SCSI: zfcp: Do not wakeup while suspended

commit cb45214960bc989af8b911ebd77da541c797717d upstream.

If the mapping of FCP device bus ID and corresponding subchannel
is modified while the Linux image is suspended, the resume of FCP
devices can fail. During resume, zfcp gets callbacks from cio regarding
the modified subchannels but they can be arbitrarily mixed with the
restore/resume callback. Since the cio callbacks would trigger
adapter recovery, zfcp could wakeup before the resume callback.
Therefore, ignore the cio callbacks regarding subchannels while
being suspended. We can safely do so, since zfcp does not deal itself
with subchannels. For problem determination purposes, we still trace the
ignored callback events.

The following kernel messages could be seen on resume:

kernel: <WWPN>: parent <FCP device bus ID> should not be sleeping

As part of adapter reopen recovery, zfcp performs auto port scanning
which can erroneously try to register new remote ports with
scsi_transport_fc and the device core code complains about the parent
(adapter) still sleeping.

kernel: zfcp.3dff9c: <FCP device bus ID>:\
 Setting up the QDIO connection to the FCP adapter failed
<last kernel message repeated 3 more times>
kernel: zfcp.574d43: <FCP device bus ID>:\
 ERP cannot recover an error on the FCP device

In such cases, the adapter gave up recovery and remained blocked along
with its child objects: remote ports and LUNs/scsi devices. Even the
adapter shutdown as part of giving up recovery failed because the ccw
device state remained disconnected. Later, the corresponding remote
ports ran into dev_loss_tmo. As a result, the LUNs were erroneously
not available again after resume.

Even a manually triggered adapter recovery (e.g. sysfs attribute
failed, or device offline/online via sysfs) could not recover the
adapter due to the remaining disconnected state of the corresponding
ccw device.

Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 63 insertions, 10 deletions

diff --git a/drivers/s390/scsi/zfcp_ccw.c b/drivers/s390/scsi/zfcp_ccw.c
index e8b7cee..de1bcfa 100644
--- a/drivers/s390/scsi/zfcp_ccw.c
+++ b/drivers/s390/scsi/zfcp_ccw.c
@@ -38,17 +38,23 @@ void zfcp_ccw_adapter_put(struct zfcp_adapter *adapter)
 	spin_unlock_irqrestore(&zfcp_ccw_adapter_ref_lock, flags);
 }
 
-static int zfcp_ccw_activate(struct ccw_device *cdev)
-
+/**
+ * zfcp_ccw_activate - activate adapter and wait for it to finish
+ * @cdev: pointer to belonging ccw device
+ * @clear: Status flags to clear.
+ * @tag: s390dbf trace record tag
+ */
+static int zfcp_ccw_activate(struct ccw_device *cdev, int clear, char *tag)
 {
 	struct zfcp_adapter *adapter = zfcp_ccw_adapter_by_cdev(cdev);
 
 	if (!adapter)
 		return 0;
 
+	zfcp_erp_clear_adapter_status(adapter, clear);
 	zfcp_erp_set_adapter_status(adapter, ZFCP_STATUS_COMMON_RUNNING);
 	zfcp_erp_adapter_reopen(adapter, ZFCP_STATUS_COMMON_ERP_FAILED,
-				"ccresu2");
+				tag);
 	zfcp_erp_wait(adapter);
 	flush_work(&adapter->scan_work);
 
@@ -163,26 +169,29 @@ static int zfcp_ccw_set_online(struct ccw_device *cdev)
 	BUG_ON(!zfcp_reqlist_isempty(adapter->req_list));
 	adapter->req_no = 0;
 
-	zfcp_ccw_activate(cdev);
+	zfcp_ccw_activate(cdev, 0, "ccsonl1");
 	zfcp_ccw_adapter_put(adapter);
 	return 0;
 }
 
 /**
- * zfcp_ccw_set_offline - set_offline function of zfcp driver
+ * zfcp_ccw_offline_sync - shut down adapter and wait for it to finish
  * @cdev: pointer to belonging ccw device
+ * @set: Status flags to set.
+ * @tag: s390dbf trace record tag
  *
  * This function gets called by the common i/o layer and sets an adapter
  * into state offline.
  */
-static int zfcp_ccw_set_offline(struct ccw_device *cdev)
+static int zfcp_ccw_offline_sync(struct ccw_device *cdev, int set, char *tag)
 {
 	struct zfcp_adapter *adapter = zfcp_ccw_adapter_by_cdev(cdev);
 
 	if (!adapter)
 		return 0;
 
