Merge remote-tracking branch 'kernelorg/linux-3.0.y' into 3_0_64

Conflicts:
	arch/arm/Kconfig
	arch/arm/include/asm/hwcap.h
	arch/arm/kernel/smp.c
	arch/arm/plat-samsung/adc.c
	drivers/gpu/drm/i915/i915_reg.h
	drivers/gpu/drm/i915/intel_drv.h
	drivers/mmc/core/sd.c
	drivers/net/tun.c
	drivers/net/usb/usbnet.c
	drivers/regulator/max8997.c
	drivers/usb/core/hub.c
	drivers/usb/host/xhci.h
	drivers/usb/serial/qcserial.c
	fs/jbd2/transaction.c
	include/linux/migrate.h
	kernel/sys.c
	kernel/time/timekeeping.c
	lib/genalloc.c
	mm/memory-failure.c
	mm/memory_hotplug.c
	mm/mempolicy.c
	mm/page_alloc.c
	mm/vmalloc.c
	mm/vmscan.c
	mm/vmstat.c
	scripts/Kbuild.include

Change-Id: I91e2d85c07320c7ccfc04cf98a448e89bed6ade6

11 files changed, 153 insertions, 35 deletions

diff --git a/drivers/s390/cio/device_pgid.c b/drivers/s390/cio/device_pgid.c
index 07a4fd2..daa6b90 100644
--- a/drivers/s390/cio/device_pgid.c
+++ b/drivers/s390/cio/device_pgid.c
@@ -234,7 +234,7 @@ static int pgid_cmp(struct pgid *p1, struct pgid *p2)
  * Determine pathgroup state from PGID data.
  */
 static void pgid_analyze(struct ccw_device *cdev, struct pgid **p,
-			 int *mismatch, int *reserved, u8 *reset)
+			 int *mismatch, u8 *reserved, u8 *reset)
 {
 	struct pgid *pgid = &cdev->private->pgid[0];
 	struct pgid *first = NULL;
@@ -248,7 +248,7 @@ static void pgid_analyze(struct ccw_device *cdev, struct pgid **p,
 		if ((cdev->private->pgid_valid_mask & lpm) == 0)
 			continue;
 		if (pgid->inf.ps.state2 == SNID_STATE2_RESVD_ELSE)
-			*reserved = 1;
+			*reserved |= lpm;
 		if (pgid_is_reset(pgid)) {
 			*reset |= lpm;
 			continue;
@@ -316,14 +316,14 @@ static void snid_done(struct ccw_device *cdev, int rc)
 	struct subchannel *sch = to_subchannel(cdev->dev.parent);
 	struct pgid *pgid;
 	int mismatch = 0;
-	int reserved = 0;
+	u8 reserved = 0;
 	u8 reset = 0;
 	u8 donepm;
 
 	if (rc)
 		goto out;
 	pgid_analyze(cdev, &pgid, &mismatch, &reserved, &reset);
-	if (reserved)
+	if (reserved == cdev->private->pgid_valid_mask)
 		rc = -EUSERS;
 	else if (mismatch)
 		rc = -EOPNOTSUPP;
@@ -336,7 +336,7 @@ static void snid_done(struct ccw_device *cdev, int rc)
 	}
 out:
 	CIO_MSG_EVENT(2, "snid: device 0.%x.%04x: rc=%d pvm=%02x vpm=%02x "
-		      "todo=%02x mism=%d rsvd=%d reset=%02x\n", id->ssid,
+		      "todo=%02x mism=%d rsvd=%02x reset=%02x\n", id->ssid,
 		      id->devno, rc, cdev->private->pgid_valid_mask, sch->vpm,
 		      cdev->private->pgid_todo_mask, mismatch, reserved, reset);
 	switch (rc) {
diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index 645b0fc..61da2cd 100644
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -518,6 +518,7 @@ struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
 
 	rwlock_init(&port->unit_list_lock);
 	INIT_LIST_HEAD(&port->unit_list);
+	atomic_set(&port->units, 0);
 
