[PATCH 1/3] zfcp: IO stall after path checker changes

[Swen Schillig <swen.schillig@freenet.de>]

From: Michael Loehr <mloehr2@linux.vnet.ibm.com>

Devices corresponding to a deleted unit are never freed.
This has the effect that slave_destroy is never called and zfcp
'thinks' that this unit is still registered.
This patch changes the zfcp behaviour the way that the
rport and sdev are not deleted anymore. The host is set to
block on 'offline'. Host online is only removing the blocked status 
and everything works as expected again.

Signed-off-by: Michael Loehr <mloehr2@linux.vnet.ibm.com>
Signed-off-by: Swen Schillig <swen@vnet.ibm.com>

---

 drivers/s390/scsi/zfcp_aux.c  |    1 +
 drivers/s390/scsi/zfcp_ccw.c  |    5 +----
 drivers/s390/scsi/zfcp_scsi.c |    3 +++
 3 files changed, 5 insertions(+), 4 deletions(-)

Index: linux_jb_patched/drivers/s390/scsi/zfcp_aux.c
===================================================================
--- linux_jb_patched.orig/drivers/s390/scsi/zfcp_aux.c
+++ linux_jb_patched/drivers/s390/scsi/zfcp_aux.c
@@ -1127,6 +1127,7 @@ zfcp_adapter_dequeue(struct zfcp_adapter
 	int retval = 0;
 	unsigned long flags;
 
+	zfcp_adapter_scsi_unregister(adapter);
 	device_unregister(&adapter->generic_services);
 	zfcp_sysfs_adapter_remove_files(&adapter->ccw_device->dev);
 	dev_set_drvdata(&adapter->ccw_device->dev, NULL);
Index: linux_jb_patched/drivers/s390/scsi/zfcp_ccw.c
===================================================================
--- linux_jb_patched.orig/drivers/s390/scsi/zfcp_ccw.c
+++ linux_jb_patched/drivers/s390/scsi/zfcp_ccw.c
@@ -189,9 +189,7 @@ zfcp_ccw_set_online(struct ccw_device *c
  * @ccw_device: pointer to belonging ccw device
  *
  * This function gets called by the common i/o layer and sets an adapter
- * into state offline. Setting an fcp device offline means that it will be
- * unregistered from the SCSI stack and that the adapter will be shut down
- * asynchronously.
+ * into state offline.
  */
 static int
 zfcp_ccw_set_offline(struct ccw_device *ccw_device)
@@ -202,7 +200,6 @@ zfcp_ccw_set_offline(struct ccw_device *
 	adapter = dev_get_drvdata(&ccw_device->dev);
 	zfcp_erp_adapter_shutdown(adapter, 0);
 	zfcp_erp_wait(adapter);
-	zfcp_adapter_scsi_unregister(adapter);
 	zfcp_erp_thread_kill(adapter);
 	zfcp_adapter_debug_unregister(adapter);
 	up(&zfcp_data.config_sema);
Index: linux_jb_patched/drivers/s390/scsi/zfcp_scsi.c
===================================================================
--- linux_jb_patched.orig/drivers/s390/scsi/zfcp_scsi.c
+++ linux_jb_patched/drivers/s390/scsi/zfcp_scsi.c
@@ -569,6 +569,9 @@ zfcp_adapter_scsi_register(struct zfcp_a
 	int retval = 0;
 	static unsigned int unique_id = 0;
 
+	if (adapter->scsi_host)
+		goto out;
+
 	/* register adapter as SCSI host with mid layer of SCSI stack */
 	adapter->scsi_host = scsi_host_alloc(&zfcp_data.scsi_host_template,
 					     sizeof (struct zfcp_adapter *));