[SCSI] zfcp: Remove global config_mutex

The global config_mutex was required for the serialization of a
configuration change within the zfcp driver.  This global locking is
now obsolete and can be removed.  The requirement of serializing the
access to a zfcp_adapter reference via a ccw_device is realized wth a
static spinlock.

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, 40 insertions, 46 deletions

diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index 8492ceac1409..ed31bd0ff3fb 100644
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -80,23 +80,21 @@ int zfcp_reqlist_isempty(struct zfcp_adapter *adapter)
 
 static void __init zfcp_init_device_configure(char *busid, u64 wwpn, u64 lun)
 {
-        struct ccw_device *ccwdev;
+        struct ccw_device *cdev;
         struct zfcp_adapter *adapter;
         struct zfcp_port *port;
         struct zfcp_unit *unit;
 
-        ccwdev = get_ccwdev_by_busid(&zfcp_ccw_driver, busid);
-        if (!ccwdev)
+        cdev = get_ccwdev_by_busid(&zfcp_ccw_driver, busid);
+        if (!cdev)
                 return;
 
-        if (ccw_device_set_online(ccwdev))
-                goto out_ccwdev;
+        if (ccw_device_set_online(cdev))
+                goto out_ccw_device;
 
-        mutex_lock(&zfcp_data.config_mutex);
-        adapter = dev_get_drvdata(&ccwdev->dev);
+        adapter = zfcp_ccw_adapter_by_cdev(cdev);
         if (!adapter)
-                goto out_unlock;
-        kref_get(&adapter->ref);
+                goto out_ccw_device;
 
         port = zfcp_get_port_by_wwpn(adapter, wwpn);
         if (!port)
@@ -105,21 +103,17 @@ static void __init zfcp_init_device_configure(char *busid, u64 wwpn, u64 lun)
         unit = zfcp_unit_enqueue(port, lun);
         if (IS_ERR(unit))
                 goto out_unit;
-        mutex_unlock(&zfcp_data.config_mutex);
 
         zfcp_erp_unit_reopen(unit, 0, "auidc_1", NULL);
         zfcp_erp_wait(adapter);
         flush_work(&unit->scsi_work);
 
-        mutex_lock(&zfcp_data.config_mutex);
 out_unit:
         put_device(&port->sysfs_device);
 out_port:
-        kref_put(&adapter->ref, zfcp_adapter_release);
-out_unlock:
-        mutex_unlock(&zfcp_data.config_mutex);
-out_ccwdev:
-        put_device(&ccwdev->dev);
+        zfcp_ccw_adapter_put(adapter);
+out_ccw_device:
+        put_device(&cdev->dev);
         return;
 }
 
@@ -184,8 +178,6 @@ static int __init zfcp_module_init(void)
         if (!zfcp_data.gid_pn_cache)
                 goto out_gid_cache;
 
-        mutex_init(&zfcp_data.config_mutex);
-
         zfcp_data.scsi_transport_template =
                 fc_attach_transport(&zfcp_transport_functions);
         if (!zfcp_data.scsi_transport_template)
@@ -296,7 +288,6 @@ static void zfcp_unit_release(struct device *dev)
  * @port: pointer to port where unit is added
  * @fcp_lun: FCP LUN of unit to be enqueued
  * Returns: pointer to enqueued unit on success, ERR_PTR on error
- * Locks: config_mutex must be held to serialize changes to the unit list
  *
  * Sets up some unit internal structures and creates sysfs entry.
  */
@@ -371,7 +362,6 @@ err_out:
 
 static int zfcp_allocate_low_mem_buffers(struct zfcp_adapter *adapter)
 {
-        /* must only be called with zfcp_data.config_mutex taken */
         adapter->pool.erp_req =
                 mempool_create_kmalloc_pool(1, sizeof(struct zfcp_fsf_req));
         if (!adapter->pool.erp_req)
@@ -419,7 +409,6 @@ static int zfcp_allocate_low_mem_buffers(struct zfcp_adapter *adapter)
 
 static void zfcp_free_low_mem_buffers(struct zfcp_adapter *adapter)
 {
-        /* zfcp_data.config_mutex must be held */
         if (adapter->pool.erp_req)
                 mempool_destroy(adapter->pool.erp_req);
         if (adapter->pool.scsi_req)
@@ -501,24 +490,22 @@ static void zfcp_destroy_adapter_work_queue(struct zfcp_adapter *adapter)
  * zfcp_adapter_enqueue - enqueue a new adapter to the list
  * @ccw_device: pointer to the struct cc_device
  *
- * Returns:     0             if a new adapter was successfully enqueued
- *              -ENOMEM       if alloc failed
+ * Returns:     struct zfcp_adapter*
  * Enqueues an adapter at the end of the adapter list in the driver data.
  * All adapter internal structures are set up.
  * Proc-fs entries are also created.
- * locks: config_mutex must be held to serialize changes to the adapter list
  */
-int zfcp_adapter_enqueue(struct ccw_device *ccw_device)
+struct zfcp_adapter *zfcp_adapter_enqueue(struct ccw_device *ccw_device)
 {
         struct zfcp_adapter *adapter;
 
