[SCSI] zfcp: attach and release SAN nameserver port on demand

Changing the zfcp behaviour from always having the nameserver port
open to an on-demand strategy.  This strategy reduces the use of
limited resources like port connections. The patch provides a common
infrastructure which could be used for all WKA ports in future.

Also reduce the number of nameserver lookups by changing the zfcp
behaviour of always querying the nameserver for the corresponding
destination ID of the remote port.  If the destination ID has changed
during the reopen process we will be informed and then trigger a
nameserver query on demand.

Signed-off-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 40 insertions, 109 deletions

diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c
index b18c6dd37294..e7d3bce51429 100644
--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -23,7 +23,6 @@ enum zfcp_erp_steps {
         ZFCP_ERP_STEP_FSF_XCONFIG       = 0x0001,
         ZFCP_ERP_STEP_PHYS_PORT_CLOSING = 0x0010,
         ZFCP_ERP_STEP_PORT_CLOSING      = 0x0100,
-        ZFCP_ERP_STEP_NAMESERVER_OPEN   = 0x0200,
         ZFCP_ERP_STEP_NAMESERVER_LOOKUP = 0x0400,
         ZFCP_ERP_STEP_PORT_OPENING      = 0x0800,
         ZFCP_ERP_STEP_UNIT_CLOSING      = 0x1000,
@@ -532,8 +531,7 @@ static void _zfcp_erp_port_reopen_all(struct zfcp_adapter *adapter,
         struct zfcp_port *port;
 
         list_for_each_entry(port, &adapter->port_list_head, list)
-                if (!(atomic_read(&port->status) & ZFCP_STATUS_PORT_WKA))
-                        _zfcp_erp_port_reopen(port, clear, id, ref);
+                _zfcp_erp_port_reopen(port, clear, id, ref);
 }
 
 static void _zfcp_erp_unit_reopen_all(struct zfcp_port *port, int clear, u8 id,
@@ -777,7 +775,6 @@ static int zfcp_erp_port_forced_strategy_close(struct zfcp_erp_action *act)
 static void zfcp_erp_port_strategy_clearstati(struct zfcp_port *port)
 {
         atomic_clear_mask(ZFCP_STATUS_COMMON_ACCESS_DENIED |
-                          ZFCP_STATUS_PORT_DID_DID |
                           ZFCP_STATUS_PORT_PHYS_CLOSING |
                           ZFCP_STATUS_PORT_INVALID_WWPN,
                           &port->status);
@@ -830,62 +827,6 @@ static int zfcp_erp_port_strategy_open_port(struct zfcp_erp_action *erp_action)
         return ZFCP_ERP_CONTINUES;
 }
 
-static void zfcp_erp_port_strategy_open_ns_wake(struct zfcp_erp_action *ns_act)
-{
-        unsigned long flags;
-        struct zfcp_adapter *adapter = ns_act->adapter;
-        struct zfcp_erp_action *act, *tmp;
-        int status;
-
-        read_lock_irqsave(&adapter->erp_lock, flags);
-        list_for_each_entry_safe(act, tmp, &adapter->erp_running_head, list) {
-                if (act->step == ZFCP_ERP_STEP_NAMESERVER_OPEN) {
-                        status = atomic_read(&adapter->nameserver_port->status);
-                        if (status & ZFCP_STATUS_COMMON_ERP_FAILED)
-                                zfcp_erp_port_failed(act->port, 27, NULL);
-                        zfcp_erp_action_ready(act);
-                }
-        }
-        read_unlock_irqrestore(&adapter->erp_lock, flags);
-}
-
-static int zfcp_erp_port_strategy_open_nameserver(struct zfcp_erp_action *act)
-{
-        int retval;
-
-        switch (act->step) {
-        case ZFCP_ERP_STEP_UNINITIALIZED:
-        case ZFCP_ERP_STEP_PHYS_PORT_CLOSING:
-        case ZFCP_ERP_STEP_PORT_CLOSING:
-                return zfcp_erp_port_strategy_open_port(act);
-
-        case ZFCP_ERP_STEP_PORT_OPENING:
-                if (atomic_read(&act->port->status) & ZFCP_STATUS_COMMON_OPEN)
-                        retval = ZFCP_ERP_SUCCEEDED;
-                else
-                        retval = ZFCP_ERP_FAILED;
-                /* this is needed anyway  */
-                zfcp_erp_port_strategy_open_ns_wake(act);
-                return retval;
-
-        default:
-                return ZFCP_ERP_FAILED;
-        }
-}
-
-static int zfcp_erp_port_strategy_open_lookup(struct zfcp_erp_action *act)
-{
-        int retval;
-
-        retval = zfcp_fc_ns_gid_pn_request(act);
-        if (retval == -ENOMEM)
-                return ZFCP_ERP_NOMEM;
-        act->step = ZFCP_ERP_STEP_NAMESERVER_LOOKUP;
-        if (retval)
-                return ZFCP_ERP_FAILED;
-        return ZFCP_ERP_CONTINUES;
-}
-
 static int zfcp_erp_open_ptp_port(struct zfcp_erp_action *act)
 {
         struct zfcp_adapter *adapter = act->adapter;
@@ -900,11 +841,25 @@ static int zfcp_erp_open_ptp_port(struct zfcp_erp_action *act)
         return zfcp_erp_port_strategy_open_port(act);
 }
 
