From: Cong Wang <xiyou.wangcong@gmail.com>
To: Vlad Buslov <vladbu@mellanox.com>
Cc: David Miller <davem@davemloft.net>,
Linux Kernel Network Developers <netdev@vger.kernel.org>,
Jamal Hadi Salim <jhs@mojatatu.com>,
Jiri Pirko <jiri@resnulli.us>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH net-next v2] net: sched: don't disable bh when accessing action idr
Date: Tue, 22 May 2018 18:10:28 -0700 [thread overview]
Message-ID: <CAM_iQpVMFSxnN6dEi0U4=aw7s7TcJ88ShiNTDXcoRUVL82jTZw@mail.gmail.com> (raw)
In-Reply-To: <1526932984-11544-1-git-send-email-vladbu@mellanox.com>
On Mon, May 21, 2018 at 1:03 PM, Vlad Buslov <vladbu@mellanox.com> wrote:
> Initial net_device implementation used ingress_lock spinlock to synchronize
> ingress path of device. This lock was used in both process and bh context.
> In some code paths action map lock was obtained while holding ingress_lock.
> Commit e1e992e52faa ("[NET_SCHED] protect action config/dump from irqs")
> modified actions to always disable bh, while using action map lock, in
> order to prevent deadlock on ingress_lock in softirq. This lock was removed
> from net_device, so disabling bh, while accessing action map, is no longer
> necessary.
>
> Replace all action idr spinlock usage with regular calls that do not
> disable bh.
While your patch is probably fine, the above justification seems not.
In the past, tc actions could be released in BH context because tc
filters use call_rcu(). However, I moved them to a workqueue recently.
So before my change I don't think you can remove the BH protection,
otherwise race with idr_remove()...
next prev parent reply other threads:[~2018-05-23 1:10 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-18 15:45 [PATCH] net: sched: don't disable bh when accessing action idr Vlad Buslov
2018-05-19 2:59 ` Cong Wang
2018-05-19 10:12 ` Vlad Buslov
2018-05-20 3:02 ` David Miller
2018-05-21 20:03 ` [PATCH net-next v2] " Vlad Buslov
2018-05-22 12:50 ` Jamal Hadi Salim
2018-05-23 1:10 ` Cong Wang [this message]
2018-05-23 6:57 ` Vlad Buslov
2018-05-23 7:32 ` Jiri Pirko
2018-05-23 8:52 ` [PATCH net-next v3] " Vlad Buslov
2018-05-23 23:14 ` Cong Wang
2018-05-24 16:54 ` Vlad Buslov
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