[SCSI] zfcp: minor erp bug fixes

Bug fixes for zfcp's erp:
- trigger adapter reopen if do_QDIO fails
- avoid erp deadlock if registration of scsi target or remote port hang
- do not treat as error if exchange port data fails
- decrease timeout for target reset and aborts
- mark unit failed if slave_destroy is called

Additionally some code cleanup was done:
- made some functions void when retval is not of interest
- shortened initialization of zfcp's host_template
- corrected some comments

Signed-off-by: Andreas Herrmann <aherrman@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 67 insertions, 129 deletions

diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c
index f74412bd9d6a..7f60b6fdf724 100644
--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -64,8 +64,8 @@ static int zfcp_erp_strategy_check_action(struct zfcp_erp_action *, int);
 static int zfcp_erp_adapter_strategy(struct zfcp_erp_action *);
 static int zfcp_erp_adapter_strategy_generic(struct zfcp_erp_action *, int);
 static int zfcp_erp_adapter_strategy_close(struct zfcp_erp_action *);
-static int zfcp_erp_adapter_strategy_close_qdio(struct zfcp_erp_action *);
-static int zfcp_erp_adapter_strategy_close_fsf(struct zfcp_erp_action *);
+static void zfcp_erp_adapter_strategy_close_qdio(struct zfcp_erp_action *);
+static void zfcp_erp_adapter_strategy_close_fsf(struct zfcp_erp_action *);
 static int zfcp_erp_adapter_strategy_open(struct zfcp_erp_action *);
 static int zfcp_erp_adapter_strategy_open_qdio(struct zfcp_erp_action *);
 static int zfcp_erp_adapter_strategy_open_fsf(struct zfcp_erp_action *);
@@ -93,10 +93,9 @@ static int zfcp_erp_unit_strategy_clearstati(struct zfcp_unit *);
 static int zfcp_erp_unit_strategy_close(struct zfcp_erp_action *);
 static int zfcp_erp_unit_strategy_open(struct zfcp_erp_action *);
 
-static int zfcp_erp_action_dismiss_adapter(struct zfcp_adapter *);
-static int zfcp_erp_action_dismiss_port(struct zfcp_port *);
-static int zfcp_erp_action_dismiss_unit(struct zfcp_unit *);
-static int zfcp_erp_action_dismiss(struct zfcp_erp_action *);
+static void zfcp_erp_action_dismiss_port(struct zfcp_port *);
+static void zfcp_erp_action_dismiss_unit(struct zfcp_unit *);
+static void zfcp_erp_action_dismiss(struct zfcp_erp_action *);
 
 static int zfcp_erp_action_enqueue(int, struct zfcp_adapter *,
 				   struct zfcp_port *, struct zfcp_unit *);
@@ -135,29 +134,39 @@ zfcp_fsf_request_timeout_handler(unsigned long data)
 	zfcp_erp_adapter_reopen(adapter, 0);
 }
 
-/*
- * function:	zfcp_fsf_scsi_er_timeout_handler
- *
- * purpose:     This function needs to be called whenever a SCSI error recovery
- *              action (abort/reset) does not return.
- *              Re-opening the adapter means that the command can be returned
- *              by zfcp (it is guarranteed that it does not return via the
- *              adapter anymore). The buffer can then be used again.
- *    
- * returns:     sod all
+/**
+ * zfcp_fsf_scsi_er_timeout_handler - timeout handler for scsi eh tasks
+ *
+ * This function needs to be called whenever a SCSI error recovery
+ * action (abort/reset) does not return.  Re-opening the adapter means
+ * that the abort/reset command can be returned by zfcp. It won't complete
+ * via the adapter anymore (because qdio queues are closed). If ERP is
+ * already running on this adapter it will be stopped.
  */
-void
-zfcp_fsf_scsi_er_timeout_handler(unsigned long data)
+void zfcp_fsf_scsi_er_timeout_handler(unsigned long data)
 {
 	struct zfcp_adapter *adapter = (struct zfcp_adapter *) data;
+	unsigned long flags;
 
 	ZFCP_LOG_NORMAL("warning: SCSI error recovery timed out. "
 			"Restarting all operations on the adapter %s\n",
 			zfcp_get_busid_by_adapter(adapter));
 	debug_text_event(adapter->erp_dbf, 1, "eh_lmem_tout");
-	zfcp_erp_adapter_reopen(adapter, 0);
 
-	return;
+	write_lock_irqsave(&adapter->erp_lock, flags);
+	if (atomic_test_mask(ZFCP_STATUS_ADAPTER_ERP_PENDING,
+			     &adapter->status)) {
+		zfcp_erp_modify_adapter_status(adapter,
+		       ZFCP_STATUS_COMMON_UNBLOCKED|ZFCP_STATUS_COMMON_OPEN,
+		       ZFCP_CLEAR);
+		zfcp_erp_action_dismiss_adapter(adapter);
+		write_unlock_irqrestore(&adapter->erp_lock, flags);
+		/* dismiss all pending requests including requests for ERP */
+		zfcp_fsf_req_dismiss_all(adapter);
+		adapter->fsf_req_seq_no = 0;
+	} else
+		write_unlock_irqrestore(&adapter->erp_lock, flags);
+	zfcp_erp_adapter_reopen(adapter, 0);
 }
 
 /*
@@ -670,17 +679,10 @@ zfcp_erp_unit_reopen(struct zfcp_unit *unit, int clear_mask)
 	return retval;
 }
 
-/*
- * function:	
- *
- * purpose:	disable I/O,
- *		return any open requests and clean them up,
- *		aim: no pending and incoming I/O
- *
- * returns:
+/**
+ * zfcp_erp_adapter_block - mark adapter as blocked, block scsi requests
  */
-static void
-zfcp_erp_adapter_block(struct zfcp_adapter *adapter, int clear_mask)
+static void zfcp_erp_adapter_block(struct zfcp_adapter *adapter, int clear_mask)
 {
 	debug_text_event(adapter->erp_dbf, 6, "a_bl");
 	zfcp_erp_modify_adapter_status(adapter,
@@ -688,15 +690,10 @@ zfcp_erp_adapter_block(struct zfcp_adapter *adapter, int clear_mask)
 				       clear_mask, ZFCP_CLEAR);
 }
 
-/*
- * function:	
- *
- * purpose:	enable I/O
- *
- * returns:
+/**
+ * zfcp_erp_adapter_unblock - mark adapter as unblocked, allow scsi requests
  */
-static void
-zfcp_erp_adapter_unblock(struct zfcp_adapter *adapter)
+static void zfcp_erp_adapter_unblock(struct zfcp_adapter *adapter)
 {
 	debug_text_event(adapter->erp_dbf, 6, "a_ubl");
 	atomic_set_mask(ZFCP_STATUS_COMMON_UNBLOCKED, &adapter->status);
@@ -897,23 +894,15 @@ zfcp_erp_strategy_check_fsfreq(struct zfcp_erp_action *erp_action)
 	return retval;
 }
 
-/*
- * purpose:	generic handler for asynchronous events related to erp_action events
- *		(normal completion, time-out, dismissing, retry after
- *		low memory condition)
- *
- * note:	deletion of timer is not required (e.g. in case of a time-out),
- *		but a second try does no harm,
- *		we leave it in here to allow for greater simplification
+/**
+ * zfcp_erp_async_handler_nolock - complete erp_action
  *
- * returns:	0 - there was an action to handle
- *		!0 - otherwise
+ * Used for normal completion, time-out, dismissal and failure after
+ * low memory condition.
  */
-static int
-zfcp_erp_async_handler_nolock(struct zfcp_erp_action *erp_action,
-			      unsigned long set_mask)
+static void zfcp_erp_async_handler_nolock(struct zfcp_erp_action *erp_action,
+					  unsigned long set_mask)
 {
-	int retval;
 	struct zfcp_adapter *adapter = erp_action->adapter;
 
 	if (zfcp_erp_action_exists(erp_action) == ZFCP_ERP_ACTION_RUNNING) {
@@ -924,43 +913,26 @@ zfcp_erp_async_handler_nolock(struct zfcp_erp_action *erp_action,
 			del_timer(&erp_action->timer);
 		erp_action->status |= set_mask;
 		zfcp_erp_action_ready(erp_action);
-		retval = 0;
 	} else {
 		/* action is ready or gone - nothing to do */
 		debug_text_event(adapter->erp_dbf, 3, "a_asyh_gone");
 		debug_event(adapter->erp_dbf, 3, &erp_action->action,
 			    sizeof (int));
-		retval = 1;
 	}
-
-	return retval;
 }
 
-/*
- * purpose:	generic handler for asynchronous events related to erp_action
- *               events	(normal completion, time-out, dismissing, retry after
- *		low memory condition)
- *
- * note:	deletion of timer is not required (e.g. in case of a time-out),
- *		but a second try does no harm,
- *		we leave it in here to allow for greater simplification
- *
- * returns:	0 - there was an action to handle
- *		!0 - otherwise
+/**
+ * zfcp_erp_async_handler - wrapper for erp_async_handler_nolock w/ locking
  */
-int
-zfcp_erp_async_handler(struct zfcp_erp_action *erp_action,
-		       unsigned long set_mask)
+void zfcp_erp_async_handler(struct zfcp_erp_action *erp_action,
+			    unsigned long set_mask)
 {
 	struct zfcp_adapter *adapter = erp_action->adapter;
 	unsigned long flags;
-	int retval;
 
 	write_lock_irqsave(&adapter->erp_lock, flags);
-	retval = zfcp_erp_async_handler_nolock(erp_action, set_mask);
+	zfcp_erp_async_handler_nolock(erp_action, set_mask);
 	write_unlock_irqrestore(&adapter->erp_lock, flags);
-
-	return retval;
 }
 
 /*
@@ -997,17 +969,15 @@ zfcp_erp_timeout_handler(unsigned long data)
 	zfcp_erp_async_handler(erp_action, ZFCP_STATUS_ERP_TIMEDOUT);
 }
 
-/*
- * purpose:	is called for an erp_action which needs to be ended
- *		though not being done,
- *		this is usually required if an higher is generated,
- *		action gets an appropriate flag and will be processed
- *		accordingly
+/**
+ * zfcp_erp_action_dismiss - dismiss an erp_action
  *
- * locks:	erp_lock held (thus we need to call another handler variant)
+ * adapter->erp_lock must be held
+ * 
+ * Dismissal of an erp_action is usually required if an erp_action of
+ * higher priority is generated.
  */
-static int
-zfcp_erp_action_dismiss(struct zfcp_erp_action *erp_action)
+static void zfcp_erp_action_dismiss(struct zfcp_erp_action *erp_action)
 {
 	struct zfcp_adapter *adapter = erp_action->adapter;
 
@@ -1015,8 +985,6 @@ zfcp_erp_action_dismiss(struct zfcp_erp_action *erp_action)
 	debug_event(adapter->erp_dbf, 2, &erp_action->action, sizeof (int));
 
 	zfcp_erp_async_handler_nolock(erp_action, ZFCP_STATUS_ERP_DISMISSED);
-
-	return 0;
 }
 
 int
@@ -2072,18 +2040,12 @@ zfcp_erp_adapter_strategy_open_qdio(struct zfcp_erp_action *erp_action)
 	return retval;
 }
 
-/*
- * function:    zfcp_qdio_cleanup
- *
- * purpose:	cleans up QDIO operation for the specified adapter
- *
- * returns:	0 - successful cleanup
- *		!0 - failed cleanup
+/**
+ * zfcp_erp_adapter_strategy_close_qdio - close qdio queues for an adapter
  */
-int
+static void
 zfcp_erp_adapter_strategy_close_qdio(struct zfcp_erp_action *erp_action)
 {
-	int retval = ZFCP_ERP_SUCCEEDED;
 	int first_used;
 	int used_count;
 	struct zfcp_adapter *adapter = erp_action->adapter;
@@ -2092,15 +2054,13 @@ zfcp_erp_adapter_strategy_close_qdio(struct zfcp_erp_action *erp_action)
 		ZFCP_LOG_DEBUG("error: attempt to shut down inactive QDIO "
 			       "queues on adapter %s\n",
 			       zfcp_get_busid_by_adapter(adapter));
-		retval = ZFCP_ERP_FAILED;
-		goto out;
+		return;
 	}
 
