Re: [PATCH v1 2/2] Bluetooth: sco: expose WBS packet length in socket option

From: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To: "Pali Rohár" <pali@kernel.org>
Cc: Joseph Hwang <josephsih@chromium.org>,
	"linux-bluetooth@vger.kernel.org"
	<linux-bluetooth@vger.kernel.org>,
	Marcel Holtmann <marcel@holtmann.org>,
	Joseph Hwang <josephsih@google.com>,
	ChromeOS Bluetooth Upstreaming 
	<chromeos-bluetooth-upstreaming@chromium.org>,
	Alain Michaud <alainm@chromium.org>,
	Abhishek Pandit-Subedi <abhishekpandit@chromium.org>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Johan Hedberg <johan.hedberg@gmail.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"open list:NETWORKING [GENERAL]" <netdev@vger.kernel.org>
Subject: Re: [PATCH v1 2/2] Bluetooth: sco: expose WBS packet length in socket option
Date: Wed, 19 Aug 2020 11:21:00 -0700	[thread overview]
Message-ID: <CABBYNZJVDk6LWqyY7h8=KwpA4Oub+aCb3WEWnxk_AGWPvgmatg@mail.gmail.com> (raw)
In-Reply-To: <20200819143716.iimo4l3uul7lrpjn@pali>

Hi Pali,

On Wed, Aug 19, 2020 at 7:37 AM Pali Rohár <pali@kernel.org> wrote:
>
> On Friday 14 August 2020 12:56:05 Luiz Augusto von Dentz wrote:
> > Hi Joseph,
> >
> > On Thu, Aug 13, 2020 at 1:42 AM Joseph Hwang <josephsih@chromium.org> wrote:
> > >
> > > It is desirable to expose the wideband speech packet length via
> > > a socket option to the user space so that the user space can set
> > > the value correctly in configuring the sco connection.
> > >
> > > Reviewed-by: Alain Michaud <alainm@chromium.org>
> > > Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
> > > Signed-off-by: Joseph Hwang <josephsih@chromium.org>
> > > ---
> > >
> > >  include/net/bluetooth/bluetooth.h | 2 ++
> > >  net/bluetooth/sco.c               | 8 ++++++++
> > >  2 files changed, 10 insertions(+)
> > >
> > > diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
> > > index 9125effbf4483d..922cc03143def4 100644
> > > --- a/include/net/bluetooth/bluetooth.h
> > > +++ b/include/net/bluetooth/bluetooth.h
> > > @@ -153,6 +153,8 @@ struct bt_voice {
> > >
> > >  #define BT_SCM_PKT_STATUS      0x03
> > >
> > > +#define BT_SCO_PKT_LEN         17
> > > +
> > >  __printf(1, 2)
> > >  void bt_info(const char *fmt, ...);
> > >  __printf(1, 2)
> > > diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
> > > index dcf7f96ff417e6..97e4e7c7b8cf62 100644
> > > --- a/net/bluetooth/sco.c
> > > +++ b/net/bluetooth/sco.c
> > > @@ -67,6 +67,7 @@ struct sco_pinfo {
> > >         __u32           flags;
> > >         __u16           setting;
> > >         __u8            cmsg_mask;
> > > +       __u32           pkt_len;
> > >         struct sco_conn *conn;
> > >  };
> > >
> > > @@ -267,6 +268,8 @@ static int sco_connect(struct sock *sk)
> > >                 sco_sock_set_timer(sk, sk->sk_sndtimeo);
> > >         }
> > >
> > > +       sco_pi(sk)->pkt_len = hdev->sco_pkt_len;
> > > +
> > >  done:
> > >         hci_dev_unlock(hdev);
> > >         hci_dev_put(hdev);
> > > @@ -1001,6 +1004,11 @@ static int sco_sock_getsockopt(struct socket *sock, int level, int optname,
> > >                         err = -EFAULT;
> > >                 break;
> > >
> > > +       case BT_SCO_PKT_LEN:
> > > +               if (put_user(sco_pi(sk)->pkt_len, (u32 __user *)optval))
> > > +                       err = -EFAULT;
> > > +               break;
> >
> > Couldn't we expose this via BT_SNDMTU/BT_RCVMTU?
>
> Hello!
>
> There is already SCO_OPTIONS sock option, uses struct sco_options and
> contains 'mtu' member.
>
> I think that instead of adding new sock option, existing SCO_OPTIONS
> option should be used.

We are moving away from type specific options to so options like
BT_SNDMTU/BT_RCVMTU should be supported in all socket types.

>
> > >         default:
> > >                 err = -ENOPROTOOPT;
> > >                 break;
> > > --
> > > 2.28.0.236.gb10cc79966-goog
> > >
> >
> >
> > --
> > Luiz Augusto von Dentz

-- 
Luiz Augusto von Dentz