         if (!get_device(&ccw_device->dev))
-                return -ENODEV;
+                return ERR_PTR(-ENODEV);
 
         adapter = kzalloc(sizeof(struct zfcp_adapter), GFP_KERNEL);
         if (!adapter) {
                 put_device(&ccw_device->dev);
-                return -ENOMEM;
+                return ERR_PTR(-ENOMEM);
         }
 
         kref_init(&adapter->ref);
@@ -578,11 +565,30 @@ int zfcp_adapter_enqueue(struct ccw_device *ccw_device)
         atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &adapter->status);
 
         if (!zfcp_adapter_scsi_register(adapter))
-                return 0;
+                return adapter;
 
 failed:
-        kref_put(&adapter->ref, zfcp_adapter_release);
-        return -ENOMEM;
+        zfcp_adapter_unregister(adapter);
+        return ERR_PTR(-ENOMEM);
+}
+
+void zfcp_adapter_unregister(struct zfcp_adapter *adapter)
+{
+        struct ccw_device *cdev = adapter->ccw_device;
+
+        cancel_work_sync(&adapter->scan_work);
+        cancel_work_sync(&adapter->stat_work);
+        zfcp_destroy_adapter_work_queue(adapter);
+
+        zfcp_fc_wka_ports_force_offline(adapter->gs);
+        zfcp_adapter_scsi_unregister(adapter);
+        sysfs_remove_group(&cdev->dev.kobj, &zfcp_sysfs_adapter_attrs);
+
+        zfcp_erp_thread_kill(adapter);
+        zfcp_dbf_adapter_unregister(adapter->dbf);
+        zfcp_qdio_destroy(adapter->qdio);
+
+        zfcp_ccw_adapter_put(adapter); /* final put to release */
 }
 
 /**
@@ -594,27 +600,16 @@ void zfcp_adapter_release(struct kref *ref)
 {
         struct zfcp_adapter *adapter = container_of(ref, struct zfcp_adapter,
                                                     ref);
-        struct ccw_device *ccw_device = adapter->ccw_device;
-
-        cancel_work_sync(&adapter->stat_work);
-
-        zfcp_fc_wka_ports_force_offline(adapter->gs);
-        sysfs_remove_group(&ccw_device->dev.kobj, &zfcp_sysfs_adapter_attrs);
-
-        dev_set_drvdata(&ccw_device->dev, NULL);
+        struct ccw_device *cdev = adapter->ccw_device;
 
         dev_set_drvdata(&adapter->ccw_device->dev, NULL);
         zfcp_fc_gs_destroy(adapter);
-        zfcp_erp_thread_kill(adapter);
-        zfcp_destroy_adapter_work_queue(adapter);
-        zfcp_dbf_adapter_unregister(adapter->dbf);
         zfcp_free_low_mem_buffers(adapter);
-        zfcp_qdio_destroy(adapter->qdio);
         kfree(adapter->req_list);
         kfree(adapter->fc_stats);
         kfree(adapter->stats_reset_data);
         kfree(adapter);
-        put_device(&ccw_device->dev);
+        put_device(&cdev->dev);
 }
 
 /**
@@ -636,7 +631,7 @@ static void zfcp_port_release(struct device *dev)
         struct zfcp_port *port = container_of(dev, struct zfcp_port,
                                               sysfs_device);
 
-        kref_put(&port->adapter->ref, zfcp_adapter_release);
+        zfcp_ccw_adapter_put(port->adapter);
         kfree(port);
 }
 
@@ -647,7 +642,6 @@ static void zfcp_port_release(struct device *dev)
  * @status: initial status for the port
  * @d_id: destination id of the remote port to be enqueued
  * Returns: pointer to enqueued port on success, ERR_PTR on error
- * Locks: config_mutex must be held to serialize changes to the port list
  *
  * All port internal structures are set up and the sysfs entry is generated.
  * d_id is used to enqueue ports with a well known address like the Directory
@@ -718,7 +712,7 @@ struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, u64 wwpn,
 err_out_put:
         device_unregister(&port->sysfs_device);
 err_out:
-        kref_put(&adapter->ref, zfcp_adapter_release);
+        zfcp_ccw_adapter_put(adapter);
         return ERR_PTR(retval);
 }