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From:   Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Date:   Fri, 15 Jan 2021 09:43:39 -0800
Message-ID: <CANFp7mUiZdCwsZfn1TA27fREWLMngELXYQNKercxEa8P6kK2cw@mail.gmail.com>
Subject: Re: [RESEND 1/2] Bluetooth: btusb: Add support for queuing during
 polling interval
To:     Archie Pusaka <apusaka@google.com>
Cc:     Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
        Alain Michaud <alainmichaud@google.com>,
        Bluez mailing list <linux-bluetooth@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hi Luiz,

I think only one patch was sent out last time. Looking back through
patchworks, I only see 1 email in that series:
https://patchwork.kernel.org/project/bluetooth/list/?series=&submitter=&state=&q=Bluetooth%3A+btusb%3A+Add+support+for+queuing+during+polling+interval&archive=both&delegate=

Abhishek

On Thu, Jan 14, 2021 at 11:05 PM Archie Pusaka <apusaka@google.com> wrote:
>
> Hi Luiz,
> I don't think we have tested the second patch yet.
>
> Hi Abhishek,
> Do you have context on this?
>
> On Thu, 14 Jan 2021 at 11:57, Luiz Augusto von Dentz
> <luiz.dentz@gmail.com> wrote:
> >
> > From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> >
> > This makes btusb to queue ACL and events during a polling interval
> > by using of a delayed work, with the interval working as a time window
> > where frames received from different endpoints are considered to be
> > arrived at same time and then attempt to resolve potential conflics by
> > processing the events ahead of ACL packets.
> >
> > It worth noting though that priorizing events over ACL data may result
> > in inverting the order compared to how they appeared over the air, for
> > instance there may be packets received before a disconnect event that
> > will be discarded and unencrypted packets received before encryption
> > change which would considered encrypted, because of these potential
> > changes on the order the support for queuing during the polling
> > interval is not enabled by default so platforms have the following
> > means to enable it:
> >
> > At build-time:
> >
> >     CONFIG_BT_HCIBTUSB_INTERVAL=y
> >
> > At runtime with use of module option:
> >
> >     enable_interval
> >
> > Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
>
> Tested-by: Archie Pusaka <apusaka@chromium.org>
>
> > ---
> >  drivers/bluetooth/Kconfig |  7 ++++
> >  drivers/bluetooth/btusb.c | 88 ++++++++++++++++++++++++++++++++++-----
> >  2 files changed, 84 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/bluetooth/Kconfig b/drivers/bluetooth/Kconfig
> > index 4e73a531b377..2f20a853d946 100644
> > --- a/drivers/bluetooth/Kconfig
> > +++ b/drivers/bluetooth/Kconfig
> > @@ -41,6 +41,13 @@ config BT_HCIBTUSB_AUTOSUSPEND
> >           This can be overridden by passing btusb.enable_autosuspend=[y|n]
> >           on the kernel commandline.
> >
> > +config BT_HCIBTUSB_INTERVAL
> > +       bool "Enable notification of USB polling interval"
> > +       depends on BT_HCIBTUSB
> > +       help
> > +         Say Y here to enable notification of USB polling interval for
> > +         Bluetooth USB devices by default.