+void zfcp_erp_port_strategy_open_lookup(struct work_struct *work)
+{
+        int retval;
+        struct zfcp_port *port = container_of(work, struct zfcp_port,
+                                              gid_pn_work);
+
+        retval = zfcp_fc_ns_gid_pn(&port->erp_action);
+        if (retval == -ENOMEM)
+                zfcp_erp_notify(&port->erp_action, ZFCP_ERP_NOMEM);
+        port->erp_action.step = ZFCP_ERP_STEP_NAMESERVER_LOOKUP;
+        if (retval)
+                zfcp_erp_notify(&port->erp_action, ZFCP_ERP_FAILED);
+
+}
+
 static int zfcp_erp_port_strategy_open_common(struct zfcp_erp_action *act)
 {
         struct zfcp_adapter *adapter = act->adapter;
         struct zfcp_port *port = act->port;
-        struct zfcp_port *ns_port = adapter->nameserver_port;
         int p_status = atomic_read(&port->status);
 
         switch (act->step) {
@@ -913,29 +868,10 @@ static int zfcp_erp_port_strategy_open_common(struct zfcp_erp_action *act)
         case ZFCP_ERP_STEP_PORT_CLOSING:
                 if (fc_host_port_type(adapter->scsi_host) == FC_PORTTYPE_PTP)
                         return zfcp_erp_open_ptp_port(act);
-                if (!ns_port) {
-                        dev_err(&adapter->ccw_device->dev,
-                                "Attaching the name server port to the "
-                                "FCP device failed\n");
-                        return ZFCP_ERP_FAILED;
-                }
-                if (!(atomic_read(&ns_port->status) &
-                      ZFCP_STATUS_COMMON_UNBLOCKED)) {
-                        /* nameserver port may live again */
-                        atomic_set_mask(ZFCP_STATUS_COMMON_RUNNING,
-                                        &ns_port->status);
-                        if (zfcp_erp_port_reopen(ns_port, 0, 77, act) >= 0) {
-                                act->step = ZFCP_ERP_STEP_NAMESERVER_OPEN;
-                                return ZFCP_ERP_CONTINUES;
-                        }
-                        return ZFCP_ERP_FAILED;
+                if (!(p_status & ZFCP_STATUS_PORT_DID_DID)) {
+                        schedule_work(&port->gid_pn_work);
+                        return ZFCP_ERP_CONTINUES;
                 }
-                /* else nameserver port is already open, fall through */
-        case ZFCP_ERP_STEP_NAMESERVER_OPEN:
-                if (!(atomic_read(&ns_port->status) & ZFCP_STATUS_COMMON_OPEN))
-                        return ZFCP_ERP_FAILED;
-                return zfcp_erp_port_strategy_open_lookup(act);
-
         case ZFCP_ERP_STEP_NAMESERVER_LOOKUP:
                 if (!(p_status & ZFCP_STATUS_PORT_DID_DID)) {
                         if (p_status & (ZFCP_STATUS_PORT_INVALID_WWPN)) {
@@ -948,25 +884,26 @@ static int zfcp_erp_port_strategy_open_common(struct zfcp_erp_action *act)
 
