[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>
diff --git a/drivers/s390/cio/css.h b/drivers/s390/cio/css.h
index e210f89..15f7f7c 100644
--- a/drivers/s390/cio/css.h
+++ b/drivers/s390/cio/css.h
@@ -136,6 +136,8 @@
extern struct css_driver io_subchannel_driver;
extern int css_probe_device(struct subchannel_id);
+extern int css_sch_device_register(struct subchannel *);
+extern void css_sch_device_unregister(struct subchannel *);
extern struct subchannel * get_subchannel_by_schid(struct subchannel_id);
extern int css_init_done;
extern int for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *);