scsi: lpfc: Slight fast-path performance optimizations

Slightly rework some error check code paths for better streamlining.

Added compiler unlikely hints to allow slightly better optimization of the
fast-path.

Removed a few pointer checks that were obviously already valid.

Link: https://lore.kernel.org/r/20191018211832.7917-9-jsmart2021@gmail.com
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_nvme.c

@@ -2093,7 +2093,7 @@ lpfc_release_nvme_buf(struct lpfc_hba *phba, struct lpfc_io_buf *lpfc_ncmd)
 	lpfc_ncmd->flags &= ~LPFC_SBUF_BUMP_QDEPTH;
 
 	qp = lpfc_ncmd->hdwq;
-	if (lpfc_ncmd->flags & LPFC_SBUF_XBUSY) {
+	if (unlikely(lpfc_ncmd->flags & LPFC_SBUF_XBUSY)) {
 		lpfc_printf_log(phba, KERN_INFO, LOG_NVME_ABTS,
 				"6310 XB release deferred for "
 				"ox_id x%x on reqtag x%x\n",

drivers/scsi/lpfc/lpfc_scsi.c

@@ -611,7 +611,7 @@ lpfc_get_scsi_buf_s3(struct lpfc_hba *phba, struct lpfc_nodelist *ndlp,
 	}
 	spin_unlock_irqrestore(&phba->scsi_buf_list_get_lock, iflag);
 
-	if (lpfc_ndlp_check_qdepth(phba, ndlp) && lpfc_cmd) {
+	if (lpfc_ndlp_check_qdepth(phba, ndlp)) {
 		atomic_inc(&ndlp->cmd_pending);
 		lpfc_cmd->flags |= LPFC_SBUF_BUMP_QDEPTH;
 	}
@@ -3826,7 +3826,7 @@ lpfc_scsi_cmd_iocb_cmpl(struct lpfc_hba *phba, struct lpfc_iocbq *pIocbIn,
 		phba->sli4_hba.hdwq[idx].scsi_cstat.io_cmpls++;
 
 #ifdef CONFIG_SCSI_LPFC_DEBUG_FS
-	if (phba->cpucheck_on & LPFC_CHECK_SCSI_IO) {
+	if (unlikely(phba->cpucheck_on & LPFC_CHECK_SCSI_IO)) {
 		cpu = raw_smp_processor_id();
 		if (cpu < LPFC_CHECK_CPU_CNT && phba->sli4_hba.hdwq)
 			phba->sli4_hba.hdwq[idx].cpucheck_cmpl_io[cpu]++;
@@ -3874,7 +3874,7 @@ lpfc_scsi_cmd_iocb_cmpl(struct lpfc_hba *phba, struct lpfc_iocbq *pIocbIn,
 	}
 #endif
 
-	if (lpfc_cmd->status) {
+	if (unlikely(lpfc_cmd->status)) {
 		if (lpfc_cmd->status == IOSTAT_LOCAL_REJECT &&
 		    (lpfc_cmd->result & IOERR_DRVR_MASK))
 			lpfc_cmd->status = IOSTAT_DRIVER_REJECT;
@@ -4615,17 +4615,18 @@ lpfc_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *cmnd)
 		err = lpfc_scsi_prep_dma_buf(phba, lpfc_cmd);
 	}
 
-	if (err == 2) {
-		cmnd->result = DID_ERROR << 16;
-		goto out_fail_command_release_buf;
-	} else if (err) {
+	if (unlikely(err)) {
+		if (err == 2) {
+			cmnd->result = DID_ERROR << 16;
+			goto out_fail_command_release_buf;
+		}
 		goto out_host_busy_free_buf;
 	}
 
 	lpfc_scsi_prep_cmnd(vport, lpfc_cmd, ndlp);
 
 #ifdef CONFIG_SCSI_LPFC_DEBUG_FS
-	if (phba->cpucheck_on & LPFC_CHECK_SCSI_IO) {
+	if (unlikely(phba->cpucheck_on & LPFC_CHECK_SCSI_IO)) {
 		cpu = raw_smp_processor_id();
 		if (cpu < LPFC_CHECK_CPU_CNT) {
 			struct lpfc_sli4_hdw_queue *hdwq =