[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/cio.h b/drivers/s390/cio/cio.h
index 0ca9873..4541c1a 100644
--- a/drivers/s390/cio/cio.h
+++ b/drivers/s390/cio/cio.h
@@ -2,6 +2,7 @@
#define S390_CIO_H
#include "schid.h"
+#include <linux/mutex.h>
/*
* where we put the ssd info
@@ -87,7 +88,7 @@
struct subchannel {
struct subchannel_id schid;
spinlock_t lock; /* subchannel lock */
-
+ struct mutex reg_mutex;
enum {
SUBCHANNEL_TYPE_IO = 0,
SUBCHANNEL_TYPE_CHSC = 1,