Commit 8ccd6926 authored by Dick Kennedy's avatar Dick Kennedy Committed by Martin K. Petersen
Browse files

scsi: lpfc: Fix RSCN timeout due to incorrect gidft counter 

In configs with a large number of initiators in the same zone (>250), RSCN
timeouts are seen when creating or deleting vports:

   lpfc 0000:07:00.1: 5:(0):0231 RSCN timeout Data: x0 x3

During RSCN processing driver issues GID_FT command to nameserver. A
counter for number of simultaneous GID_FT commands is maintained (an
unsigned value). The counter is incremented when the GID_FT is issued.  If
the GID_FT command fails for some reason the driver retries the GID_FT from
the completion call back. But the counter was decremented before the retry
was issued.  When the second GID_FT completes, the callback again tries to
decrement the counter, possibly wrapping to a very large non-zero value,
which causes the RSCN cleanup code to not execute. Thus the RSCN timeout
failure.

Do not decrement the counter on a retry. Also add defensive checks to
ensure the counter is not decremented if already zero.

Link: https://lore.kernel.org/r/20200803210229.23063-4-jsmart2021@gmail.com


Signed-off-by: default avatarDick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: default avatarJames Smart <jsmart2021@gmail.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 9e3e365a

drivers/scsi/lpfc/lpfc_ct.c

+16 −6
Original line number Diff line number Diff line
@@ -713,6 +713,7 @@ lpfc_cmpl_ct_cmd_gid_ft(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb, 
		/* This is a GID_FT completing so the gidft_inp counter was

		 * incremented before the GID_FT was issued to the wire.

		 */

		if (vport->gidft_inp)

			vport->gidft_inp--;



		/*
@@ -741,11 +742,14 @@ lpfc_cmpl_ct_cmd_gid_ft(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb, 
				goto out;



			/* CT command is being retried */

			vport->gidft_inp--;

			rc = lpfc_ns_cmd(vport, SLI_CTNS_GID_FT,

					 vport->fc_ns_retry, type);

			if (rc == 0)

				goto out;

			else { /* Unable to send NS cmd */

				if (vport->gidft_inp)

					vport->gidft_inp--;

			}

		}

		if (vport->fc_flag & FC_RSCN_MODE)

			lpfc_els_flush_rscn(vport);
@@ -825,6 +829,7 @@ lpfc_cmpl_ct_cmd_gid_ft(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb, 
				(uint32_t) CTrsp->ReasonCode,

				(uint32_t) CTrsp->Explanation);

		}

		if (vport->gidft_inp)

			vport->gidft_inp--;

	}
@@ -918,6 +923,7 @@ lpfc_cmpl_ct_cmd_gid_pt(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb, 
		/* This is a GID_PT completing so the gidft_inp counter was

		 * incremented before the GID_PT was issued to the wire.

		 */

		if (vport->gidft_inp)

			vport->gidft_inp--;



		/*
@@ -942,11 +948,14 @@ lpfc_cmpl_ct_cmd_gid_pt(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb, 
				vport->fc_ns_retry++;



			/* CT command is being retried */

			vport->gidft_inp--;

			rc = lpfc_ns_cmd(vport, SLI_CTNS_GID_PT,

					 vport->fc_ns_retry, GID_PT_N_PORT);

			if (rc == 0)

				goto out;

			else { /* Unable to send NS cmd */

				if (vport->gidft_inp)

					vport->gidft_inp--;

			}

		}

		if (vport->fc_flag & FC_RSCN_MODE)

			lpfc_els_flush_rscn(vport);
@@ -1027,6 +1036,7 @@ lpfc_cmpl_ct_cmd_gid_pt(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb, 
				(uint32_t)CTrsp->ReasonCode,

				(uint32_t)CTrsp->Explanation);

		}

		if (vport->gidft_inp)

			vport->gidft_inp--;

	}

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