 	/*
 	 * Get queue_lock and clear QDIOUP flag. Thus it's guaranteed that
 	 * do_QDIO won't be called while qdio_shutdown is in progress.
 	 */
-
 	write_lock_irq(&adapter->request_queue.queue_lock);
 	atomic_clear_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &adapter->status);
 	write_unlock_irq(&adapter->request_queue.queue_lock);
@@ -2132,8 +2092,6 @@ zfcp_erp_adapter_strategy_close_qdio(struct zfcp_erp_action *erp_action)
 	adapter->request_queue.free_index = 0;
 	atomic_set(&adapter->request_queue.free_count, 0);
 	adapter->request_queue.distance_from_int = 0;
- out:
-	return retval;
 }
 
 static int
@@ -2256,11 +2214,11 @@ zfcp_erp_adapter_strategy_open_fsf_xport(struct zfcp_erp_action *erp_action)
 			      "%s)\n", zfcp_get_busid_by_adapter(adapter));
 		ret = ZFCP_ERP_FAILED;
 	}
-	if (!atomic_test_mask(ZFCP_STATUS_ADAPTER_XPORT_OK, &adapter->status)) {
-		ZFCP_LOG_INFO("error: exchange port data failed (adapter "
+
+	/* don't treat as error for the sake of compatibility */
+	if (!atomic_test_mask(ZFCP_STATUS_ADAPTER_XPORT_OK, &adapter->status))
+		ZFCP_LOG_INFO("warning: exchange port data failed (adapter "
 			      "%s\n", zfcp_get_busid_by_adapter(adapter));
-		ret = ZFCP_ERP_FAILED;
-	}
 
 	return ret;
 }
@@ -2290,18 +2248,12 @@ zfcp_erp_adapter_strategy_open_fsf_statusread(struct zfcp_erp_action
 	return retval;
 }
 
-/*
- * function:    zfcp_fsf_cleanup
- *
- * purpose:	cleanup FSF operation for specified adapter
- *
- * returns:	0 - FSF operation successfully cleaned up
- *		!0 - failed to cleanup FSF operation for this adapter
+/**
+ * zfcp_erp_adapter_strategy_close_fsf - stop FSF operations for an adapter
  */
-static int
+static void
 zfcp_erp_adapter_strategy_close_fsf(struct zfcp_erp_action *erp_action)
 {
-	int retval = ZFCP_ERP_SUCCEEDED;
 	struct zfcp_adapter *adapter = erp_action->adapter;
 
 	/*
@@ -2315,8 +2267,6 @@ zfcp_erp_adapter_strategy_close_fsf(struct zfcp_erp_action *erp_action)
 	/* all ports and units are closed */
 	zfcp_erp_modify_adapter_status(adapter,
 				       ZFCP_STATUS_COMMON_OPEN, ZFCP_CLEAR);
-
-	return retval;
 }
 
 /*
@@ -3291,10 +3241,8 @@ zfcp_erp_action_cleanup(int action, struct zfcp_adapter *adapter,
 }
 
 
-static int
-zfcp_erp_action_dismiss_adapter(struct zfcp_adapter *adapter)
+void zfcp_erp_action_dismiss_adapter(struct zfcp_adapter *adapter)
 {
-	int retval = 0;
 	struct zfcp_port *port;
 
 	debug_text_event(adapter->erp_dbf, 5, "a_actab");
@@ -3303,14 +3251,10 @@ zfcp_erp_action_dismiss_adapter(struct zfcp_adapter *adapter)
 	else
 		list_for_each_entry(port, &adapter->port_list_head, list)
 		    zfcp_erp_action_dismiss_port(port);
-
-	return retval;
 }
 
-static int
-zfcp_erp_action_dismiss_port(struct zfcp_port *port)
+static void zfcp_erp_action_dismiss_port(struct zfcp_port *port)
 {
-	int retval = 0;
 	struct zfcp_unit *unit;
 	struct zfcp_adapter *adapter = port->adapter;
 
@@ -3321,22 +3265,16 @@ zfcp_erp_action_dismiss_port(struct zfcp_port *port)
 	else
 		list_for_each_entry(unit, &port->unit_list_head, list)
 		    zfcp_erp_action_dismiss_unit(unit);
-
-	return retval;
 }
 
-static int
-zfcp_erp_action_dismiss_unit(struct zfcp_unit *unit)
+static void zfcp_erp_action_dismiss_unit(struct zfcp_unit *unit)
 {
-	int retval = 0;
 	struct zfcp_adapter *adapter = unit->port->adapter;
 
 	debug_text_event(adapter->erp_dbf, 5, "u_actab");
 	debug_event(adapter->erp_dbf, 5, &unit->fcp_lun, sizeof (fcp_lun_t));
 	if (atomic_test_mask(ZFCP_STATUS_COMMON_ERP_INUSE, &unit->status))
 		zfcp_erp_action_dismiss(&unit->erp_action);
-
-	return retval;
 }
 
 static inline void