[ofw] [PATCH] SRP dreq deadlock

[Usha Srinivasan]

Hi Yossi,
Alex Estrin here at QLogic KOP has a couple of SRP patches pending to be
merged into Win OF. One patch addresses this deadlock bug along with QP
err handling and session recovery. A second patch will add a bit for
flow control handling in order to withstand heavy load. 

Alex will be preparing his patch and will submit them to the community
for review hopefully next week.

Usha

-----Original Message-----
From: ofw-bounces at lists.openfabrics.org
[mailto:ofw-bounces at lists.openfabrics.org] On Behalf Of Yossi Leybovich
Sent: Thursday, February 14, 2008 5:58 AM
To: Leonid Keller; ofw at lists.openfabrics.org
Subject: [ofw] [PATCH] SRP dreq deadlock

Leonid

While working Windows SRP with Linux SRPT (OFED) I discover that after
removing the SRPT the windows side stop receiving MADs.
The problem is that the SRP while handling the dreq callback of the
target try to reconnect and wait (in the context of the callback thread)
to the connect operation to end.
This is deadlock as the operation will not finish till SRP release the
callback thread.

This patch remove the reconnect code from the dreq callback.

Thanks
Yossi
Index: srp_connection.c
===================================================================
--- srp_connection.c	(revision 2166)
+++ srp_connection.c	(working copy)
@@ -285,8 +285,8 @@
 	ib_cm_drep_t    cm_drep;
 	ib_api_status_t status;
 	int             i;
-	int             retry_count = 0;
 
+
 	SRP_ENTER( SRP_DBG_PNP );
 
 	SRP_PRINT( TRACE_LEVEL_INFORMATION, SRP_DBG_DEBUG,
@@ -334,75 +334,9 @@
 	SRP_PRINT( TRACE_LEVEL_VERBOSE, SRP_DBG_DEBUG,
 		("Session Object ref_cnt = %d\n",
p_srp_session->obj.ref_cnt) );
 	cl_obj_destroy( &p_srp_session->obj );
-
-	do
-	{
-		retry_count++;
-
-		SRP_PRINT( TRACE_LEVEL_INFORMATION, SRP_DBG_DEBUG,
-			("Attempting to reconnect %s. Connection Attempt
Count = %d.\n",
-			 p_hba->ioc_info.profile.id_string,
-			 retry_count) );
-
-		SRP_PRINT( TRACE_LEVEL_VERBOSE, SRP_DBG_DEBUG,
-			("Creating New Session For Service Entry Index
%d.\n",
-			p_hba->ioc_info.profile.num_svc_entries));
-		p_srp_session = srp_new_session(
-			p_hba, &p_hba->p_svc_entries[i], &status );
-		if ( p_srp_session == NULL )
-		{
-			status = IB_INSUFFICIENT_MEMORY;
-			break;
-		}
-
-		SRP_PRINT( TRACE_LEVEL_VERBOSE, SRP_DBG_DEBUG,
-			("New Session For Service Entry Index %d
Created.\n",
-			p_hba->ioc_info.profile.num_svc_entries));
-		SRP_PRINT( TRACE_LEVEL_VERBOSE, SRP_DBG_DEBUG,
-			("Logging Into Session.\n"));
-		status = srp_session_login( p_srp_session );
-		if ( status == IB_SUCCESS )
-		{
-			if ( p_hba->max_sg >
p_srp_session->connection.max_scatter_gather_entries )
-			{
-				p_hba->max_sg =
p_srp_session->connection.max_scatter_gather_entries;
-			}
-
-			if ( p_hba->max_srb_ext_sz >
p_srp_session->connection.init_to_targ_iu_sz )
-			{
-				p_hba->max_srb_ext_sz =
-					sizeof( srp_send_descriptor_t )
-
-					SRP_MAX_IU_SIZE +
-
p_srp_session->connection.init_to_targ_iu_sz;
-			}
-
-			cl_obj_lock( &p_hba->obj );
-			p_hba->session_list[i] = p_srp_session;
-			cl_obj_unlock( &p_hba->obj );
-
-			SRP_PRINT( TRACE_LEVEL_VERBOSE, SRP_DBG_DEBUG,
-				("Session Login Issued
Successfully.\n"));
-		}
-		else
-		{
-			SRP_PRINT( TRACE_LEVEL_ERROR, SRP_DBG_ERROR,
-				("Session Login Failure Status = %d.\n",
status));
-			SRP_PRINT( TRACE_LEVEL_VERBOSE, SRP_DBG_DEBUG,
-				 ("Session Object ref_cnt = %d\n",
p_srp_session->obj.ref_cnt) );
-			cl_obj_destroy( &p_srp_session->obj );
-		}
-	} while ( (status != IB_SUCCESS) && (retry_count < 3) );
-
-	if ( status == IB_SUCCESS )
-	{
-		SRP_PRINT( TRACE_LEVEL_INFORMATION, SRP_DBG_DEBUG,
-			 ("Resuming Adapter for %s.\n",
p_hba->ioc_info.profile.id_string) );
-		p_hba->adapter_paused = FALSE;
-		StorPortReady( p_hba->p_ext );
-//		StorPortNotification( BusChangeDetected, p_hba->p_ext, 0
);
-	}
-
+	
 	SRP_EXIT( SRP_DBG_PNP );
+	return ;
 }
 
 /* __srp_cm_reply_cb */