[S390] cio: improve error recovery for internal I/Os

Improve error recovery for internal I/Os by repeating each I/O
256 times per path to cope with long-running non-permanent error
conditions. Also retry each path twice to cope with link flapping,
i.e. single paths becoming unavailable in the order in which they
are tried.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/device_pgid.c b/drivers/s390/cio/device_pgid.c
index 5bcefea..aad188e 100644
--- a/drivers/s390/cio/device_pgid.c
+++ b/drivers/s390/cio/device_pgid.c
@@ -20,7 +20,7 @@
 #include "device.h"
 #include "io_sch.h"
 
-#define PGID_RETRIES	5
+#define PGID_RETRIES	256
 #define PGID_TIMEOUT	(10 * HZ)
 
 /*