[SCSI] zfcp: fix: allow more time for adapter initialization

From: Maxim Shchetynin <maxim@de.ibm.com>

Extend the time for adapter initialization: In case of protocol
status HOST_CONNECTION_INITIALIZING for the exchange config data
command do a first retry in 1 second, then double the sleep time for
each following retry until recovery exceeds 2 minutes. The old
behaviour of allowing 6 retries with .5 seconds delay between retries
was insufficient and qdio queues were shut down too erarly.
Signed-off-by: NAndreas Herrmann <aherrman@de.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

drivers/s390/scsi/zfcp_def.h

@@ -149,8 +149,10 @@ typedef u32 scsi_lun_t;
 #define FSF_QTCB_UNSOLICITED_STATUS		0x6305
 #define ZFCP_STATUS_READ_FAILED_THRESHOLD	3
 #define ZFCP_STATUS_READS_RECOM		        FSF_STATUS_READS_RECOM
-#define ZFCP_EXCHANGE_CONFIG_DATA_RETRIES	6
-#define ZFCP_EXCHANGE_CONFIG_DATA_SLEEP		50
+
+/* Do 1st retry in 1 second, then double the timeout for each following retry */
+#define ZFCP_EXCHANGE_CONFIG_DATA_FIRST_SLEEP	100
+#define ZFCP_EXCHANGE_CONFIG_DATA_RETRIES	7
 
 /* timeout value for "default timer" for fsf requests */
 #define ZFCP_FSF_REQUEST_TIMEOUT (60*HZ);

drivers/s390/scsi/zfcp_erp.c

@@ -2286,12 +2286,12 @@ zfcp_erp_adapter_strategy_open_fsf_xconfig(struct zfcp_erp_action *erp_action)
 {
 	int retval = ZFCP_ERP_SUCCEEDED;
 	int retries;
+	int sleep = ZFCP_EXCHANGE_CONFIG_DATA_FIRST_SLEEP;
 	struct zfcp_adapter *adapter = erp_action->adapter;
 
 	atomic_clear_mask(ZFCP_STATUS_ADAPTER_XCONFIG_OK, &adapter->status);
-	retries = ZFCP_EXCHANGE_CONFIG_DATA_RETRIES;
 
-	do {
+	for (retries = ZFCP_EXCHANGE_CONFIG_DATA_RETRIES; retries; retries--) {
 		atomic_clear_mask(ZFCP_STATUS_ADAPTER_HOST_CON_INIT,
 				  &adapter->status);
 		ZFCP_LOG_DEBUG("Doing exchange config data\n");
@@ -2329,16 +2329,17 @@ zfcp_erp_adapter_strategy_open_fsf_xconfig(struct zfcp_erp_action *erp_action)
 				      zfcp_get_busid_by_adapter(adapter));
 			break;
 		}
-		if (atomic_test_mask(ZFCP_STATUS_ADAPTER_HOST_CON_INIT,
-				     &adapter->status)) {
-			ZFCP_LOG_DEBUG("host connection still initialising... "
-				       "waiting and retrying...\n");
-			/* sleep a little bit before retry */
-			msleep(jiffies_to_msecs(ZFCP_EXCHANGE_CONFIG_DATA_SLEEP));
-		}
-	} while ((retries--) &&
-		 atomic_test_mask(ZFCP_STATUS_ADAPTER_HOST_CON_INIT,
-				  &adapter->status));
+
+		if (!atomic_test_mask(ZFCP_STATUS_ADAPTER_HOST_CON_INIT,
+				     &adapter->status))
+			break;
+
+		ZFCP_LOG_DEBUG("host connection still initialising... "
+			       "waiting and retrying...\n");
+		/* sleep a little bit before retry */
+		msleep(jiffies_to_msecs(sleep));
+		sleep *= 2;
+	}
 
 	if (!atomic_test_mask(ZFCP_STATUS_ADAPTER_XCONFIG_OK,
 			      &adapter->status)) {