 	INIT_WORK(&port->gid_pn_work, zfcp_fc_port_did_lookup);
 	INIT_WORK(&port->test_link_work, zfcp_fc_link_test_work);
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,
 };
diff --git a/drivers/s390/scsi/zfcp_cfdc.c b/drivers/s390/scsi/zfcp_cfdc.c
index fab2c25..8ed63aa 100644
--- a/drivers/s390/scsi/zfcp_cfdc.c
+++ b/drivers/s390/scsi/zfcp_cfdc.c
@@ -293,7 +293,7 @@ void zfcp_cfdc_adapter_access_changed(struct zfcp_adapter *adapter)
 	}
 	read_unlock_irqrestore(&adapter->port_list_lock, flags);
 
-	shost_for_each_device(sdev, port->adapter->scsi_host) {
+	shost_for_each_device(sdev, adapter->scsi_host) {
 		zfcp_sdev = sdev_to_zfcp(sdev);
 		status = atomic_read(&zfcp_sdev->status);
 		if ((status & ZFCP_STATUS_COMMON_ACCESS_DENIED) ||
diff --git a/drivers/s390/scsi/zfcp_dbf.c b/drivers/s390/scsi/zfcp_dbf.c
index 96d1462..8b18dc0 100644
--- a/drivers/s390/scsi/zfcp_dbf.c
+++ b/drivers/s390/scsi/zfcp_dbf.c
@@ -163,6 +163,26 @@ void zfcp_dbf_hba_bit_err(char *tag, struct zfcp_fsf_req *req)
 	spin_unlock_irqrestore(&dbf->hba_lock, flags);
 }
 
+/**
+ * zfcp_dbf_hba_basic - trace event for basic adapter events
+ * @adapter: pointer to struct zfcp_adapter
+ */
+void zfcp_dbf_hba_basic(char *tag, struct zfcp_adapter *adapter)
+{
+	struct zfcp_dbf *dbf = adapter->dbf;
+	struct zfcp_dbf_hba *rec = &dbf->hba_buf;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dbf->hba_lock, flags);
+	memset(rec, 0, sizeof(*rec));
+
+	memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN);
+	rec->id = ZFCP_DBF_HBA_BASIC;
+
+	debug_event(dbf->hba, 1, rec, sizeof(*rec));
+	spin_unlock_irqrestore(&dbf->hba_lock, flags);
+}
+
 static void zfcp_dbf_set_common(struct zfcp_dbf_rec *rec,
 				struct zfcp_adapter *adapter,
 				struct zfcp_port *port,
diff --git a/drivers/s390/scsi/zfcp_dbf.h b/drivers/s390/scsi/zfcp_dbf.h
index 714f087..3ac7a4b 100644
--- a/drivers/s390/scsi/zfcp_dbf.h
+++ b/drivers/s390/scsi/zfcp_dbf.h
@@ -154,6 +154,7 @@ enum zfcp_dbf_hba_id {
 	ZFCP_DBF_HBA_RES	= 1,
 	ZFCP_DBF_HBA_USS	= 2,
 	ZFCP_DBF_HBA_BIT	= 3,
+	ZFCP_DBF_HBA_BASIC	= 4,
 };
 
