[ofw] correctly handle IOU manager destruction without ASSERT firing.

[Smith, Stan]

Hello Leonid,
  While testing your ibbus.sys ControlDeviceObject code, on HCA disable attempts I kept hitting an al_common.c ASSERT() which was triggered by calling deref_al_obj( &p_ext->h_ca->obj ); @ line #423 in bus_iou_mgr.c:free_iou_mgr().
The ASSERT() fired due to the fact the AL object p_ext->h_ca->obj was in an incorrect CL_STATE; already in the CL_DESTROYED state, ref_cnt == 0, already destroyed?

The issue was traced back to iou_mgr_iou_remove() where the p_ext->h_ca field was never set to NULL after the last IOU PDO removal.  A non-NULL h_ca field allowed free_iou_mgr() to attempt an extra deref_al_obj() on an object which had already been destroyed by virtue of it's ref_cnt going to zero from the deref_al_obj() call in iou_mgr_remove().

Fix - NULL out the h_ca field when removing the last IOU PDO.
Additionally, extraenous debug code is removed.

If you approve, I will svn commit.

Thank you,

Stan.


Signed off by stan.smith at intel.com

diff U3 C:/Documents and Settings/scsmith/Local Settings/Temp/bus_iou_mgr.c-revBASE.svn000.tmp.c C:/Documents and Settings/scsmith/My Documents/openIB-windows/SVN/gen1/trunk/core/bus/kernel/bus_iou_mgr.c
--- bus_iou_mgr.c-revBASE.svn000.tmp.c  Tue Apr 14 16:22:16 2009
+++ core/bus/kernel/bus_iou_mgr.c       Tue Apr 14 16:02:11 2009
@@ -426,11 +426,6 @@
                                        p_bfi->whoami, p_ext->cl_ext.vfptr_pnp_po->identity,
                                        p_ext->cl_ext.p_self_do, p_ext ) );

-               BUS_TRACE( BUS_DBG_PNP,("%s p_ext->h_ca->obj.state %d ref_cnt %d\n",
-                                       p_bfi->whoami,
-                                       p_ext->h_ca->obj.state,
-                                       p_ext->h_ca->obj.ref_cnt));
-
                IoDeleteDevice( p_ext->cl_ext.p_self_do );
        }

@@ -868,7 +863,8 @@
                        p_ext->cl_ext.vfptr_pnp_po->identity, p_ext->cl_ext.p_self_do,
                        p_ext, p_ext->b_present,
                        p_ext->b_reported_missing, p_ext->b_hibernating ) );
-               goto hca_deref;
+               deref_al_obj( &p_ext->h_ca->obj );
+               goto xit;
        }

        p_ext->b_present = FALSE;
@@ -890,9 +886,10 @@
        /* free PNP context */
        cl_free( p_ctx );
        p_pnp_rec->pnp_rec.context = NULL;
-
-hca_deref:
        deref_al_obj( &p_ext->h_ca->obj );
+       p_ext->h_ca = NULL;     // for free_iou_mgr()
+
+xit:
        cl_mutex_release( &gp_iou_mgr->pdo_mutex );

        BUS_EXIT( BUS_DBG_PNP );