> > +
> >  config BT_HCIBTUSB_BCM
> >         bool "Broadcom protocol support"
> >         depends on BT_HCIBTUSB
> > diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
> > index b14102fba601..38cb5448fc69 100644
> > --- a/drivers/bluetooth/btusb.c
> > +++ b/drivers/bluetooth/btusb.c
> > @@ -30,7 +30,7 @@
> >  static bool disable_scofix;
> >  static bool force_scofix;
> >  static bool enable_autosuspend = IS_ENABLED(CONFIG_BT_HCIBTUSB_AUTOSUSPEND);
> > -
> > +static bool enable_interval = IS_ENABLED(CONFIG_BT_HCIBTUSB_INTERVAL);
> >  static bool reset = true;
> >
> >  static struct usb_driver btusb_driver;
> > @@ -519,8 +519,12 @@ struct btusb_data {
> >
> >         unsigned long flags;
> >
> > -       struct work_struct work;
> > -       struct work_struct waker;
> > +       struct work_struct  work;
> > +       struct work_struct  waker;
> > +       struct delayed_work rx_work;
> > +
> > +       struct sk_buff_head acl_q;
> > +       struct sk_buff_head evt_q;
> >
> >         struct usb_anchor deferred;
> >         struct usb_anchor tx_anchor;
> > @@ -557,7 +561,7 @@ struct btusb_data {
> >         int isoc_altsetting;
> >         int suspend_count;
> >
> > -       int (*recv_event)(struct hci_dev *hdev, struct sk_buff *skb);
> > +       int (*recv_event)(struct btusb_data *data, struct sk_buff *skb);
> >         int (*recv_bulk)(struct btusb_data *data, void *buffer, int count);
> >
> >         int (*setup_on_usb)(struct hci_dev *hdev);
> > @@ -707,7 +711,7 @@ static int btusb_recv_intr(struct btusb_data *data, void *buffer, int count)
> >
> >                 if (!hci_skb_expect(skb)) {
> >                         /* Complete frame */
> > -                       data->recv_event(data->hdev, skb);
> > +                       data->recv_event(data, skb);
> >                         skb = NULL;
> >                 }
> >         }
> > @@ -718,6 +722,25 @@ static int btusb_recv_intr(struct btusb_data *data, void *buffer, int count)
> >         return err;
> >  }
> >
> > +static int btusb_rx_queue(struct btusb_data *data, struct sk_buff *skb,
> > +                         struct sk_buff_head *queue, unsigned int interval)
> > +{
> > +       skb_queue_tail(queue, skb);
> > +
> > +       schedule_delayed_work(&data->rx_work, interval);
> > +
> > +       return 0;
> > +}
> > +
> > +static int btusb_recv_acl(struct btusb_data *data, struct sk_buff *skb)
> > +{
> > +       if (!enable_interval)
> > +               return hci_recv_frame(data->hdev, skb);
> > +
> > +       /* TODO: Calculate polling interval based on endpoint bInterval? */
> > +       return btusb_rx_queue(data, skb, &data->acl_q, msecs_to_jiffies(1));
> > +}
> > +
> >  static int btusb_recv_bulk(struct btusb_data *data, void *buffer, int count)
> >  {
> >         struct sk_buff *skb;
> > @@ -765,7 +788,7 @@ static int btusb_recv_bulk(struct btusb_data *data, void *buffer, int count)
> >
> >                 if (!hci_skb_expect(skb)) {
> >                         /* Complete frame */
> > -                       hci_recv_frame(data->hdev, skb);
> > +                       btusb_recv_acl(data, skb);
> >                         skb = NULL;
> >                 }
> >         }
> > @@ -1383,9 +1406,13 @@ static int btusb_close(struct hci_dev *hdev)
> >
> >         BT_DBG("%s", hdev->name);
> >
> > +       cancel_delayed_work(&data->rx_work);
> >         cancel_work_sync(&data->work);
> >         cancel_work_sync(&data->waker);
> >
> > +       skb_queue_purge(&data->acl_q);
> > +       skb_queue_purge(&data->evt_q);
> > +
> >         clear_bit(BTUSB_ISOC_RUNNING, &data->flags);
> >         clear_bit(BTUSB_BULK_RUNNING, &data->flags);
> >         clear_bit(BTUSB_INTR_RUNNING, &data->flags);
> > @@ -1417,6 +1444,11 @@ static int btusb_flush(struct hci_dev *hdev)
> >
> >         BT_DBG("%s", hdev->name);
> >
> > +       cancel_delayed_work(&data->rx_work);
> > +
> > +       skb_queue_purge(&data->acl_q);
