[S390] dasd: add device attribute to disable blocking on lost paths

When the connection between host and storage server is lost, the
dasd device driver usually blocks all I/O on affected devices and
waits for them to reappear. In some setups however it would be
better if the I/O is returned as error so that device can be
recovered by some other means, eg. in a raid or multipath setup.

Signed-off-by: Holger Smolinski <Holger.Smolinski@de.ibm.com>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/dasd.h b/arch/s390/include/asm/dasd.h
index 55b2b80..fb50a78 100644
--- a/arch/s390/include/asm/dasd.h
+++ b/arch/s390/include/asm/dasd.h
@@ -78,6 +78,7 @@
 #define DASD_FEATURE_USEDIAG	     0x02
 #define DASD_FEATURE_INITIAL_ONLINE  0x04
 #define DASD_FEATURE_ERPLOG	     0x08
+#define DASD_FEATURE_FAILFAST	     0x10
 
 #define DASD_PARTN_BITS 2