[SCSI] zfcp: Use SCSI device data zfcp_scsi_dev instead of zfcp_unit

This is the large change to switch from using the data in
zfcp_unit to zfcp_scsi_dev. Keeping everything working requires doing
the switch in one piece. To ensure that no code keeps using the data
in zfcp_unit, this patch also removes the data from zfcp_unit that is
now being replaced with zfcp_scsi_dev.

For zfcp, the scsi_device together with zfcp_scsi_dev exist from the
call of slave_alloc to the call of slave_destroy. The data in
zfcp_scsi_dev is initialized in zfcp_scsi_slave_alloc and the LUN is
opened; the final shutdown for the LUN is run from slave_destroy.

Where the scsi_device or zfcp_scsi_dev is needed, the pointer to the
scsi_device is passed as function argument and inside the function
converted to the pointer to zfcp_scsi_dev; this avoids back and forth
conversion betweeen scsi_device and zfcp_scsi_dev.

While changing the function arguments from zfcp_unit to scsi_device,
the functions names are renamed form "unit" to "lun". This is to have
a seperation between zfcp_scsi_dev/LUN and the zfcp_unit; only code
referring to the remaining configuration information in zfcp_unit
struct uses "unit".

Reviewed-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/s390/scsi/zfcp_dbf.c

@@ -482,7 +482,7 @@ static int zfcp_dbf_rec_view_format(debug_info_t *id, struct debug_view *view,
 		zfcp_dbf_out(&p, "fcp_lun", "0x%016Lx", r->u.trigger.fcp_lun);
 		zfcp_dbf_out(&p, "adapter_status", "0x%08x", r->u.trigger.as);
 		zfcp_dbf_out(&p, "port_status", "0x%08x", r->u.trigger.ps);
-		zfcp_dbf_out(&p, "unit_status", "0x%08x", r->u.trigger.us);
+		zfcp_dbf_out(&p, "lun_status", "0x%08x", r->u.trigger.ls);
 		break;
 	case ZFCP_REC_DBF_ID_ACTION:
 		zfcp_dbf_out(&p, "erp_action", "0x%016Lx", r->u.action.action);
@@ -600,19 +600,20 @@ void zfcp_dbf_rec_port(char *id, void *ref, struct zfcp_port *port)
 }
 
 /**
- * zfcp_dbf_rec_unit - trace event for unit state change
+ * zfcp_dbf_rec_lun - trace event for LUN state change
  * @id: identifier for trigger of state change
  * @ref: additional reference (e.g. request)
- * @unit: unit
+ * @sdev: SCSI device
  */
-void zfcp_dbf_rec_unit(char *id, void *ref, struct zfcp_unit *unit)
+void zfcp_dbf_rec_lun(char *id, void *ref, struct scsi_device *sdev)
 {
-	struct zfcp_port *port = unit->port;
+	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
+	struct zfcp_port *port = zfcp_sdev->port;
 	struct zfcp_dbf *dbf = port->adapter->dbf;
 
-	zfcp_dbf_rec_target(id, ref, dbf, &unit->status,
-				  &unit->erp_counter, port->wwpn, port->d_id,
-				  unit->fcp_lun);
+	zfcp_dbf_rec_target(id, ref, dbf, &zfcp_sdev->status,
+			    &zfcp_sdev->erp_counter, port->wwpn, port->d_id,
+			    zfcp_scsi_dev_lun(sdev));
 }
 
 /**
@@ -624,11 +625,11 @@ void zfcp_dbf_rec_unit(char *id, void *ref, struct zfcp_unit *unit)
  * @action: address of error recovery action struct
  * @adapter: adapter
  * @port: port
- * @unit: unit
+ * @sdev: SCSI device
  */
 void zfcp_dbf_rec_trigger(char *id2, void *ref, u8 want, u8 need, void *action,
 			  struct zfcp_adapter *adapter, struct zfcp_port *port,
-			  struct zfcp_unit *unit)
+			  struct scsi_device *sdev)
 {
 	struct zfcp_dbf *dbf = adapter->dbf;
 	struct zfcp_dbf_rec_record *r = &dbf->rec_buf;
@@ -647,9 +648,10 @@ void zfcp_dbf_rec_trigger(char *id2, void *ref, u8 want, u8 need, void *action,
 		r->u.trigger.ps = atomic_read(&port->status);
 		r->u.trigger.wwpn = port->wwpn;
 	}
-	if (unit)
-		r->u.trigger.us = atomic_read(&unit->status);
-	r->u.trigger.fcp_lun = unit ? unit->fcp_lun : ZFCP_DBF_INVALID_LUN;
+	if (sdev)
+		r->u.trigger.ls = atomic_read(&sdev_to_zfcp(sdev)->status);
+	r->u.trigger.fcp_lun = sdev ? zfcp_scsi_dev_lun(sdev) :
+				      ZFCP_DBF_INVALID_LUN;
 	debug_event(dbf->rec, action ? 1 : 4, r, sizeof(*r));
 	spin_unlock_irqrestore(&dbf->rec_lock, flags);
 }