         case ZFCP_ERP_STEP_PORT_OPENING:
                 /* D_ID might have changed during open */
-                if ((p_status & ZFCP_STATUS_COMMON_OPEN) &&
-                    (p_status & ZFCP_STATUS_PORT_DID_DID))
-                        return ZFCP_ERP_SUCCEEDED;
+                if (p_status & ZFCP_STATUS_COMMON_OPEN) {
+                        if (p_status & ZFCP_STATUS_PORT_DID_DID)
+                                return ZFCP_ERP_SUCCEEDED;
+                        else {
+                                act->step = ZFCP_ERP_STEP_PORT_CLOSING;
+                                return ZFCP_ERP_CONTINUES;
+                        }
                 /* fall through otherwise */
+                }
         }
         return ZFCP_ERP_FAILED;
 }
 
-static int zfcp_erp_port_strategy_open(struct zfcp_erp_action *act)
-{
-        if (atomic_read(&act->port->status) & (ZFCP_STATUS_PORT_WKA))
-                return zfcp_erp_port_strategy_open_nameserver(act);
-        return zfcp_erp_port_strategy_open_common(act);
-}
-
 static int zfcp_erp_port_strategy(struct zfcp_erp_action *erp_action)
 {
         struct zfcp_port *port = erp_action->port;
 
+        if (atomic_read(&port->status) & ZFCP_STATUS_COMMON_NOESC)
+                goto close_init_done;
+
         switch (erp_action->step) {
         case ZFCP_ERP_STEP_UNINITIALIZED:
                 zfcp_erp_port_strategy_clearstati(port);
@@ -979,12 +916,12 @@ static int zfcp_erp_port_strategy(struct zfcp_erp_action *erp_action)
                         return ZFCP_ERP_FAILED;
                 break;
         }
+
+close_init_done:
         if (erp_action->status & ZFCP_STATUS_ERP_CLOSE_ONLY)
                 return ZFCP_ERP_EXIT;
-        else
-                return zfcp_erp_port_strategy_open(erp_action);
 
-        return ZFCP_ERP_FAILED;
+        return zfcp_erp_port_strategy_open_common(erp_action);
 }
 
 static void zfcp_erp_unit_strategy_clearstati(struct zfcp_unit *unit)
@@ -1296,12 +1233,10 @@ static void zfcp_erp_rport_register(struct zfcp_port *port)
 static void zfcp_erp_rports_del(struct zfcp_adapter *adapter)
 {
         struct zfcp_port *port;
-        list_for_each_entry(port, &adapter->port_list_head, list)
-                if (port->rport && !(atomic_read(&port->status) &
-                                        ZFCP_STATUS_PORT_WKA)) {
-                        fc_remote_port_delete(port->rport);
-                        port->rport = NULL;
-                }
+        list_for_each_entry(port, &adapter->port_list_head, list) {
+                fc_remote_port_delete(port->rport);
+                port->rport = NULL;
+        }
 }
 
 static void zfcp_erp_action_cleanup(struct zfcp_erp_action *act, int result)
@@ -1737,9 +1672,8 @@ static void zfcp_erp_port_access_changed(struct zfcp_port *port, u8 id,
 
         if (!(status & (ZFCP_STATUS_COMMON_ACCESS_DENIED |
                         ZFCP_STATUS_COMMON_ACCESS_BOXED))) {
-                if (!(status & ZFCP_STATUS_PORT_WKA))
-                        list_for_each_entry(unit, &port->unit_list_head, list)
-                                zfcp_erp_unit_access_changed(unit, id, ref);
+                list_for_each_entry(unit, &port->unit_list_head, list)
+                                    zfcp_erp_unit_access_changed(unit, id, ref);
                 return;
         }
 
@@ -1762,10 +1696,7 @@ void zfcp_erp_adapter_access_changed(struct zfcp_adapter *adapter, u8 id,
                 return;
 
         read_lock_irqsave(&zfcp_data.config_lock, flags);
-        if (adapter->nameserver_port)
-                zfcp_erp_port_access_changed(adapter->nameserver_port, id, ref);
         list_for_each_entry(port, &adapter->port_list_head, list)
-                if (port != adapter->nameserver_port)
-                        zfcp_erp_port_access_changed(port, id, ref);
+                zfcp_erp_port_access_changed(port, id, ref);
         read_unlock_irqrestore(&zfcp_data.config_lock, flags);
 }