[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>

1 files changed, 19 insertions, 15 deletions

diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h
index d31158c..6dfae70 100644
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/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 *);
 };