scsi: lpfc: Decrement ndlp kref after FDISC retries exhausted

The kref for Fabric_DID ndlps is not decremented after repeated FDISC
failures and exhausting maximum allowed retries.  This can leave the
ndlp lingering unnecessarily.  Add a test and set bit operation for the
NLP_DROPPED flag. If not previously set, then a kref is decremented. The
ndlp is freed when the remaining reference for the completing ELS is
put.

Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Message-ID: <20250915180811.137530-6-justintee8345@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: Justin Tee

drivers/scsi/lpfc/lpfc_els.c

@@ -11259,6 +11259,11 @@ lpfc_cmpl_els_fdisc(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 		lpfc_vlog_msg(vport, KERN_WARNING, LOG_ELS,
 			      "0126 FDISC cmpl status: x%x/x%x)\n",
 			      ulp_status, ulp_word4);
+
+		/* drop initial reference */
+		if (!test_and_set_bit(NLP_DROPPED, &ndlp->nlp_flag))
+			lpfc_nlp_put(ndlp);
+
 		goto fdisc_failed;
 	}