-	zfcp_erp_adapter_shutdown(adapter, 0, "ccsoff1");
+	zfcp_erp_set_adapter_status(adapter, set);
+	zfcp_erp_adapter_shutdown(adapter, 0, tag);
 	zfcp_erp_wait(adapter);
 
 	zfcp_ccw_adapter_put(adapter);
@@ -190,6 +199,18 @@ static int zfcp_ccw_set_offline(struct ccw_device *cdev)
 }
 
 /**
+ * zfcp_ccw_set_offline - set_offline function of zfcp driver
+ * @cdev: pointer to belonging ccw device
+ *
+ * This function gets called by the common i/o layer and sets an adapter
+ * into state offline.
+ */
+static int zfcp_ccw_set_offline(struct ccw_device *cdev)
+{
+	return zfcp_ccw_offline_sync(cdev, 0, "ccsoff1");
+}
+
+/**
  * zfcp_ccw_notify - ccw notify function
  * @cdev: pointer to belonging ccw device
  * @event: indicates if adapter was detached or attached
@@ -206,6 +227,11 @@ static int zfcp_ccw_notify(struct ccw_device *cdev, int event)
 
 	switch (event) {
 	case CIO_GONE:
+		if (atomic_read(&adapter->status) &
+		    ZFCP_STATUS_ADAPTER_SUSPENDED) { /* notification ignore */
+			zfcp_dbf_hba_basic("ccnigo1", adapter);
+			break;
+		}
 		dev_warn(&cdev->dev, "The FCP device has been detached\n");
 		zfcp_erp_adapter_shutdown(adapter, 0, "ccnoti1");
 		break;
@@ -215,6 +241,11 @@ static int zfcp_ccw_notify(struct ccw_device *cdev, int event)
 		zfcp_erp_adapter_shutdown(adapter, 0, "ccnoti2");
 		break;
 	case CIO_OPER:
+		if (atomic_read(&adapter->status) &
+		    ZFCP_STATUS_ADAPTER_SUSPENDED) { /* notification ignore */
+			zfcp_dbf_hba_basic("ccniop1", adapter);
+			break;
+		}
 		dev_info(&cdev->dev, "The FCP device is operational again\n");
 		zfcp_erp_set_adapter_status(adapter,
 					    ZFCP_STATUS_COMMON_RUNNING);
@@ -250,6 +281,28 @@ static void zfcp_ccw_shutdown(struct ccw_device *cdev)
 	zfcp_ccw_adapter_put(adapter);
 }
 
+static int zfcp_ccw_suspend(struct ccw_device *cdev)
+{
+	zfcp_ccw_offline_sync(cdev, ZFCP_STATUS_ADAPTER_SUSPENDED, "ccsusp1");
+	return 0;
+}
+
+static int zfcp_ccw_thaw(struct ccw_device *cdev)
+{
+	/* trace records for thaw and final shutdown during suspend
+	   can only be found in system dump until the end of suspend
+	   but not after resume because it's based on the memory image
+	   right after the very first suspend (freeze) callback */
+	zfcp_ccw_activate(cdev, 0, "ccthaw1");
+	return 0;
+}
+
+static int zfcp_ccw_resume(struct ccw_device *cdev)
+{
+	zfcp_ccw_activate(cdev, ZFCP_STATUS_ADAPTER_SUSPENDED, "ccresu1");
+	return 0;
+}
+
 struct ccw_driver zfcp_ccw_driver = {
 	.driver = {
 		.owner	= THIS_MODULE,
@@ -262,7 +315,7 @@ struct ccw_driver zfcp_ccw_driver = {
 	.set_offline = zfcp_ccw_set_offline,
 	.notify      = zfcp_ccw_notify,
 	.shutdown    = zfcp_ccw_shutdown,
-	.freeze      = zfcp_ccw_set_offline,
-	.thaw	     = zfcp_ccw_activate,
-	.restore     = zfcp_ccw_activate,
+	.freeze      = zfcp_ccw_suspend,
+	.thaw	     = zfcp_ccw_thaw,
+	.restore     = zfcp_ccw_resume,
 };