[PATCH net] net: sched: fix lockdep_set_class() typo error for sch->seqlock

From: Yunsheng Lin <linyunsheng@huawei.com>
To: <davem@davemloft.net>, <kuba@kernel.org>
Cc: <jhs@mojatatu.com>, <xiyou.wangcong@gmail.com>,
	<jiri@resnulli.us>, <pabeni@redhat.com>, <ap420073@gmail.com>,
	<netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linuxarm@openeuler.org>
Subject: [PATCH net] net: sched: fix lockdep_set_class() typo error for sch->seqlock
Date: Tue, 3 Aug 2021 18:58:21 +0800	[thread overview]
Message-ID: <1627988301-55801-1-git-send-email-linyunsheng@huawei.com> (raw)

According to comment in qdisc_alloc(), sch->seqlock's lockdep
class key should be set to qdisc_tx_busylock, due to possible
type error, sch->busylock's lockdep class key is set to
qdisc_tx_busylock, which is duplicated because sch->busylock's
lockdep class key is already set in qdisc_alloc().

So fix it by replacing sch->busylock with sch->seqlock.

Fixes: 96009c7d500e ("sched: replace __QDISC_STATE_RUNNING bit with a spin lock")
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
commit ab92d68fc22f ("net: core: add generic lockdep keys")
seems to fix the above error without mentioning that, and then
it is reverted by commit 1a33e10e4a95 ("net: partially revert
dynamic lockdep key changes"), but the blamed commit still be
96009c7d500e ("sched: replace __QDISC_STATE_RUNNING bit with
a spin lock").
---
 net/sched/sch_generic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index d9ac60f..a8dd06c 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -913,7 +913,7 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 
 	/* seqlock has the same scope of busylock, for NOLOCK qdisc */
 	spin_lock_init(&sch->seqlock);
-	lockdep_set_class(&sch->busylock,
+	lockdep_set_class(&sch->seqlock,
 			  dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
 
 	seqcount_init(&sch->running);
-- 
2.7.4

