From: Cong Wang <xiyou.wangcong@gmail.com>
To: Chengfeng Ye <dg573847474@gmail.com>
Cc: Jakub Kicinski <kuba@kernel.org>,
jhs@mojatatu.com, jiri@resnulli.us, davem@davemloft.net,
edumazet@google.com, pabeni@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net/sched: use spin_lock_bh() on &gact->tcf_lock
Date: Sun, 8 Oct 2023 10:56:09 -0700 [thread overview]
Message-ID: <ZSLtOViO2p31Jzd6@pop-os.localdomain> (raw)
In-Reply-To: <CAAo+4rW=zh_d7AxJSP0uLuO7w+_PmbBfBr6D4=4X2Ays7ATqoA@mail.gmail.com>
On Thu, Oct 05, 2023 at 05:01:07PM +0800, Chengfeng Ye wrote:
> Hi Jakub,
>
> Thanks for the reply,
>
> I inspected the code a bit more, it seems that the TC action is called from
> tcf_proto_ops.classify() callback, which is called from Qdisc_ops enqueue
> callback.
>
> Then Qdisc enqueue callback is from
>
> -> __dev_queue_xmit()
> -> __dev_xmit_skb()
> -> dev_qdisc_enqueue()
>
> inside the net core. It seems that this __dev_queue_xmit() callback is
> typically called from BH context (e.g., NET_TX_SOFTIRQ) with BH
> already disabled, but sometimes also can from a work queue under
> process context, one case is the br_mrp_test_work_expired() inside
> net/bridge/br_mrp.c. Does it indicate that this TC action could also be
> called with BH enable? I am not a developer so really not sure about it,
> as the networking code is a bit long and complicated.
Doesn't __dev_queue_xmit() itself disable BH with rcu_read_lock_bh()??
Thanks.
next prev parent reply other threads:[~2023-10-08 17:56 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-26 18:26 [PATCH] net/sched: use spin_lock_bh() on &gact->tcf_lock Chengfeng Ye
2023-10-01 17:54 ` Simon Horman
2023-10-01 18:32 ` Cong Wang
2023-10-01 18:53 ` Chengfeng Ye
2023-10-05 0:01 ` Jakub Kicinski
2023-10-05 9:01 ` Chengfeng Ye
2023-10-05 11:46 ` Jamal Hadi Salim
2023-10-05 12:15 ` Chengfeng Ye
2023-10-09 6:35 ` Horatiu Vultur
2023-10-09 15:52 ` Jamal Hadi Salim
2023-10-08 17:56 ` Cong Wang [this message]
2023-10-08 18:06 ` Chengfeng Ye
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