 0)
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/unix/af_unix.c

@@ -950,15 +950,13 @@ static int unix_release(struct socket *sock)
 	return 0;
 }
 
-static int unix_autobind(struct socket *sock)
+static int unix_autobind(struct sock *sk)
 {
-	struct sock *sk = sock->sk;
-	struct net *net = sock_net(sk);
 	struct unix_sock *u = unix_sk(sk);
-	static u32 ordernum = 1;
 	struct unix_address *addr;
-	int err;
 	unsigned int retries = 0;
+	static u32 ordernum = 1;
+	int err;
 
 	err = mutex_lock_interruptible(&u->bindlock);
 	if (err)
@@ -985,7 +983,8 @@ static int unix_autobind(struct socket *sock)
 	spin_lock(&unix_table_lock);
 	ordernum = (ordernum+1)&0xFFFFF;
 
-	if (__unix_find_socket_byname(net, addr->name, addr->len, addr->hash)) {
+	if (__unix_find_socket_byname(sock_net(sk), addr->name, addr->len,
+				      addr->hash)) {
 		spin_unlock(&unix_table_lock);
 		/*
 		 * __unix_find_socket_byname() may take long time if many names
@@ -1161,7 +1160,7 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 		return -EINVAL;
 
 	if (addr_len == offsetof(struct sockaddr_un, sun_path))
-		return unix_autobind(sock);
+		return unix_autobind(sk);
 
 	err = unix_mkname(sunaddr, addr_len, &hash);
 	if (err < 0)
@@ -1231,8 +1230,11 @@ static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
 		alen = err;
 
 		if (test_bit(SOCK_PASSCRED, &sock->flags) &&
-		    !unix_sk(sk)->addr && (err = unix_autobind(sock)) != 0)
+		    !unix_sk(sk)->addr) {
+			err = unix_autobind(sk);
+			if (err)
 				goto out;
+		}
 
 restart:
 		other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err);
@@ -1337,9 +1339,11 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
 		goto out;
 	addr_len = err;
 
-	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
-	    (err = unix_autobind(sock)) != 0)
+	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr) {
+		err = unix_autobind(sk);
+		if (err)
 			goto out;
+	}
 
 	timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
 
@@ -1791,9 +1795,11 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
 			goto out;
 	}
 
-	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
-	    && (err = unix_autobind(sock)) != 0)
+	if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr) {
+		err = unix_autobind(sk);
+		if (err)
 			goto out;
+	}
 
 	err = -EMSGSIZE;
 	if (len > sk->sk_sndbuf - 32)