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

1 files changed, 12 insertions, 11 deletions

diff --git a/drivers/s390/scsi/zfcp_ccw.c b/drivers/s390/scsi/zfcp_ccw.c
index e08339428ecf..aca2047dc2d5 100644
--- a/drivers/s390/scsi/zfcp_ccw.c
+++ b/drivers/s390/scsi/zfcp_ccw.c
@@ -100,10 +100,11 @@ static void zfcp_ccw_remove(struct ccw_device *ccw_device)
 
         mutex_lock(&zfcp_data.config_mutex);
         adapter = dev_get_drvdata(&ccw_device->dev);
-        if (!adapter)
-                goto out;
         mutex_unlock(&zfcp_data.config_mutex);
 
+        if (!adapter)
+                return;
+
         cancel_work_sync(&adapter->scan_work);
 
         mutex_lock(&zfcp_data.config_mutex);
@@ -111,18 +112,21 @@ static void zfcp_ccw_remove(struct ccw_device *ccw_device)
         /* this also removes the scsi devices, so call it first */
         zfcp_adapter_scsi_unregister(adapter);
 
-        write_lock_irq(&zfcp_data.config_lock);
-        list_for_each_entry_safe(port, p, &adapter->port_list_head, list) {
-                list_for_each_entry_safe(unit, u, &port->unit_list_head, list) {
-                        list_move(&unit->list, &unit_remove_lh);
+        write_lock_irq(&adapter->port_list_lock);
+        list_for_each_entry_safe(port, p, &adapter->port_list, list) {
+                write_lock(&port->unit_list_lock);
+                list_for_each_entry_safe(unit, u, &port->unit_list, list) {
                         atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE,
                                         &unit->status);
+                        list_move(&unit->list, &unit_remove_lh);
                 }
-                list_move(&port->list, &port_remove_lh);
+                write_unlock(&port->unit_list_lock);
                 atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &port->status);
+                list_move(&port->list, &port_remove_lh);
         }
         atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &adapter->status);
-        write_unlock_irq(&zfcp_data.config_lock);
+        write_unlock_irq(&adapter->port_list_lock);
+        mutex_unlock(&zfcp_data.config_mutex);
 
         list_for_each_entry_safe(port, p, &port_remove_lh, list) {
                 list_for_each_entry_safe(unit, u, &unit_remove_lh, list)
@@ -131,9 +135,6 @@ static void zfcp_ccw_remove(struct ccw_device *ccw_device)
         }
         wait_event(adapter->remove_wq, atomic_read(&adapter->refcount) == 0);
         zfcp_adapter_dequeue(adapter);
-
-out:
-        mutex_unlock(&zfcp_data.config_mutex);
 }
 
 /**