[SCSI] zfcp: Fix oops when port disappears

The zfcp_port might have been removed, while the FC fast_io_fail timer
is still running and could trigger the terminate_rport_io callback.
Set the pointer to the zfcp_port to NULL and check accordingly
before using it.

Reviewed-by: Martin Petermann <martin@linux.vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

3 files changed, 24 insertions, 8 deletions

diff --git a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
index a00d2bb9559c..3ac27ee47396 100644
--- a/drivers/s390/scsi/zfcp_aux.c
+++ b/drivers/s390/scsi/zfcp_aux.c
@@ -671,8 +671,7 @@ void zfcp_port_dequeue(struct zfcp_port *port)
         list_del(&port->list);
         write_unlock_irq(&zfcp_data.config_lock);
         if (port->rport)
-                fc_remote_port_delete(port->rport);
-        port->rport = NULL;
+                port->rport->dd_data = NULL;
         zfcp_adapter_put(port->adapter);
         sysfs_remove_group(&port->sysfs_device.kobj, &zfcp_sysfs_port_attrs);
         device_unregister(&port->sysfs_device);
diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index 3f365ace7711..74dee32afba8 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -172,12 +172,16 @@ static void zfcp_fsf_link_down_info_eval(struct zfcp_fsf_req *req, char *id,
                                          struct fsf_link_down_info *link_down)
 {
         struct zfcp_adapter *adapter = req->adapter;
+        unsigned long flags;
 
         if (atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED)
                 return;
 
         atomic_set_mask(ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED, &adapter->status);
+
+        read_lock_irqsave(&zfcp_data.config_lock, flags);
         zfcp_scsi_schedule_rports_block(adapter);
+        read_unlock_irqrestore(&zfcp_data.config_lock, flags);
 
         if (!link_down)
                 goto out;
diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index e7d065209065..e8fbeaeb5fbf 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -486,10 +486,12 @@ static void zfcp_set_rport_dev_loss_tmo(struct fc_rport *rport, u32 timeout)
  */
 static void zfcp_scsi_dev_loss_tmo_callbk(struct fc_rport *rport)
 {
-        struct zfcp_port *port = rport->dd_data;
+        struct zfcp_port *port;
 
         write_lock_irq(&zfcp_data.config_lock);
-        port->rport = NULL;
+        port = rport->dd_data;
+        if (port)
+                port->rport = NULL;
         write_unlock_irq(&zfcp_data.config_lock);
 }
 
@@ -503,9 +505,18 @@ static void zfcp_scsi_dev_loss_tmo_callbk(struct fc_rport *rport)
  */
 static void zfcp_scsi_terminate_rport_io(struct fc_rport *rport)
 {
-        struct zfcp_port *port = rport->dd_data;
+        struct zfcp_port *port;
+
+        write_lock_irq(&zfcp_data.config_lock);
+        port = rport->dd_data;
+        if (port)
+                zfcp_port_get(port);
+        write_unlock_irq(&zfcp_data.config_lock);
 
-        zfcp_erp_port_reopen(port, 0, "sctrpi1", NULL);
+        if (port) {
+                zfcp_erp_port_reopen(port, 0, "sctrpi1", NULL);
+                zfcp_port_put(port);
+        }
 }
 
 static void zfcp_scsi_rport_register(struct zfcp_port *port)
@@ -534,8 +545,10 @@ static void zfcp_scsi_rport_register(struct zfcp_port *port)
 
 static void zfcp_scsi_rport_block(struct zfcp_port *port)
 {
-        if (port->rport)
-                fc_remote_port_delete(port->rport);
+        struct fc_rport *rport = port->rport;
+
+        if (rport)
+                fc_remote_port_delete(rport);
 }
 
 void zfcp_scsi_schedule_rport_register(struct zfcp_port *port)