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

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Date:   Fri, 06 Aug 2021 10:51:14 +0200
From:   Mattijs Korpershoek <mkorpershoek@...libre.com>
To:     Kai-Heng Feng <kai.heng.feng@...onical.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

Hi Kai-Heng,

Kai-Heng Feng <kai.heng.feng@...onical.com> writes:

> Hi Mattijs,
>
> On Thu, Aug 5, 2021 at 2:55 PM Mattijs Korpershoek
> <mkorpershoek@...libre.com> wrote:
>>
>> Hi Kai-Heng,
>>
>> Thanks for your patch,
>>
>> Kai-Heng Feng <kai.heng.feng@...onical.com> writes:
>>
>
> [snipped]
>
>> I confirm this diff works for me:
>>
>> root@...0-pumpkin:~# hciconfig hci0 up
>> root@...0-pumpkin:~# hciconfig hci0 down
>> root@...0-pumpkin:~# hciconfig hci0 up
>> root@...0-pumpkin:~# hciconfig hci0
>> hci0:   Type: Primary  Bus: SDIO
>>         BD Address: 00:0C:E7:55:FF:12  ACL MTU: 1021:8  SCO MTU: 244:4
>>         UP RUNNING
>>         RX bytes:11268 acl:0 sco:0 events:829 errors:0
>>         TX bytes:182569 acl:0 sco:0 commands:829 errors:0
>>
>> root@...0-pumpkin:~# hcitool scan
>> Scanning ...
>>         <redacted>       Pixel 3 XL
>>
>> Tested-by: Mattijs Korpershoek <mkorpershoek@...libre.com>
>
> I found that btmtksdio_flush() only cancels the work instead of doing
> flush_work(). That probably explains why putting ->shutdown right
> before ->flush doesn't work.
> So can you please test the following again:
> diff --git a/drivers/bluetooth/btmtksdio.c b/drivers/bluetooth/btmtksdio.c
> index 9872ef18f9fea..b33c05ad2150b 100644
> --- a/drivers/bluetooth/btmtksdio.c
> +++ b/drivers/bluetooth/btmtksdio.c
> @@ -649,9 +649,9 @@ static int btmtksdio_flush(struct hci_dev *hdev)
>  {
>         struct btmtksdio_dev *bdev = hci_get_drvdata(hdev);
>
> -       skb_queue_purge(&bdev->txq);
> +       flush_work(&bdev->tx_work);
>
> -       cancel_work_sync(&bdev->tx_work);
> +       skb_queue_purge(&bdev->txq);
>
>         return 0;
>  }
> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> index 2560ed2f144d4..a61e610a400cb 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);
I've tried this but I have the same (broken) symptoms as before.

Here are some logs of v3:
dmesg: https://pastebin.com/1x4UHkzy
ftrace: https://pastebin.com/Lm1d6AWy

Mattijs

>
> Kai-Heng