scsi: lpfc: Ignore GID-FT response that may be received after a link flip

When a link bounce happens, there is a possibility that responses to
requests posted prior to the link bounce could be received. This is
problematic as the counter to track reglogin completion after link up can
become out of sync with the real state.

As there is no reason to process a request made in a prior link up context,
eliminate all the disturbance by tagging the request with the event_tag
maintained by the SLI Port for the link. The event_tag will change on every
link state transition.  As long as the tag matches the current event_tag,
the response can be processed. If it doesn't match, just discard the
response.

Link: https://lore.kernel.org/r/20210514195559.119853-8-jsmart2021@gmail.comCo-developed-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_ct.c

@@ -587,7 +587,7 @@ lpfc_gen_req(struct lpfc_vport *vport, struct lpfc_dmabuf *bmp,
 	     struct lpfc_dmabuf *inp, struct lpfc_dmabuf *outp,
 	     void (*cmpl) (struct lpfc_hba *, struct lpfc_iocbq *,
 		     struct lpfc_iocbq *),
-	     struct lpfc_nodelist *ndlp, uint32_t usr_flg, uint32_t num_entry,
+	     struct lpfc_nodelist *ndlp, uint32_t event_tag, uint32_t num_entry,
 	     uint32_t tmo, uint8_t retry)
 {
 	struct lpfc_hba  *phba = vport->phba;
@@ -608,15 +608,14 @@ lpfc_gen_req(struct lpfc_vport *vport, struct lpfc_dmabuf *bmp,
 	icmd->un.genreq64.bdl.bdeFlags = BUFF_TYPE_BLP_64;
 	icmd->un.genreq64.bdl.bdeSize = (num_entry * sizeof(struct ulp_bde64));
 
-	if (usr_flg)
-		geniocb->context3 = NULL;
-	else
-		geniocb->context3 = (uint8_t *) bmp;
+	geniocb->context3 = (uint8_t *) bmp;
 
 	/* Save for completion so we can release these resources */
 	geniocb->context1 = (uint8_t *) inp;
 	geniocb->context2 = (uint8_t *) outp;
 
+	geniocb->event_tag = event_tag;
+
 	/* Fill in payload, bp points to frame payload */
 	icmd->ulpCommand = CMD_GEN_REQUEST64_CR;
 
@@ -707,8 +706,8 @@ lpfc_ct_cmd(struct lpfc_vport *vport, struct lpfc_dmabuf *inmp,
 	 * lpfc_alloc_ct_rsp.
 	 */
 	cnt += 1;
-	status = lpfc_gen_req(vport, bmp, inmp, outmp, cmpl, ndlp, 0,
-			      cnt, 0, retry);
+	status = lpfc_gen_req(vport, bmp, inmp, outmp, cmpl, ndlp,
+			phba->fc_eventTag, cnt, 0, retry);
 	if (status) {
 		lpfc_free_ct_rsp(phba, outmp);
 		return -ENOMEM;
@@ -957,6 +956,13 @@ lpfc_cmpl_ct_cmd_gid_ft(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 		 "GID_FT cmpl:     status:x%x/x%x rtry:%d",
 		irsp->ulpStatus, irsp->un.ulpWord[4], vport->fc_ns_retry);
 
+	/* Ignore response if link flipped after this request was made */
+	if (cmdiocb->event_tag != phba->fc_eventTag) {
+		lpfc_printf_vlog(vport, KERN_INFO, LOG_DISCOVERY,
+				 "9043 Event tag mismatch. Ignoring NS rsp\n");
+		goto out;
+	}
+
 	/* Don't bother processing response if vport is being torn down. */
 	if (vport->load_flag & FC_UNLOADING) {
 		if (vport->fc_flag & FC_RSCN_MODE)
@@ -1167,6 +1173,13 @@ lpfc_cmpl_ct_cmd_gid_pt(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 			      irsp->ulpStatus, irsp->un.ulpWord[4],
 			      vport->fc_ns_retry);
 
