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From: Steffen Maier <maier@linux.ibm.com>
Date: Thu, 12 Mar 2020 18:44:57 +0100
Subject: scsi: zfcp: expose fabric name as common fc_host sysfs attribute
Patch-mainline: v5.7-rc1
Git-commit: e05a10a055098bf55168a9d682156e38c6b00cfa
References: bsc#1158050

FICON Express8S or older, as well as card features newer than FICON
Express16S+ have no certain firmware level requirement.

FICON Express16S or FICON Express16S+ have the following
minimum firmware level requirements to show a proper fabric name value:

 z13 machine
  FICON Express16S  , MCL P08424.005 , LIC version 0x00000721
 z14 machine
  FICON Express16S  , MCL P42611.008 , LIC version 0x10200069
  FICON Express16S+ , MCL P42625.010 , LIC version 0x10300147

Otherwise, the read value is not the fabric name.

Each FCP channel of these card features might need one SAN fabric re-login
after concurrent microcode update in order to show the proper fabric name.
Possible ways to trigger a SAN fabric re-login are one of: Pull fibres
between FCP channel port and SAN switch port on either side and re-plug,
disable SAN switch port adjacent to FCP channel port and re-enable switch
port, or at Service Element toggle off all CHPIDs of FCP channel over all
LPARs and toggle CHPIDs on again.  Zfcp operating subchannels (FCP devices)
on such FCP channel recovers a fabric re-login.

Initialize fabric name for any topology and have it an invalid WWPN 0x0 for
anything but fabric topology.  Otherwise for e.g. point-to-point topology
one could see the initial -1 from fc_host_setup() and after a link unplug
our fabric name would turn to 0x0 (with subsequent commit ("zfcp: fix
fc_host attributes that should be unknown on local link down") and stay 0x0
on link replug.  I did not initialize to 0x0 somewhere even earlier in the
code path such that it would not flap from real to 0x0 to real on e.g. an
exchange config data with fabric topology.

Link: https://lore.kernel.org/r/20200312174505.51294-3-maier@linux.ibm.com
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Martin Wilck <mwilck@suse.com>
---
 drivers/s390/scsi/zfcp_fsf.c  |    5 +++++
 drivers/s390/scsi/zfcp_scsi.c |    1 +
 2 files changed, 6 insertions(+)

--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -532,8 +532,10 @@ static int zfcp_fsf_exchange_config_eval
 		adapter->peer_wwpn = be64_to_cpu(plogi->fl_wwpn);
 		adapter->peer_wwnn = be64_to_cpu(plogi->fl_wwnn);
 		fc_host_port_type(shost) = FC_PORTTYPE_PTP;
+		fc_host_fabric_name(shost) = 0;
 		break;
 	case FSF_TOPO_FABRIC:
+		fc_host_fabric_name(shost) = be64_to_cpu(plogi->fl_wwnn);
 		if (bottom->connection_features & FSF_FEATURE_NPIV_MODE)
 			fc_host_port_type(shost) = FC_PORTTYPE_NPIV;
 		else
@@ -541,8 +543,10 @@ static int zfcp_fsf_exchange_config_eval
 		break;
 	case FSF_TOPO_AL:
 		fc_host_port_type(shost) = FC_PORTTYPE_NLPORT;
+		fc_host_fabric_name(shost) = 0;
 		/* fall through */
 	default:
+		fc_host_fabric_name(shost) = 0;
 		dev_err(&adapter->ccw_device->dev,
 			"Unknown or unsupported arbitrated loop "
 			"fibre channel topology detected\n");
@@ -601,6 +605,7 @@ static void zfcp_fsf_exchange_config_dat
 		fc_host_node_name(shost) = 0;
 		fc_host_port_name(shost) = 0;
 		fc_host_port_id(shost) = 0;
+		fc_host_fabric_name(shost) = 0;
 		fc_host_speed(shost) = FC_PORTSPEED_UNKNOWN;
 		fc_host_port_type(shost) = FC_PORTTYPE_UNKNOWN;
 		adapter->hydra_version = 0;
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -871,5 +871,6 @@ struct fc_function_template zfcp_transpo
 	.show_host_symbolic_name = 1,
 	.show_host_speed = 1,
 	.show_host_port_id = 1,
+	.show_host_fabric_name = 1,
 	.dd_bsg_size = sizeof(struct zfcp_fsf_ct_els),
 };