[ofw] RE: When one can release CA interface

[Leonid Keller]

 see inline

> -----Original Message-----
> From: Smith, Stan [mailto:stan.smith at intel.com] 
> Sent: Tuesday, September 01, 2009 9:06 PM
> To: Leonid Keller; Tzachi Dar
> Cc: ofw_list
> Subject: RE: When one can release CA interface
> 
> Leonid Keller wrote:
> > I don't quite understand that.
> > If CA has been deregistered, i.e. ib_deregister_ca() has 
> been called, 
> > there is more CI_CA object.
> > All resources (PDs, CQs, QPs) are released.
> > How can IBAL send to CA MADs ?
> 
> The CI_CA object still exists due to the reference still held 
> on the HCA.
Did you see that for real ?

Technically, CI_CA is created as a synchronic object (see in
create_ci_ca)

	init_al_obj( &p_ci_ca->obj, p_ci_ca, FALSE, 
		destroying_ci_ca, cleanup_ci_ca, free_ci_ca );

and when ib_deregister_ca() exits, CI_CA should be fully destroyed.

>From the design point of view, deregister_ca is a function of IBAL low
interface.
It is to be called by HCA low-level driver upon card ejecting.
In other words, there is no HCA card after returning from this function
!

Am I missing something ?


> 
> >
> >
> >> -----Original Message-----
> >> From: Smith, Stan [mailto:stan.smith at intel.com]
> >> Sent: Tuesday, September 01, 2009 7:29 PM
> >> To: Leonid Keller; Tzachi Dar
> >> Cc: ofw_list
> >> Subject: RE: When one can release CA interface
> >>
> >> Leonid Keller wrote:
> >>> fdo_release_resources() in bus_pnp.c releases the last interface 
> >>> with low-level driver only after IBAL cleanup with the following
> >>> explanation:
> >>>
> >>> /* AL needs the HCA to stick around until AL cleanup has 
> completed.
> >>> ... */
> >>>
> >>> My question is - why ?
> >>> How may/can IBAL proceed to work with HCA after CA has been 
> >>> deregistered ? What kind of works could be still pending ?
> >>
> >>
> >> IBAL MAD processing threads may be in process of forwarding a MAD 
> >> and/or MAD processing with the outcome of eventually accessing the 
> >> HCA device. If the HCA is remove before AL shutdown.....boom!
> 
>