linux-kernel - Re: [PATCH] Bluetooth: Move shutdown callback before flushing tx and rx queue

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Date:   Tue, 10 Aug 2021 12:37:22 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     Hsin-Yi Wang <hsinyi@...omium.org>
Cc:     Marcel Holtmann <marcel@...tmann.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Luiz Augusto von Dentz <luiz.dentz@...il.com>,
        Mattijs Korpershoek <mkorpershoek@...libre.com>,
        Guenter Roeck <linux@...ck-us.net>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        "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] Bluetooth: Move shutdown callback before flushing tx and
 rx queue

On Tue, Aug 10, 2021 at 12:10 PM Hsin-Yi Wang <hsinyi@...omium.org> wrote:
>
> On Tue, Aug 10, 2021 at 1:44 AM Kai-Heng Feng
> <kai.heng.feng@...onical.com> wrote:
> >
> > Commit 0ea9fd001a14 ("Bluetooth: Shutdown controller after workqueues
> > are flushed or cancelled") introduced a regression that makes mtkbtsdio
> > driver stops working:
> > [   36.593956] Bluetooth: hci0: Firmware already downloaded
> > [   46.814613] Bluetooth: hci0: Execution of wmt command timed out
> > [   46.814619] Bluetooth: hci0: Failed to send wmt func ctrl (-110)
> >
> > The shutdown callback depends on the result of hdev->rx_work, so we
> > should call it before flushing rx_work:
> > -> btmtksdio_shutdown()
> >  -> mtk_hci_wmt_sync()
> >   -> __hci_cmd_send()
> >    -> wait for BTMTKSDIO_TX_WAIT_VND_EVT gets cleared
> >
> > -> btmtksdio_recv_event()
> >  -> hci_recv_frame()
> >   -> queue_work(hdev->workqueue, &hdev->rx_work)
> >    -> clears BTMTKSDIO_TX_WAIT_VND_EVT
> >
> > So move the shutdown callback before flushing TX/RX queue to resolve the
> > issue.
> >
> > Reported-and-tested-by: Mattijs Korpershoek <mkorpershoek@...libre.com>
> > Tested-by: Hsin-Yi Wang <hsinyi@...omium.org>
>
> Hello,
>
> Sorry for confusion, but the version I tested is this one:
> https://lkml.org/lkml/2021/8/4/486 (shutdown is prior to the
> test_and_clear HCI_UP)
> I tested this version and still see the error I've seen before.

Ah, sorry for causing your trouble, I am the one who got confused :(
HCI_UP is obviously required for hci_req_sync() to work.

Let me resend one, and sorry again!

Kai-Heng

>
>
>
>
> > Cc: Guenter Roeck <linux@...ck-us.net>
> > Fixes: 0ea9fd001a14 ("Bluetooth: Shutdown controller after workqueues are flushed or cancelled")
> > Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
> > ---
> >  net/bluetooth/hci_core.c | 16 ++++++++--------
> >  1 file changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> > index cb2e9e513907..8da04c899197 100644
> > --- a/net/bluetooth/hci_core.c
> > +++ b/net/bluetooth/hci_core.c
> > @@ -1735,6 +1735,14 @@ int hci_dev_do_close(struct hci_dev *hdev)
> >
> >         hci_leds_update_powered(hdev, false);
> >
> > +       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 RX and TX works */
> >         flush_work(&hdev->tx_work);
> >         flush_work(&hdev->rx_work);
> > @@ -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);
> >
> > --
> > 2.31.1
> >