Re: [PATCHv2] Bluetooth: Add refcnt to l2cap_conn

[Andrei Emeltchenko <Andrei.Emeltchenko.news@gmail.com>]

Hi Mat,

On Fri, Jun 22, 2012 at 03:09:08PM -0700, Mat Martineau wrote:
> >Adding kref to l2cap_conn helps to better handle racing when deleting
> >l2cap_conn. Races are created when deleting conn from timeout and from
> >the other execution path.
> >
> >Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
> >---
> >include/net/bluetooth/l2cap.h |    6 ++
> >net/bluetooth/l2cap_core.c    |  128 +++++++++++++++++++++++++++++++++--------
> >net/bluetooth/smp.c           |    7 +--
> >3 files changed, 113 insertions(+), 28 deletions(-)
> >
> 
> This v2 patch adds reference counting for the info timer.  Are there
> any other changes compared to v1?
> 
> I'm still concerned that this "reference counting" does not count
> every reference.  It only counts references used by the timers and
> in l2cap_security_cfm.  This is a fragile approach - as the code
> evolves, it's not clear what the rules are for using reference
> counting with l2cap_conn.  I think the most maintainable and robust
> approach is to make the rule "Count every reference" (including
> those in hci_conn and l2cap_chan).  

Yes this should actually evolve to this.

> What rules do you think are best
> for reference counting in this case?  It might be good to include
> that information in the commit message or comments.

I am thinking to add also reference counting for each l2cap_chan created
in l2cap_conn.

Best regards 
Andrei Emeltchenko