netdev - Re: [PATCH v2] Bluetooth: Shutdown controller after workqueues are flushed or cancelled

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Message-ID: <CAAd53p6T_K67CPthLPObF=OWWCEChW4pMFMwuq87qWmTmzP2VA@mail.gmail.com>
Date:   Wed, 4 Aug 2021 22:42:09 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     Mattijs Korpershoek <mkorpershoek@...libre.com>
Cc:     Marcel Holtmann <marcel@...tmann.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Luiz Augusto von Dentz <luiz.dentz@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Fabien Parent <fparent@...libre.com>,
        Sean Wang <sean.wang@...iatek.com>,
        "open list:BLUETOOTH SUBSYSTEM" <linux-bluetooth@...r.kernel.org>,
        "open list:NETWORKING [GENERAL]" <netdev@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] Bluetooth: Shutdown controller after workqueues are
 flushed or cancelled

On Tue, Aug 3, 2021 at 4:21 PM Mattijs Korpershoek
<mkorpershoek@...libre.com> wrote:
>
> Hi Kai-Heng,
>
> Kai-Heng Feng <kai.heng.feng@...onical.com> writes:
>
> > Hi Mattijs,
> >
> > On Fri, Jul 30, 2021 at 7:40 PM Mattijs Korpershoek
> > <mkorpershoek@...libre.com> wrote:
> >>
> >> Hi Kai-Heng,
> >
> > [snipped]
> >
> >> Thank you for your help. Sorry I did not post the logs previously.
> >>
> >> dmesg: https://pastebin.com/tpWDNyQr
> >> ftrace on btmtksdio: https://pastebin.com/jmhvmwUw
> >
> > Seems like btmtksdio needs shudown() to be called before flush().
> > Since the order was there for a very long time, changing the calling
> > order indeed can break what driver expects.
> > Can you please test the following patch:
> > diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> > index 2560ed2f144d..a61e610a400c 100644
> > --- a/net/bluetooth/hci_core.c
> > +++ b/net/bluetooth/hci_core.c
> > @@ -1785,6 +1785,14 @@ int hci_dev_do_close(struct hci_dev *hdev)
> >         aosp_do_close(hdev);
> >         msft_do_close(hdev);
> >
> > +       if (!hci_dev_test_flag(hdev, HCI_UNREGISTER) &&
> > +           !hci_dev_test_flag(hdev, HCI_USER_CHANNEL) &&
> > +           test_bit(HCI_UP, &hdev->flags)) {
> > +               /* Execute vendor specific shutdown routine */
> > +               if (hdev->shutdown)
> > +                       hdev->shutdown(hdev);
> > +       }
> > +
> >         if (hdev->flush)
> >                 hdev->flush(hdev);
> >
> > @@ -1798,14 +1806,6 @@ int hci_dev_do_close(struct hci_dev *hdev)
> >                 clear_bit(HCI_INIT, &hdev->flags);
> >         }
> >
> > -       if (!hci_dev_test_flag(hdev, HCI_UNREGISTER) &&
> > -           !hci_dev_test_flag(hdev, HCI_USER_CHANNEL) &&
> > -           test_bit(HCI_UP, &hdev->flags)) {
> > -               /* Execute vendor specific shutdown routine */
> > -               if (hdev->shutdown)
> > -                       hdev->shutdown(hdev);
> > -       }
> > -
> >         /* flush cmd  work */
> >         flush_work(&hdev->cmd_work);
>
> Thanks for the patch and your help.
> I've tried it, but it seems that it does not improve for me.
> I'm still observing:
>
> i500-pumpkin login: root
> root@...0-pumpkin:~# hciconfig hci0 up
> Can't init device hci0: Connection timed out (110)
>
> Logs for this session:
> dmesg:   https://pastebin.com/iAFk5Tzi
> ftrace:  https://pastebin.com/kEMWSYrE

Thanks for the testing!
What about moving the shutdown() part right after hci_req_sync_lock()
so tx/rx can still work:

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 2560ed2f144d4..be3113fb7d4b0 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1727,6 +1727,14 @@ int hci_dev_do_close(struct hci_dev *hdev)
        hci_request_cancel_all(hdev);
        hci_req_sync_lock(hdev);

+       if (!hci_dev_test_flag(hdev, HCI_UNREGISTER) &&
+           !hci_dev_test_flag(hdev, HCI_USER_CHANNEL) &&
+           test_bit(HCI_UP, &hdev->flags)) {
+               /* Execute vendor specific shutdown routine */
+               if (hdev->shutdown)
+                       hdev->shutdown(hdev);
+       }
+
        if (!test_and_clear_bit(HCI_UP, &hdev->flags)) {
                cancel_delayed_work_sync(&hdev->cmd_timer);
                hci_req_sync_unlock(hdev);
@@ -1798,14 +1806,6 @@ int hci_dev_do_close(struct hci_dev *hdev)
                clear_bit(HCI_INIT, &hdev->flags);
        }

-       if (!hci_dev_test_flag(hdev, HCI_UNREGISTER) &&
-           !hci_dev_test_flag(hdev, HCI_USER_CHANNEL) &&
-           test_bit(HCI_UP, &hdev->flags)) {
-               /* Execute vendor specific shutdown routine */
-               if (hdev->shutdown)
-                       hdev->shutdown(hdev);
-       }
-
        /* flush cmd  work */
        flush_work(&hdev->cmd_work);





>
>
> >
> > Kai-Heng
> >
> >>
> >> Mattijs
> >> >
> >> > Kai-Heng
> >> >
> >> >>
> >> >> Thanks,
> >> >> Mattijs Korpershoek
> >> >>
> >> >>
> >> >> >
> >> >> > Regards
> >> >> >
> >> >> > Marcel