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From: Archie Pusaka <apusaka@google.com>
Date: Sun, 28 Jan 2024 20:17:50 +0800
Message-ID: <CAJQfnxFwuhDnZRKYXMO3-i0YVuHTXgp6wdRNmAmob_xMm4n+5Q@mail.gmail.com>
Subject: Re: [Bluez PATCH] Monitor: Remove handle before assigning
To: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc: linux-bluetooth <linux-bluetooth@vger.kernel.org>, 
	Johan Hedberg <johan.hedberg@gmail.com>, Marcel Holtmann <marcel@holtmann.org>, 
	CrosBT Upstreaming <chromeos-bluetooth-upstreaming@chromium.org>, 
	Archie Pusaka <apusaka@chromium.org>, Zhengping Jiang <jiangzp@google.com>
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Hi Luiz,

On Sat, 27 Jan 2024 at 03:01, Luiz Augusto von Dentz
<luiz.dentz@gmail.com> wrote:
>
> Hi Archie,
>
> On Fri, Jan 26, 2024 at 1:42=E2=80=AFAM Archie Pusaka <apusaka@google.com=
> wrote:
> >
> > From: Archie Pusaka <apusaka@chromium.org>
> >
> > It is possible to have some handles not removed, for example the host
> > may decide not to wait for disconnection complete event when it is
> > suspending. In this case, when the peer device reconnected, we might
> > have two of the same handle assigned and create problem down the road.
> >
> > This patch solves the issue by always removing any previous handles
> > when assigning a new handle if they are the same.
> >
> > Reviewed-by: Zhengping Jiang <jiangzp@google.com>
> >
> > ---
> >
> >  monitor/packet.c | 50 +++++++++++++++++++++++++-----------------------
> >  1 file changed, 26 insertions(+), 24 deletions(-)
> >
> > diff --git a/monitor/packet.c b/monitor/packet.c
> > index 42e711cafa..b5dea6384a 100644
> > --- a/monitor/packet.c
> > +++ b/monitor/packet.c
> > @@ -189,11 +189,33 @@ static struct packet_conn_data *lookup_parent(uin=
t16_t handle)
> >         return NULL;
> >  }
> >
> > +static void release_handle(uint16_t handle)
> > +{
> > +       int i;
> > +
> > +       for (i =3D 0; i < MAX_CONN; i++) {
> > +               struct packet_conn_data *conn =3D &conn_list[i];
> > +
> > +               if (conn->handle =3D=3D handle) {
> > +                       if (conn->destroy)
> > +                               conn->destroy(conn->data);
> > +
> > +                       queue_destroy(conn->tx_q, free);
> > +                       queue_destroy(conn->chan_q, free);
> > +                       memset(conn, 0, sizeof(*conn));
> > +                       conn->handle =3D 0xffff;
> > +                       break;
> > +               }
> > +       }
> > +}
>
> We might as well return if we find out there is a packet_conn_data,
> that way we don't need to do 2 lookups in a row.

Do you mean to return the index, so we can immediately use the index
in the assign_handle function?
>
> >  static void assign_handle(uint16_t index, uint16_t handle, uint8_t typ=
e,
> >                                         uint8_t *dst, uint8_t dst_type)
> >  {
> >         int i;
> >
> > +       release_handle(handle);
> > +
> >         for (i =3D 0; i < MAX_CONN; i++) {
> >                 if (conn_list[i].handle =3D=3D 0xffff) {
> >                         hci_devba(index, (bdaddr_t *)conn_list[i].src);
> > @@ -225,26 +247,6 @@ static void assign_handle(uint16_t index, uint16_t=
 handle, uint8_t type,
> >         }
> >  }
> >
> > -static void release_handle(uint16_t handle)
> > -{
> > -       int i;
> > -
> > -       for (i =3D 0; i < MAX_CONN; i++) {
> > -               struct packet_conn_data *conn =3D &conn_list[i];
> > -
> > -               if (conn->handle =3D=3D handle) {
> > -                       if (conn->destroy)
> > -                               conn->destroy(conn->data);
> > -
> > -                       queue_destroy(conn->tx_q, free);
> > -                       queue_destroy(conn->chan_q, free);
> > -                       memset(conn, 0, sizeof(*conn));
> > -                       conn->handle =3D 0xffff;
> > -                       break;
> > -               }
> > -       }
> > -}
> > -
> >  struct packet_conn_data *packet_get_conn_data(uint16_t handle)
> >  {
> >         int i;
> > @@ -10076,7 +10078,7 @@ static void conn_complete_evt(struct timeval *t=
v, uint16_t index,
> >         const struct bt_hci_evt_conn_complete *evt =3D data;
> >
> >         print_status(evt->status);
> > -       print_handle(evt->handle);
> > +       print_field("Handle: %d", le16_to_cpu(evt->handle));
> >         print_bdaddr(evt->bdaddr);
> >         print_link_type(evt->link_type);
> >         print_enable("Encryption", evt->encr_mode);
> > @@ -10648,7 +10650,7 @@ static void sync_conn_complete_evt(struct timev=
al *tv, uint16_t index,
> >         const struct bt_hci_evt_sync_conn_complete *evt =3D data;
> >
> >         print_status(evt->status);
> > -       print_handle(evt->handle);
> > +       print_field("Handle: %d", le16_to_cpu(evt->handle));
> >         print_bdaddr(evt->bdaddr);
> >         print_link_type(evt->link_type);
> >         print_field("Transmission interval: 0x%2.2x", evt->tx_interval)=
;
> > @@ -11077,7 +11079,7 @@ static void le_conn_complete_evt(struct timeval=
 *tv, uint16_t index,
> >         const struct bt_hci_evt_le_conn_complete *evt =3D data;
> >
> >         print_status(evt->status);
> > -       print_handle(evt->handle);
> > +       print_field("Handle: %d", le16_to_cpu(evt->handle));
> >         print_role(evt->role);
> >         print_peer_addr_type("Peer address type", evt->peer_addr_type);
> >         print_addr("Peer address", evt->peer_addr, evt->peer_addr_type)=
;
> > @@ -11206,7 +11208,7 @@ static void le_enhanced_conn_complete_evt(struc=
t timeval *tv, uint16_t index,
> >         const struct bt_hci_evt_le_enhanced_conn_complete *evt =3D data=
;
> >
> >         print_status(evt->status);
> > -       print_handle(evt->handle);
> > +       print_field("Handle: %d", le16_to_cpu(evt->handle));
> >         print_role(evt->role);
> >         print_peer_addr_type("Peer address type", evt->peer_addr_type);
> >         print_addr("Peer address", evt->peer_addr, evt->peer_addr_type)=
;
>
> Are these changes really intentional? Or perhaps we don't want to
> attempt to resolve the address since these are the event that would
> assign them in the first place? In that case I had these fixed
> separately with a proper patch description.

Yes, these are intentional. Otherwise, we would still print the
previous (faulty) address as the printing happens before we release
the handle.
Also, we print the (correct) address anyway immediately on the next line.
Do you still want this to be in a separate patch?
>
> > --
> > 2.43.0.429.g432eaa2c6b-goog
> >
>
>
> --
> Luiz Augusto von Dentz

Thanks,
Archie