[S390] subchannel register/unregister mutex.

Add a reg_mutex to prevent unregistering a subchannel before it has been
registered. Since 2.6.17, we've seen oopses in kslowcrw when a device is
found to be not operational during sense id when doing initial device
recognition; it is not clear yet why that particular problem was not (yet)
observed with earlier kernels...

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index 67f0de6aed33..9db09870b2ae 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -280,7 +280,7 @@ ccw_device_remove_disconnected(struct ccw_device *cdev)
          * 'throw away device'.
          */
         sch = to_subchannel(cdev->dev.parent);
-        device_unregister(&sch->dev);
+        css_sch_device_unregister(sch);
         /* Reset intparm to zeroes. */
         sch->schib.pmcw.intparm = 0;
         cio_modify(sch);
@@ -625,7 +625,7 @@ ccw_device_do_unreg_rereg(void *data)
                                         other_sch->schib.pmcw.intparm = 0;
                                         cio_modify(other_sch);
                                 }
-                                device_unregister(&other_sch->dev);
+                                css_sch_device_unregister(other_sch);
                         }
                 }
                 /* Update ssd info here. */
@@ -709,7 +709,7 @@ ccw_device_call_sch_unregister(void *data)
         struct subchannel *sch;
 
         sch = to_subchannel(cdev->dev.parent);
-        device_unregister(&sch->dev);
+        css_sch_device_unregister(sch);
         /* Reset intparm to zeroes. */
         sch->schib.pmcw.intparm = 0;
         cio_modify(sch);