[SCSI] zfcp: Dont block zfcp_wq with scan

When running the scsi_scan from the zfcp workqueue and the target
device does not respond, the zfcp workqueue can block until the
scsi_scan hits a timeout. Move the work to the scsi host workqueue,
since this one is also used for the scan from the SCSI midlayer.

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>

diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index 616c60f..5a01ef9 100644 (file)
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -97,9 +97,7 @@ static void __init zfcp_init_device_configure(char *busid, u64 wwpn, u64 lun)
        ccw_device_set_online(adapter->ccw_device);
 
        zfcp_erp_wait(adapter);
-       wait_event(adapter->erp_done_wqh,
-                  !(atomic_read(&unit->status) &
-                               ZFCP_STATUS_UNIT_SCSI_WORK_PENDING));
+       flush_work(&unit->scsi_work);
 
        down(&zfcp_data.config_sema);
        zfcp_unit_put(unit);
@@ -279,6 +277,7 @@ struct zfcp_unit *zfcp_unit_enqueue(struct zfcp_port *port, u64 fcp_lun)
 
        atomic_set(&unit->refcount, 0);
        init_waitqueue_head(&unit->remove_wq);
+       INIT_WORK(&unit->scsi_work, zfcp_scsi_scan);
 
        unit->port = port;
        unit->fcp_lun = fcp_lun;

diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h
index a031863..4c362a9 100644 (file)
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/drivers/s390/scsi/zfcp_def.h
@@ -255,7 +255,6 @@ enum zfcp_wka_status {
 /* logical unit status */
 #define ZFCP_STATUS_UNIT_SHARED                        0x00000004
 #define ZFCP_STATUS_UNIT_READONLY              0x00000008
-#define ZFCP_STATUS_UNIT_SCSI_WORK_PENDING     0x00000020
 
 /* FSF request status (this does not have a common part) */
 #define ZFCP_STATUS_FSFREQ_TASK_MANAGEMENT     0x00000002
@@ -530,6 +529,7 @@ struct zfcp_unit {
        struct zfcp_erp_action erp_action;     /* pending error recovery */
         atomic_t               erp_counter;
        struct zfcp_latencies   latencies;
+       struct work_struct      scsi_work;
 };
 
 /* FSF request */

diff --git a/drivers/s390/scsi/zfcp_erp.c b/drivers/s390/scsi/zfcp_erp.c
index 631bdb1..4e16052 100644 (file)
--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -1176,48 +1176,6 @@ static void zfcp_erp_action_dequeue(struct zfcp_erp_action *erp_action)
        }
 }
 
-struct zfcp_erp_add_work {
-       struct zfcp_unit  *unit;
-       struct work_struct work;
-};
-
-static void zfcp_erp_scsi_scan(struct work_struct *work)
-{
-       struct zfcp_erp_add_work *p =
-               container_of(work, struct zfcp_erp_add_work, work);
-       struct zfcp_unit *unit = p->unit;
-       struct fc_rport *rport = unit->port->rport;
-
-       if (rport && rport->port_state == FC_PORTSTATE_ONLINE)
-               scsi_scan_target(&rport->dev, 0, rport->scsi_target_id,
-                        scsilun_to_int((struct scsi_lun *)&unit->fcp_lun), 0);
-       atomic_clear_mask(ZFCP_STATUS_UNIT_SCSI_WORK_PENDING, &unit->status);
-       zfcp_unit_put(unit);
-       wake_up(&unit->port->adapter->erp_done_wqh);
-       kfree(p);
-}
-
-static void zfcp_erp_schedule_work(struct zfcp_unit *unit)
-{
-       struct zfcp_erp_add_work *p;
-
-       p = kzalloc(sizeof(*p), GFP_KERNEL);
-       if (!p) {
-               dev_err(&unit->port->adapter->ccw_device->dev,
-                       "Registering unit 0x%016Lx on port 0x%016Lx failed\n",
-                       (unsigned long long)unit->fcp_lun,
-                       (unsigned long long)unit->port->wwpn);
-               return;
-       }
-
-       zfcp_unit_get(unit);
-       atomic_set_mask(ZFCP_STATUS_UNIT_SCSI_WORK_PENDING, &unit->status);
-       INIT_WORK(&p->work, zfcp_erp_scsi_scan);
-       p->unit = unit;
-       if (!queue_work(zfcp_data.work_queue, &p->work))
-               zfcp_unit_put(unit);
-}
-
 static void zfcp_erp_action_cleanup(struct zfcp_erp_action *act, int result)
 {
        struct zfcp_adapter *adapter = act->adapter;
@@ -1226,11 +1184,11 @@ static void zfcp_erp_action_cleanup(struct zfcp_erp_action *act, int result)
 
        switch (act->action) {
        case ZFCP_ERP_ACTION_REOPEN_UNIT:
-               flush_work(&port->rport_work);
                if ((result == ZFCP_ERP_SUCCEEDED) && !unit->device) {
-                       if (!(atomic_read(&unit->status) &
-                             ZFCP_STATUS_UNIT_SCSI_WORK_PENDING))
-                               zfcp_erp_schedule_work(unit);
+                       zfcp_unit_get(unit);
+                       if (scsi_queue_work(unit->port->adapter->scsi_host,
+                                           &unit->scsi_work) <= 0)
+                               zfcp_unit_put(unit);
                }
                zfcp_unit_put(unit);
                break;

diff --git a/drivers/s390/scsi/zfcp_ext.h b/drivers/s390/scsi/zfcp_ext.h
index f6399ca..df740f1 100644 (file)
--- a/drivers/s390/scsi/zfcp_ext.h
+++ b/drivers/s390/scsi/zfcp_ext.h
@@ -158,6 +158,7 @@ extern void zfcp_scsi_rport_work(struct work_struct *);
 extern void zfcp_scsi_schedule_rport_register(struct zfcp_port *);
 extern void zfcp_scsi_schedule_rport_block(struct zfcp_port *);
 extern void zfcp_scsi_schedule_rports_block(struct zfcp_adapter *);
+extern void zfcp_scsi_scan(struct work_struct *);
 
 /* zfcp_sysfs.c */
 extern struct attribute_group zfcp_sysfs_unit_attrs;

diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index 58201e1..5b11386 100644 (file)
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -583,6 +583,23 @@ void zfcp_scsi_rport_work(struct work_struct *work)
 }
 
 
+void zfcp_scsi_scan(struct work_struct *work)
+{
+       struct zfcp_unit *unit = container_of(work, struct zfcp_unit,
+                                             scsi_work);
+       struct fc_rport *rport;
+
+       flush_work(&unit->port->rport_work);
+       rport = unit->port->rport;
+
+       if (rport && rport->port_state == FC_PORTSTATE_ONLINE)
+               scsi_scan_target(&rport->dev, 0, rport->scsi_target_id,
+                                scsilun_to_int((struct scsi_lun *)
+                                               &unit->fcp_lun), 0);
+
+       zfcp_unit_put(unit);
+}
+
 struct fc_function_template zfcp_transport_functions = {
        .show_starget_port_id = 1,
        .show_starget_port_name = 1,