netdev - [Patch net] af_unix: remove redundant lockdep class

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Date:   Mon,  2 Apr 2018 11:01:27 -0700
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     netdev@...r.kernel.org
Cc:     Cong Wang <xiyou.wangcong@...il.com>,
        Paolo Abeni <pabeni@...hat.com>
Subject: [Patch net] af_unix: remove redundant lockdep class

After commit 581319c58600 ("net/socket: use per af lockdep classes for sk queues")
sock queue locks now have per-af lockdep classes, including unix socket.
It is no longer necessary to workaround it.

I noticed this while looking at a syzbot deadlock report, this patch
itself doesn't fix it (this is why I don't add Reported-by).

Fixes: 581319c58600 ("net/socket: use per af lockdep classes for sk queues")
Cc: Paolo Abeni <pabeni@...hat.com>
Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
---
 net/unix/af_unix.c | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 2d465bdeccbc..45971e173924 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -745,14 +745,6 @@ static struct proto unix_proto = {
 	.obj_size		= sizeof(struct unix_sock),
 };
 
-/*
- * AF_UNIX sockets do not interact with hardware, hence they
- * dont trigger interrupts - so it's safe for them to have
- * bh-unsafe locking for their sk_receive_queue.lock. Split off
- * this special lock-class by reinitializing the spinlock key:
- */
-static struct lock_class_key af_unix_sk_receive_queue_lock_key;
-
 static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
 {
 	struct sock *sk = NULL;
@@ -767,8 +759,6 @@ static struct sock *unix_create1(struct net *net, struct socket *sock, int kern)
 		goto out;
 
 	sock_init_data(sock, sk);
-	lockdep_set_class(&sk->sk_receive_queue.lock,
-				&af_unix_sk_receive_queue_lock_key);
 
 	sk->sk_allocation	= GFP_KERNEL_ACCOUNT;
 	sk->sk_write_space	= unix_write_space;
-- 
2.13.0