 /**
diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h
index 527ba48..ebbf760 100644
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/drivers/s390/scsi/zfcp_def.h
@@ -76,6 +76,7 @@ struct zfcp_reqlist;
 #define ZFCP_STATUS_ADAPTER_SIOSL_ISSUED	0x00000004
 #define ZFCP_STATUS_ADAPTER_XCONFIG_OK		0x00000008
 #define ZFCP_STATUS_ADAPTER_HOST_CON_INIT	0x00000010
+#define ZFCP_STATUS_ADAPTER_SUSPENDED		0x00000040
 #define ZFCP_STATUS_ADAPTER_ERP_PENDING		0x00000100
 #define ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED	0x00000200
 #define ZFCP_STATUS_ADAPTER_DATA_DIV_ENABLED	0x00000400
@@ -203,6 +204,7 @@ struct zfcp_port {
 	struct zfcp_adapter    *adapter;       /* adapter used to access port */
 	struct list_head	unit_list;	/* head of logical unit list */
 	rwlock_t		unit_list_lock; /* unit list lock */
+	atomic_t		units;	       /* zfcp_unit count */
 	atomic_t	       status;	       /* status of this remote port */
 	u64		       wwnn;	       /* WWNN if known */
 	u64		       wwpn;	       /* WWPN */
diff --git a/drivers/s390/scsi/zfcp_ext.h b/drivers/s390/scsi/zfcp_ext.h
index 03627cfd..3ad6399 100644
--- a/drivers/s390/scsi/zfcp_ext.h
+++ b/drivers/s390/scsi/zfcp_ext.h
@@ -53,6 +53,7 @@ extern void zfcp_dbf_hba_fsf_uss(char *, struct zfcp_fsf_req *);
 extern void zfcp_dbf_hba_fsf_res(char *, struct zfcp_fsf_req *);
 extern void zfcp_dbf_hba_bit_err(char *, struct zfcp_fsf_req *);
 extern void zfcp_dbf_hba_berr(struct zfcp_dbf *, struct zfcp_fsf_req *);
+extern void zfcp_dbf_hba_basic(char *, struct zfcp_adapter *);
 extern void zfcp_dbf_san_req(char *, struct zfcp_fsf_req *, u32);
 extern void zfcp_dbf_san_res(char *, struct zfcp_fsf_req *);
 extern void zfcp_dbf_san_in_els(char *, struct zfcp_fsf_req *);
@@ -157,6 +158,7 @@ extern void zfcp_scsi_dif_sense_error(struct scsi_cmnd *, int);
 extern struct attribute_group zfcp_sysfs_unit_attrs;
 extern struct attribute_group zfcp_sysfs_adapter_attrs;
 extern struct attribute_group zfcp_sysfs_port_attrs;
+extern struct mutex zfcp_sysfs_port_units_mutex;
 extern struct device_attribute *zfcp_sysfs_sdev_attrs[];
 extern struct device_attribute *zfcp_sysfs_shost_attrs[];
 
diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index 022fb6a..6e73bfe 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -219,7 +219,7 @@ static void zfcp_fsf_status_read_handler(struct zfcp_fsf_req *req)
 		return;
 	}
 
-	zfcp_dbf_hba_fsf_uss("fssrh_2", req);
+	zfcp_dbf_hba_fsf_uss("fssrh_4", req);
 
 	switch (sr_buf->status_type) {
 	case FSF_STATUS_READ_PORT_CLOSED:
@@ -771,12 +771,14 @@ out:
 static void zfcp_fsf_abort_fcp_command_handler(struct zfcp_fsf_req *req)
 {
 	struct scsi_device *sdev = req->data;
-	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
+	struct zfcp_scsi_dev *zfcp_sdev;
 	union fsf_status_qual *fsq = &req->qtcb->header.fsf_status_qual;
 
 	if (req->status & ZFCP_STATUS_FSFREQ_ERROR)
 		return;
 
+	zfcp_sdev = sdev_to_zfcp(sdev);
+
 	switch (req->qtcb->header.fsf_status) {
 	case FSF_PORT_HANDLE_NOT_VALID:
 		if (fsq->word[0] == fsq->word[1]) {
@@ -885,7 +887,7 @@ static void zfcp_fsf_send_ct_handler(struct zfcp_fsf_req *req)
 
 	switch (header->fsf_status) {
         case FSF_GOOD:
-		zfcp_dbf_san_res("fsscth1", req);
+		zfcp_dbf_san_res("fsscth2", req);
 		ct->status = 0;
 		break;
         case FSF_SERVICE_CLASS_NOT_SUPPORTED:
@@ -1730,13 +1732,15 @@ static void zfcp_fsf_open_lun_handler(struct zfcp_fsf_req *req)
 {
 	struct zfcp_adapter *adapter = req->adapter;
 	struct scsi_device *sdev = req->data;
-	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
+	struct zfcp_scsi_dev *zfcp_sdev;
 	struct fsf_qtcb_header *header = &req->qtcb->header;
 	struct fsf_qtcb_bottom_support *bottom = &req->qtcb->bottom.support;
 
 	if (req->status & ZFCP_STATUS_FSFREQ_ERROR)
 		return;
 
