Re: [PATCH 16/22] Store new configuration values in l2cap_pinfo

["Gustavo F. Padovan" <padovan@profusion.mobi>]

Hi Mat,

* Mat Martineau <mathewm@codeaurora.org> [2010-09-03 14:46:58 -0700]:

> 
> Gustavo -
> 
> On Fri, 3 Sep 2010, Gustavo F. Padovan wrote:
> 
> > Hi Mat,
> >
> > * Mat Martineau <mathewm@codeaurora.org> [2010-09-03 13:58:46 -0700]:
> >
> >>
> >> On Fri, 3 Sep 2010, haijun liu wrote:
> >>
> >>> On Fri, Sep 3, 2010 at 7:02 AM, Mat Martineau <mathewm@codeaurora.org> wrote:
> >>>>
> >>>> On Thu, 26 Aug 2010, haijun liu wrote:
> >>>>
> >>>>> From d093975dde6d85c824a5aaac943d676100810010 Mon Sep 17 00:00:00 2001
> >>>>> From: haijun.liu <haijun.liu@atheros.com>
> >>>>> Date: Mon, 23 Aug 2010 00:09:56 +0800
> >>>>> Subject: [PATCH 16/22] Store new configuration values in l2cap_pinfo.
> >>>>>
> >>>>> ---
> >>>>> include/net/bluetooth/l2cap.h |    9 +++++++++
> >>>>> 1 files changed, 9 insertions(+), 0 deletions(-)
> >>>>>
> >>>>> diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
> >>>>> index 2d864d4..f2dd65d 100644
> >>>>> --- a/include/net/bluetooth/l2cap.h
> >>>>> +++ b/include/net/bluetooth/l2cap.h
> >>>>> @@ -406,6 +406,15 @@ struct l2cap_pinfo {
> >>>>>        __u16           remote_mps;
> >>>>>        __u16           mps;
> >>>>>
> >>>>> +       __u8            ext_flowspec_enable;
> >>>>> +       struct ext_flow_spec    loc_efs;
> >>>>> +       struct ext_flow_spec    rem_efs;
> >>>>> +
> >>>>> +       __u8            extwin_enable;
> >>>>> +       __u16           extwin_size;
> >>>>> +       __u8            rem_extwin_enable;
> >>>>> +       __u16           rem_extwin_size;
> >>>>> +
> >>>>>        __le16          sport;
> >>>>>
> >>>>>        struct timer_list       retrans_timer;
> >>>>
> >>>> Regarding the new "extwin" structure members, have you considered changing
> >>>> the existing tx_win and remote_tx_win members to __u16 and using them with
> >>>> both standard and extended window sizes?
> >>>>
> >>>> The spec also requires that both directions of the link use the same type of
> >>>> control field (standard or extended).  After L2CAP configuration is done,
> >>>> all the information required for the transmit window is the control field
> >>>> type, tx_win, and remote_tx_win.  The control field would be set to
> >>>> 'extended' if a successful configuration response is sent or received for
> >>>> the extended window size option.
> >>>
> >>> Yes, we do, please look into the patch, we use __u16 for extwin_size &
> >>> rem_extwin_size
> >>> +       __u8            extwin_enable;
> >>> +       __u16           extwin_size;
> >>> +       __u8            rem_extwin_enable;
> >>> +       __u16           rem_extwin_size;
> >>>
> >>> You are exactly right, in our implementation, choosing standard or
> >>> extended window, it depends whether successful configuration
> >>> response contain the extended window size option.
> >>
> >> Haijin -
> >>
> >> Thank you for your explanation.  I was trying to suggest something
> >> different - sorry I did not explain myself well.
> >>
> >> I think that extwin_enable, extwin_size, rem_extwin_enable, and
> >> rem_extwin_size are not needed in l2cap_pinfo.  Instead, I suggest
> >> this:
> >>
> >> @@ -349,15 +349,17 @@ struct l2cap_pinfo {
> >>
> >>          __u8            ident;
> >>
> >> -       __u8            tx_win;
> >> +       __u16           tx_win;
> >>          __u8            max_tx;
> >> -       __u8            remote_tx_win;
> >> +       __u16           remote_tx_win;
> >>          __u8            remote_max_tx;
> >>          __u16           retrans_timeout;
> >>          __u16           monitor_timeout;
> >>          __u16           remote_mps;
> >>          __u16           mps;
> >>
> >> +       __u8            extended_control;
> >> +
> >>          __le16          sport;
> >>
> >>          struct timer_list       retrans_timer;
> >>
> >> Here, tx_win and remote_tx_win are always used to record the window
> >> size, whether extended or standard.  extended_control is used to
> >> specify standard or extended control fields.
> >
> > Then you don't need extended_control here, a bit in the conf_state field
> > should be enough.
> 
> It looks like conf_state is not currently used once the connection is 
> made.  The extended_control information is accessed when parsing 
> headers in every incoming PDU and generating every outgoing PDU. 
> Usage is a lot like l2cap_pinfo.fcs
> 
> If you still want to squeeze this extended control bit in an existing 
> l2cap_pinfo member, would conn_state be better?

Yes, this one is better.

-- 
Gustavo F. Padovan
ProFUSION embedded systems - http://profusion.mobi