[S390] vmur: add "top of queue" sanity check for reader open
If the z/VM reader is already open, it can happen that after opening the
Linux reader device, not the topmost file is processed. According the
semantics of the Linux z/VM unit record device driver, always the topmost
file has to be processed. With this fix an error is returned if that is
not the case.
Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/char/vmur.h b/drivers/s390/char/vmur.h
index 522a9df..2b3c564 100644
--- a/drivers/s390/char/vmur.h
+++ b/drivers/s390/char/vmur.h
@@ -53,6 +53,7 @@
#define FLG_SYSTEM_HOLD 0x04
#define FLG_CP_DUMP 0x10
#define FLG_USER_HOLD 0x20
+#define FLG_IN_USE 0x80
/*
* A struct urdev is created for each ur device that is made available