+	/* Ignore response if link flipped after this request was made */
+	if (cmdiocb->event_tag != phba->fc_eventTag) {
+		lpfc_printf_vlog(vport, KERN_INFO, LOG_DISCOVERY,
+				 "9044 Event tag mismatch. Ignoring NS rsp\n");
+		goto out;
+	}
+
 	/* Don't bother processing response if vport is being torn down. */
 	if (vport->load_flag & FC_UNLOADING) {
 		if (vport->fc_flag & FC_RSCN_MODE)
@@ -1366,6 +1379,13 @@ lpfc_cmpl_ct_cmd_gff_id(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 		"GFF_ID cmpl:     status:x%x/x%x did:x%x",
 		irsp->ulpStatus, irsp->un.ulpWord[4], did);
 
+	/* Ignore response if link flipped after this request was made */
+	if (cmdiocb->event_tag != phba->fc_eventTag) {
+		lpfc_printf_vlog(vport, KERN_INFO, LOG_DISCOVERY,
+				 "9045 Event tag mismatch. Ignoring NS rsp\n");
+		goto iocb_free;
+	}
+
 	if (irsp->ulpStatus == IOSTAT_SUCCESS) {
 		/* Good status, continue checking */
 		CTrsp = (struct lpfc_sli_ct_request *) outp->virt;
@@ -1479,6 +1499,7 @@ lpfc_cmpl_ct_cmd_gff_id(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 		lpfc_disc_start(vport);
 	}
 
+iocb_free:
 	free_ndlp = cmdiocb->context_un.ndlp;
 	lpfc_ct_free_iocb(phba, cmdiocb);
 	lpfc_nlp_put(free_ndlp);
@@ -1506,6 +1527,13 @@ lpfc_cmpl_ct_cmd_gft_id(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 			      "GFT_ID cmpl: status:x%x/x%x did:x%x",
 			      irsp->ulpStatus, irsp->un.ulpWord[4], did);
 
+	/* Ignore response if link flipped after this request was made */
+	if ((uint32_t) cmdiocb->event_tag != phba->fc_eventTag) {
+		lpfc_printf_vlog(vport, KERN_INFO, LOG_DISCOVERY,
+				 "9046 Event tag mismatch. Ignoring NS rsp\n");
+		goto out;
+	}
+
 	/* Preserve the nameserver node to release the reference. */
 	ns_ndlp = cmdiocb->context_un.ndlp;
 
@@ -1572,6 +1600,7 @@ lpfc_cmpl_ct_cmd_gft_id(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 		lpfc_printf_vlog(vport, KERN_ERR, LOG_TRACE_EVENT,
 				 "3065 GFT_ID failed x%08x\n", irsp->ulpStatus);
 
+out:
 	lpfc_ct_free_iocb(phba, cmdiocb);
 	lpfc_nlp_put(ns_ndlp);
 }

drivers/scsi/lpfc/lpfc_sli.h

 /*******************************************************************
  * This file is part of the Emulex Linux Device Driver for         *
  * Fibre Channel Host Bus Adapters.                                *
- * Copyright (C) 2017-2020 Broadcom. All Rights Reserved. The term *
+ * Copyright (C) 2017-2021 Broadcom. All Rights Reserved. The term *
  * “Broadcom” refers to Broadcom Inc. and/or its subsidiaries.     *
  * Copyright (C) 2004-2016 Emulex.  All rights reserved.           *
  * EMULEX and SLI are trademarks of Emulex.                        *
@@ -106,6 +106,7 @@ struct lpfc_iocbq {
 	void *context1;		/* caller context information */
 	void *context2;		/* caller context information */
 	void *context3;		/* caller context information */
+	uint32_t event_tag;	/* LA Event tag */
 	union {
 		wait_queue_head_t    *wait_queue;
 		struct lpfc_iocbq    *rsp_iocb;