scsi: zfcp: drop duplicate seq_no from zfcp_fsf_req which is also in QTCB header

There is no point for double bookkeeping especially just for tracing.  The
trace can take it from the QTCB which always exists for non-SRB responses
traced with zfcp_dbf_hba_fsf_res().

As a side effect, this removes an alignment hole and reduces the size of
struct zfcp_fsf_req, and thus of each pending request, by 8 bytes.

Before:
$ pahole -C zfcp_fsf_req drivers/s390/scsi/zfcp.ko
...
	struct fsf_qtcb *          qtcb;                 /*   144     8 */
	u32                        seq_no;               /*   152     4 */
	/* XXX 4 bytes hole, try to pack */
	void *                     data;                 /*   160     8 */
...
	/* size: 296, cachelines: 2, members: 14 */
	/* sum members: 288, holes: 2, sum holes: 8 */
	/* last cacheline: 40 bytes */
After:
$ pahole -C zfcp_fsf_req drivers/s390/scsi/zfcp.ko
...
	struct fsf_qtcb *          qtcb;                 /*   144     8 */
	void *                     data;                 /*   152     8 */
...
	/* size: 288, cachelines: 2, members: 13 */
        /* sum members: 284, holes: 1, sum holes: 4 */
Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/s390/scsi/zfcp_dbf.c

@@ -82,7 +82,7 @@ void zfcp_dbf_hba_fsf_res(char *tag, int level, struct zfcp_fsf_req *req)
 	rec->fsf_req_id = req->req_id;
 	rec->fsf_req_status = req->status;
 	rec->fsf_cmd = q_head->fsf_command;
-	rec->fsf_seq_no = req->seq_no;
+	rec->fsf_seq_no = q_pref->req_seq_no;
 	rec->u.res.req_issued = req->issued;
 	rec->u.res.prot_status = q_pref->prot_status;
 	rec->u.res.fsf_status = q_head->fsf_status;

drivers/s390/scsi/zfcp_def.h

@@ -278,7 +278,6 @@ static inline u64 zfcp_scsi_dev_lun(struct scsi_device *sdev)
  * @completion: used to signal the completion of the request
  * @status: status of the request
  * @qtcb: associated QTCB
- * @seq_no: sequence number of this request
  * @data: private data
  * @timer: timer data of this request
  * @erp_action: reference to erp action if request issued on behalf of ERP
@@ -294,7 +293,6 @@ struct zfcp_fsf_req {
 	struct completion	completion;
 	u32			status;
 	struct fsf_qtcb		*qtcb;
-	u32			seq_no;
 	void			*data;
 	struct timer_list	timer;
 	struct zfcp_erp_action	*erp_action;

drivers/s390/scsi/zfcp_fsf.c

@@ -724,7 +724,6 @@ static struct zfcp_fsf_req *zfcp_fsf_req_create(struct zfcp_qdio *qdio,
 			return ERR_PTR(-ENOMEM);
 		}
 
-		req->seq_no = adapter->fsf_req_seq_no;
 		req->qtcb->prefix.req_seq_no = adapter->fsf_req_seq_no;
 		req->qtcb->prefix.req_id = req->req_id;
 		req->qtcb->prefix.ulp_info = 26;