+	zfcp_sdev = sdev_to_zfcp(sdev);
+
 	atomic_clear_mask(ZFCP_STATUS_COMMON_ACCESS_DENIED |
 			  ZFCP_STATUS_COMMON_ACCESS_BOXED |
 			  ZFCP_STATUS_LUN_SHARED |
@@ -1847,11 +1851,13 @@ out:
 static void zfcp_fsf_close_lun_handler(struct zfcp_fsf_req *req)
 {
 	struct scsi_device *sdev = req->data;
-	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
+	struct zfcp_scsi_dev *zfcp_sdev;
 
 	if (req->status & ZFCP_STATUS_FSFREQ_ERROR)
 		return;
 
+	zfcp_sdev = sdev_to_zfcp(sdev);
+
 	switch (req->qtcb->header.fsf_status) {
 	case FSF_PORT_HANDLE_NOT_VALID:
 		zfcp_erp_adapter_reopen(zfcp_sdev->port->adapter, 0, "fscuh_1");
@@ -1941,7 +1947,7 @@ static void zfcp_fsf_req_trace(struct zfcp_fsf_req *req, struct scsi_cmnd *scsi)
 {
 	struct fsf_qual_latency_info *lat_in;
 	struct latency_cont *lat = NULL;
-	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(scsi->device);
+	struct zfcp_scsi_dev *zfcp_sdev;
 	struct zfcp_blk_drv_data blktrc;
 	int ticks = req->adapter->timer_ticks;
 
@@ -1956,6 +1962,7 @@ static void zfcp_fsf_req_trace(struct zfcp_fsf_req *req, struct scsi_cmnd *scsi)
 
 	if (req->adapter->adapter_features & FSF_FEATURE_MEASUREMENT_DATA &&
 	    !(req->status & ZFCP_STATUS_FSFREQ_ERROR)) {
+		zfcp_sdev = sdev_to_zfcp(scsi->device);
 		blktrc.flags |= ZFCP_BLK_LAT_VALID;
 		blktrc.channel_lat = lat_in->channel_lat * ticks;
 		blktrc.fabric_lat = lat_in->fabric_lat * ticks;
@@ -1993,12 +2000,14 @@ static void zfcp_fsf_fcp_handler_common(struct zfcp_fsf_req *req)
 {
 	struct scsi_cmnd *scmnd = req->data;
 	struct scsi_device *sdev = scmnd->device;
-	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
+	struct zfcp_scsi_dev *zfcp_sdev;
 	struct fsf_qtcb_header *header = &req->qtcb->header;
 
 	if (unlikely(req->status & ZFCP_STATUS_FSFREQ_ERROR))
 		return;
 
+	zfcp_sdev = sdev_to_zfcp(sdev);
+
 	switch (header->fsf_status) {
 	case FSF_HANDLE_MISMATCH:
 	case FSF_PORT_HANDLE_NOT_VALID:
diff --git a/drivers/s390/scsi/zfcp_sysfs.c b/drivers/s390/scsi/zfcp_sysfs.c
index cdc4ff7..9e62210 100644
--- a/drivers/s390/scsi/zfcp_sysfs.c
+++ b/drivers/s390/scsi/zfcp_sysfs.c
@@ -227,6 +227,8 @@ static ssize_t zfcp_sysfs_port_rescan_store(struct device *dev,
 static ZFCP_DEV_ATTR(adapter, port_rescan, S_IWUSR, NULL,
 		     zfcp_sysfs_port_rescan_store);
 
+DEFINE_MUTEX(zfcp_sysfs_port_units_mutex);
+
 static ssize_t zfcp_sysfs_port_remove_store(struct device *dev,
 					    struct device_attribute *attr,
 					    const char *buf, size_t count)
@@ -249,6 +251,16 @@ static ssize_t zfcp_sysfs_port_remove_store(struct device *dev,
 	else
 		retval = 0;
 
