[ofw][patch][ibal] make IBBUS start up synchronous.

[Leonid Keller]

Applied in 2062


________________________________

	From: ofw-bounces at lists.openfabrics.org
[mailto:ofw-bounces at lists.openfabrics.org] On Behalf Of Leonid Keller
	Sent: Wednesday, March 25, 2009 4:02 PM
	To: ofw at lists.openfabrics.org
	Subject: [ofw][patch][ibal] make IBBUS start up synchronous.
	
	
	IBAL start up has by design two stages.
	  - initialization and preparing for getting IBAL PnP events
(synchronous on fdo_start);
	  - completing the start up upon receiving ADD_CA event
(asynchronous, after fdo_start).
	 
	It means, that IBBUS driver notifies the completion of the
driver start operation before it really has finished it.
	It causes races in quick HCA disable/enable sequences.
	 
	This patch makes IBBUS start up synchronous by adding a wait in
the first stage till the end of the second stage.
	 
	 
	Index: core/al/kernel/al_pnp.c
	
===================================================================
	--- core/al/kernel/al_pnp.c (revision 2055)
	+++ core/al/kernel/al_pnp.c (working copy)
	@@ -1152,6 +1152,7 @@
	  cl_status_t   cl_status;
	  al_pnp_ca_event_t *p_event_rec;
	  ib_ca_attr_t  *p_old_ca_attr;
	+ uint32_t   ref_cnt, prev_cnt, i;
	 
	  AL_ENTER( AL_DBG_PNP );
	 
	@@ -1232,9 +1233,18 @@
	  }
	 
	  /* Queue the event to the async processing manager. */
	- ref_al_obj( &gp_pnp->obj );
	+ ref_cnt = ref_al_obj( &gp_pnp->obj );
	  cl_async_proc_queue( gp_async_pnp_mgr,
&p_event_rec->async_item );
	 
	+ /* wait up to 3 seconds for the end of event propagation 
	+ It is needed for enabling quick HCA disable/enable scenarios.
*/
	+ prev_cnt = ref_cnt - 1;
	+ for ( i = 0; i < 30; ++i ) {
	+  if (ref_cnt <= prev_cnt)
	+   break;
	+  cl_thread_suspend(100);
	+ }
	+
	  AL_EXIT( AL_DBG_PNP );
	  return IB_SUCCESS;
	 }
	

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