drivers/s390/scsi/zfcp_dbf.h

@@ -60,7 +60,7 @@ struct zfcp_dbf_rec_record_trigger {
 	u8 need;
 	u32 as;
 	u32 ps;
-	u32 us;
+	u32 ls;
 	u64 ref;
 	u64 action;
 	u64 wwpn;
@@ -350,16 +350,16 @@ void zfcp_dbf_scsi_abort(const char *tag, struct zfcp_dbf *dbf,
 /**
  * zfcp_dbf_scsi_devreset - trace event for Logical Unit or Target Reset
  * @tag: tag indicating success or failure of reset operation
+ * @scmnd: SCSI command which caused this error recovery
  * @flag: indicates type of reset (Target Reset, Logical Unit Reset)
- * @unit: unit that needs reset
- * @scsi_cmnd: SCSI command which caused this error recovery
  */
 static inline
-void zfcp_dbf_scsi_devreset(const char *tag, u8 flag, struct zfcp_unit *unit,
-			    struct scsi_cmnd *scsi_cmnd)
+void zfcp_dbf_scsi_devreset(const char *tag, struct scsi_cmnd *scmnd, u8 flag)
 {
+	struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(scmnd->device);
+
 	zfcp_dbf_scsi(flag == FCP_TMF_TGT_RESET ? "trst" : "lrst", tag, 1,
-			    unit->port->adapter->dbf, scsi_cmnd, NULL, 0);
+		      zfcp_sdev->port->adapter->dbf, scmnd, NULL, 0);
 }
 
 #endif /* ZFCP_DBF_H */

drivers/s390/scsi/zfcp_def.h

@@ -85,8 +85,8 @@ struct zfcp_reqlist;
 #define ZFCP_STATUS_PORT_LINK_TEST		0x00000002
 
 /* logical unit status */
-#define ZFCP_STATUS_UNIT_SHARED			0x00000004
-#define ZFCP_STATUS_UNIT_READONLY		0x00000008
+#define ZFCP_STATUS_LUN_SHARED			0x00000004
+#define ZFCP_STATUS_LUN_READONLY		0x00000008
 
 /* FSF request status (this does not have a common part) */
 #define ZFCP_STATUS_FSFREQ_TASK_MANAGEMENT	0x00000002
@@ -118,7 +118,7 @@ struct zfcp_erp_action {
 	int action;	              /* requested action code */
 	struct zfcp_adapter *adapter; /* device which should be recovered */
 	struct zfcp_port *port;
-	struct zfcp_unit *unit;
+	struct scsi_device *sdev;
 	u32		status;	      /* recovery status */
 	u32 step;	              /* active step of this erp action */
 	unsigned long		fsf_req_id;
@@ -219,17 +219,23 @@ struct zfcp_port {
 	unsigned int		starget_id;
 };
 
+/**
+ * struct zfcp_unit - LUN configured via zfcp sysfs
+ * @dev: struct device for sysfs representation and reference counting
+ * @list: entry in LUN/unit list per zfcp_port
+ * @port: reference to zfcp_port where this LUN is configured
+ * @fcp_lun: 64 bit LUN value
+ * @scsi_work: for running scsi_scan_target
+ *
+ * This is the representation of a LUN that has been configured for
+ * usage. The main data here is the 64 bit LUN value, data for
+ * running I/O and recovery is in struct zfcp_scsi_dev.
+ */
 struct zfcp_unit {
-	struct device          dev;
-	struct list_head       list;	       /* list of logical units */
-	struct zfcp_port       *port;	       /* remote port of unit */
-	atomic_t	       status;	       /* status of this logical unit */
-	u64		       fcp_lun;	       /* own FCP_LUN */
-	u32		       handle;	       /* handle assigned by FSF */
-        struct scsi_device     *device;        /* scsi device struct pointer */
-	struct zfcp_erp_action erp_action;     /* pending error recovery */
-        atomic_t               erp_counter;
-	struct zfcp_latencies	latencies;
+	struct device		dev;
+	struct list_head	list;
+	struct zfcp_port	*port;
+	u64			fcp_lun;
 	struct work_struct	scsi_work;
 };
 
@@ -288,7 +294,6 @@ static inline u64 zfcp_scsi_dev_lun(struct scsi_device *sdev)
  * @erp_action: reference to erp action if request issued on behalf of ERP
  * @pool: reference to memory pool if used for this request
  * @issued: time when request was send (STCK)
- * @unit: reference to unit if this request is a SCSI request
  * @handler: handler which should be called to process response
  */
 struct zfcp_fsf_req {
@@ -306,7 +311,6 @@ struct zfcp_fsf_req {
 	struct zfcp_erp_action	*erp_action;
 	mempool_t		*pool;
 	unsigned long long	issued;
-	struct zfcp_unit	*unit;
 	void			(*handler)(struct zfcp_fsf_req *);
 };