> > +       skb_queue_purge(&data->evt_q);
> > +
> >         usb_kill_anchored_urbs(&data->tx_anchor);
> >         btusb_free_frags(data);
> >
> > @@ -1769,6 +1801,25 @@ static void btusb_waker(struct work_struct *work)
> >         usb_autopm_put_interface(data->intf);
> >  }
> >
> > +static void btusb_rx_dequeue(struct btusb_data *data,
> > +                            struct sk_buff_head *queue)
> > +{
> > +       struct sk_buff *skb;
> > +
> > +       while ((skb = skb_dequeue(queue)))
> > +               hci_recv_frame(data->hdev, skb);
> > +}
> > +
> > +static void btusb_rx_work(struct work_struct *work)
> > +{
> > +       struct btusb_data *data = container_of(work, struct btusb_data,
> > +                                              rx_work.work);
> > +
> > +       /* Process HCI event packets so states changes are synchronized first */
> > +       btusb_rx_dequeue(data, &data->evt_q);
> > +       btusb_rx_dequeue(data, &data->acl_q);
> > +}
> > +
> >  static int btusb_setup_bcm92035(struct hci_dev *hdev)
> >  {
> >         struct sk_buff *skb;
> > @@ -2304,10 +2355,8 @@ static void btusb_intel_secure_send_result(struct btusb_data *data,
> >                 wake_up_bit(&data->flags, BTUSB_DOWNLOADING);
> >  }
> >
> > -static int btusb_recv_event_intel(struct hci_dev *hdev, struct sk_buff *skb)
> > +static int btusb_recv_event_intel(struct btusb_data *data, struct sk_buff *skb)
> >  {
> > -       struct btusb_data *data = hci_get_drvdata(hdev);
> > -
> >         if (test_bit(BTUSB_BOOTLOADER, &data->flags)) {
> >                 struct hci_event_hdr *hdr = (void *)skb->data;
> >
> > @@ -2336,7 +2385,7 @@ static int btusb_recv_event_intel(struct hci_dev *hdev, struct sk_buff *skb)
> >                 }
> >         }
> >
> > -       return hci_recv_frame(hdev, skb);
> > +       return hci_recv_frame(data->hdev, skb);
> >  }
> >
> >  static int btusb_send_frame_intel(struct hci_dev *hdev, struct sk_buff *skb)
> > @@ -4279,6 +4328,15 @@ static int btusb_shutdown_qca(struct hci_dev *hdev)
> >         return 0;
> >  }
> >
> > +static int btusb_recv_evt(struct btusb_data *data, struct sk_buff *skb)
> > +{
> > +       if (!enable_interval)
> > +               return hci_recv_frame(data->hdev, skb);
> > +
> > +       /* Don't delay event processing */
> > +       return btusb_rx_queue(data, skb, &data->evt_q, 0);
> > +}
> > +
> >  static int btusb_probe(struct usb_interface *intf,
> >                        const struct usb_device_id *id)
> >  {
> > @@ -4362,6 +4420,11 @@ static int btusb_probe(struct usb_interface *intf,
> >
> >         INIT_WORK(&data->work, btusb_work);
> >         INIT_WORK(&data->waker, btusb_waker);
> > +       INIT_DELAYED_WORK(&data->rx_work, btusb_rx_work);
> > +
> > +       skb_queue_head_init(&data->acl_q);
> > +       skb_queue_head_init(&data->evt_q);
> > +
> >         init_usb_anchor(&data->deferred);
> >         init_usb_anchor(&data->tx_anchor);
> >         spin_lock_init(&data->txlock);
> > @@ -4378,7 +4441,7 @@ static int btusb_probe(struct usb_interface *intf,
> >                 data->recv_bulk = btusb_recv_bulk_intel;
> >                 set_bit(BTUSB_BOOTLOADER, &data->flags);
> >         } else {
> > -               data->recv_event = hci_recv_frame;
> > +               data->recv_event = btusb_recv_evt;
> >                 data->recv_bulk = btusb_recv_bulk;
> >         }
> >
> > @@ -4867,6 +4930,9 @@ MODULE_PARM_DESC(force_scofix, "Force fixup of wrong SCO buffers size");
> >  module_param(enable_autosuspend, bool, 0644);
> >  MODULE_PARM_DESC(enable_autosuspend, "Enable USB autosuspend by default");
> >
> > +module_param(enable_interval, bool, 0644);
> > +MODULE_PARM_DESC(enable_interval, "Enable USB polling interval by default");
> > +
> >  module_param(reset, bool, 0644);
> >  MODULE_PARM_DESC(reset, "Send HCI reset command on initialization");
> >
> > --
> > 2.26.2
> >
>
> Thanks,
> Archie