+	mutex_lock(&zfcp_sysfs_port_units_mutex);
+	if (atomic_read(&port->units) > 0) {
+		retval = -EBUSY;
+		mutex_unlock(&zfcp_sysfs_port_units_mutex);
+		goto out;
+	}
+	/* port is about to be removed, so no more unit_add */
+	atomic_set(&port->units, -1);
+	mutex_unlock(&zfcp_sysfs_port_units_mutex);
+
 	write_lock_irq(&adapter->port_list_lock);
 	list_del(&port->list);
 	write_unlock_irq(&adapter->port_list_lock);
@@ -289,12 +301,14 @@ static ssize_t zfcp_sysfs_unit_add_store(struct device *dev,
 {
 	struct zfcp_port *port = container_of(dev, struct zfcp_port, dev);
 	u64 fcp_lun;
+	int retval;
 
 	if (strict_strtoull(buf, 0, (unsigned long long *) &fcp_lun))
 		return -EINVAL;
 
-	if (zfcp_unit_add(port, fcp_lun))
-		return -EINVAL;
+	retval = zfcp_unit_add(port, fcp_lun);
+	if (retval)
+		return retval;
 
 	return count;
 }
diff --git a/drivers/s390/scsi/zfcp_unit.c b/drivers/s390/scsi/zfcp_unit.c
index 20796eb..4e6a535 100644
--- a/drivers/s390/scsi/zfcp_unit.c
+++ b/drivers/s390/scsi/zfcp_unit.c
@@ -104,7 +104,7 @@ static void zfcp_unit_release(struct device *dev)
 {
 	struct zfcp_unit *unit = container_of(dev, struct zfcp_unit, dev);
 
-	put_device(&unit->port->dev);
+	atomic_dec(&unit->port->units);
 	kfree(unit);
 }
 
@@ -119,16 +119,27 @@ static void zfcp_unit_release(struct device *dev)
 int zfcp_unit_add(struct zfcp_port *port, u64 fcp_lun)
 {
 	struct zfcp_unit *unit;
+	int retval = 0;
+
+	mutex_lock(&zfcp_sysfs_port_units_mutex);
+	if (atomic_read(&port->units) == -1) {
+		/* port is already gone */
+		retval = -ENODEV;
+		goto out;
+	}
 
 	unit = zfcp_unit_find(port, fcp_lun);
 	if (unit) {
 		put_device(&unit->dev);
-		return -EEXIST;
+		retval = -EEXIST;
+		goto out;
 	}
 
 	unit = kzalloc(sizeof(struct zfcp_unit), GFP_KERNEL);
-	if (!unit)
-		return -ENOMEM;
+	if (!unit) {
+		retval = -ENOMEM;
+		goto out;
+	}
 
 	unit->port = port;
 	unit->fcp_lun = fcp_lun;
@@ -139,28 +150,33 @@ int zfcp_unit_add(struct zfcp_port *port, u64 fcp_lun)
 	if (dev_set_name(&unit->dev, "0x%016llx",
 			 (unsigned long long) fcp_lun)) {
 		kfree(unit);
-		return -ENOMEM;
+		retval = -ENOMEM;
+		goto out;
 	}
 
-	get_device(&port->dev);
-
 	if (device_register(&unit->dev)) {
 		put_device(&unit->dev);
-		return -ENOMEM;
+		retval = -ENOMEM;
+		goto out;
 	}
 
 	if (sysfs_create_group(&unit->dev.kobj, &zfcp_sysfs_unit_attrs)) {
 		device_unregister(&unit->dev);
-		return -EINVAL;
+		retval = -EINVAL;
+		goto out;
 	}
 
+	atomic_inc(&port->units); /* under zfcp_sysfs_port_units_mutex ! */
+
 	write_lock_irq(&port->unit_list_lock);
 	list_add_tail(&unit->list, &port->unit_list);
 	write_unlock_irq(&port->unit_list_lock);
 
 	zfcp_unit_scsi_scan(unit);
 
-	return 0;
+out:
+	mutex_unlock(&zfcp_sysfs_port_units_mutex);
+	return retval;
 }
 
 /**