[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, 23 insertions, 29 deletions

diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index f54655998bd5..6feece3b2e36 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -128,49 +128,44 @@ static int zfcp_scsi_queuecommand(struct scsi_cmnd *scpnt,
 }
 
 static struct zfcp_unit *zfcp_unit_lookup(struct zfcp_adapter *adapter,
-                                          int channel, unsigned int id,
-                                          unsigned int lun)
+                                          unsigned int id, u64 lun)
 {
+        unsigned long flags;
         struct zfcp_port *port;
-        struct zfcp_unit *unit;
-        int scsi_lun;
+        struct zfcp_unit *unit = NULL;
 
-        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->rport || (id != port->rport->scsi_target_id))
                         continue;
-                list_for_each_entry(unit, &port->unit_list_head, list) {
-                        scsi_lun = scsilun_to_int(
-                                (struct scsi_lun *)&unit->fcp_lun);
-                        if (lun == scsi_lun)
-                                return unit;
-                }
+                unit = zfcp_get_unit_by_lun(port, lun);
+                if (unit)
+                        break;
         }
+        read_unlock_irqrestore(&adapter->port_list_lock, flags);
 
-        return NULL;
+        return unit;
 }
 
 static int zfcp_scsi_slave_alloc(struct scsi_device *sdp)
 {
         struct zfcp_adapter *adapter;
         struct zfcp_unit *unit;
-        unsigned long flags;
-        int retval = -ENXIO;
+        u64 lun;
 
         adapter = (struct zfcp_adapter *) sdp->host->hostdata[0];
         if (!adapter)
                 goto out;
 
-        read_lock_irqsave(&zfcp_data.config_lock, flags);
-        unit = zfcp_unit_lookup(adapter, sdp->channel, sdp->id, sdp->lun);
+        int_to_scsilun(sdp->lun, (struct scsi_lun *)&lun);
+        unit = zfcp_unit_lookup(adapter, sdp->id, lun);
         if (unit) {
                 sdp->hostdata = unit;
                 unit->device = sdp;
-                zfcp_unit_get(unit);
-                retval = 0;
+                return 0;
         }
-        read_unlock_irqrestore(&zfcp_data.config_lock, flags);
 out:
-        return retval;
+        return -ENXIO;
 }
 
 static int zfcp_scsi_eh_abort_handler(struct scsi_cmnd *scpnt)
@@ -338,12 +333,12 @@ void zfcp_adapter_scsi_unregister(struct zfcp_adapter *adapter)
         if (!shost)
                 return;
 
-        read_lock_irq(&zfcp_data.config_lock);
-        list_for_each_entry(port, &adapter->port_list_head, list)
+        read_lock_irq(&adapter->port_list_lock);
+        list_for_each_entry(port, &adapter->port_list, list)
                 if (port->rport)
                         port->rport = NULL;
+        read_unlock_irq(&adapter->port_list_lock);
 
-        read_unlock_irq(&zfcp_data.config_lock);
         fc_remove_host(shost);
         scsi_remove_host(shost);
         scsi_host_put(shost);
@@ -508,7 +503,7 @@ static void zfcp_set_rport_dev_loss_tmo(struct fc_rport *rport, u32 timeout)
  * @rport: The FC rport where to teminate I/O
  *
  * Abort all pending SCSI commands for a port by closing the
- * port. Using a reopen for avoids a conflict with a shutdown
+ * port. Using a reopen avoiding a conflict with a shutdown
  * overwriting a reopen.
  */
 static void zfcp_scsi_terminate_rport_io(struct fc_rport *rport)
@@ -518,11 +513,7 @@ static void zfcp_scsi_terminate_rport_io(struct fc_rport *rport)
         struct zfcp_adapter *adapter =
                 (struct zfcp_adapter *)shost->hostdata[0];
 
-        write_lock_irq(&zfcp_data.config_lock);
         port = zfcp_get_port_by_wwpn(adapter, rport->port_name);
-        if (port)
-                zfcp_port_get(port);
-        write_unlock_irq(&zfcp_data.config_lock);
 
         if (port) {
                 zfcp_erp_port_reopen(port, 0, "sctrpi1", NULL);
@@ -589,10 +580,13 @@ void zfcp_scsi_schedule_rport_block(struct zfcp_port *port)
 
 void zfcp_scsi_schedule_rports_block(struct zfcp_adapter *adapter)
 {
+        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)
                 zfcp_scsi_schedule_rport_block(port);
+        read_unlock_irqrestore(&adapter->port_list_lock, flags);
 }
 
 void zfcp_scsi_rport_work(struct work_struct *work)