[SCSI] zfcp: Replace global config_lock with local list locks
The global config_lock was used to protect the configuration organized
in independent lists. It is not necessary to have a lock on driver
level for this purpose. This patch replaces the global config_lock
with a set of local list locks.
Signed-off-by: Swen Schillig <[email protected]>
Signed-off-by: Christof Schmitt <[email protected]>
Signed-off-by: James Bottomley <[email protected]>
diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index 2889e5f..883e139 100644
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -187,7 +187,6 @@
goto out_gid_cache;
mutex_init(&zfcp_data.config_mutex);
- rwlock_init(&zfcp_data.config_lock);
zfcp_data.scsi_transport_template =
fc_attach_transport(&zfcp_transport_functions);
@@ -238,12 +237,18 @@
*/
struct zfcp_unit *zfcp_get_unit_by_lun(struct zfcp_port *port, u64 fcp_lun)
{
+ unsigned long flags;
struct zfcp_unit *unit;
- list_for_each_entry(unit, &port->unit_list_head, list)
+ read_lock_irqsave(&port->unit_list_lock, flags);
+ list_for_each_entry(unit, &port->unit_list, list)
if ((unit->fcp_lun == fcp_lun) &&
- !(atomic_read(&unit->status) & ZFCP_STATUS_COMMON_REMOVE))
- return unit;
+ !(atomic_read(&unit->status) & ZFCP_STATUS_COMMON_REMOVE)) {
+ zfcp_unit_get(unit);
+ read_unlock_irqrestore(&port->unit_list_lock, flags);
+ return unit;
+ }
+ read_unlock_irqrestore(&port->unit_list_lock, flags);
return NULL;
}
@@ -257,12 +262,18 @@
struct zfcp_port *zfcp_get_port_by_wwpn(struct zfcp_adapter *adapter,
u64 wwpn)
{
+ unsigned long flags;
struct zfcp_port *port;
- list_for_each_entry(port, &adapter->port_list_head, list)
+ read_lock_irqsave(&adapter->port_list_lock, flags);
+ list_for_each_entry(port, &adapter->port_list, list)
if ((port->wwpn == wwpn) &&
- !(atomic_read(&port->status) & ZFCP_STATUS_COMMON_REMOVE))
+ !(atomic_read(&port->status) & ZFCP_STATUS_COMMON_REMOVE)) {
+ zfcp_port_get(port);
+ read_unlock_irqrestore(&adapter->port_list_lock, flags);
return port;
+ }
+ read_unlock_irqrestore(&adapter->port_list_lock, flags);
return NULL;
}
@@ -284,12 +295,11 @@
{
struct zfcp_unit *unit;
- read_lock_irq(&zfcp_data.config_lock);
- if (zfcp_get_unit_by_lun(port, fcp_lun)) {
- read_unlock_irq(&zfcp_data.config_lock);
+ unit = zfcp_get_unit_by_lun(port, fcp_lun);
+ if (unit) {
+ zfcp_unit_put(unit);
return ERR_PTR(-EINVAL);
}
- read_unlock_irq(&zfcp_data.config_lock);
unit = kzalloc(sizeof(struct zfcp_unit), GFP_KERNEL);
if (!unit)
@@ -335,13 +345,13 @@
zfcp_unit_get(unit);
- write_lock_irq(&zfcp_data.config_lock);
- list_add_tail(&unit->list, &port->unit_list_head);
+ write_lock_irq(&port->unit_list_lock);
+ list_add_tail(&unit->list, &port->unit_list);
+ write_unlock_irq(&port->unit_list_lock);
+
atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
atomic_set_mask(ZFCP_STATUS_COMMON_RUNNING, &unit->status);
- write_unlock_irq(&zfcp_data.config_lock);
-
zfcp_port_get(port);
return unit;
@@ -356,11 +366,11 @@
*/
void zfcp_unit_dequeue(struct zfcp_unit *unit)
{
+ struct zfcp_port *port = unit->port;
+
wait_event(unit->remove_wq, atomic_read(&unit->refcount) == 0);
- write_lock_irq(&zfcp_data.config_lock);
- list_del(&unit->list);
- write_unlock_irq(&zfcp_data.config_lock);
- zfcp_port_put(unit->port);
+ list_del(&unit->list); /* no list locking required */
+ zfcp_port_put(port);
sysfs_remove_group(&unit->sysfs_device.kobj, &zfcp_sysfs_unit_attrs);
device_unregister(&unit->sysfs_device);
}
@@ -539,11 +549,13 @@
if (zfcp_fc_gs_setup(adapter))
goto generic_services_failed;
+ rwlock_init(&adapter->port_list_lock);
+ INIT_LIST_HEAD(&adapter->port_list);
+
init_waitqueue_head(&adapter->remove_wq);
init_waitqueue_head(&adapter->erp_ready_wq);
init_waitqueue_head(&adapter->erp_done_wqh);
- INIT_LIST_HEAD(&adapter->port_list_head);
INIT_LIST_HEAD(&adapter->erp_ready_head);
INIT_LIST_HEAD(&adapter->erp_running_head);
@@ -650,19 +662,20 @@
{
struct zfcp_port *port;
- read_lock_irq(&zfcp_data.config_lock);
- if (zfcp_get_port_by_wwpn(adapter, wwpn)) {
- read_unlock_irq(&zfcp_data.config_lock);
- return ERR_PTR(-EINVAL);
+ port = zfcp_get_port_by_wwpn(adapter, wwpn);
+ if (port) {
+ zfcp_port_put(port);
+ return ERR_PTR(-EEXIST);
}
- read_unlock_irq(&zfcp_data.config_lock);
port = kzalloc(sizeof(struct zfcp_port), GFP_KERNEL);
if (!port)
return ERR_PTR(-ENOMEM);
+ rwlock_init(&port->unit_list_lock);
+ INIT_LIST_HEAD(&port->unit_list);
+
init_waitqueue_head(&port->remove_wq);
- INIT_LIST_HEAD(&port->unit_list_head);
INIT_WORK(&port->gid_pn_work, zfcp_fc_port_did_lookup);
INIT_WORK(&port->test_link_work, zfcp_fc_link_test_work);
INIT_WORK(&port->rport_work, zfcp_scsi_rport_work);
@@ -698,13 +711,13 @@
zfcp_port_get(port);
- write_lock_irq(&zfcp_data.config_lock);
- list_add_tail(&port->list, &adapter->port_list_head);
+ write_lock_irq(&adapter->port_list_lock);
+ list_add_tail(&port->list, &adapter->port_list);
+ write_unlock_irq(&adapter->port_list_lock);
+
atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &port->status);
atomic_set_mask(ZFCP_STATUS_COMMON_RUNNING, &port->status);
- write_unlock_irq(&zfcp_data.config_lock);
-
zfcp_adapter_get(adapter);
return port;
}
@@ -715,12 +728,11 @@
*/
void zfcp_port_dequeue(struct zfcp_port *port)
{
- write_lock_irq(&zfcp_data.config_lock);
- list_del(&port->list);
- write_unlock_irq(&zfcp_data.config_lock);
+ struct zfcp_adapter *adapter = port->adapter;
+
+ list_del(&port->list); /* no list locking required here */
wait_event(port->remove_wq, atomic_read(&port->refcount) == 0);
- cancel_work_sync(&port->rport_work); /* usually not necessary */
- zfcp_adapter_put(port->adapter);
+ zfcp_adapter_put(adapter);
sysfs_remove_group(&port->sysfs_device.kobj, &zfcp_sysfs_port_attrs);
device_unregister(&port->sysfs_device);
}
