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Message-ID: <cecf89520de89bfba231c80c5ddb6b357722d6de.camel@sipsolutions.net>
Subject: Re: [PATCH 3/4] Bluetooth: hci_core: Signal TX failure if sending a
 frame failed
From:   Benjamin Berg <benjamin@sipsolutions.net>
To:     Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc:     "linux-bluetooth@vger.kernel.org" <linux-bluetooth@vger.kernel.org>
Date:   Wed, 10 Nov 2021 09:46:34 +0100
In-Reply-To: <CABBYNZJ2mXOTQygWWgHMN+pkqYoY_cudqrbW6aOHozo7soUZhA@mail.gmail.com>
References: <20211109164113.65981-1-benjamin@sipsolutions.net>
         <20211109164113.65981-4-benjamin@sipsolutions.net>
         <CABBYNZJ2mXOTQygWWgHMN+pkqYoY_cudqrbW6aOHozo7soUZhA@mail.gmail.com>
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Hi Luiz,

On Tue, 2021-11-09 at 15:13 -0800, Luiz Augusto von Dentz wrote:
> Hi Benjamin,
>=20
> On Tue, Nov 9, 2021 at 2:35 PM Benjamin Berg <benjamin@sipsolutions.net> =
wrote:
> >=20
> > From: Benjamin Berg <bberg@redhat.com>
> >=20
> > Call the hci_tx_error handler in case a frame cannot be send.
> >=20
> > Signed-off-by: Benjamin Berg <bberg@redhat.com>
> > ---
> >  net/bluetooth/hci_core.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >=20
> > diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> > index bbb35188e41f..8664c2fbacdb 100644
> > --- a/net/bluetooth/hci_core.c
> > +++ b/net/bluetooth/hci_core.c
> > @@ -4200,6 +4200,8 @@ static void hci_send_frame(struct hci_dev *hdev, =
struct sk_buff *skb)
> >         if (err < 0) {
> >                 bt_dev_err(hdev, "sending frame failed (%d)", err);
> >                 kfree_skb(skb);
> > +
> > +               hci_tx_error(hdev, -err);
>=20
> Either we do this here by calling directly hci_cmd_sync_cancel like I
> suggested previously or perhaps we should have the error returned by
> hci_send_frame otherwise the current thread still has to wait to get
> the error from req_result which perhaps is not necessary if we already
> got a proper error here just return it so the thread doesn't even need
> to sleep.

Yes, returning the error is a good idea.

I think that means doing the cancellation from hci_cmd_work. As I
understand it, the frame is sent from the main workqueue so we are not
avoiding the context switches for now. But that may well change in the
future.

Benjamin

> >         }
> >  }
> >=20
> > --
> > 2.31.1
> >=20
>=20
>=20


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